UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The objectivity of colour-statements 1976

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
UBC_1976_A1 H37_5.pdf [ 9.85MB ]
Metadata
JSON: 1.0093781.json
JSON-LD: 1.0093781+ld.json
RDF/XML (Pretty): 1.0093781.xml
RDF/JSON: 1.0093781+rdf.json
Turtle: 1.0093781+rdf-turtle.txt
N-Triples: 1.0093781+rdf-ntriples.txt
Citation
1.0093781.ris

Full Text

THE OBJECTIVITY OF COLOUR-STATEMENTS by Jean Harvey B.A. (Hons.), U n i v e r s i t y o f Wales, 1968 M.A., Simon F r a s e r U n i v e r s i t y , 1970 M.A. ( E d u c ) , Simon F r a s e r U n i v e r s i t y , 1971 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES Department o f P h i l s o s o p h y We a c c e p t t h i s t h e s i s as conforming to t he r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA August, 1976 (c) Jean Harvey, 1976 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s for an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag ree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g of t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department or by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d that c o p y i n g or pub l ica t ion of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h Co lumbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date 7 Oct, /C(76 i i ABSTRACT The main purpose o f the t h e s i s i s t o i n v e s t i g a t e c o l o u r - c o n c e p t s as t h e y are a p p l i e d t o p h y s i c a l o b j e c t s t o see what i s r e q u i r e d i f they a r e t o meet the r e q u i r e m e n t s f o r o b j e c t i v i t y . The f i r s t p a r t o f the work i s t o s e t o u t i n g e n e r a l terms the c o n d i t i o n t h a t must be met f o r an e m p i r i c a l s tatement t o be o b j e c t i v e , and t h a t c o n d i t i o n i s c l a i m e d t o be c o r r i g i b i l i t y . I f an e m p i r i c a l statement i s t o be c o r r i g i b l e i n the r e q u i r e d s e n s e , then i t must be " p o s s i b l e " f o r a human b e i n g t o t e s t t h a t s tatement " s o u n d l y " , and mere l o g i c a l p o s s i b i l i t y i s not what i s l o o k e d f o r . When someone t e s t s an e m p i r i - c a l s t a t e m e n t and reaches a v e r d i c t as t o i t s t r u t h o r f a l s i t y , t h a t v e r d i c t i s " b a s i c a l l y sound" o n l y i f he f o l l o w s t he t e s t - i n s t r u c t i o n s c o r r e c t l y and has the minimum p e r c e p t u a l a b i l i t y needed f o r t h a t t e s t t o be r e l i a b l e i n the s i t u a t i o n i n which i t i s used. O t h e r c o n d i t i o n s a f f e c t i n g t he v e r d i c t ' s soundness a r e d e s i r a b l e , but t h e s e two a r e r e q u i r e d i f the v e r d i c t i s not to be r e j e c t e d o u t r i g h t as unsound. So i f any e m p i r i c a l s t a t e m e n t i s t o be ob- j e c t i v e , i t must be p o s s i b l e to r e a c h b a s i c a l l y sound v e r d i c t s about i t , and so i t must be p o s s i b l e t o g i v e sense t o the soundness c o n d i t i o n s and t o de- t e c t i n g when t h e y do not h o l d . The f o c u s i s then d i r e c t e d t o c o l o u r - s t a t e m e n t s about p h y s i c a l o b j e c t s - statements a s c r i b i n g p a r t i c u l a r c o l o u r s , such as r e d o r g r e e n , t o p h y s i c a l ob- j e c t s , and a l s o statements about the s a m e n e s s / d i f f e r e n c e i n c o l o u r o f a p a i r o f o b j e c t s . I t i s argued t h a t i t ts_ p o s s i b l e t o d e t e c t i f two peo p l e have ( q u a l i t a t i v e l y ) t h e same p e r c e i v e d c o l o u r s when they l o o k a t the same p h y s i c a l o b j e c t i n t h e same environment, even i f t h e r e i s a ' s y s t e m a t i c t r a n s p o s i t i o n ' o f c o l o u r s h o l d i n g between them. I t i s a l s o argued t h a t f o r a v i a b l e c oncept o f "the c o l o u r o f a p h y s i c a l o b j e c t " t h e r e must be a g e n e r a l u n i f o r m i t y among th e p e r c e i v e d c o l o u r s human bein g s . h a v e on v i e w i n g p h y s i c a l o b j e c t s . I t i s i i i t h i s r e q u i r e d u n i f o r m i t y t h a t makes t h a t c o n c e p t a n t h r o p o c e n t r i c i n n a t u r e . For the u n i f o r m i t y t o be ' n o n - a c c i d e n t a l 1 , we need to p r o v i d e a d e s c r i p t i o n o f a human vi e w e r ' s p h y s i c a l s t a t e , a d e s c r i p t i o n t h a t w i l l c o v e r t h e v a s t m a j o r i t y o f a l l v i e w e r s ' p h y s i c a l s t a t e s . The d e s c r i p t i o n I r e f e r t o as the " s t a n d a r d - s t a t e d e s c r i p t i o n " ; i t must d e s c r i b e t h o s e f e a t u r e s o f a v i e w e r ' s s t a t e t h a t a r e r e l e v a n t t o c o l o u r - v i s i o n , and t h e r e a r e l i m i t s as to how im- p r e c i s e i t can be and s t i l l r e t a i n i t s r e q u i r e d r o l e . A f t e r e x p l a i n i n g what i s i n v o l v e d i n the c o n c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " , I i n d i c a t e how we c o u l d d e r i v e p r a c t i c a l t e s t s f o r the p a r t i c u l a r c o l o u r o f a p h y s i c a l o b j e c t , and i f we can g i v e sense t o the b a s i c soundness c o n d i t i o n f o r t h e s e t e s t s , and t o d e t e c t i n g when t h e s e soundness c o n d i t i o n s do not h o l d , t h e n , I c l a i m , such statements would be o b j e c t i v e . F i n a l l y , a c o n d i t i o n i s p l a c e d on who would count as a " f i n e d i s c r i m i n a t o r " o f p h y s i c a l o b j e c t s by t h e i r c o l o u r , and t h i s i l l u m i n a t e s the a n t h r o p o c e n t r i c n a t u r e o f the c o n c e p t o f "the d i f - f e r e n c e o f c o l o u r between two p h y s i c a l o b j e c t s " . SECTIONS Pages I. . I n t r o d u c t i o n 1 - 2 2. A Note on the Lockean Background o f the Treatment o f Q u a l i t i e s . 3 - 4 3. P u b l i c i t y , P r i v a c y , and P a s s i v i t y w i t h r e s p e c t t o Lockean Ideas . 5 - 9 4. The P a s s i v i t y P r i n c i p l e o f P e r c e p t i o n . 1 0 - 1 5 5. Lewis's Assumption about the T e s t a b i l i t y o f E m p i r i c a l Statements . 1 6 - 2 2 6. E m p i r i c a l Statements and the ' P o s s i b i l i t y o f E r r o r ' 2 3 - 3 3 7. I n t e r - S u b j e c t i v i t y and N o r m a l i t y - R e q u i r e m e n t s 3 4 - 4 4 8. R e s o l v i n g D i s p u t e s 4 5 - 5 2 9. T e s t i n g f o r the S a m e n e s s / D i f f e r e n c e o f C o l o u r o f P h y s i c a l O b j e c t s . 53 - 60 10. Smart, on C o l o u r s 6 1 - 7 4 I I . T r a n s p o s i t i o n o f C o l o u r s Between P e r c e i v e r s 75 - 113 T h e ' T i r s t B a s i s " and I t s Use :78 - 89 The "Second B a s i s " :89 - 97 The Use o f the "Second B a s i s " :98 - 113 12. A s c r i b i n g P a r t i c u l a r C o l o u r s t o P h y s i c a l O b j e c t s 1 1 7 - 1 3 2 13. S t a n d a r d - S t a t e P e r c e i v e r s 1 3 3 - 1 5 3 14. T e s t i n g f o r the P a r t i c u l a r C o l o u r o f a P h y s i c a l O b j e c t 154 - 171 15. The A n t h r o p o c e n t r i c Nature o f D i f f e r e n c e i n C o l o u r between 1 7 2 - 1 8 2 P h y s i c a l O b j e c t s 16. Summary 1 8 3 - 1 8 6 B i b l i o g r a p h y 1 8 7 - 1 8 8 1 1. I n t r o d u c t i o n The main purpose o f the t h e s i s i s t o i n v e s t i g a t e c o l o u r - c o n c e p t s as t h e y a r e a p p l i e d t o p h y s i c a l o b j e c t s t o see what i s r e q u i r e d i f t h e y a r e t o meet the r e q u i r e m e n t s f o r o b j e c t i v i t y . The f i r s t p a r t o f the work i s t o s e t out i n g e n e r a l terms the c o n d i t i o n t h a t must be met f o r an e m p i r i c a l statement t o be o b j e c t i v e , and t h a t c o n d i t i o n i s c l a i m e d t o be c o r r i g i b i 1 i t y . I f an e m p i r i c a l s t atement i s t o be c o r r i g i b l e i n the r e q u i r e d sense, then i t must be " p o s s i b l e " f o r a human b e i n g t o t e s t t h a t s tatement " s o u n d l y " , and mere l o g i c a l p o s s i b i l - i t y i s not what i s l o o k e d f o r . When someone t e s t s an e m p i r i c a l statement and r e aches a v e r d i c t as t o i t s t r u t h o r f a l s i t y , t h a t v e r d i c t i s " b a s i c a l l y sound" o n l y i f he f o l l o w s the t e s t - i n s t r u c t i o n s c o r r e c t l y and has the minimum pe r c e p - t u a l a b i l i t y needed f o r t h a t t e s t t o be r e l i a b l e i n the s i t u a t i o n i n which i t i s used. Other c o n d i t i o n s a f f e c t i n g the v e r d i c t ' s soundness are d e s i r a b l e , but t h e s e two are r e q u i r e d i f the v e r d i c t i s not t o be r e j e c t e d o u t r i g h t as unsound. So i f any e m p i r i c a l statement i s t o be o b j e c t i v e , i t must be p o s s i b l e t o r e a c h b a s i c a l l y sound v e r d i c t s about i t , and so i t must be p o s s i b l e t o g i v e sense t o the soundness c o n d i t i o n s and t o d e t e c t i n g when th e y do not h o l d . The f o c u s i s then d i r e c t e d t o c o l o u r - s t a t e m e n t s about p h y s i c a l o b j e c t s - s tatements a s c r i b i n g p a r t i c u l a r c o l o u r s , such as red o r g r e e n , t o p h y s i c a l ob- j e c t s , and a l s o statements about the s a m e n e s s / d i f f e r e n c e i n c o l o u r o f a p a i r o f o b j e c t s . I t i s argued t h a t i t ' i _ s p o s s i b l e t o d e t e c t i f two people have ( q u a l i t a t i v e l y ) t h e same p e r c e i v e d c o l o u r s when they l o o k a t the same p h y s i c a l o b j e c t i n the same environment, even i f t h e r e i s a ' s y s t e m a t i c t r a n s p o s i t i o n ' o f c o l o u r s h o l d i n g between them. I t i s a l s o argued t h a t f o r a v i a b l e c o n c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " t h e r e must be a g e n e r a l u n i f o r m i t y among the p e r c e i v e d c o l o u r s human be i n g s have on v i e w i n g p h y s i c a l o b j e c t s . I t i s t h i s r e q u i r e d u n i f o r m i t y t h a t makes t h a t c o n c e p t a n t h r o p o c e n t r i c i n n a t u r e . For the u n i f o r m i t y t o be ' n o n - a c c i d e n t a l ' , we need t o p r o v i d e a d e s c r i p t i o n o f '2 a human vi e w e r ' s p h y s i c a l s t a t e , a d e s c r i p t i o n t h a t w i l l c o v e r t h e v a s t major- i t y o f a l l v i e w e r s ' p h y s i c a l s t a t e s . The d e s c r i p t i o n I r e f e r t o as the " s t a n - d a r d - s t a t e d e s c r i p t i o n " ; i t must d e s c r i b e t h o s e f e a t u r e s o f a v i e w e r ' s s t a t e t h a t a re r e l e v a n t t o c o l o u r - v i s i o n , and t h e r e a r e l i m i t s as t o how i m p r e c i s e i t can be and s t i l l r e t a i n i t s r e q u i r e d r o l e . A f t e r e x p l a i n i n g what i s i n - v o l v e d i n the co n c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " , I i n d i c a t e how we c o u l d d e r i v e p r a c t i c a l t e s t s f o r t h e p a r t i c u l a r c o l o u r o f a p h y s i c a l o b j e c t , and i f we can g i v e sense t o the b a s i c soundness c o n d i t i o n s f o r t h e s e t e s t s , and t o d e t e c t i n g when t h e s e soundness c o n d i t i o n s do not h o l d , t h e n , I c l a i m , such s t a t e m e n t s would be o b j e c t i v e . F i n a l l y , a c o n d i t i o n i s p l a c e d on who would c o u n t as a " f i n e d i s c r i m i n a t o r " o f p h y s i c a l o b j e c t s by t h e i r c o l o u r , and t h i s i l l u m i n a t e s the a n t h r o p o c e n t r i c n a t u r e o f t h e c o n c e p t o f "the d i f f e r e n c e o f c o l o u r between two p h y s i c a l o b j e c t s " . 3 2. A Note on t h e Lockean Background o f the Treatment o f Q u a l i t i e s P h i l o s o p h e r s a t the b e g i n n i n g o f t h i s c e n t u r y a r e w r i t i n g a g a i n s t the background o f B r i t i s h e m p i r i c i s m , most t r a d i t i o n s o f which stem from t he work o f Locke. Very b r i e f l y l e t us see what Locke's main p o i n t s a r e w i t h r e g a r d t o c o l o u r - q u a l i t i e s . Locke c l a i m s t h a t we a r e p a s s i v e w i t h r e g a r d t o p e r c e p t i o n i n two r e - s p e c t s : (a) The s i m p l e i d e a s o f s e n s a t i o n r e c e i v e d i n p a r t i c u l a r p e r c e p t u a l hap- penings a r e p a s s i v e l y r e c e i v e d : "For i n bare naked p e r c e p t i o n , the mind i s , f o r t h e most p a r t , o n l y p a s s i v e ; and what i t p e r c e i v e s , i t cannot a v o i d p e r - c e i v i n g . " 1 The s i m p l e i d e a s o f s e n s a t i o n r e c e i v e d i n p a r t i c u l a r p e r c e p t i o n s may, o f c o u r s e , be a l r e a d y f a m i l i a r ; not a l l w i l l be new ( i . e . , o f a type p r e - v i o u s l y u n e n c o u n t e r e d ) . (b) The ' s t o r e ' o f s i m p l e i d e a s o f s e n s a t i o n a g a i n s t which t he mind 'com- p a r e s ' s i m p l e i d e a s o f s e n s a t i o n r e c e i v e d i n p a r t i c u l a r p e r c e p t i o n s cannot i t s e l f be e n l a r g e d e x c e p t p a s s i v e l y by the r e c e p t i o n o f a h i t h e r t o unencoun- t e r e d s i m p l e i d e a v i a t he se n s e s : These s i m p l e i d e a s , the m a t e r i a l s o f a l l our knowledge, a r e sug- g e s t e d and f u r n i s h e d t o the mind o n l y by t h o s e two ways above mentioned, v i z . s e n s a t i o n and r e f l e c t i o n . When the u n d e r s t a n d i n g i s once s t o r e d w i t h t h e s e s i m p l e i d e a s , i t has the power t o r e - p e a t , compare, and u n i t e them, even t o an al m o s t i n f i n i t e v a r i e t y , and so can make a t p l e a s u r e new complex i d e a s . But i t i s not i n the power o f the most e x a l t e d w i t , o r e n l a r g e d u n d e r s t a n d i n g , by any q u i c k n e s s o r v a r i e t y o f though t , t o i n v e n t o r frame one new si m p l e i d e a i n the mind, not taken i n by the ways b e f o r e men- t i o n e d : n o r can any f o r c e o f t h e u n d e r s t a n d i n g d e s t r o y t h o s e t h a t a r e t h e r e . 2 The m i s t a k e s i n v o l v e d i n u s i n g " i d e a " t o c o v e r t h i n g s o f such d i f f e r e n t k i n d s ^ o h n Locke, An Essay C o n c e r n i n g Human U n d e r s t a n d i n g (New York, 1959), Book I I , chap, i x , s e c t . 1 I b i d . , chap, i i , s e c t . 2. (Locke sometimes makes a p a s s i v i t y c l a i m wi r e s p e c t t o s i m p l e i d e a s g e n e r a l l y , a consequence o f h i s d o u b l e use o f " i d e.g. Book I I , chap xxx, s e c t . 3.) 4 as s e n s e - d a t a (as i n (a) above) and c o n c e p t s (as i n the above q u o t a t i o n ) a r e 3 p o i n t e d out and d i s c u s s e d by Bennett. " S i m p ! e " - q u a l i t y terms a r e j u s t t he names o f the s i m p l e i d e a s ' s t o r e d ' i n t h e mind, and th e y can be un d e r s t o o d o n l y as l a b e l s o f t h e s e i d e a s . Thus a l t h o u g h Locke manages a t l e a s t t o d i s - t i n g u i s h a s i m p l e i d e a o f s e n s a t i o n from t he term r e f e r r i n g t o i t ( i t s name), he does not admit the p o s s i b i l i t y o f u s i n g the term m e a n i n g f u l l y e x c e p t as the l a b e l o f the r e l e v a n t s i m p l e i d e a . In the sense o f " d e f i n i t i o n " Locke u s e s - - "showing the meaning o f one word by s e v e r a l o t h e r not synonymous terms' 1^-- the names o f s i m p l e i d e a s cannot be d e f i n e d s i n c e "the s e v e r a l terms o f a d e f i n i t i o n , s i g n i f y i n g s e v e r a l i d e a s , they can a l l t o g e t h e r by no means r e p - c r e s e n t an i d e a which has no c o m p o s i t i o n a t a l l . . . ." T h i s i n d e f i n a b i l i t y o f t he names o f s i m p l e i d e a s p r e v e n t s the d e f i n i n g o f o t h e r terms from b e i n g an i n f i n i t e l y l o n g t a s k , and thus an e p i s t e m o l o g i c a l ' h i e r a r c h y ' o f con c e p t s begins t o emerge. There i s a c e r t a i n p e c u l i a r i t y i n Locke's a c c o u n t . A l t h o u g h a s i m p l e i d e a o f s e n s a t i o n r e c e i v e d i n some p a r t i c u l a r p e r c e p t i o n i s c a l l e d , say, "white" by somehow matching i t w i t h the s i m p l e i d e a o f wh i t e ' s t o r e d ' i n our mind, we a r e g i v e n no s i m i l a r e x p l a n a t i o n o f how we always manage t o a p p l y the term "white" c o n s i s t e n t l y to one and the same exemplary i d e a . I f we can a p p l y the term "white" t o one and the same exemplary i d e a c o n s i s t e n t l y w i t h o u t the need t o i n t r o d u c e some y e t more shadowy super-example, then one wonders why we c o u l d n o t a l s o manage to c o n s i s t e n t l y i d e n t i f y s i m p l e i d e a s o f wh i t e i n p a r t i c u l a r p e r c e p t i o n s . Jonathan B e n n e t t , Locke, B e r e k e l y , Hume: C e n t r a l Themes (London, 1971), pp. 25-30. 4 Locke, Book I I I , chap, i v , s e c t . 6. 5 I b i d . , s e c t . 7. 5 3. P u b l i c i t y , P r i v a c y , and P a s s i v i t y w i t h r e s p e c t t o Lockean Ideas Locke draws a d i s t i n c t i o n between what he c a l l s a " q u a l i t y " and an " i d e a " : "Whatsoever the mind p e r c e i v e s i n i t s e l f , o r i s the immediate o b j e c t o f p e r c e p t i o n , thought, o r u n d e r s t a n d i n g , t h a t I c a l l i d e a ; and the power t o produce any i d e a i n o u r mind, I c a l l q u a l i t y o f the s u b j e c t wherein t h a t power i s . " ^ He f u r t h e r d i s t i n g u i s h e s p r i m a r y q u a l i t i e s ( s o l i d i t y , e x t e n s i o n , f i - g u r e , and m o b i l i t y ) which " i n a l l the a l t e r a t i o n s and changes Ethe bodyj s u f f e r s , a l l t h e f o r c e can be used upon i t , i t c o n s t a n t l y keeps . . . ." from the secondary q u a l i t i e s ( e . g . , c o l o u r s , s m e l l s , t a s t e s , sounds) "which i n t r u t h a r e n o t h i n g i n the o b j e c t s t hemselves but powers t o produce v a r i o u s s e n s a t i o n s i n us by t h e i r p r i m a r y q u a l i t i e s . . . ."̂  Now o f c o u r s e Locke has d e f i n e d " q u a l i t i e s " as such (both p r i m a r y and s e c o n d a r y ) as "powers i n the o b j e c t s t o produce i d e a s i n us", but what i s i m p o r t a n t i s t h a t a l t h o u g h the i d e a s o f p r i m a r y q u a l i t i e s a r e "resemblances" o f p r o p e r t i e s o f the p h y s i c a l o b j e c t i n i t s e l f such t h a t " t h e i r p a t t e r n s do r e a l l y e x i s t i n the b o d i e s 4 t h e mselves. . . ." , t h i s i s n o t the c a s e f o r t h e i d e a s o f s e c o n d a r y q u a l i - t i e s . Presumably the p r o p e r t i e s r e s e m b l i n g our i d e a s o f p r i m a r y q u a l i t i e s a r e n o n - d i s p o s i t i o n a l , i . e . , not "powers". There i s some c o n f u s i o n i n Locke i n t h a t sometimes he remembers h i s d e f i n i t i o n o f " q u a l i t i e s " as "powers", but sometimes uses " q u a l i t i e s " t o r e f e r t o n o n - d i s p o s i t i o n a l p r o p e r t i e s o f p h y s i - c a l o b j e c t s . For Locke, c o l o u r s as q u a l i t i e s o f p h y s i c a l o b j e c t s and c o l o u r s as we o r d i n a r i l y t h i n k o f them a r e two d i f f e r e n t k i n d s o f t h i n g s . Says Locke: *Locke, Book I I , chap, v i i i , s e c t . 8. 2 I b i d . , s e c t . 9. 3 I b i d . , s e c t . 10. 4 I b i d . , s e c t . 15. 6 1) Al t h o u g h we may l e g i t i m a t e l y speak o f p h y s i c a l o b j e c t s as h a v i n g c o l o u r s , we are r e f e r r i n g o n l y t o c e r t a i n "powers" the o b j e c t s have t o produce c e r - t a i n i d e a s i n us. (2) On the o t h e r hand, what we n o r m a l l y t h i n k o f when we speak o f c o l o u r s a r e the i d e a s o f r e d and w h i t e , e t c . , which a r e caused i n us by the p r i m a r y q u a l i - t i e s o f p h y s i c a l o b j e c t s . These i d e a s a re p r i v a t e i n the sense t h a t t h e y a r e 5 6 " i n v i s i b l e " " i n t e r n a l c o n c e p t i o n s " w i t h i n one's own mind , dependent f o r t h e i r e x i s t e n c e on t h e i r b e i n g d i r e c t l y p e r c e i v e d (which Locke u s u a l l y remem- b e r s ) such t h a t I am d i r e c t l y a c q u a i n t e d w i t h mine ( a l t h o u g h no-one e l s e l o g i - c a l l y can b e ) . Thus the c o l o u r r e d , as o r d i n a r i l y thought o f , i s an i d e a , not a p r o p e r t y o f a p u b l i c o b j e c t which e x i s t s i n d e p e n d e n t l y o f our p e r c e p - t i o n s . F u r t h e r , t h e r e i s no p r o p e r t y which a p h y s i c a l o b j e c t has i n i t s e l f which "resembles" our i d e a o f r e d , a l t h o u g h we t e n d , m i s t a k e n l y , t o "impute" such a p r o p e r t y t o p h y s i c a l o b j e c t s . Locke t r i e s t o make t h i s l a s t p o i n t by s a y i n g t h a t p r i m a r y q u a l i t i e s are " r e a l " , whereas c o l o u r q u a l i t i e s and o t h e r s e c o n d a r y q u a l i t i e s a r e "im- puted"^, but t h i s i s m i s l e a d i n g . A l l " q u a l i t i e s " a r e e q u a l l y r e a l i n the sense t h a t a l l q u a l i t i e s , by Locke's d e f i n i t i o n , a re powers. Presumably the p o i n t i s t h a t a p h y s i c a l o b j e c t has i t s p r i m a r y - q u a l i t y powers by v i r t u e o f h a v i n g ( u n d e r l y i n g ) n o n - d i s p o s i t i o n a l p r o p e r t i e s which resemble o u r i d e a s o f i t s p r i m a r y q u a l i t i e s , but has no n o n - d i s p o s i t i o n a l p r o p e r t i e s which resemble our i d e a s o f i t s s e c o n d a r y q u a l i t i e s . In the l i g h t o f t h i s i t may be wondered how some s i m p l e i d e a s , namely th o s e o f a l l but the p r i m a r y q u a l i t i e s o f b o d i e s , can f u n c t i o n as the "ma- t e r i a l s o f knowledge", s i n c e t h e y a re n e i t h e r f e a t u r e s o f p u b l i c o b j e c t s nor 5 I b i d . , Book I I I , chap, i i , s e c t . 1. 6 I b i d . , chap, i , s e c t . 2. 7 I b i d . , Book I I , chap, v i i i , s e c t . 22. do t h e y resemble such f e a t u r e s . Locke, n e v e r t h e l e s s , i s c a r e f u l t o bestow upon the s i m p l e i d e a s o f s e c o n d a r y q u a l i t i e s a c e r t i f i c a t e o f r e a l i t y i n ano- t h e r s e n s e . They a r e t o be d i s t i n g u i s h e d from " f a n t a s t i c a l " i d e a s which a r e those h a v i n g "no f o u n d a t i o n i n n a t u r e , n o r . . . any c o n f o r m i t y w i t h t h a t o r e a l i t y o f b e i n g t o which t h e y a r e t a c i t l y r e f e r r e d , as t o t h e i r a r c h e t y p e s . " Thus he w r i t e s : But, though w h i t e n e s s and c o l d n e s s a r e no more i n snow than p a i n i s ; y e t t h o s e i d e a s o f w h i t e n e s s and c o l d n e s s , p a i n , e t c . , b e i n g i n us the e f f e c t s o f powers i n t h i n g s w i t h o u t us, o r d a i n e d by o u r Maker t o produce i n us such s e n s a t i o n s ; t h e y a r e r e a l i d e a s i n us, whereby we d i s t i n g u i s h the q u a l i t i e s t h a t a r e r e a l l y i n t h i n g s t h e m s e l v e s . F o r , t h e s e s e v e r a l appearances b e i n g de- signed. to.be the mark whereby we a r e t o know and d i s t i n g u i s h t h i n g s which we have t o do w i t h , o u r i d e a s do as w e l l s e r v e us t o t h a t p u r p o s e , and are as r e a l d i s t i n g u i s h i n g c h a r a c t e r s , whe- t h e r t h e y be o n l y c o n s t a n t e f f e c t s , o r e l s e e x a c t resemblances o f something i n t h e t h i n g s t h e m s e l v e s : the r e a l i t y l y i n g i n t h a t s t e a d y c o r r e s p o n d e n c e t h e y have w i t h t h e d i s t i n c t c o n s t i t u - t i o n s o f r e a l b e i n g s . But whether t h e y answer t o t h o s e c o n s t i - t u t i o n s , as t o causes o r p a t t e r n s , i t matters not . . . .9 Thus f o r o u r i d e a s o f s e c o n d a r y q u a l i t i e s , t h e i r b e i n g caused by " e x t e r n a l o b j e c t s " , even though t h e y do n o t "resemble" a c t u a l f e a t u r e s o f the o b j e c t s , i s e p i s t e m o l o g i c a l l y v i t a l . But how i n f a c t does Locke make t h i s move? H i s d i s t i n c t i o n between s i m p l e i d e a s o f s e n s a t i o n and s i m p l e i d e a s o f r e f l e c t i o n i s d e f i n e d i n terms o f the s o u r c e s o f t h e s e s e t s o f i d e a s : s i m p l e i d e a s o f r e f l e c t i o n a re t h o s e r e s u l t i n g from "the p e r c e p t i o n o f the o p e r a t i o n s o f our mind w i t h i n us, as i t i s employed about the i d e a s i t has g o t . . . . Of the o t h e r s e t he w r i t e s : ". . .our Senses, c o n v e r s a n t about p a r t i c u l a r sen- s i b l e o b j e c t s , do convey i n t o the mind s e v e r a l d i s t i n c t p e r c e p t i o n s o f t h i n g s , a c c o r d i n g t o t h o s e v a r i o u s ways wherein t h o s e o b j e c t s do a f f e c t them", a d d i n g the c l a r i f i c a t i o n , "when I say the senses convey i n t o the mind, I mean, th e y 8 I b i d . , Book I I , chap, xxx, s e c t . 1 9 I b i d . , s e c t . 2. ^°Ibid., chap, i , s e c t . 4. from e x t e r n a l o b j e c t s convey i n t o t h e mind what produces t h e r e t h o s e p e r c e p - t i o n s . " 1 ^ He never s a t i s f a c t o r i l y s u p p o r t s t h e c l a i m t h a t i d e a s o f w h i t e , y e l l o w , h e a t , e t c . , must be s i m p l e i d e a s o f s e n s a t i o n , f o r , i t has j u s t been n o t e d , he d e f i n e s " s i m p l e i d e a s o f s e n s a t i o n " i n terms o f t h e i r s o u r c e , and he does not t r y t o show t h a t one c o u l d not a c q u i r e the i d e a o f w h i t e , f o r example, e x c e p t as i t i s caused by an e x t e r n a l o b j e c t . H i s not f e e l i n g t h e need t o s u p p o r t t h i s c l a i m i s i n l a r g e measure a r e s u l t o f h i s r e p e a t e d c l a i m s t h a t the two s o u r c e s he m e n t i o n s — b e i n g caused by an e x t e r n a l o b j e c t , and r e s u l t i n g from the mind's o p e r a t i o n s on a l r e a d y r e c e i v e d i d e a s — a r e exhaus- 1? t i v e . ( T h i s c l a i m too r e c e i v e s no adequate s u p p o r t . ) Thus f o r L o c k e , t o deny t h a t the i d e a o f w h i t e i s a s i m p l e i d e a o f s e n s a t i o n , i . e . , i s caused by an e x t e r n a l o b j e c t , i s t o say t h a t i t i s a c q u i r e d as a r e s u l t o f the mind's o p e r a t i o n s on a l r e a d y r e c e i v e d i d e a s . A t t h i s p o i n t he i m p l i c i t l y r e l i e s on the e a r l i e r mentioned p a s s i v i t y c l a i m s he makes. He r e l i e s on them v e r y h e a v i l y as g u i d e s t o the e p i s t e m o l o g i c a l t r u s t w o r t h i n e s s o f , i n p a r t i c u l a r , s i m p l e i d e a s o f s e n s a t i o n . In a r e v e a l i n g passage i m m e d i a t e l y f o l l o w i n g t h a t a l r e a d y quoted from Book I I , chap, xxx, s e c t . 2, and i n the same c o n t e x t o f the s i m p l e i d e a s o f sense b e i n g t h e c o n s t a n t e f f e c t s o f " r e a l b e i n g s " , he a r - gues: And thus our s i m p l e i d e a s a r e a l l r e a l and t r u e , because t h e y answer and agree t o t h o s e powers o f t h i n g s which produce them i n our minds; t h a t b e i n g a l l t h a t i s r e q u i s i t e t o make them r e a l , and not f i c t i o n s a t p l e a s u r e . For i n s i m p l e i d e a s (as has been shown) the mind i s w h o l l y c o n f i n e d t o the o p e r a t i o n s o f t h i n g s upon i t , and can make t o i t s e l f no s i m p l e i d e a , more than what i t has r e c e i v e d . Now I t h i n k t h a t Locke c o u l d make a p l a u s i b l e case f o r the c l a i m t h a t v f "the mind" i s p a s s i v e w i t h r e s p e c t t o s i m p l e i d e a s o f s e n s a t i o n , then t h e s e i d e a s ( s i n c e , i n Locke's t h e o r y , none i s i n n a t e ) e i t h e r a r i s e c o m p l e t e l y s p o n t a n o u s l y 1 1 1 b i d . , s e c t . 3. 12 See, f o r example, Book I I , chap. 1, s e c t s . 2 and 4. c ( i . e . , a r e un c a u s e d ) , o r a r e caused by something " e x t e r n a l t o t h e mind". A l s o I t h i n k a p l a u s i b l e case c o u l d be made a g a i n s t the former o f the a l t e r - n a t i v e s . Even s o , he would be l e f t w i t h t he metaphor t h a t the s o u r c e o f t h e s e i d e a s i s some cause " e x t e r n a l t o the mind", and t h i s means s i m p l y "some cause o t h e r than the mind". I t does n o t mean "some cause e x t e r n a l t o my body"; t h e r e i s no re a s o n prima f a c i e why ev e n t s o r changes i n my body c o u l d n o t , even f o r Locke, cause the p a s s i v e r e c e p t i o n o f some s i m p l e i d e a o f sense by "my mind", y e t he r e p e a t e d l y speaks o f t h e o n l y p o s s i b l e s o u r c e o f such i d e a s as " e x t e r n a l o b j e c t s " meaning " p h y s i c a l o b j e c t s o t h e r than my body". L i k e most o t h e r p h i l o s o p h e r s , Locke c o n t i n u o u s l y i g n o r e s t he r o l e o f one's own 13 body i n the realm o f p e r c e p t i o n . We may a l s o n o t e , b e f o r e p h i l o s o p h e r s w i t h B e r k e l e i a n t e n d e n c i e s b e g i n t o prod us, t h a t even i f we had a w a r r a n t f o r c l a i m i n g t h a t s i m p l e i d e a s o f sense a r e caused not by our own mind (whatever t h a t would mean), but by something " e x t e r n a l t o " ( i . e . , o t h e r than) our own body, t h i s s t i l l i s not t o say t h a t t h e y a r e caused by e x t e r n a l p h y s i c a l ob- j e c t s . In t h i s t h e s i s I s h a l l make e x p l i c i t t h a t the so u r c e o f some o f o u r a c t u a l i d e a s j_s i m p o r t a n t f o r e p i s t e m o l o g i c a l r e a s o n s , but i t w i l l be shown t h a t e m p h a s i z i n g t h e " p a s s i v i t y " o f the a c q u i r i n g o f some o f o u r i d e a s w i l l n o t h e l p t o c l a r i f y t h i s p o i n t . T h i s i n d i c a t i n g o f t h e p a s s i v i t y o f t h e a c - q u i r i n g o f s i m p l e i d e a s o f sense as ' p r o o f o f t h e i r e p i s t e m o l o g i c a l r e l i - a b i l i t y i s n o t a p e c u l i a r i t y o f Locke. I t i s found a g a i n and a g a i n w i t h v a r y - i n g degrees o f e x p l i c i t n e s s i n w r i t i n g s on p e r c e p t i o n t h e o r y i n p h i l o s o p h y . L e t u s , t h e n , l o o k f u r t h e r a t t h i s a p p a r e n t c o n n e c t i o n between p a s s i v i t y w i t h - i n p e r c e p t i o n and t h e e p i s t e m o l o g i c a l r e l i a b i l i t y o f some o f our i d e a s . One o f the v e r y few mentions i s i n do w i t h h e a t , o f how water may be f e l t o t h e r ; Book I I , chap, v i i i , s e c t . 21. the c o n t e x t o f one o f h i s examples t o as c o l d by one hand and warm by the K 4. The P a s s i v i t y P r i n c i p l e o f P e r c e p t i o n For t he purpose o f t h i s s e c t i o n , and i n f a c t f o r the r e s t o f t h e t h e s i s , we can c o n s t r u e "an i d e a " t o mean "an it e m Locke would c a l l a s i m p l e i d e a o f s e n s a t i o n , e.g., an i d e a o f w h i t e , o f y e l l o w " , w i t h o u t , however, i m p o r t i n g the n o t i o n o f the cause o f t h e i d e a i n t o the d e f i n i t i o n o f the term. Given t he scope o f the work, I s h a l l not i n t h i s t h e s i s s e t o u t to a r - gue f o r the e x i s t e n c e o f p h y s i c a l o b j e c t s , but the p o i n t s made a r e made on the assumption t h a t t h e r e a r e p h y s i c a l o b j e c t s . I s h a l l s t a t e t h e P a s s i v i t y P r i n c i p l e as t h e c l a i m t h a t "Ideas o f sense o f t h e p h y s i c a l w o r l d (as op- posed t o i d e a s o f r e f l e c t i o n , i n the Lockean sense) a r e n e c e s s a r i l y a c q u i r e d i n v o l u n t a r i l y o r p a s s i v e l y . " T h a t i s t o say, p a s s i v i t y i s a n e c e s s a r y c o n d i - t i o n f o r a c q u i r i n g i d e a s o f t h i s k i n d , but c l e a r l y n o t a s u f f i c i e n t c o n d i t i o n . ( H a l l u c i n a t i o n s , f o r example, c o u l d be p e r c e i v e d p a s s i v e l y . ) A t f i r s t g l a n c e t h i s p r i n c i p l e seems t o r e l a t e t o t h e n o t i o n o f o b j e c t i v i t y a t l e a s t i n the f o l l o w i n g l o o s e way. Many statements about p h y s i c a l o b j e c t s seem e x c e l l e n t c a n d i d a t e s f o r the t i t l e " o b j e c t i v e s t a t e m e n t s " . So we must c o n s i d e r t he p o s s i b i l i t y t h a t t h e P a s s i v i t y P r i n c i p l e s t a t e s a n e c e s s a r y c o n d i t i o n which our s e n s e - e x p e r i e n c e must have, v i z , p a s s i v i t y , i f t h a t e x p e r i e n c e i s t o be a l e g i t i m a t e b a s i s f o r making c l a i m s about p h y s i c a l o b j e c t s . I f p a s s i v i t y i s a r e q u i r e m e n t t h a t must be met f o r our s e n s e - e x p e r i e n c e t o be used f o r t h i s p urpose, and i f i t i s t r u e t h a t many stat e m e n t s about p h y s i c a l o b j e c t s a r e e x c e l l e n t c a n d i d a t e s f o r b e i n g o b j e c t i v e s t a t e m e n t s , then t h i s opens the pos- s i b i l i t y t h a t t h e p a s s i v i t y o f o u r s e n s e - e x p e r i e n c e i s a k e y - f e a t u r e o f the s i t u a t i o n as r e g a r d s t he o b j e c t i v i t y o f t h o s e s t a t e m e n t s . I s h a l l b e g i n by l o o k i n g a t a c l a i m d i s c u s s e d by A y e r s , namely: "The i n t u i t i v e p r i n c i p l e t h a t i d e a s h a v i n g r e a l i t y a r e n e c e s s a r i l y i n v o l u n - t a r y . . . ."1, s i n c e " p e r c e p t i o n i s not a v o l u n t a r y a c t i v i t y . As Locke puts i t , 'The o b j e c t s o f our senses do obt r u d e t h e i r p a r t i c u l a r i d e a s upon o u r 2 minds whether we w i l l o r no."' (Ayers seems t o use the term " i d e a " i n the same way as I do.) T h i s seems t o be c l o s e l y a k i n t o the P a s s i v i t y P r i n c i p l e as g i v e n a t the b e g i n n i n g o f t h i s s e c t i o n , but l e t us see how h e l p f u l A y e r s ' f o r m u l a t i o n i s . S t r i c t l y s p e a k i n g i t i s not the i d e a s which a r e p a s s i v e o r a c t i v e , but our a c q u i r i n g o f them. We a r e t o c o n t r a s t i d e a s which a r e r e c e i v e d p a s s i v e l y w i t h t h o s e which we a c t i v e l y ' b r i n g about', f o r i t i s h e l d t h a t " i f I am i n - d u c i n g my own s t a t e s o f mind a t w i l l , I may be p i c t u r i n g o r i m a g i n i n g , but I 3 cannot be p e r c e i v i n g . " Ayers a t t r i b u t e s the p r i n c i p l e t o both Locke and B e r k e l e y , and su g g e s t s t h a t Locke c o n s i d e r s t o be " r e a l " i d e a s t h o s e which 4 have " r e a l o b j e c t s " , w h i l e B e r k e l e y d e f i n e s what a R e a l i s t would c a l l " p h y s i - c a l r e a l i t y " i n terms o f the i n v o l u n t a r i n e s s o f our i d e a s t o g e t h e r w i t h t h e i r d i s t i n c t n e s s , c o h e r e n c e , c o n s t a n c y , and r e g u l a r i t y ( w i t h , o f c o u r s e , no men- t i o n o f o b j e c t s i n the Lockean s e n s e ) . For both p h i l o s o p h e r s , i n s p i t e o f t h e i r d i f f e r i n g o n t o l o g i e s , t he c o n c e p t o f r e a l i t y s e r v e s t o d i s t i n g u i s h per- c e p t i o n , where the i d e a s a r e a c q u i r e d i n v o l u n t a r i l y , from v o l u n t a r y imaging. My v e r s i o n o f t h e p r i n c i p l e may, i n f a c t , be a c c e p t a b l e t o Ayers s i n c e he does not s u b s c r i b e t o B e r k e l e y ' s n o t i o n o f " r e a l i t y " , and I s h a l l attempt v a r i o u s f a i r l y o b v i o u s i n t e r p r e t a t i o n s o f t h i s v e r s i o n , t r y i n g t o make the p r i n c i p l e a u s e f u l ' t o o l ' f o r my i n q u i r y . ^.R. A y e r s , " P e r c e p t i o n and A c t i o n , " Knowledge and N e c e s s i t y , Royal I n s t i - t u t e o f P h i l o s o p h y L e c t u r e s , v o l . 3, 1968-69 (London, 1970), p. 95. 2 I b i d . , p. 91. 3 I b i d . , p. 95. 4 I b i d . , p. 98. 12 I am not d i s c u s s i n g i n t h i s s e c t i o n the d i s t i n c t i o n between a 'sense- c o n t e n t ' and i t s ' i n t e r p r e t a t i o n ' , though t h i s i s o f t e n t hought t o c o r r e l a t e w i t h t h e p a s s i v e - a c t i v e d i s t i n c t i o n . Assuming, as i s w i d e l y a g r e e d , t h a t i n t e r p r e t i n g and c l a s s i f y i n g a r e a c t i v i t i e s , and a l l o w i n g t h a t i t i s hard o r even i m p o s s i b l e f o r an a d u l t t o apprehend s e n s u o u s l y w i t h o u t i n t e r p r e t i n g and c l a s s i f y i n g , s t i l l I agree w i t h Lemos t h a t t h e r e i s something " g i v e n " i n o r d i - nary p e r c e p t u a l s i t u a t i o n s : "The f a c t t h a t t h e g i v e n cannot be d e s c r i b e d w i t h o u t t r a n s c e n d i n g i t does not mean t h a t t h e r e i s no g i v e n element i n p e r - c e p t i o n . In f a c t , t h e v e r y statement o f t h i s o b j e c t i o n presupposes t h a t some- 5 t h i n g i s g i v e n . " What I am commenting on i n t h i s s e c t i o n i s what some pe o p l e c a l l "the g i v e n " , meaning the s o r t o f i t e m I am r e f e r r i n g t o as "an i d e a " . Our i d e a s o f p e r c e p t i o n , as opposed t o i d e a s o f r e f l e c t i o n i n Locke's sense, v a r y w i t h s e v e r a l f a c t o r s . Some may be d e s c r i b e d as " e x t e r n a l c o n d i - t i o n s " , e.g., t h e l o c a t i o n o f t h e p e r c e i v e r and o f t h e o b j e c t s p e r c e i v e d , how much l i g h t t h e r e i s , whether o r not t h e r e a r e s e v e r a l n o i s e s b e s i d e s the n o i s e he i s i n t e r e s t e d i n , e t c . . Many o f t h e s e c o n d i t i o n s a r e r e l e v a n t t o o n l y one o r two o f t h e f i v e sense-modes. Other f a c t o r s may be a p p r o p r i a t e l y c a l l e d " i n t e r n a l c o n d i t i o n s " : t he b o d i l y s t a t e o f the p e r c e i v e r , e s p e c i a l l y the s t a t e o f h i s s e n s o r y a p p a r a t u s , and h i s p s y c h o l o g i c a l s t a t e ( e . g . , h i s hopes, e x p e c t a t i o n s ) . I can o f t e n choose t o change any o r a l l o f t h e e x t e r - nal f a c t o r s mentioned: I can move up to an o b j e c t , b r i n g i t c l o s e r t o a l i g h t , change the l i g h t i n g , b r i n g i t i n s i d e o u t o f the f o g , e t c . , and my p e r - c e p t i o n s w i l l o f t e n v a r y as I do so. The P a s s i v i t y P r i n c i p l e cannot mean s i m p l y t h a t : 5 Ramon M. Lemos, " S e n s a t i o n , P e r c e p t i o n , and the G i v e n , " R a t i o , V I , 1964, p,.,72. See C.W.K. Mundle, P e r c e p t i o n : F a c t s and T h e o r i e s (London, 1971), p. 30. I am not s u g g e s t i n g t h a t a person's p s y c h o l o g i c a l s t a t e has no p h y s i c a l s t a t e c o r r e l a t e . I t may, however, be e a s i e r t o i d e n t i f y some o f t h e s e k i n d s o f p s y c h o l o g i c a l s t a t e s by the person's b e h a v i o u r r a t h e r than by l o o k i n g f o r the p h y s i c a l s t a t e c o r r e l a t e . 1 3 i ) N o t h i n g I can do w i l l p r e v e n t i d e a s o f p e r c e p t i o n o f t h e p h y s i c a l w o r l d (as t h i s phrase has been e x p l a i n e d e a r l i e r ) b e i n g r e c e i v e d , and t h e r e i s n o t h i n g I can do i n o r d e r to a c q u i r e such i d e a s . Both p a r t s o f ( i ) a r e f a l s e s i n c e my changing my p o s i t i o n o r the l i g h t i n g , e t c . , w i l l both g i v e r i s e to my a c q u i r i n g c e r t a i n i d e a s I s h o u l d not o t h e r - w i se have a c q u i r e d , and t o my n o t a c q u i r i n g c e r t a i n i d e a s t h a t I s h o u l d o t h e r - wise have a c q u i r e d . We c o u l d t r y t o i n t e r p r e t the p r i n c i p l e t o mean: i i ) N othing I can do e x c e p t making a change i n the e x t e r n a l c o n d i t i o n s , o r i n the e x t e r n a l p h y s i c a l w o r l d ( e . g . , by chan g i n g my p o s i t i o n , o r moving the o b j e c t p e r c e i v e d ) w i l l p r e v e n t i d e a s o f p e r c e p t i o n o f the p h y s i c a l w o r l d from b e i n g a c q u i r e d which o t h e r w i s e would have been a c q u i r e d a t t h a t time by me, and n o t h i n g I can do e x c e p t making a change i n the e x t e r n a l p h y s i c a l w o r l d w i l l b r i n g about my a c q u i r i n g i d e a s o f p e r c e p t i o n o f the p h y s i c a l w o r l d which o t h e r w i s e I s h o u l d not have a c q u i r e d . T h i s i s more p r o m i s i n g t h a n ( i ) , b ut even t h i s i s f a l s e , s i n c e t h e r e a r e some changes t h a t I can v o l u n t a r i l y b r i n g about i n my b o d i l y s t a t e which w i l l a f - f e c t t h e i d e a s o f p e r c e p t i o n o f t h e p h y s i c a l w o r l d t h a t I have. E.g., I can c l o s e one eye when l o o k i n g a t the o b j e c t o f p e r c e p t i o n , o r take c e r t a i n k i n d s o f d r u g s , known to a f f e c t the s e n s o r y a p p a r a t u s , b e f o r e v i s u a l l y o r t a c t u a l l y p e r c e i v i n g p h y s i c a l o b j e c t s around me. A t t h i s p o i n t many p h i l o s o p h e r s w i l l wish t o d r i v e a wedge between (a) our c h a n g i n g t he p o s i t i o n o f the o b j e c t p e r c e i v e d , o r o u r c l o s i n g an eye, and (b) our a c q u i r i n g o f the new i d e a s o f the o b j e c t ( s ) . They w i l l c l a i m t h a t w h i l e (a) a r e a c t i v i t i e s , (b) a r e n o t . Our a c q u i r i n g o f the i d e a s , i t w i l l be c l a i m e d , i s p a s s i v e . With r e s p e c t t o such a c o n t r a s t , I f i n d no d i f f i c u l t y i n u n d e r s t a n d i n g the a c t i v e s i d e o f i t . I have agreed a l l a l o n g t h a t what a r e mentioned under (a) a r e a c t i v i t i e s . But t h e r e i s a d i f f i c u l t y i n acknowledg- i n g t h a t t h e s e a c t i v i t i e s 'give r i s e t o ' the a c q u i r i n g o f i d e a s t h a t o t h e r w i s e 14 we s h o u l d not a c q u i r e , and y e t a t the same time t r y i n g t o g i v e sense t o the c l a i m t h a t " r e a l " i d e a s ( i . e . , i d e a s o f p e r c e p t i o n o f the p h y s i c a l world) a r e n e v e r t h e l e s s p a s s i v e l y a c q u i r e d . I t i s the c o n j u n c t i o n o f t h e s e two c l a i m s which i s p a r a d o x i c a l . L e t us t r y t o i n t e r p r e t the P a s s i v i t y P r i n c i p l e as the c l a i m t h a t : i i i ) T here a r e l i m i t s as t o which i d e a s o f p e r c e p t i o n o f the p h y s i c a l w o r l d may be a c q u i r e d i n any p a r t i c u l a r s e t o f c i r c u m s t a n c e s . U n l i k e ( i ) and ( i i ) , t h i s i s a t l e a s t t r u e , but as i t stands i t does not p e r - form the f u n c t i o n (mentioned by A y e r s ) which one e x p e c t s the P a s s i v i t y P r i n - c i p l e t o perform, v i z , t o d i s t i n g u i s h p e r c e p t i o n from v o l u n t a r y imaging. Even though, as Ayers remarks, i t i s l o g i c a l l y p o s s i b l e t h a t "a man s h o u l d be cap- a b l e o f p u t t i n g h i m s e l f a t w i l l i n t o mental s t a t e s j u s t l i k e p e r c e p t u a l s t a t e s . . t h e r e would be l i m i t s as t o the mental s t a t e s which c o u l d be s e l f - i n d u c e d a t any one time. A l t h o u g h i n t h e case o f v o l u n t a r y imaging the i n f l u e n c e o f the e x t e r n a l f a c t o r s which Mundle mentions a r e , ex h y p o t h e s i , e l i m i n a t e d , t h e r e s t i l l remain what he c a l l s t h e i n t e r n a l f a c t o r s s e t t i n g l i m i t s on what can be v o l u n t a r i l y imaged a t any one t i m e . There would a l s o be l i m i t a t i o n s imposed by o u r knowledge a c q u i r e d so f a r . To i n t e r p r e t the P a s s i v i t y P r i n c i p l e as meaning s i m p l y t h a t t h e r e a r e l i m i t s as to which i d e a s may be a c q u i r e d i n any p a r t i c u l a r s e t o f c i r c u m s t a n c e s by p e r c e p t i o n o f the p h y s i c a l w o r l d , removes t h e r a t h e r p a r a d o x i c a l a i r from the c o n j u n c t i o n men- t i o n e d above, but i t w i l l not g i v e a b a s i s f o r d i s t i n g u i s h i n g p e r c e p t i o n from v o l u n t a r y imaging. N o n e t h e l e s s , a l t h o u g h t h e r e a r e l i m i t s as t o which i d e a s can be a c q u i r e d i n any p a r t i c u l a r c a s e o f v o l u n t a r y imaging, and i n any p a r t i c u l a r i n s t a n c e o f p e r c e p t i o n o f the p h y s i c a l w o r l d , the k i n d s o f l i m i t s and the reasons f o r them a r e n o t t h e same. Our m i s t a k e has been t o t r y t o make sense o f t h e p a s s i v i t y c l a i m w i t h o u t i n t r o d u c i n g t h e r o l e o f p h y s i c a l e n t i t i e s i n the 'producing o f 15 t h e s e i d e a s . Even though I may ( a c t i v e l y ) change the e x t e r n a l c o n d i t i o n s o r my b o d i l y s t a t e (thus a f f e c t i n g which i d e a s o f p e r c e p t i o n o f the p h y s i c a l w o r l d I r e c e i v e ) , the i d e a s I r e c e i v e a r e n o n e t h e l e s s "determined by" p h y s i - c a l e n t i t i e s around me, t h e i r p r o p e r t i e s , and changes o c c u r r i n g t o them, i n s h o r t , by the p h y s i c a l w o r l d around me. In t h i s s e n s e , even when such changes a r e made, the i d e a s o f p e r c e p t i o n o f t h e p h y s i c a l w o r l d a re n e v e r t h e l e s s "pas- s i v e l y " a c q u i r e d . T h i s t o o i s the f o r c e o f s a y i n g t h a t the ki n d s o f l i m i t s imposed on an i n s t a n c e o f p e r c e p t i o n and on an i n s t a n c e o f v o l u n t a r y imaging a r e d i f f e r e n t . For an i n s t a n c e o f p e r c e p t i o n t o be an i n s t a n c e o f p e r c e p t i o n , the i d e a s a c q u i r e d must be " l i m i t e d " o r "determined by" the p h y s i c a l w o r l d p r e s e n t t o the p e r c e i v e r . In a ca s e o f v o l u n t a r y imaging t h i s i s not the way i n which the i d e a s a c q u i r e d a r e l i m i t e d . The P a s s i v i t y P r i n c i p l e i n i t s e l f , i n s p i t e o f t h e many a p p e a l s made t o i t i n i t s v a r i o u s forms, I f i n d completely u n i l l u m i n a t i n g . To c l a i m p a s s i v i t y i n t h i s c o n t e x t does not i n d i c a t e c l e a r l y the r e s t r i c t i o n s t h a t a r e supposed t o be imposed on t h e a c q u i r i n g o f the i d e a s i n q u e s t i o n . The hope was t o use " p a s s i v i t y " as p a r t o f a c r i t e r i o n f o r " i d e a s ( o f p e r c e p t i o n ) o f t h e p h y s i c a l w o r l d " , b ut i n f a c t we can g i v e sense to t h i s n o t i o n o f " p a s s i v i t y " o n l y by r e - i n t r o d u c i n g " i d e a s o f the p h y s i c a l w o r l d " i n i t s c l a r i f i c a t i o n ; and t h i s i s c l e a r l y c i r c u l a r . We a r e l e f t w i t h t h e s t a t e m e n t : ( i v ) I t i s a n e c e s s a r y c o n d i t i o n o f i d e a s ( o r p e r c e p t i o n ) o f a p a r t o f the p h y s i c a l w o r l d t h a t they a re "determined by" t h a t p a r t o f the p h y s i c a l w o r l d . T h i s t a u t o l o g y may seem t r i v i a l , b u t i n f a c t i t i s v e r y i m p o r t a n t and v e r y use- f u l t o bear i n mind. I t p l a y s a c r u c i a l r o l e i n some o f the l a t e r s e c t i o n s o f the t h e s i s . 16 5. Lewis's Assumption about the T e s t a b i l i t y o f E m p i r i c a l Statements The p o s s i b i l i t y o f t e s t i n g and r e - t e s t i n g f o r the t r u t h ( o r f a l s i t y ) o f a statement w i l l be c e n t r a l t o my c o n c e p t o f an o b j e c t i v e e m p i r i c a l s t a t e - ment. In t h i s s e c t i o n I wish t o l o o k a t a c o n d i t i o n C.I. Lewis c l a i m s must h o l d f o r an e m p i r i c a l statement t o be t e s t a b l e . T h i s w i l l p r o v i d e a s t a r t i n g - p l a c e f o r e x p l a i n i n g my c o n c e p t o f o b j e c t i v i t y . Throughout the t h e s i s I am concerned o n l y w i t h s t a t e m e n t s which: a) do n o t c o n t a i n any term whose d e f i n i t i o n i n c l u d e s the p r o p e r t y o f e m o t i o n a l l y a t t r a c t i n g o r e m o t i o n a l l y r e p e l l i n g one person o r more; and, b) may be t e s t e d by u s i n g one o r more o f the s e n s e s . T h i s i s what I i n t e n d t o b e c a p t u r e d b y " e m p i r i c a l s t a t e m e n t s " . In h i s e a r l i e r work, Mind and the World O r d e r \ Lewis's comments on q u a l i t i e s a r e e x c l u s i v e l y about what he c a l l s " o b j e c t i v e q u a l i t i e s " , by which he m e a n s " q u a l i t i e s o f p h y s i c a l o b j e c t s " . H i s r e f u s a l t o countenance s t a t e - ments about q u a l i t i e s which a r e not q u a l i t i e s o f p h y s i c a l o b j e c t s i s based on an assumption he makes about t h e n a t u r e o f v e r i f i c a t i o n . I t i s t h i s assump- t i o n I s h a l l d i s c u s s i n t h i s s e c t i o n . Lewis r e s e r v e s the word "knowledge" f o r " t h a t which i s a r t i c u l a t e and 2 v e r i f i a b l e , and has a s i g n i f i c a n t o p p o s i t e , ' e r r o r ' . " He argues t h a t knowl- 3 edge "always t r a n s c e n d s t h e i m m e d i a t e l y g i v e n . " He r e s t s h i s c o n c e p t o f knowledge on a c l a i m about the n a t u r e o f c o n c e p t s i n g e n e r a l , on t h e c l a i m t h a t t h e r e i s no c o n c e p t t h e d e n o t a t i o n o f which does not extend beyond the 4 i m m e d i a t e l y g i v e n , and beyond what c o u l d be i m m e d i a t e l y g i v e n . ^ C l a r e n c e I r v i n g L e w i s , Mind and t h e World O r d e r (New York, 1929). 2 I b i d . , p. 146. 3 I b i d . , p. 118. 4 I b i d . , p. 121. 17 "The p r e d i c a t i o n o f a p r o p e r t y on t h e b a s i s o f momentarily p r e s e n t e d e x p e r i - ence, i s i n the n a t u r e o f an h y p o t h e s i s , which p r e d i c t s something d e f i n i t e l y s p e c i f i a b l e i n f u r t h e r p o s s i b l e e x p e r i e n c e , and something which such e x p e r i - 5 ence may c o r r o b o r a t e o r f a l s i f y . " Lewis makes t h i s as a g e n e r a l c l a i m about the a p p l i c a t i o n o f any c o n c e p t . For example, t o say t h a t I have an a p p l e i n my hand i s t o imply something about what i t w i l l t a s t e l i k e i f I b i t e i t , what w i l l happen i f I drop i t on a hard f l o o r , what i t w i l l l o o k l i k e i f I s l i c e i t i n two, e t c . . We may c a l l t h e s e " c o n d i t i o n a l p r e d i c t i o n s " , s i n c e they take Ft the form: " I f I a c t i n c e r t a i n ways, s p e c i f i a b l e e x p e r i e n c e w i l l e v e n t u a t e . " Even p r e d i c t i o n s which appear not t o be c o n d i t i o n a l can l e g i t i m a t e l y be con- s t r u e d as c o n d i t i o n a l ; f o r example, i t i s t r u e t h a t t o c a l l something "an apple' i s to i m p l y t h a t i n a damp atmosphere i t w i l l s t a r t t o r o t w i t h i n t h r e e weeks, but we may c o n s t r u e t h i s as " I f , a f t e r l e a v i n g i t i n the damp f o r t h r e e weeks, you poke i t , smell i t , and look a t i t , you w i l l f i n d i t i s s o f t , s m e l l s r o t - t e n , and l o o k s mouldy." From t h i s g e n e r a l c l a i m about the h y p o t h e t i c a l n a t u r e o f a c o n c e p t when used, Lewis i n f e r s t h a t " i f c o n c e p t s a r e to be a r t i c u l a t e and m e a n i n g f u l , then the a p p l i c a t i o n o f them must be something v e r i f i a b l e ; which means t h a t what they denote must have a temporal s p r e a d . " 7 I t i s impor- t a n t t h a t Lewis speaks o f c o n c e p t s b e i n g a p p l i c a b l e i n a s e t o f c i r c u m s t a n c e s o n l y i n terms o f the r e l a t i o n s h i p o f d e n o t i n g : t o say t h a t a c o n c e p t i s a p p l i - c a b l e on some o c c a s i o n i s t o say t h a t i t denotes something on t h a t o c c a s i o n . And s i n c e he i n s i s t s on the p r e d i c t i v e n a t u r e o f any c o n c e p t used (and thus a l s o t h a t i t t a k e s time t o v e r i f y t h a t a c oncept a p p l i e s ) , he c o n c l u d e s t h a t t h a t which the c o n c e p t denotes must have a temporal s p r e a d . But i t i s n o t o b v i o u s t h a t t h i s f o l l o w s . I t i s p l a u s i b l e t o c l a i m t h a t a ( v e r i - f i a b l e ) e m p i r i c a l s tatement must be open t o the p o s s i b i l i t y o f r e assessment 5 I b i d . , p. 131. 6 I b i d . , p. 140 7 I b i d . , p. 130. My emphasis. 18 i n the l i g h t o f f u r t h e r e x p e r i e n c e , and y e t t h a t such a sta t e m e n t need not be about any t h i n g which l a s t s through time. T h i s , i n f a c t , seems t o be Goodman's p o s i t i o n i n The S t r u c t u r e o f Ap- pearance. Such ' t h i n g s ' as p o t a t o e s and t a b l e s a r e n o t c o n c e i v e d by Goodman as b e i n g m a t e r i a l o b j e c t s i n the t r a d i t i o n a l s e n se, as they seem to be by Lewis. "Our t a b l e s , steam y a c h t s , and p o t a t o e s a r e events o f c o m p a r a t i v e l y o s m a l l s p a t i a l and l a r g e temporal d i m e n s i o n s . " These 'events' c o n s i s t o f a number o f p r e s e n t a t i o n s o f appearances: " I f a t h i n g can remain t he same w h i l e i t s appearance changes, then c l e a r l y the r e a l and the a p p a r e n t a r e d i f - f e r e n t . But t h i s means n o t t h a t t h e . r e a l t h i n g must be something q u i t e sepa- r a t e from i t s appearances but o n l y t h a t a r e a l t h i n g comprises many appear- 9 ances." "... the i d e n t i t y o f a t h i n g a t d i f f e r e n t moments i s the i d e n t i t y o f a t o t a l i t y embracing d i f f e r e n t e l e m e n t s . " ^ These p r e s e n t a t i o n s a r e , f o r Goodman, "momentary and u n r e c a l l a b l e " W i t h o u t g i v i n g u n necessary d e t a i l , a p r e s e n t a t i o n o f an appearance i s t h e p r e s e n t a t i o n o f many " c o n c r e t a " — each concretum composed o f a c o l o u r - q u a l e , a s p o t ( i n the v i s u a l f i e l d ) , and a moment (a time s p o t ) - - f o r m i n g a p a t t e r n which we i d e n t i f y a s , say, a t a b l e . Goodman c l a i m s t h a t judgements about t h e s e momentary p r e s e n t a t i o n s a r e v e r i f i a b l e i n a s p e c i f i c f a s h i o n , and t h i s I t h i n k i s t r u e . A comparison o f t e m p o r a l l y d i v e r s e p r e s e n t a t i o n s i s i n d e e d im- mune from t h e d i r e c t t e s t o f s i m u l t a n e o u s comparison. I f I say t h a t t he green p r e s e n t e d by the g r a s s now i s the same as the green p r e s e n t e d by i t a t a c e r t a i n p a s t moment, I cannot v e r i f y t h a t s t a t e m e n t by r e v i v i n g the p a s t p r e s e n t a t i o n f o r f r e s h i n - s p e c t i o n . My statement might thus be l o o k e d upon as a d e c r e e . But such d e c r e e s a r e not t h e r e f o r e haphazard. . . . A d e c r e e , however s a f e i t i s from d i s p r o o f , i s v u l n e r a b l e t o c a n c e l l a t i o n g N e l s o n Goodman, The S t r u c t u r e o f Appearance, 2nd ed. ( I n d i a n a p o l i s , 1966), p. 128. 9 I b i d . , pp. 127-128. 1 0 I b i d . , p. 129. 1 1 I b i d . s p. 132. 19 by a n o t h e r d e c r e e . . . . Most i m p o r t a n t a r e the consequences, a c t u a l o r p r o s p e c t i v e , o f a g i v e n d e c r e e . When a d e c r e e causes too much t r o u b l e , we abandon i t ; and our d e c r e e s can l e a d us i n t o such s e r i o u s t r o u b l e as o u t r i g h t i n c o n s i s t e n c y . 1 2 These d e c r e e s a r e s u b j e c t to c a n c e l l a t i o n a t l e a s t i n the f o l l o w i n g way. A l - though the p r e s e n t a t i o n s o f q u a l i a a r e momentary and cease t o be, by d e f i - n i t i o n , as soon as t h e y a r e apprehended ( i . e . , t h e y do not have temporal spr e a d i n Lewis's s e n s e ) , i t i s o b v i o u s I t h i n k t h a t we may r e a s s e s s a j u d g e - ment about such a p r e s e n t a t i o n i f , i n the l i g h t o f f u r t h e r e x p e r i e n c e , we a r - r i v e a t a g e n e r a l statement b e a r i n g on the f i r s t . Goodman h i m s e l f does not mention t h i s p o s s i b i l i t y . A t t h e end o f t h e passage quoted he does g i v e an example o f a d e c r e e b e i n g c a n c e l l e d , but h i s example does not make use o f the p o s s i b i l i t y o f b e i n g c a n c e l l e d i n the l i g h t o f a g e n e r a l statement a c q u i r e d a f t e r the decree was f i r s t made. In h i s example o f c a n c e l l i n g a d e c r e e he draws upon what he c a l l s "the u s e f u l p r i n c i p l e o f t r a n s i t i v i t y o f i d e n t i t y ( o f o b j e c t s ) " , even though he makes no attempt t o e x p l a i n how we a r r i v e a t the n o t i o n o f i d e n t i t y o f , s a y , a t a b l e through t i m e , when a l l t h a t the t a b l e comprises are q u a l i t a t i v e l y s i m i l a r , momentary p r e s e n t a t i o n s o f q u a l i a which form p a t t e r n s a p p e a r i n g and d i s a p p e a r i n g i n o u r v i s u a l f i e l d . In p a r t i c u l a r , he does n o t say which p r i n - c i p l e s o f s e l e c t i o n would a l l o w us t o d i s t i n g u i s h an element o f some a l r e a d y s p e c i f i e d t o t a l i t y ( h i s term f o r ' o b j e c t ' ) from a q u a l i t a t i v e l y s i m i l a r e l e - ment o f a h i t h e r t o unmet t o t a l i t y ; y e t w i t h o u t such p r i n c i p l e s and g i v e n h i s p h e n o m e n a l i s t i c o n t o l o g y , h i s n o t i o n o f t h e i d e n t i t y o f a ' t h i n g ' t h r o u g h time does not g e t o f f t h e ground. But t h i s i s not the p l a c e to examine t h e s e d i f - f i c u l t i e s ; f o r the p r e s e n t purpose i t i s enough t o show t h a t h i s q u a l i a - s t atements a r e open t o reassessment i n the l i g h t . o f f u r t h e r e x p e r i e n c e even w i t h o u t u s i n g o b j e c t - i d e n t i t y s t a t e m e n t s . Goodman s t a t e s t h a t judgements about momentary p r e s e n t a t i o n s o f q u a l i a 1 2 I b i d . , p. 134. "cannot be t e s t e d " , but t h i s i s f a l s e . I f t h e statements a r e about momen- t a r y q u a l i a , then I wish t o say t h a t t h e y may not be re-examined i n i s o l a t i o n . By t h i s I mean t h a t they have the s t a t u s o f d e c r e e s i n the sense t h a t f o r such a p a r t i c u l a r judgement p--a judgment about a p a r t i c u l a r p r e s e n t e d appearance a t a p a r t i c u l a r time--no f u t u r e e x p e r i e n c e w i l l s u p p o r t the statement not-p w i t h o u t t he i n t e r v e n t i o n o f g e n e r a l statements o f a s p e c i f i c k i n d . Only i f we can ' b u i l d up' some g e n e r a l s tatement which i n t u r n i m p l i e s not-p ( o r , p) w i l l t h e o r i g i n a l s t a t e m e n t , p, be open to an i n d i r e c t r e a s s e s s m e n t . Depending upon whether t h e g e n e r a l s tatement i m p l i e s p, o r n o t - p , t he re a s s e s s m e n t can c o n s i s t o f r e j e c t i n g t h e o r i g i n a l p, o r i n c o n s i d e r i n g i t t o have f u r t h e r sup- p o r t than i t d i d o r i g i n a l l y . I s h a l l g i v e an example t o h e l p c l a r i f y where the g e n e r a l s t a t e m e n t e n t e r s . On f i r s t o b s e r v i n g a 'swan', i . e . , a p r e s e n t a t i o n o f q u a l i a o f the ap- p r o p r i a t e p a t t e r n , I may make the c l a i m t h a t the b i r d p r e s e n t s b l u e c o l o u r - qua! i a . And t h i s may l a t e r be r e j e c t e d as the p r o d u c t o f an i n a t t e n t i v e g l a n c e o r an i l l u s i o n , when I l a t e r p e r c e i v e many o t h e r p a t t e r n s o f the same s p a t i a l c o n f i g u r a t i o n s as the o r i g i n a l p a t t e r n , a l l o f which p r e s e n t what I c l a i m a r e w h i t e c o l o u r - q u a l i a . As a r e s u l t o f t h i s f u r t h e r e x p e r i e n c e I may ' b u i l d up' a g e n e r a l s tatement about the c o l o u r - q u a l i a p r e s e n t e d by ' t h i n g s ' o f t he s p a t i a l d imensions i n q u e s t i o n , and v i a t h i s s t a t e m e n t r e j e c t o r r e - voke my f i r s t d e c r e e . E q u a l l y my o r i g i n a l s tatement may be s u p p o r t e d by f u r t h e r e x p e r i e n c e , i . e . , by p e r c e i v i n g many o t h e r p r e s e n t a t i o n s o f ' t h i n g s ' o f the same s p a t i a l c o n f i g u r a t i o n s p r e s e n t i n g the same c o l o u r - q u a l i a as the o r i g i n a l p r e s e n t a t i o n . Goodman i s v e r y q u i e t about how a de c r e e r e c e i v e s s u p p o r t , but s u r e l y t h e same e x p e c t e d u n i f o r m i t y which s e r v e s as a b a s i s f o r d o u b t i n g t he p a r t i c u l a r s t a t e m e n t i n the f i r s t c ase s e r v e s as a b a s i s f o r b e i n g more c o n f i d e n t about t h e p a r t i c u l a r s tatement i n the second c a s e . T h i s 1 3 I b i d . , pp. 133 & 134. n o t i o n o f a decree i s thus v e r y f a r from b e i n g e q u i v a l e n t t o the n o t i o n o f a p u r p o r t e d l y e m p i r i c a l s tatement which t u r n s out t o be u n v e r i f i a b l e . What I have s a i d does no t show t h a t t h e r e are no s i g n i f i c a n t d i f f e r e n c e s between the p o s s i b i l i t y o f r e a s s e s s i n g statements about p h y s i c a l o b j e c t s ( i n the usual sense o f " p h y s i c a l o b j e c t " ) and the p o s s i b i l i t y o f r e a s s e s s i n g q u a l i a - s t a t e - ments o f Goodman's k i n d . I t may w e l l be t h a t the r e a s s e s s a b i l i t y i n the second c a s e i s i n some way n o t as ' f u l l - b l o o d e d ' as i n the case o f statements about q u a l i t i e s o f p h y s i c a l o b j e c t s , e.g., the f a c t t h a t we cannot d i r e c t l y r e a s s e s s a s t a t e m e n t about a p a s t p r e s e n t a t i o n o f q u a l i a w i t h o u t i n t r o d u c i n g a s p e c i f i c g e n e r a l statement (as d e s c r i b e d above) may have s i g n i f i c a n t i m p l i - c a t i o n s n o t mentioned i n t h i s s e c t i o n . N o n e t h e l e s s we do have a form o f r e a s sessment i n the l i g h t o f f u r t h e r e x p e r i e n c e , even though the momentary p r e s e n t a t i o n o f q u a l i a which the o r i g i n a l s t a t e m e n t i s about does not have "tempo- r a l s p r e a d " ( i n L e w i s ' s sense) and so cannot be re-examined. On t h i s p o i n t , t h e n , Lewis i s m i s t a k e n . I t may be argued t h a t a s tatement about an e n d u r i n g o b j e c t i s no more open to r e assessment i n i s o l a t i o n than i s a d e c r e e , so t h a t the two k i n d s o f s t a t e m e n t s a r e t h e same i n t h i s r e s p e c t . Suppose we want t o r e a s s e s s the s t atement t h a t some p h y s i c a l o b j e c t i s b l u e by moving c l o s e r t o the o b j e c t , o r b r u s h i n g away the d u s t , o r t u r n i n g on the l i g h t , e t c . . Even i f the ob- j e c t i s kept i n view t h r o u g h o u t , so t h a t t h e r e i s no problem about r e - i d e n t i - f y i n g i t , s t i l l we i m p l i c i t l y c a l l upon g e n e r a l s t a t e m e n t s ( n o t n e c e s s a r i l y u n i v e r s a l ) o f t h e form: " W i t h i n c e r t a i n s p e c i f i a b l e l i m i t s , moving c l o s e r t o an o b j e c t w i l l p r o v i d e a b e t t e r b a s i s f o r s t a t i n g the c o l o u r o f a p h y s i c a l o b j e c t than s t a n d i n g a t a d i s t a n c e " , o r "A s tatement about the ' r e a l ' c o l o u r o f a p h y s i c a l o b j e c t made a f t e r d u s t has been brushed away w i l l be made on b e t t e r e v i d e n c e than one made when i t i s c o v e r e d w i t h d u s t " , e t c . . T h i s p o i n t seems p l a u s i b l e , but s t i l l t h e r e i s a n o t i c e a b l e d i f f e r e n c e i n how s p e c i f i c t h e s e g e n e r a l i z a t i o n s a r e as opposed t o how s p e c i f i c the 2; g e n e r a l i z a t i o n used i n r e a s s e s s i n g the q u a l i a - s t a t e m e n t needed t o be. In the c a s e o f the q u a l i a - s t a t e m e n t , the g e n e r a l statement t h a t p e r m i t t e d r e a s - sessment o f t h e o r i g i n a l s t a t e m e n t was about a l l p r e s e n t a t i o n s o f q u a l i a having t h e same ' p a t t e r n ' as the p r e s e n t a t i o n mentioned i n the o r i g i n a l s t a t e - ment, i . e . , the g e n e r a l statement was v e r y s p e c i f i c . 2: 6. E m p i r i c a l Statements and the ' P o s s i b i l i t y o f E r r o r ' I t i s g e n e r a l l y c l a i m e d t h a t a l l e m p i r i c a l s tatements a r e 'open t o e r r o r ' , but the c l a i m i s o f t e n ambiguous. We need t o d i s t i n g u i s h two d i f - f e r e n t senses o f "open t o e r r o r " . On the one hand t h e phrase can mean "non- n e c e s s a r y " , and on the o t h e r "open t o assessment and rea s s e s s m e n t i n the l i g h t o f s e n s o r y e x p e r i e n c e " ( o r s i m p l y , " c o r r i g i b l e " ) . A l l e m p i r i c a l s t a t e m e n t s a r e d i s t i n g u i s h e d from o t h e r s t a t e m e n t s by t h e i r n o n - n e c e s s i t y - - t h e y a r e a l l c a p a b l e o f b e i n g f a c t u a l l y f a l s e . I t i s c o n t r o v e r s i a l whether o r not a l l e m p i r i c a l s t a t e m e n t s a re c o r r i g i b l e . For example, i t i s some- times c l a i m e d t h a t some f i r s t - p e r s o n , p r e s e n t t e n s e s tatements cannot be d i s - c o v e r e d t o be f a c t u a l l y f a l s e , t h a t they a r e perhaps t he o n l y e m p i r i c a l s t a t e - ments t h a t a re i n c o r r i g i b l e i n t h a t t h e y a r e "immune t o the d e t e c t i o n and c o r - r e c t i o n o f f a c t u a l error"."'' My co n c e p t o f an o b j e c t i v e e m p i r i c a l s t a t e m e n t i s t h a t o f an e m p i r i c a l s tatement open t o rea s s e s s m e n t ( r e g a r d i n g i t s t r u t h - v a l u e ) i n the l i g h t o f f u r t h e r e x p e r i e n c e , o f a c o r r i g i b l e e m p i r i c a l s t a t e m e n t , i n f a c t . The c o n c e p t w i l l be r e f i n e d i n t h i s s e c t i o n . As a f i r s t s t e p we may d i s t i n g u i s h i n t e r - s u b j e c t i v e c o r r i g i b i l i t y from the p o s s i b i l i t y o f s e l f - c o r r e c t i o n ( o r , i n t r a - s u b j e c t i v e c o r r i g i b i l i t y ) . Some p h i l o s o p h e r s , n o t a b l y W i t t g e n s t e i n and h i s f o l l o w e r s , i d e n t i f y c o r r i g i b i l i t y w i t h i n t e r - s u b j e c t i v e c o r r i g i b i l i t y , w i t h t he i m p l i c a t i o n t h a t t h e r e cannot be a m e a n i n g f u l c o n c e p t o f s e l f - c o r r e c t i o n . W i t t g e n s t e i n r e f u s e s t o speak o f seeming e m p i r i c a l s t a t e m e n t s which f a i l t h e i n t e r - s u b j e c t i v i t y c r i t e r i o n as b e i n g genuine statements a t a l l . Thus avowals o f p a i n and so on a r e not t r e a t e d as h a v i n g t r u t h - v a l u e s ( a l t h o u g h t h i r d - p e r s o n a s c r i p t i o n s o f p a i n a r e ) . However, c o r r i g i b i l i t y need n o t be i n t e r - s u b j e c t i v e s i n c e , as we have "^This i s R.D. B r a d l e y ' s e x p l a n a t i o n o f " i n c o r r i g i b l e " i n "Avowals o f Imme- d i a t e E x p e r i e n c e , " Mind, 73, 1964, p. 190. My d i s t i n c t i o n a t t h i s p o i n t i s e s s e n t i a l l y B r a d l e y ' s , a l t h o u g h I p r e f e r t o speak o f c o r r i g i b i l i t y and non- n e c e s s i t y , r a t h e r than c o r n g i b i l i t y and d u b i t a b i l i t y as B r a d l e y does. seen, someone working w i t h the m a t e r i a l s Goodman has to hand seems t o have some n o t i o n o f c o r r i g i b i l i t y a v a i l a b l e , v i z , reassessment o f a statement i n the l i g h t o f f u r t h e r e x p e r i e n c e . T h i s c o r r i g i b i l i t y o f Goodman's q u a l i a - s tatements c o u l d be i n t r a - s u b j e c t i v e . In e x p l a i n i n g how a person may r e - a s s e s s a p a r t i c u l a r q u a l i a - s t a t e m e n t ( i . e . , a statement about a p a r t i c u l a r p r e s e n t a t i o n of, q u a l i a ) by a p p e a l i n g to a g e n e r a l statement ' b u i l t up' i n the l i g h t o f f u r t h e r e x p e r i e n c e , we d i d n o t have t o suppose t h a t t h e c o l o u r - s p o t - moment c o n c r e t a i n v o l v e d were i n any sense p u b l i c . L e t us suppose f o r the moment t h a t they a r e r a d i c a l l y n o n - p u b l i c i n t h a t i t i s l o g i c a l l y i m p o s s i b l e f o r two peop l e t o be a c q u a i n t e d w i t h one and the same concretum. Then my r e a s s e s s i n g a statement about a p a r t i c u l a r s e t o f c o n c r e t a i n v o l v e s my r e c o g - n i t i o n o f the c o l o u r and p a t t e r n i n v o l v e d , and a l s o i n v o l v e s my memory o f p a s t p r e s e n t a t i o n s o f t h i s k i n d . R e l i a n c e on my own f a c u l t i e s r e g a r d i n g such ' n o n - p u b l i c ' e n t i t i e s has been r e g a r d e d w i t h s c e p t i c a l eyes by f o l l o w e r s o f the W i t t g e n s t e i n t r a d i t i o n , but t o t a l s c e p t i c i s m on t h i s m a t t e r w i l l l e a v e us s t r a n d e d w i t h no means where- by t o t e s t any e m p i r i c a l s t a t ement, whether about a p u b l i c e n t i t y o r not. As Ayer w r i t e r s : . . . u n l e s s t h e r e i s something t h a t one i s a l l o w e d t o r e c o g n i z e , no t e s t can e v e r be completed: t h e r e w i l l be no j u s t i f i c a t i o n f o r the use o f any s i g n a t a l l . I check my memory o f the time a t which the t r a i n i s due to l e a v e by v i s u a l i z i n g a page o f the t i m e - t a b l e ; and I am r e q u i r e d t o check t h i s i n i t s t u r n by l o o k i n g up the page. But u n l e s s I can t r u s t my e y e s i g h t a t t h i s p o i n t , u n l e s s I can r e c o g n i z e t he f i g u r e s t h a t I see w r i t t e n down, I am s t i l l no b e t t e r o f f . I t i s t r u e t h a t i f I d i s t r u s t my e y e s i g h t I have t h e r e s o u r c e o f c o n s u l t i n g o t h e r p e o p l e ; but then I have t o u n d e r s t a n d t h e i r t e s t i m o n y , I have c o r r e c t l y t o i d e n t i f y the s i g n s t h a t they make.2 Thus, even when such t h i n g s as books, t i m e t a b l e s , and a l s o o t h e r p e o p l e a re c a l l e d upon i n t e s t i n g , u l t i m a t e l y I must s t i l l r e l y on my b e i n g a b l e t o r e c o g - n i z e what I see and the sounds t h a t I hear, e t c . . So Goodman's q u a l i a - s t a t e - ments may be r e a s s e s s a b l e i n the l i g h t o f f u r t h e r e x p e r i e n c e even i f the 2 A . J . Ayer, "Can There Be A P r i v a t e Language?", symposium w i t h R. Rhees, A r i s t o t e l i a n S o c i e t y , Supplementary v o l . XXVIII, 1954, p. 68. 11 c o n c r e t a t h e y a r e about a r e not p u b l i c i n any o b v i o u s sense. There i s , t h e n , a v i a b l e c o n c e p t o f s e l f - c o r r e c t i o n , a l t h o u g h j u s t how ' r o b u s t ' i t i s has not been e s t a b l i s h e d . S i n c e t h e phrase "open t o e r r o r " i s ambiguous, I s h a l l use i n s t e a d the two phrases "non-necessary" and " c o r r i g i b l e " . In the t e r m i n o l o g y I s h a l l use, t o say t h a t an e m p i r i c a l statement i s n o n - n e c e s s a r y i s t o say o n l y t h a t we can g i v e sense t o someone's h a v i n g r e a c h e d the wrong v e r d i c t as t o i t s t r u t h - v a l u e , w i t h o u t any i m p l i c a t i o n about the p o s s i b i l i t y o f d e t e c t i n g the wrong v e r d i c t . To say t h a t an e m p i r i c a l s t a t e m e n t i s c o r r i g i b l e i s t o say t h a t v e r d i c t s a r e open t o r e a s s e s s m e n t i n the l i g h t o f f u r t h e r e x p e r i e n c e . The t h e s i s w i l l n o t examine the g e n e r a l q u e s t i o n o f whether o r n o t t h e r e can be grounds f o r deeming some s e n t e n c e s t o e x p r e s s genuine e m p i r i c a l , n o n - n e c e s s a r y s t a t e m e n t s , w h i l e d e n y i n g t h a t t h e s e statements are c o r r i g i b l e . I now d e f i n e "an o b j e c t i v e e m p i r i c a l statement" as one which i s c o r r i g i b l e , and I s h o u l d s t a t e i m m e d i a t e l y t h a t the d e t a i l e d i n t e r p r e t a t i o n I s h a l l g i v e t o " c o r r i g i b l e " i s n o t one I a t t r i b u t e t o B r a d l e y . In o u t l i n e the more d e t a i l e d i n t e r p r e - t a t i o n i s as f o l l o w s . For a v e r d i c t , V, about the t r u t h - v a l u e o f an e m p i r i c a l s t a t e m e n t t o be open t o r e a s s e s s m e n t i n the l i g h t o f f u r t h e r e x p e r i e n c e , i t must be " p o s s i b l e " t o t e s t f o r i t s b e i n g i n f a c t an i n c o r r e c t v e r d i c t (and i f i t i s , t o c o r r e c t i t ) . I s h a l l i n t e r p r e t t h i s to mean t h a t : i t must be c o n c e i v a b l e f o r a human b e i n g , u s i n g "genuine t e s t - p r o c e d u r e s " , t o t e s t f o r not-V s o u n d l y , where the f o l l o w i n g b a s i c soundness c o n d i t i o n s a r e r e q u i r e d : 1) the t e s t - p r o c e d u r e s a r e f o l l o w e d f a u l t l e s s l y 2) by someone h a v i n g t h e minimum p e r c e p t u a l a b i l i t y f o r the p r o c e d u r e s t o be r e l i a b l e i n the environment i n q u e s t i o n . Once t h i s i n t e r p r e t a t i o n i s u n d e r s t o o d , i t w i l l be c l e a r t h a t i f i t i s con- c e i v a b l e f o r a human t o t e s t f o r not-V s o u n d l y , i t i s c o n c e i v a b l e t o t e s t f o r V s o u n d l y . That i s t o say an e m p i r i c a l s t a t e m e n t i s c o r r i g i b l e i f and o n l y i f i t i s c o n c e i v a b l e f o r a human t o t e s t t h e statement s o u n d l y . The r e s t o f the s e c t i o n i s g i v e n t o e x p l a i n i n g more f u l l y t h e terms o f t h e i n t e r p r e t a t i o n o f " c o r r i g i b i l i t y " j u s t o u t l i n e d . F i r s t , l e t my e x p l a i n b r i e f l y what t e s t - p r o c e d u r e s a r e . I mentioned i n S e c t i o n 5 Lewis's c l a i m t h a t v e r i f i c a t i o n o f a statement makes use o f " c o n d i - t i o n a l p r e d i c t i o n s " . These a r e p r e d i c t i o n s o f t h e form: " I f I a c t i n c e r - t a i n ways, s p e c i f i a b l e e x p e r i e n c e w i l l e v e n t u a t e . " T h i s I t h i n k i s a u s e f u l way o f l o o k i n g a t the n o t i o n o f t e s t i n g a s t a t e m e n t , but t h e r e i s one p o i n t t o be made e x p l i c i t . F o r some t e s t s o f some stat e m e n t s what t h e t e s t e r i s r e q u i r e d t o do b e f o r e he can see i f t h e " s p e c i f i a b l e e x p e r i e n c e w i l l e v e n t u - a t e " i n v o l v e s a l o t o f b o d i l y movement. He may be r e q u i r e d t o run a c o m p l i - c a t e d e x p e r i m e n t u s i n g t e s t - t u b e s , bunsen b u r n e r , a c i d s , e t c . . On t h e o t h e r hand some t e s t s f o r some statements i n v o l v e v e r y l i t t l e b o d i l y movement, e.g., t h e y may r e q u i r e a t e s t e r t o go t o a c e r t a i n p l a c e and then s i m p l y t o watch f o r something, l i k e w a t c h i n g f o r a shadow t o c o v e r t h e sun i n a n e c l i p s e . And f u r t h e r , some t e s t s f o r some statements may i n v o l v e no b o d i l y movement a t a l l . T h i s i s e s p e c i a l l y l i k e l y t o be the case f o r some s t a t e - ments about a per s o n ' s s e n s e - d a t a a l o n e . N o n e t h e l e s s we can w i t h o u t s t r a i n s t i l l speak o f t e s t i n g t h e s e s t a t e m e n t s v i a " c o n d i t i o n a l p r e d i c t i o n s " s i n c e the p e r s o n concerned may s t i l l be r e q u i r e d t o w a i t and t o pay a t t e n t i o n t o s e n s e - d a t a o f such-and-such a k i n d . And " p a y i n g a t t e n t i o n t o " a t any r a t e , i s an a c t i v i t y - c o n c e p t . L o o k i n g a t the form o f a c o n d i t i o n a l p r e d i c t i o n , I s h a l l a l l o w the f i r s t p a r t o f i t , v i z , " I f I a c t i n c e r t a i n ways", t o c o v e r such t h i n g s as " I f I pay a t t e n t i o n t o my v i s u a l s e n s e - d a t a " . With Lewis's c o n d i t i o n a l p r e d i c t i o n s i n mind, I am u s i n g " t e s t - p r o c e d u r e s " t o mean "the i n s t r u c t i o n s s t a t i n g what one must do_ i n o r d e r t o see i f the a p p r o p r i a t e ' s p e c i f i a b l e e x p e r i e n c e ' w i l l e v e n t u a t e ' " . A s e t o f i n s t r u c t i o n s c o n s t i t u t e genuine t e s t - p r o c e d u r e s f o r a c e r t a i n s t a t e m e n t when what a t e s t e r i s r e q u i r e d t o do i s i n f a c t r e l e v a n t to f i n d i n g the t r u t h - v a l u e o f t h a t s t a t e m e n t . As a r a t h e r crude example, suppose t h a t two p e o p l e , A and B, have w i d e l y d i f f e r - i n g a c c o u n t s o f an i n c i d e n t t h e y both w i t n e s s e d , and t h a t each person accuses t h e o t h e r o f l y i n g . The p r o c e d u r e s "Have A and B f i g h t i n s i n g l e combat and see who i s t h e v i c t o r " a r e not r e l e v a n t t o the t r u t h - v a l u e o f t h e statement "Person A, n o t B, i s l y i n g i n h i s account o f t h e i n c i d e n t . " T h i s use o f "genuine t e s t - p r o c e d u r e s " does n o t r e l y on the n o t i o n o f t h e p r o p e r o r h e a l t h y f u n c t i o n i n g o f the human s e n s o r y a p p a r a t u s . The r e q u i r e m e n t t h a t the p r o c e - dures be genuine does n o t p r e c l u d e t h e r e b e i n g some t e s t which o n l y an un- h e a l t h y o r m a l f u n c t i o n i n g p e r c e i v e r can use r e l i a b l y t o t e s t f o r the t r u t h o f some st a t e m e n t . I have c l a i m e d t h a t f o r an e m p i r i c a l statement t o be c o r r i g i b l e i t must be c o n c e i v a b l e f o r a human b e i n g t o t e s t t h a t s t a t e m e n t s o u n d l y . Throughout t h e t h e s i s t he term " c o n c e i v a b l e " w i l l have the s p e c i a l meaning I g i v e i t i n t h i s s e c t i o n . To u n d e r s t a n d t h i s meaning I need t o i n t r o d u c e the phrase " g i v - en f a c t " . I am t a k i n g as g i v e n such f a c t s as t h a t t h i s o r t h a t p a r t i c u l a r c a u s a l law h o l d s , and the f a c t t h a t t h e r e i s no_ c a u s a l c o n n e c t i o n between an ev e n t o f such-and-such a k i n d and an event o f some o t h e r k i n d . A g r e a t deal more c a u t i o u s l y I am t a k i n g as g i v e n t he f a c t t h a t t h e r e i s a l e s s than u n i - v e r s a l c o r r e l a t i o n a l law h o l d i n g between some p a r t i c u l a r p a i r o f v a r i a b l e s , and t h e f a c t t h a t t h e r e i s no such c o r r e l a t i o n h o l d i n g between some o t h e r p a i r o f v a r i a b l e s . In t h e s e l a s t examples I have i n mind t h e s o r t o f c o r r e l a t i o n a l laws o f t e n used i n e x p e r i m e n t a l p s y c h o l o g y where t e s t e r s f r e q u e n t l y seek c o r - r e l a t i o n s which a r e s i g n i f i c a n t a t the 5% l e v e l , i . e . , g i v e n t h a t t h e sample o f t h i n g s / p e o p l e t e s t e d i s a random one, the n t h e r e i s a t most a one i n twenty chance o f t h e c o r r e l a t i o n ' s b e i n g a c c i d e n t a l . More c a u t i o n i s needed i n t a k - i n g t h e s e c o r r e l a t i o n a l laws as g i v e n s i m p l y because some p r o b a b i l i t y o f the c o r r e l a t i o n s ' b e i n g mere c o i n c i d e n c e s r e m a i n s , even i f t h a t p r o b a b i l i t y i s one i n twenty, o r l e s s . We may a c c e p t t h e s e c o r r e l a t i o n s l e s s t e n t a t i v e l y as g i v e n i f we can r e l a t e them t o some w e l l e s t a b l i s h e d t h e o r y . For the r e s t o f t h e t h e s i s when I c l a i m t h a t something i s " c o n c e i v a b l e " , what i s meant i s " c o n c e i v a b l e w i t h o u t r e j e c t i n g any g i v e n f a c t " . I s h a l l r e s e r v e t he phrase " l o g i c a l l y p o s s i b l e " and i t s v a r i a t i o n s f o r p o s s i b i l i t y not q u a l i f i e d i n t h i s way, i . e . , f o r p o s s i b i l i t y w i t h o u t r e g a r d t o any g i v e n f a c t . For i t t o be c o n c e i v a b l e f o r a human t o use s o u n d l y some genuine t e s t - p r o c e d u r e s f o r some st a t e m e n t , t he t e s t - p r o c e d u r e s must be w i t h i n a human's c a p a c i t y t o do and i t must be c o n c e i v a b l e f o r a human t o have the p e r c e p t u a l a b i l i t y r e q u i r e d t o use t h o s e p r o c e d u r e s r e l i a b l y i n t h e s i t u a t i o n i n ques- t i o n . What the f i r s t o f t h e s e two r e q u i r e m e n t s means i s t h a t i t must be con- c e i v a b l e w i t h o u t r e j e c t i n g any g i v e n f a c t f o r a human t o f o l l o w t he t e s t - i n s t r u c t i o n s c o r r e c t l y . For example, c o n s i d e r t he " p o s s i b i l i t y " o f " f i s s i o n " o f a person's b r a i n , where each new b r a i n r e s u l t i n g from t he f i s s i o n i s com- p l e t e i n i t s p a r t s , i . e . , each new b r a i n i s a complete b r a i n a l t h o u g h perhaps s m a l l e r than t h e o r i g i n a l one b r a i n . I f b i n a r y f i s s i o n o f a person's b r a i n i s p r o h i b i t e d by some g i v e n f a c t , then a statement t h a t can be t e s t e d o n l y by ha v i n g some person undergo such a f i s s i o n i s not c o r r i g i b l e ; t h e t e s t - i n - ; s t r u c t i o n s c o u l d n o t c o n c e i v a b l y be f o l l o w e d c o r r e c t l y . I do not have enough p h y s i o l o g i c a l knowledge t o be s u r e t h a t t h i s example i s c o r r e c t , b ut i n any case i t w i l l s e r v e t o i l l u s t r a t e t h e p o i n t . I have s a i d t h a t t h e r e can be genuine t e s t - p r o c e d u r e s f o r some statement where o n l y someone who i s u n h e a l t h y can use the t e s t r e l i a b l y . There may even be some genuine t e s t f o r a s t a t e - ment where you need t o be u n h e a l t h y not o n l y t o use the t e s t r e l i a b l y , but even i n o r d e r t o f o l l o w the t e s t - i n s t r u c t i o n s c o r r e c t l y . In e i t h e r o f t h e s e two s i t u a t i o n s the q u a l i f i c a t i o n I have g i v e n t he term " c o n c e i v a b l e " l i m i t s my i n t e r e s t t o i l l n e s s e s (and m a l f u n c t i o n s ) which a r e not p r o h i b i t e d by any g i v e n f a c t , i . e . , t o thos e which c o u l d o c c u r . So f o r an e m p i r i c a l s t a t e m e n t t o be c o r r i g i b l e I r e q u i r e t h a t t h e r e be a s e t o f (genuine) t e s t - p r o c e d u r e s which i t i s c o n c e i v a b l e f o r a human t o f o l l o w c o r r e c t l y and where i t i s con- c e i v a b l e f o r a human t o have t h e p e r c e p t u a l a b i l i t y to use t h o s e p r o c e d u r e s 2S r e l i a b l y i n the s i t u a t i o n i n q u e s t i o n . Whether i t i s c o n c e i v a b l e o r o n l y l o g i c a l l y p o s s i b l e f o r e v i d e n c e f o r the sta t e m e n t and f o r e v i d e n c e a g a i n s t t h e statement t o r e s u l t i s unimportant f o r my concept o f c o r r i g i b i l i t y . T h i s l a s t p o i n t has one v e r y u s e f u l consequence i n d e a l i n g w i t h t he c o r r i g i b i l i t y o f t r u e c a u s a l laws, and I t h i n k i t i s worth e x p l a i n i n g . P h i l o s o p h e r s sometimes speak o f an e m p i r i c a l s t a t e m e n t ' s b e i n g c o r r i - g i b l e i f e v i d e n c e f o r i t s b e i n g t r u e and e v i d e n c e f o r i t s b e i n g f a l s e a re b o t h , i n some s e n s e , " p o s s i b l e " . Immediately, we may see t h a t i n t e r p r e t i n g t h i s t o mean " i n some way e m p i r i c a l l y p o s s i b l e " p r e s e n t s problems. T h e r e a r e some v a r i a t i o n s i n d e f i n i t i o n s o f " e m p i r i c a l l y p o s s i b l e " but t o say t h a t something i s e m p i r i c a l l y p o s s i b l e means a t l e a s t t h a t i t i s not p r o h i b i t e d by some t r u e and u n i v e r s a l c a u s a l law. We have good r e a s o n t o b e l i e v e t h a t the law o f g r a v i t y i s such a law, v i z , "The f o r c e o f g r a v i t a t i o n f o r any two s u f f i c i e n t l y m a ssive b o d i e s i s d i r e c t l y p r o p o r t i o n a l t o the pr o d u c t o f t h e i r masses and i n - v e r s e l y p r o p o r t i o n a l t o the square o f the d i s t a n c e between them." (One can say what the mass i s below which a p a r t i c l e i s n o t " s u f f i c i e n t l y m a s s i v e " i n the sense o f the law.) I f t h i s i s so, then i t i s not e m p i r i c a l l y p o s s i b l e , under any i n t e r p r e t a t i o n o f t h a t p h r a s e , f o r the f o r c e o f g r a v i t y f o r a p a i r o f s u f f i c i e n t l y massive b o d i e s t o be o t h e r than what c o u l d be c a l c u l a t e d u s i n g t h i s law. In e f f e c t d e f i n i n g " c o r r i g i b i l i t y o f e m p i r i c a l s t a t e m e n t s " i n terms o f e m p i r i c a l l y p o s s i b l e and c o r r e c t l y p e r c e i v e d e v i d e n c e both f o r and a g a i n s t the s t a t e m e n t s , has t h e r e s u l t t h a t t r u e and u n i v e r s a l c a u s a l laws are i n c o r - r i g i b l e . The most f r e q u e n t s o l u t i o n to t h i s i s t o say t h a t an e m p i r i c a l s t a t e m e n t i s c o r r i g i b l e i f e v i d e n c e f o r and e v i d e n c e a g a i n s t i t are both l o g i - c a l l y p o s s i b l e . For my purposes t h i s i s i n a d e q u a t e . In i t s e l f i t does n o t ensure t h a t humans c o u l d t e s t t he statements i n the sense t h a t i t i s w i t h i n the c a p a c i t y o f humans t o t e s t them. T h i s I have s e c u r e d by s a y i n g t h a t i n o r d e r t o be c o r r i g i b l e i t must be c o n c e i v a b l e f o r a human t o t e s t t h e s t a t e - ment s o u n d l y . A f t e r a l l , my p r i m a r y i n t e r e s t i s w i t h the p o t e n t i a l e p i s t e m o l o g i c a l soundness o f t r u t h / f a l s i t y v e r d i c t s about c e r t a i n e m p i r i c a l s t a t e m e n t s , and i n p a r t i c u l a r I p l a c e r e s t r i c t i o n s on what i s t o count as the p o t e n t i a l t o t e s t an e m p i r i c a l statement. On my d e f i n i t i o n o f " c o r r i - g i b i l i t y o f e m p i r i c a l s t a t e m e n t s " t h e r e i s no problem i n the case o f t r u e and u n i v e r s a l c a u s a l laws. They a r e c o r r i g i b l e s i n c e i t i s c o n c e i v a b l e f o r humans t o t e s t them s o u n d l y , and t h a t i s a l l t h a t i s r e q u i r e d . L o o k i n g a t the whole d e f i n i t i o n o f " c o r r i g i b l e ( e m p i r i c a l ) statement" i t i s worth p o i n t i n g out t h a t some c o n t i n g e n t f a c t s a r e not r e l e v a n t t o c o r - r i g i b i l i t y . C o n s i d e r t h e s tatement "The f r o n t o f the o b j e c t i s c i r c u l a r " where the o b j e c t r e f e r r e d t o i s s e v e r a l f e e t h i g h , i n good l i g h t i n g , approach- a b l e t o w i t h i n s i x f e e t o r s o , n o t c o v e r e d by a n y t h i n g , e t c . . Suppose now t h a t the o b j e c t soon m e l t s and t h a t t h e o n l y person near enough b e f o r e i t m e l t s i s b l i n d . Then i t may be " i n f a c t i m p o s s i b l e " f o r anyone t o t e s t t h e s t a t e m e n t , s i n c e o n l y the b l i n d person was near enough. However, t h i s does not mean the statement i s i n c o r r i g i b l e as I am u s i n g the term. I t i s con- c e i v a b l e f o r a human b e i n g t o t e s t the s t a t e m e n t s o u n d l y , and no more i s needed. I t may be o b j e c t e d t h a t t h i s i n t e r p r e t a t i o n o f " c o r r i g i b i l i t y " l e a d s t o an i n f i n i t e r e g r e s s o f t e s t s . I f s o u n d l y t e s t i n g an e m p i r i c a l s tatement r e - q u i r e s the two b a s i c soundness c o n d i t i o n s t o h o l d , then does not t e s t i n g the s t a t e m e n t i n v o l v e a l s o e s t a b l i s h i n g t h a t the two c o n d i t i o n s do h o l d ? But i f i t does, then e s t a b l i s h i n g each o f the c o n d i t i o n s w i l l i t s e l f i n v o l v e a f u r t h e r s e t o f soundness c o n d i t i o n s , and t h e s e r e q u i r e m e n t s i n t u r n w i l l have t o be e s t a b l i s h e d . And so on. In r e p l y t o t h i s , I s h o u l d p o i n t o u t t h a t u s u a l l y i f we t e s t a s t a t e - ment and r e a c h a v e r d i c t which i s f u r t h e r c o n f i r m e d , we do not q u e s t i o n t h a t the b a s i c soundness c o n d i t i o n s h o l d . I t i s when we r e a c h c o n f l i c t i n g v e r - d i c t s about a statement t h a t we query t h e soundness o f both v e r d i c t s . Even here we a r e not i n v o l v e d i n an i n f i n i t e r e g r e s s o f t e s t s i f we can s o l v e t h e 31 dispute by testing for the soundness conditions non-circularly. Suppose two people are testing the statement "The front of the object is circular" by looking through the fog at i t from a f a i r distance away. Their verdicts con- f l i c t . Given that looking at the object is a genuine test, then the two soundness conditions hold for both verdicts i f : 1) neither makes a mistake in his following of the test-instructions and, 2) both have the minimum per- ceptual a b i l i t y required for the test to be reliable in the circumstances in question. The second requirement, for example, can be tested by using test- procedures which do not themselves involve the same requirement. This con- stitutes a non-circular testing of requirement (2) provided that defects in the kind of visual perception in question are not systematically correlated with defects in the different kind of perception they now propose to use. If one of the two people is suspected of having an illness which interferes with both visual and tactual perception, then both people cannot test non-circul- arly the hypothesis about defective visual perception i f reliable tactual per- ception is required to do i t . In such a case we may say that the two kinds of perception are not independent in the sense required for non-circular testing of a suspected low perceptual a b i l i t y . In our example, suppose both people approach the object and touch i t , and feel sharp protuberances on what should be the smooth circumference of a c i r c l e . Both then agree that the original statement about the shape of the object is false. The earlier conflict of verdicts may then be resolved by concluding that one of the two people did not have the perceptual a b i l i t y to test the statement reliably using the visual- perception test in those circumstances. This is to say, they may conclude that the second soundness requirement does not hold for one person. It would constitute non-circular testing of the requirement since only tactual per- ception is used to do i t , and the requirement is to do with some kind of vis- ual perception. Thus the poor visual perceiver himself can take part in this test to show that he has poor visual perception relative to the visual- 32 p e r c e p t i o n t e s t mentioned. The most i n t e r e s t i n g c a s e s where the second soundness r e q u i r e m e n t does not h o l d a r e where one o r more t e s t e r s can f o l l o w the t e s t - i n s t r u c t i o n s and y e t do n o t have the r e q u i r e d minimum p e r c e p t u a l a b i l i t y . Cases where the second r e q u i r e m e n t does not h o l d because the ' t e s t e r ' cannot even f o l l o w the i n s t r u c t i o n s p r e s e n t no s p e c i a l d i f f i c u l t i e s . For example, a b l i n d man can- not meet the second r e q u i r e m e n t f o r a t e s t r e l y i n g on v i s u a l p e r c e p t i o n , but t h i s i s v e r y e a s i l y s p o t t e d . My f o c u s w i l l be on t h e l e s s s t r a i g h t f o r w a r d c a s e s . To r e t u r n t o o u r example, the t a c t u a l t e s t t o show t h a t the second soundness r e q u i r e m e n t does n o t h o l d f o r one person w i l l i t s e l f i n v o l v e some r e q u i r e m e n t o f the same form, but we a r e not i n v o l v e d i n a v i c i o u s r e g r e s s o f such t e s t s . I f t h e o r i g i n a l d i s p u t e can be r e s o l v e d i n t h i s way then the t e s t i n g s t o p s h e r e . T h e r e i s always some f i n a l r e q u i r e m e n t which remains a s - sumed r a t h e r than t e s t e d , but t h i s i s not t o deny t h a t the f i n a l r e q u i r e m e n t i s c l e a r l y n o n - n e c e s s a r y . Indeed, t h e r e may be c i r c u m s t a n c e s where i t would be absurd t o t e s t f o r t h i s r e q u i r e m e n t , a l t h o u g h a t some l a t e r time i n the l i g h t o f f r e s h e v i d e n c e i t may become absurd not t o . I f someone reaches a v e r d i c t u s i n g a genuine t e s t and the two b a s i c soundness c o n d i t i o n s h o l d , t h i s o f c o u r s e does not l o g i c a l l y e n t a i l t h a t the v e r d i c t i s c o r r e c t , nor even t h a t t h i s i s the soundest v e r d i c t we can r e a c h . However, I am s u g g e s t i n g t h a t t h i s i s the l e a s t we r e q u i r e f o r a v e r d i c t t o have some e p i s t e m o l o g i c a l worth. That i s t o s a y , showing t h a t one o r both o f t h e c o n d i t i o n s do n o t h o l d i s enough t o r e j e c t the v e r d i c t as unsound, whereas the f a c t t h a t o t h e r p o s s i b l e soundness c o n d i t i o n s do not h o l d does n o t w a r r a n t an o u t r i g h t r e j e c t i o n . For example, we n a t u r a l l y assume t h a t a v e r d i c t r e a c h e d u s i n g the most r e l i a b l e t e s t a v a i l a b l e i s c o n s e q u e n t l y sounder than one reached u s i n g some o t h e r t e s t . A l s o , we t e n d t o assume t h a t a v e r - d i c t which c o n c u r s w i t h the r e s u l t s o f o t h e r "independent" t e s t s i s sounder than a v e r d i c t t h a t c o n f l i c t s w i t h them. ( U s u a l l y we assume t h a t d i f f e r e n t t e s t s performed by some one p e r s o n , and the same t e s t performed by d i f f e r e n t p e o p l e , c o n s t i t u t e independent t e s t s . ) Such f e a t u r e s c e r t a i n l y may 'weight' t h e d e c i s i o n between c o n f l i c t i n g v e r d i c t s , s i n c e t h e y a r e c l e a r l y d e s i r a b l e f e a t u r e s . 34 7. I n t e r - S u b j e c t i v i t y and N o r m a l i t y - R e q u i r e m e n t s I now wish to examine s p e c i f i c a l l y the c o r r i g i b i l i t y o f i n t e r - s u b j e c t i v e s t a t e m e n t s . There i s i n t e r - s u b j e c t i v i t y , i n the sense I want t o c a p t u r e , i f the judgement o f one p e r s o n , made as a r e s u l t o f f o l l o w i n g t h e p r o c e d u r e s f o r t e s t i n g the t r u t h / f a l s i t y o f the s t a t e m e n t , P, i s r e l e v a n t t o the judgement which a n o t h e r person makes about P as a r e s u l t o f f o l l o w i n g the t e s t - p r o c e - d u r e s . Where t h i s relevance o b t a i n s , the s tatement i s i n t e r - s u b j e c t i v e l y c o r r i g i b l e . In my g e n e r a l d e f i n i t i o n o f " c o r r i g i b i l i t y " I have not r e q u i r e d i n t e r - s u b j e c t i v i t y ; I am n o t t a k i n g f o r g r a n t e d t h a t t h e r e a r e no s t a t e m e n t s open t o s e l f - c o r r e c t i o n , o r , t h a t t h e r e a r e no s tatements which a r e open t o s e l f - c o r r e c t i o n and t o no o t h e r c o r r e c t i o n . So, I s h a l l say t h a t an e m p i r i - c a l s tatement i s i n t e r - s u b j e c t i v e l y c o r r i g i b l e i f and o n l y i f : I t i s c o n c e i v a b l e f o r a human b e i n g t o t e s t i t s o u n d l y , where the t e s t can be a d e q u a t e l y d e s c r i b e d w i t h o u t d e s i g n a t i n g any p a r t i c u l a r i n d i v i d u a l as t h e t e s t e r . So f o r a s tatement t o be i n t e r - s u b j e c t i v e , the t e s t f o r i t must not r e q u i r e , e i t h e r l o g i c a l l y o r c a u s a l l y , some p a r t i c u l a r i n d i v i d u a l t o be the t e s t e r . 1 For a s e t o f p r o c e d u r e s t o be commonly a c c e p t e d as a t e s t f o r some s t a t e - ment, t h e y must be s u c c e s s f u l l y employable by most peo p l e a t l e a s t t o some minimum e x t e n t , a l t h o u g h f o r some s t a t e m e n t s * t h e r e may be s e v e r a l t e s t s which a r e o f unequal s t a n d i n g . For example, i n the n o r t h e r n hemisphere one can t e s t the s t a t e m e n t "I am f a c i n g n o r t h " by making use o f t h e f a c t t h a t moss grows on the n o r t h e r n s i d e s o f t r e e s . But moss can be c o n f u s e d w i t h l i c h e n , and the n o r t h e r n s i d e o f a t r e e may be q u i t e wide; and so t h i s t e s t i s both v u l n e r a b l e 1 T h i s f e a t u r e was not g u a r a n t e e d , i n t h e case o f Goodman's q u a l i a - s t a t e m e n t s , where i t was c l a i m e d t h a t a p a r t i c u l a r q u a l i a - s t a t e m e n t i s r e a s s e s s a b l e i n the l i g h t o f some g e n e r a l s t a t e m e n t ' b u i l t up' l a t e r . I t remains p o s s i b l e t h a t l o g i c a l l y o n l y one p e r s o n can s u p p o r t such a g e n e r a l s t a t e m e n t ( i f q u a l i a a r e r a d i c a l l y n o n - p u b l i c e n t i t i e s ) , i n which case i t would not be an i n s t a n c e o f i n t e r - s u b j e c t i v e c o r r i g i b i 1 i t y . and i m p r e c i s e . I t would be b e t t e r t o use a compass i f one i s a v a i l a b l e . However, i n both c a s e s t h e I n t e r ^ S u b j e c t i v i t y c o n d i t i o n g i v e n a b o v e — I - S c o n d i t i o n , f o r s h o r t - - h o l d s . Both are i n t e r - s u b j e c t i v e l y c o r r i g i b l e i n the r e q u i r e d sense and t h e r e f o r e a f o r t i o r i both s t a t e m e n t s a r e o b j e c t i v e . Sometimes a t e s t i s d e s c r i b e d i n a way which i n v o l v e s t h e n o t i o n o f b e t t e r o r worse i m p l e m e n t a t i o n o f i t . For example, the statement "Bob h i t the b u l l ' s - e y e w i t h h i s l a s t s h o t " may be v e r i f i e d by the t e s t "Move as c l o s e 2 as p o s s i b l e t o the optimum d i s t a n c e from the t a r g e t and l o o k a t i t . " T h i s t e s t i s b e t t e r implemented by g o i n g to w i t h i n t e n f e e t o f the t a r g e t and l o o k - i n g than by g o i n g to f i f t y f e e t and l o o k i n g . For s i m p l i c i t y , I s h a l l speak o f t e s t X b e i n g more adequate than t e s t Y both i n the case o f X's b e i n g s t r a i g h t f o r w a r d l y d i f f e r e n t and b e t t e r than Y, and i n the case o f X and Y's b e i n g d i f f e r e n t i m p l e m e n t a t i o n s o f some f o r m u l a t a b l e , common pro c e d u r e where X i s a b e t t e r i m p l e m e n t a t i o n than Y. When we a r e d i s c u s s i n g a sound v e r d i c t r eached a f t e r u s i n g some v e r y common t e s t , the second soundness r e q u i r e m e n t , but not the f i r s t , v e r y o f t e n ta k e s a s p e c i a l form. I n s t e a d o f s i m p l y "The t e s t e r must have the minimum p e r c e p t u a l a b i l i t y f o r t h e t e s t t o be r e l i a b l e i n the environment i n q u e s t i o n " (which i s the g e n e r a l form o f the second soundness c o n d i t i o n ) , we have the s p e c i a l form, "The t e s t e r must have ( a t l e a s t ) normal p e r c e p t u a l a b i l i t y o f the k i n d r e q u i r e d . " That t h i s i_s o n l y a s p e c i a l form o f t h e second c o n d i t i o n t e n d s t o be o v e r l o o k e d , s i n c e many w r i t e r s r e f e r o n l y t o t h i s v e r s i o n . As an example, l e t P be the statement "The two vases are d i f f e r e n t shapes", and l e t us assume t h a t the I-S c o n d i t i o n h o l d s , i . e . , t h a t the t e s t - p r o c e d u r e s do not e s s e n t i a l l y i n v o l v e any p a r t i c u l a r i n d i v i d u a l . I f the commonly used t e s t i n - v o l v e s l o o k i n g a t the shape o f the two o b j e c t s , then we r e q u i r e than an 2 There w i l l be some minimum d i s t a n c e , v a r y i n g w i t h the s i z e o f the b u l l e t o r c a n n o n b a l l used, a t which t e s t e r s s h o u l d s t a n d i f t h e i r v i e w i n g i s t o be the most e f f e c t i v e p o s s i b l e . a c c e p t a b l e t e s t e r f o l l o w t h e t e s t - i n s t r u c t i o n s c o r r e c t l y and have ( a t l e a s t ) normal v i s u a l p e r c e p t i o n o f shape. I f two t e s t e r s d i s a g r e e about the s t a t e - ment, P, we may be a b l e t o r e s o l v e the d i s p u t e by f i n d i n g t h a t one o f them has made a m i s t a k e i n h i s f o l l o w i n g o f the t e s t - i n s t r u c t i o n , f o r example, perhaps he has viewed the wrong p a i r o f o b j e c t s . But i f we cannot f i n d such an e r r o r , and i f the t e s t i t s e l f i s g e n e r a l l y adequate, then we must c o n s i d e r i f we are m i s t a k e n i n assuming what we do about the t e s t e r s . The o b v i o u s a s - sumption t o query i n t h i s case i s t h a t t h e y both have ( a t l e a s t ) normal v i s u a l p e r c e p t i o n o f shape. Q u i t e o f t e n , once f o r m u l a t e d the two soundness c o n d i t i o n s can be n o n - c i r c u l a r l y t e s t e d , and t h i s h o l d s t r u e f o r t h i s s p e c i a l form o f the second o f t h e s e c o n d i t i o n s , v i z , where ( a t l e a s t ) normal p e r c e p t u a l a b i l i t y i s r e q u i r e d . S i n c e t h i s s p e c i a l form o f the second c o n d i t i o n i s used so o f t e n (namely, i n c a s e s where the t e s t i s commonly a c c e p t e d as r e l i a b l e ) , I now wish to examine i t q u i t e c l o s e l y . Suppose t h a t a r e q u i r e m e n t o f t h i s k i n d - - t h a t the t e s t e r s have a t l e a s t normal p e r c e p t u a l a b i l i t y — d o e s n o t h o l d . Then i t i s t r u e t o s a y , r e l a t i v e t o some commonly a c c e p t e d t e s t , something o f t h e form: "At l e a s t one t e s t e r i s an a b n o r m a l l y poor ^ - p e r c e i v e r . " T h i s c o n c e p t o f n o r m a l i t y w i l l r e s t u l t i - m a t e l y on the c o n c e p t o f one p e r s o n ' s b e i n g b e t t e r than a n o t h e r a t ^ - p e r c e p - t i o n , and t h i s p r i m a r y c o n c e p t w i l l be c o n s t r u e d t h r o u g h o u t as one person's b e i n g more r e l i a b l e , more l i k e l y t o have h i s v e r d i c t f u r t h e r c o n f i r m e d , than someone e l s e . F i r s t I want to l o o k a t t h i s b a s i c i.ssue--the ways i n which one person may show h i m s e l f t o be a p o o r e r 0 - p e r c e i v e r than a n o t h e r , o r a p o o r e r 0 - p e r c e i v e r than most p e o p l e . Sometimes a person can o b v i o u s l y make f i n e r d i s c r i m i n a t i o n s o f some kind than can someone e l s e . I am p a r t i c u l a r l y i n t e r e s t e d i n c a s e s where t h i s can be n o n - c i r c u l a r l y t e s t e d . Suppose we s u s p e c t t h a t a p e r s o n , A, cannot make as f i n e v i s u a l s h a p e - d i s c r i m i n a t i o n s as can someone e l s e , B. We can prove t h i s t o the s a t i s f a c t i o n o f both A and B p r o v i d i n g we can use some f e a t u r e o t h e r than shape t o show t h a t B can c o n s i s t e n t l y d i s c r i m i n a t e o b j e c t s which A cannot 37 where the o n l y p l a u s i b l e e x p l a n a t i o n i s t h a t B i s d i s c r i m i n a t i n g by v i s u a l shape. For example, suppose t h a t B can lo o k a t randomly p r e s e n t e d p a i r s o f o b j e c t s which a r e v e r y s l i g h t l y d i f f e r e n t i n shape ( e . g . , v a r i o u s s o l i d b l o c k s ) but which a r e the same c o l o u r , same ' v i s i b l e ' t e x t u r e , from h i s view- p o i n t . (They may w e l l d i f f e r v e r y s l i g h t l y i n s i z e , because o f the s l i g h t d i f f e r e n c e i n shape.) And suppose t h a t B can c o n s i s t e n t l y d i s c r i m i n a t e be- tween some p a i r s which A f i n d s v i s u a l l y i n d i s t i n g u i s h a b l e . Both the t e s t e r s may agree t h a t A has t h e p o o r e r v i s u a l s h a p e - d i s c r i m i n a t i o n p r o v i d i n g t he ob- j e c t s can be i d e n t i f i e d by both i n some o t h e r way, f o r example, i f each o b j e c t has a d i f f e r e n t embossed number on i t , h i d d e n from the v i e w p o i n t , which can be t a c t u a l l y p e r c e i v e d . As a more c a u t i o u s f o r m u l a t i o n o f the d i f f e r i n g a b i l i - t i e s o f A and B we may say, f o r example, t h a t A has p o o r e r v i s u a l d i s c r i m i - n a t i o n o f ov a l shapes than does B, i f t h i s i s a l l we a r e a c t u a l l y t e s t i n g f o r . For t h i s d i s c r i m i n a t i o n t e s t we r e q u i r e t h a t both people have normal o r b e t t e r t a c t u a l p e r c e p t i o n o f shapes i f they a r e both t o d i s c o v e r t h a t A has the p o o r e r v i s u a l d i s c r i m i n a t i o n o f o v a l shapes ( i f t h a t i s what shape the o v o i d s p r e s e n t as t h e y a re s e t o u t ) . N o n e t h e l e s s the t e s t i n g o f "A has p o o r e r v i s u a l d i s c r i m i - n a t i o n o f ov a l shapes" i s n o n - c i r c u l a r . I f we can show one person t o be p o o r e r / b e t t e r than a n o t h e r a t some k i n d o f p e r c e p t u a l d i s c r i m i n a t i o n , we can a l s o show one person t o be p o o r e r / b e t t e r than most pe o p l e . Experiments s i m i l a r i n d e s i g n (but h o p e f u l l y l e s s p r i m i t i v e ) can thus be used t o t e s t f o r e x t r e m e l y d e f e c t i v e v i s u a l s h a p e - p e r c e p t i o n . In our example about the vases b e i n g d i f f e r e n t shapes, i f we can show t h a t t h e r e a r e many k i n d s o f shapes ( b e s i d e s o v a l s ) such t h a t A cannot d i s c r i m i n a t e be- tween o b j e c t s on the b a s i s o f ' v i s u a l ' shape a l t h o u g h most people ( i n c l u d i n g B) can d i s c r i m i n a t e t h o s e o b j e c t s , then our o r i g i n a l d i s p u t e about the v a s e s ' b e i n g d i f f e r e n t shapes can be r e s o l v e d . S i n c e the a b i l i t y to d i s c r i m i n a t e v i s u a l l y between shapes i s needed f o r t e s t i n g t he s t a t e m e n t , and s i n c e A i s p o o r e r a t t h i s than B, A s h o u l d d e f e r t o B. B's v e r d i c t i s f a r more l i k e l y t o be c o r r e c t than A's where t h e s e c o n f l i c t , a l t h o u g h i t always remains pos- s i b l e t h a t B 4 s v e r d i c t w i l l be r e j e c t e d l a t e r i n the l i g h t o f f r e s h e v i d e n c e . In p r a c t i c e , we may sometimes l e a v e such d i s p u t e s u n r e s o l v e d . I am s u g g e s t i n g t h a t i f some group o f peop l e can make f i n e r d i s c r i m i n a t i o n s than some o t h e r group, we may c o n c l u d e t h a t r f one group i s t o d e f e r f o r e p i s t e m o l o g i c a l l y r e l e v a n t r e a s o n s , then t h e l a t t e r s h o u l d d e f e r t o the former. Of c o u r s e , on o c c a s i o n t h i s may mean t h a t the m a j o r i t y s h o u l d d e f e r t o some m i n o r i t y who ar e f a r b e t t e r than normal a t t h a t k i n d o f d i s c r i m i n a t i o n . For a l l o f the f i v e s e n s e s , we may employ t h i s n o t i o n o f a person's making f i n e r / p o o r e r p e r c e p t u a l d i s c r i m i n a t i o n s than most p e o p l e . A person i s a b e t t e r j ^ - p e r c e i v e r than a n o t h e r i f he can use some o r a l l t e s t s r e q u i r i n g ^ - p e r c e p t i o n more s u c c e s s f u l l y than can the o t h e r p e r s o n i n c e r t a i n environments. (Remember t h a t I am not d e a l i n g here w i t h one p e r - son's b e i n g w o r s e / b e t t e r than a n o t h e r a t ^ - p e r c e p t i o n because o f how a c c u - r a t e l y he f o l l o w s the t e s t - i n s t r u c t i o n s f o r which ^ - p e r c e p t i o n happens t o be r e q u i r e d . T h i s f a l l s under t h e f i r s t soundness c o n d i t i o n , not the second.) Suppose t h e r e a r e two t e s t s , X and Y, f o r some st a t e m e n t , P, and t h a t X i s a b e t t e r t e s t than Y. One t e s t can be b e t t e r than a n o t h e r i n b e i n g more r e l i - a b l e and/or i n b e i n g c a p a b l e o f t e s t i n g s tatements o f g r e a t e r p r e c i s i o n . For s i m p l i c i t y , I s h a l l f o c u s o n l y on r e l i a b i l i t y . For example, the t e s t o f l o o k - i n g a t a compass i s more r e l i a b l e than t he t e s t o f l o o k i n g f o r moss on t r e e s I t i s p o s s i b l e on o c c a s i o n s t h a t the more d i s c r i m i n a t o r y s h o u l d d e f e r t o the l e s s d i s c r i m i n a t o r y f o r reasons which a r e not e p i s t e m o l o g i c a l l y r e l e v a n t . For example, suppose a small m i n o r i t y o f people can d i s c r i m i n a t e c o n s i s t e n t l y be- tween the t a s t e s o f two k i n d s o f f o o d a l t h o u g h t h e m a j o r i t y o f p e o p l e c a n n o t , such t h a t the m a j o r i t y ( l e f t t o themselves) c l a i m t he st a t e m e n t , "These two kinds o f food have no d i f f e r e n c e i n t a s t e " t o be t r u e . Now i f an agreement about the statement i s r e q u i r e d i n o r d e r t o d e c i d e whether o r not t o o f f e r one o f the k i n d s o f f o o d as an a l t e r n a t i v e f i r s t c o u rse t o the o t h e r i n a p u b l i c r e s t a u r a n t , then t h e f i n e r d i s c r i m i n a t i n g w i l l p r o b a b l y d e f e r t o the m a j o r i t y . T h i s i s not a c a s e o f the m i n o r i t y ' s coming t o agree w i t h the m a j o r i t y as t o the t r u t h o r f a l s i t y o f the statement. They d e f e r p r e c i s e l y because the major- i t y o f people a r e so much worse a t t a s t e - d i s c r i m i n a t i n g than they a r e . i f we are t r y i n g t o t e s t the s tatement "He i s f a c i n g a p p r o x i m a t e l y n o r t h " . U s i n g a compass i s a l s o c a p a b l e o f t e s t i n g statements o f g r e a t e r p r e c i s i o n than can the l o o k i n g - f o r - m o s s t e s t ( e . g . , "He i s f a c i n g i n a d i r e c t i o n w i t h i n one degree o f n o r t h " ) , but l e t us l e a v e t h i s a s i d e . To say t h a t t e s t X i s more r e l i a b l e than t e s t Y i s t o s a y : For the normal p e r c e i v e r , i f a v e r d i c t a r r i v e d a t a f t e r f a u l t l e s s l y f o l l o w i n g the i n s t r u c t i o n s f o r t e x t X c o n f l i c t s w i t h a v e r d i c t reached a f t e r f a u l t l e s s l y f o l l o w i n g the i n s t r u c t i o n s f o r t e s t Y, then the former v e r d i c t i s more l i k e l y t o be c o r r e c t , and so more l i k e l y t o r e c e i v e f u r t h e r c o n f i r m a t i o n than t h a t the l a t t e r i s . ( T h i s i s c o m p a t i b l e w i t h the two v e r d i c t s ' u s u a l l y c o n c u r r i n g . ) So A i s p o o r e r a t ^ - p e r c e p t i o n than B i f B has more s u c c e s s w i t h v e r - d i c t s reached a f t e r c o r r e c t l y f o l l o w i n g t e s t - i n s t r u c t i o n s r e q u i r i n g ^ - p e r - c e p t i o n than does A. Suppose t h a t f o r t h e p o o r e r t e s t , Y, ^ - p e r c e p t i o n i s r e q u i r e d , and t h a t f o r t h e b e t t e r t e s t , X, ^ - p e r c e p t i o n i s r e q u i r e d . I f they t e s t some sta t e m e n t u s i n g Y and r e a c h d i f f e r e n t v e r d i c t s , and i f l a t e r t h e y t e s t t h e same statement u s i n g the b e t t e r t e s t , X, and agree t h a t B's e a r l i e r v e r d i c t i s c o n f i r m e d , then they w i l l have shown t h a t B used t e s t Y more s u c c e s s f u l l y than d i d A, and t h a t t h e r e f o r e ( g i v e n t h a t t h e y both f o l l o w e d the t e s t - i n s t r u c t i o n s c o r r e c t l y ) i t i s v e r y l i k e l y t h a t B i s a b e t t e r fi - p e r c e i v e r than i s A. I have a l r e a d y r e f e r r e d t o a case o f t h i s k i n d , where two p e o p l e t e s t the s tatement "The f r o n t o f the o b j e c t i s c i r c u l a r " f i r s t by l o o k i n g a t i t and then by t o u c h i n g i t (above, pp.30-32 ). Suppose t h a t A and B a r e t e s t i n g t h a t statement by u s i n g f i r s t the t e s t , "Stand s i x t y f e e t from the o b j e c t i n good l i g h t i n g and l o o k a t ( t h e shape o f ) i t " 4 , where t h i s t e s t r e q u i r e s ^ - p e r c e p t i o n , which I s h a l l l e a v e u n i n t e r p r e t e d f o r t h e moment. Both A and B f o l l o w the t e s t - i n s t r u c t i o n s c o r r e c t l y , n e i t h e r l o o k s i n the wrong d i r e c t i o n nor a t the wrong o b j e c t , e t c . , but t h e i r v e r d i c t s 4 S i n c e a l i t t l e more d e t a i l may be h e l p f u l h e r e , assume t h a t t h e o b j e c t i s v e r y s m a l l , some f o u r i n c h e s h i g h , so t h a t the two t e s t s a r e on an unequal f o o t i n g . 4( c o n f l i c t . Suppose now t h e y r e - t e s t the s tatement u s i n g the much b e t t e r t e s t , "Run y o u r f i n g e r s around the edge o f the f r o n t f a c e o f the o b j e c t . " They both agree t h a t the s tatement i s f a l s e s i n c e t h e y can f e e l sharp p r o - t u b e r a n c e s on what s h o u l d be the smooth c i r c u m f e r e n c e o f the c i r c l e . T h i s b e t t e r t e s t i n v o l v e s o n l y a r e q u i r e m e n t about normal t a c t u a l p e r c e p t i o n , and so we know a t l e a s t t h a t t h e r e q u i r e m e n t about " ft - p e r c e p t i o n " i s something d i f f e r e n t , s i n c e the p o o r e r t e s t i n v o l v e s o n l y the v i s u a l sense. I f , t h e n , i t i s B's e a r l i e r v e r d i c t which r e c e i v e s f u r t h e r c o n f i r m a t i o n , the s t a t e m e n t "B i s b e t t e r than A a t ^ - p e r c e p t i o n " i s n o n - c i r c u l a r l y t e s t e d , and t h e s t a t e - ment i s shown to be t r u e t o t h e s a t i s f a c t i o n o f both A and B. How s h o u l d we i n t e r p r e t " <fi - p e r c e p t i o n " i n t h i s case? We c o u l d say t h a t B i s b e t t e r than A a t d i s t a n t , v i s u a l p e r c e p t i o n . But t h i s s u g g e s t s t h a t he i s b e t t e r than A a t , f o r example, c o l o u r - p e r c e p t i o n a t a d i s t a n c e , and p e r - haps a t some o t h e r k i n d s o f p e r c e p t i o n i n v o l v i n g v i s i o n . But t o assume, e.g., t h a t A i s a p o o r e r c o l o u r - p e r c e i v e r o f o b j e c t s a t a d i s t a n c e , s i m p l y on the b a s i s o f t h i s t e s t , i s t o presume too much. We may c l a i m t h a t B has b e t t e r v i s u a l , s h a p e - p e r c e p t i o n . T h i s sounds more p l a u s i b l e , but i t i s not v e r y i n - f o r m a t i v e . E.g., perhaps he can make f i n e r d i s c r i m i n a t i o n s than A even a t v e r y c l o s e range. Or perhaps he has b e t t e r v i s u a l , s h a p e - p e r c e p t i o n i n some p a r t i c u l a r l y a d verse c o n d i t i o n s . The above case i s o f t h a t k i n d , but so a l s o would be a case o f B's b e i n g a b l e t o d e t e c t v i s u a l l y a shape i n semi- d a r k n e s s , o r i n a v e r y s h o r t space o f t i m e , where A cannot. We can be more i n f o r m a t i v e as t o the k i n d o f a d v e r s e c o n d i t i o n s i n which B r e v e a l s t h a t he i s b e t t e r than A by s a y i n g t h a t B has b e t t e r v i s u a l , s h a p e - p e r c e p t i o n a t a d i s t a n c e than A. T h i s c a u t i o u s f o r m u l a t i o n a v o i d s s u g g e s t i n g t h a t B i s b e t t e r than A i n some o f t h o s e o t h e r c o n d i t i o n s . Indeed, i t remains p o s s i b l e t h a t B, who i s l o n g - s i g h t e d , i s much p o o r e r than A a t v i s u a l , s h a p e - p e r c e p t i o n a t v e r y c l o s e q u a r t e r s . Depending on how s u c c e s s f u l most people are i n u s i n g t h e p o o r e r t e s t , we may f i n d t h a t A i s p o o r e r than most a t v i s u a l , shape- p e r c e p t i o n a t a d i s t a n c e , o r perhaps t h a t B i s b e t t e r than most. O r d i n a r i l y when a statement i s i n t e r - s u b j e c t i v e l y t e s t e d , u s i n g r e l i - a b l e p r o c e d u r e s , and t h e v e r d i c t i s agreed upon, we need not ask i f the t e s t e r s ar e normal p e r c e i v e r s . A f t e r a l l , t o say t h a t the t e s t i s ( i n g e n e r a l ) r e l i - a b l e means t h a t i t i s r e l i a b l e f o r most p e o p l e . I f we do f o r m u l a t e t h i s r e - quirement i n such a c a s e , we may be c o n t e n t t o do so i n v e r y g e n e r a l terms; e.g., " T h i s t e s t i s d e s i g n e d f o r t e s t e r s h a v i n g ( a t l e a s t ) normal c o l o u r - p e r c e p t i o n " , o r , " T h i s t e s t i s d e s i g n e d f o r t e s t e r s h a v i n g ( a t l e a s t ) normal t a c t u a l p e r c e p t i o n . " Only when i t i s d o u b t f u l t h a t a l l t h e t e s t e r s f i t the requirements do we query them and, i n p a r t i c u l a r , d e c i d e how s p e c i f i c t h e s e r e q u i r e m e n t s s h o u l d be. We must d e c i d e j u s t what the t e s t s we employ t o query the r e q u i r e m e n t s do, i n f a c t , t e s t , and i t may take c o n s i d e r a b l e j u d g e - ment t o r e a c h t h e d e s c r i p t i o n w i t h t h e most p r e d i c t i v e v a l u e . A person who i s w e l l t r a i n e d i n the p s y c h o l o g y o f p e r c e p t i o n may be aware o f which p e r c e p - t u a l a b n o r m a l i t i e s a r e u s u a l l y c o r r e l a t e d w i t h some o t h e r s , and so may be a b l e , j u s t i f i a b l y , t o g i v e a l e s s s p e c i f i c d e s c r i p t i o n o f t h e k i n d o f p e r c e p - t i o n r e q u i r e d than someone not so t r a i n e d . L i k e w i s e a person so t r a i n e d may g i v e a more s p e c i f i c d e s c r i p t i o n than would someone e l s e , s i n c e he may know t h a t c e r t a i n i n t u i t i v e l y e x p e c t e d c o r r e l a t i o n s between the t y p e o f p e r c e p t i o n t e s t e d f o r and some o t h e r type o f p e r c e p t i o n , i n f a c t , do not h o l d . ( F o r example, i t i s easy t o assume t h a t i f someone i s worse than the m a j o r i t y a t d i s c r i m i n a t i n g brown shades, then he i s worse than the m a j o r i t y a t d i s c r i m i - n a t i n g shades o f any c o l o u r ; but t h i s may be f a l s e . ) In the example above we make t h e f a i r l y c a u t i o u s s t a t e m e n t t h a t A i s p o o r e r than B a t v i s u a l , shape- p e r c e p t i o n a t a d i s t a n c e . I t i s i n t u i t i v e l y p l a u s i b l e t o e x p e c t A t o be p o o r e r than B a t v i s u a l , s i z e - p e r c e p t i o n a t a d i s t a n c e as w e l l , e s p e c i a l l y i n t e s t i n g s tatements o f the form: "Those two small o b j e c t s a r e the same s i z e . " There may even be a l o g i c a l c o n n e c t i o n between the a b i l i t y t o p e r c e i v e shape and t h e a b i l i t y t o p e r c e i v e s i z e . But i f t h e y a r e not l o g i c a l l y c o n n e c t e d i n 42 a t i g h t enough way, then i t i s w i s e s t t o make no commitment about t h e i r b e i n g c o n t i n g e n t l y c o n n e c t e d u n t i l we have a l l the r e l e v a n t e m p i r i c a l e v i d e n c e . I have d e s c r i b e d ways i n which a person c o u l d r e v e a l t h a t he i s a p o o r e r ft - p e r c e i v e r than most p e o p l e . The one t h i n g common to a l l cases i s s i m p l y t h a t i f t h e v e r d i c t o f the poor p e r c e i v e r c o n f l i c t s w i t h t h a t o f most p e o p l e , then i t i s more l i k e l y t h a t h i s v e r d i c t i s wrong than t h a t t h e i r s i s . H i s ver- d i c t i s l e s s l i k e l y t o r e c e i v e f u r t h e r c o n f i r m a t i o n . The comparisons a r e be- tween the v e r d i c t he reaches and the v e r d i c t s the m a j o r i t y o f p e o p l e r e a c h when th e y a l l t e s t the same statement u s i n g the same t e s t i n the same e n v i r o n - ment. T h i s l a s t term i s g i v e n a s p e c i a l meaning i n t h i s t h e s i s , and i t w i l l be used q u i t e o f t e n i n r e g a r d t o v i s u a l p e r c e p t i o n . A p e r c e p t u a l environment f o r t e s t i n g some statement about a p h y s i c a l o b j e c t / g r o u p o f them by u s i n g v i s u a l - p e r c e p t i o n remains c o n s t a n t p r o v i d i n g a l l f e a t u r e s e x c e p t the s t a t e o f the p e r - c e i v e r remain c o n s t a n t , i . e . , i f the p a r t o f the p h y s i c a l w o r l d viewed r e - mains c o n s t a n t , and i f the l o c a t i o n o f the p e r c e i v e r remains c o n s t a n t . The l o c a t i o n i n c l u d e s the d i r e c t i o n he i s f a c i n g , and the o r i e n t a t i o n o f h i s eyes. The s t a t e o f t h e p e r c e i v e r i s not i n c l u d e d i n "the environment". The p e r - c e n t e r ' s s t a t e can v a r y and y e t the environment remain c o n s t a n t . ( M u t a t i s mutandis f o r two e n v i r o n m e n t s ' b e i n g the same.) There a r e two o p t i o n s as to how we d e f i n e "normal p e r c e i v e r " . In one o f them t h e r e i s no r e f e r e n c e , e i t h e r e x p l i c i t l y o r i m p l i c i t l y , t o a c e r t a i n l e v e l o f a b i l i t y a person must have i n o r d e r t o be a normal p e r c e i v e r ; t o be p r e c i s e t h e r e i s no r e q u i r e m e n t t h a t a normal p e r c e i v e r be a b l e t o use r e l i a b l y c e r t a i n t e s t s i n c e r t a i n environments. E.g., suppose you d e f i n e "the a b i l i t y o f a normal p e r c e i v e r " as "the a b i l i t y o f the m a j o r i t y o f the p e o p l e now a l i v e and as they are r i g h t now". Then on t h i s usage, i t w i l l be l o g i c a l l y i m p o s s i b l e f o r the m a j o r i t y o f p e o p l e a t any one time t o be abnor- m a l l y poor p e r c e i v e r s , but the l e v e l o f a b i l i t y o f a normal p e r c e i v e r can v a r y from one time t o a n o t h e r s i n c e the l e v e l o f a b i l i t y o f the m a j o r i t y o f p e o p l e can v a r y from one time t o a n o t h e r . The o t h e r o p t i o n i s t o d e f i n e "normal p e r c e i v e r " so t h a t i t does make r e f e r e n c e , e x p l i c i t l y o r i m p l i c i t l y , t o a l e v e l o f a b i l i t y , so t h a t t h e r e are. c e r t a i n t e s t s a person must be a b l e t o use r e l i a b l y i n c e r t a i n environments i f he i s t o q u a l i f y as a normal p e r c e i v e r . In f a c t , t h i s i s t h e o p t i o n I have had i n mind d u r i n g t h i s s e c t i o n . F or the p o i n t s i n t h i s s e c t i o n I have i n mind t h e minimum l e v e l o f p e r c e p t u a l a b i l i t y found i n the m a j o r i t y o f a s p e c i f i c group o f p e r c e i v e r s , v i z , the a c t u a l i n d i v i d u a l s now a l i v e and as the y a re now. On t h i s usage i t i s p o s s i b l e a t some o t h e r time t h a t t h e major i t y o f peop l e then l i v i n g and as th e y then a r e a r e a b n o r m a l l y poor p e r c e i v e r s f o r some k i n d s o f p e r c e p t i o n . The p o i n t i s t h a t some peopl e w i l l d i e , some w i l l be b o r n , and i n any ca s e an i n d i v i d u a l ' s l e v e l o f p e r c e p t u a l a b i l i t y can v a r y . There may be a g e n e r a l d e c r e a s e i n a b i l i t y o f some k i n d , o r even a g e n e r a l l o s s o f t h a t p e r c e p t u a l a b i l i t y a l t o g e t h e r , so t h a t t e s t s now r e l i a b l may then r e q u i r e t h a t t e s t e r s have a minimum l e v e l o f a b i l i t y which i s much h i g h e r than most people then have. In t h i s c a s e , most people a t t h a t time would not s a t i s f y t he n o r m a l i t y - r e q u i r e m e n t s as I have here i n t e r p r e t e d them. Of c o u r s e t h e r e may be c i r c u m s t a n c e s t h a t would prompt us t o change t h e s p e c i f i c group o f peopl e t h a t c o n s t i t u t e t he r e f e r e n c e group. E.g., we may keep i t as I have s u g g e s t e d — m o s t p e o p l e now a l i v e and as t h e y a r e now--if a gener a l l o s s o f a b i l i t y i s temporary, but we may change the r e f e r e n c e group i f some g e n e r a l l o s s becomes a permanent f e a t u r e o f humans. I s t i l l p r e f e r t h i s way o f d e f i n i n g "normal p e r c e i v e r " o v e r t h e f i r s t o p t i o n , s i n c e t h i s l a s t way makes i t c l e a r t h a t when we say "a t e s t i s r e l i a b l e " we mean i t i s r e l i a b l e f o r p e o p l e h a v i n g a c e r t a i n minimum l e v e l o f p e r c e p t u a l a b i l i t y . I t i s t h e o r e t i c a l l y i m p o r t a n t not t o f o r g e t t h i s and suppose, e.g., t h a t any r e l i - a b l e t e s t i s always r e l i a b l e f o r t h e m a j o r i t y o f p e o p l e a t any t i m e . Of c o u r s e , we e x p e c t a person's p e r c e p t u a l a b i l i t y t o remain f a i r l y c o n s t a n t f o r v e r y l o n g s t r e t c h e s o f ti m e , and we a l s o t e n d t o assume t h a t which group we r e f e r t o i n s p e a k i n g o f "the m a j o r i t y " does not u s u a l l y m a t t e r , but i t 4< c o u l d m a t t e r . Given the o p t i o n I have chosen, i . e . , g i v e n t h a t my d e f i n i t i o n o f "normal p e r c e i v e r " makes use o f a s p e c i f i e d r e f e r e n c e group o f p e r c e i v e r s , an a b n o r m a l l y poor ^ - p e r c e i v e r i s a p e r c e i v e r whose a b i l i t y i s l e s s than t h a t common t o t h e m a j o r i t y o f peop l e o f t h e r e f e r e n c e group. And g i v e n t he r e f e r e n c e group I have chosen, an a b n o r m a l l y poor ^ - p e r c e i v e r i s worse a t p - p e r c e p t i o n than the m a j o r i t y o f people now a l i v e as th e y a r e now. An ab- n o r m a l l y good ^ - p e r c e i v e r i s one who i s b e t t e r a t t h i s k i n d o f p e r c e p t i o n than t he m a j o r i t y o f t h e r e f e r e n c e group. 4! 8. R e s o l v i n g D i s p u t e s As y e t n o t h i n g has been s a i d about the causes o f a b n o r m a l l y poor p e r - c e p t i o n , but knowledge o f such causes may be v e r y u s e f u l . Having an ab- normal b o d i l y s t a t e which i n t e r f e r e s w i t h p e r c e p t i o n can be u s e f u l l y c h a r a c - t e r i z e d i n a t l e a s t two ways: a) " h a v i n g an u n n a t u r a l s t a t e which i n t e r f e r e s . . .", and b) " h a v i n g an u n h e a l t h y s t a t e which . . ." . a) "An u n n a t u r a l s t a t e o f the body's s e n s o r y a p p a r a t u s " Even t h e n o t i o n o f " u n n a t u r a l " i s open-ended, but i t i s t o i n c l u d e such a s t a t e as h a v i n g a r t i f i c i a l l i m b s o r s e n s e - o r g a n s , o r p i e c e s o f s h r a p n e l i n the body, o r h a v i n g some p a r t o f t h e body m i s s i n g , e t c . . With the e x c e p t i o n o f t he l a s t , t h e s e s t a t e s may be r o u g h l y c h a r a c t e r i z e d as " h a v i n g a f o r e i g n body/substance e i t h e r i n the body o r as p a r t o f i t " . An u n n a t u r a l s t a t e o f the s e n s o r y a p p a r a t u s i s one o f t h e s e s t a t e s o r a s t a t e o f t h e s e n s o r y ap- p a r a t u s which r e s u l t s from one o f t h e s e s t a t e s . b) "An u n h e a l t h y s t a t e o f the body's s e n s o r y a p p a r a t u s " Some i m p r e c i s i o n remains h e r e , f i r s t , because i t i s u s u a l l y supposed t h a t one o f t he f e a t u r e s o f a h e a l t h y s t a t e i s t h a t i t i s d e s i r a b l e , and s e c o n d l y , be- cause h e a l t h y and u n h e a l t h y s t a t e s l i e on a continuum. Sometimes i t i s d i f - f i c u l t t o d e c i d e i f someone i s u n h e a l t h y o r n o t , f o r example, i f someone has no d i s e a s e o r i n j u r y but l a c k s stamina through l a c k o f e x e r c i s e . We do not even have a d e f i n i t e number o f o b v i o u s l y u n h e a l t h y s t a t e s , s i n c e we are s t i l l a c c u m u l a t i n g knowledge o f t h e human body. For t h i s r e a s o n we may more c o n f i - d e n t l y d e s c r i b e a b o d i l y s t a t e as u n n a t u r a l than as u n h e a l t h y . We e x p e c t i t t o be g e n e r a l l y e a s i e r t o d e s i g n r e l i a b l e t e s t s f o r p e o p l e not h a v i n g an abnormal s t a t e o f t h e s e n s o r y a p p a r a t u s than i t i s t o d e s i g n them f o r t h o s e who do have such a s t a t e . T h i s i s not an e n t i r e l y a r b i t r a r y e x p e c t a t i o n and i t s b a s i s i s not s i m p l y t h a t t h e r e are f a r more people w i t h o u t such s t a t e s than t h e r e a r e w i t h them ( i f , i n f a c t , t h i s i s t r u e ) . I t i s based on a f u r t h e r b e l i e f : where t h e r e i s a d i f f e r e n c e between t h e l e v e l s o f p e r c e p t u a l a b i l i t y between a group ha v i n g some abnormal s t a t e o f t h i s k i n d a f f e c t i n g p e r c e p t i o n , and a group h a v i n g no such s t a t e , then p r o v i d i n g t he abnormal s t a t e was not d e l i b e r a t e l y b r o u g h t about i n o r d e r t o improve the person's p e r c e p t i o n , the group w i t h o u t t h e abnormal s t a t e w i l l be more l i k e l y t o have the h i g h e r a b i l i t y ; t h e y w i l l be more l i k e l y t o re a c h c o r r e c t v e r d i c t s . We do n o t e x p e c t abnormal s t a t e s t o cause an i n c r e a s e i n p e r c e p t u a l a b i l i t y . N a t u r a l l y , we e x p e c t i t t o be e a s i e r t o d e s i g n t e s t s f o r t h o s e w i t h t he h i g h e r l e v e l o f a b i l i t y , s i n c e they a r e l e s s r e s t r i c t e d i n t h e t e s t s t h e y can use r e l i a b l y . In our examinations o f t h e human body we assume t h a t t he v a r i o u s organs and p a r t s have some f u n c t i o n o r o t h e r and t h a t t h i s f u n c t i o n i s b e s t d i s p l a y e d when t h e body i s h e a l t h y and not u n n a t u r a l l y tampered w i t h . As I mentioned, i t i s u s u a l l y supposed t h a t a h e a l t h y s t a t e i s d e s i r a b l e , and one o f t h e ways i t can be d e s i r a b l e i s i n p e r m i t t i n g the body's f u n c t i o n s t o be performed w e l l . A s t a t e which causes a l o w e r i n g o f p e r c e p t u a l a b i l i t y o f some k i n d be- comes a prime c a n d i d a t e f o r t h e l a b e l ' " u n h e a l t h y s t a t e " o r " i m p a i r e d s t a t e " , and, s i g n i f i c a n t l y , t h e s e l a b e l s a r e o f t e n i n t e r c h a n g e a b l e . We may sometimes be a b l e t o d e s i g n a t e s t which can be used r e l i a b l y by an u n h e a l t h y person w i t h lowered p e r c e p t u a l a b i l i t y . I t i s even c o n c e i v a b l e t h a t some abnormal s t a t e may cause an i n c r e a s e i n p e r c e p t u a l a b i l i t y and so make d e s i g n i n g a r e l i a b l e t e s t much e a s i e r . E.g., a b o d i l y s t a t e may be deemed u n h e a l t h y i f i t i s u n d e s i r a b l e because i t causes p a i n and d i s c o m f o r t , even though i t does n o t i m p a i r any b o d i l y f u n c t i o n o r even though i t causes a b e t t e r f u n c t i o n i n g i n some way. Many u n h e a l t h y b o d i l y s t a t e s do i m p a i r our p e r c e p t i o n s i n c e t h i s i s o f t e n t he grounds f o r t h e i r b e i n g c a l l e d " u n h e a l t h y " . F or o t h e r abnormal b o d i l y s t a t e s we can see i f they tend t o cause a s i g n i f i c a n t l o s s o f perceptual 4; a b i l i t y i f we can have a f f e c t e d persons u s i n g c e r t a i n t e s t s i n v o l v i n g t he k i n d o f p e r c e p t i o n i n q u e s t i o n , and l o o k f o r f u r t h e r c o n f i r m a t i o n o f . t h e i r v e r d i c t s , and compare t h e i r r a t e o f s u c c e s s w i t h t h a t o f h e a l t h y p e r c e i v e r s i n the same en v i r o n m e n t s . Of c o u r s e , t h e y may be b o d i l y s t a t e s which cannot a p t l y be d e s c r i b e d as e i t h e r " u n n a t u r a l " o r " u n h e a l t h y " , but which do cause a d e c r e a s e i n p e r c e p t u a l a b i l i t y , and t h e r e may be some u n n a t u r a l o r un- h e a l t h y s t a t e s which do not cause poor p e r c e p t i o n . N o n e t h e l e s s , t h e two c h a r a c t e r i z a t i o n s o f "abnormal b o d i l y s t a t e " a re u s e f u l . There i s a f a i r l y h i g h c o r r e l a t i o n between h a v i n g them and h a v i n g i m p a i r e d p e r c e p t i o n o f some k i n d because o f the t e l e o l o g i c a l assumptions we a r e e n t i t l e d t o make about t h e human body. Knowing such causes o f p e r c e p t u a l impairment can be u s e f u l i n r e s o l v i n g d i s p u t e s . In ca s e o f c o n f l i c t i n g v e r d i c t s between two p e o p l e , i f we show t h a t one has an abnormal s t a t e o f t h e s e n s o r y a p p a r a t u s which tends t o im- p a i r t he k i n d o f p e r c e p t i o n b e i n g used, then we know t h a t h i s v e r d i c t i s p r o b a b l y wrong. I t i s o b v i o u s l y b e t t e r t o check t h e v e r d i c t s d i r e c t l y , by l o o k i n g f o r f u r t h e r c o n f i r m a t i o n o f one o f them u s i n g o p t i m a l l y d i f f e r e n t t e s t s , r a t h e r than assume t h a t t h e i l l t e s t e r ' s v e r d i c t i s i n c o r r e c t ( a l - though we e x p e c t t o re a c h t he same c o n c l u s i o n both ways). However, t h e r e may be o c c a s i o n s when c o n t i n g e n c i e s make t h e usual f u r t h e r t e s t s i m p o s s i b l e ; e.g., we may t e s t f o r t h e shape o f a small o b j e c t by l o o k i n g a t i t from s i x t y f e e t away and then f i n d i t m e l t s b e f o r e we can re a c h i t t o t e s t t he statement t a c - t u a l l y . Then b e i n g a b l e t o show t h a t one o f the d i s p u t a n t s has such a b o d i l y s t a t e g i v e s us a n o n - a r b i t r a r y s o l u t i o n by showing i _ n d i r e c t l y which v e r d i c t i s l i k e l y to be i n c o r r e c t . In paradigm case s o f t h i s s o r t we a r e drawing on g e n e r a l i n f o r m a t i o n about the e f f e c t s o f t h e abnormal s t a t e , where t h i s i n f o r - m ation was a c q u i r e d when i t was i n f a c t p o s s i b l e t o t e s t the v e r d i c t s o f a f f e c t e d p e o p l e by u s i n g independent t e s t s . A l s o i t may be p o s s i b l e t o show n o n - c i r c u l a r l y t h a t someone has such an abnormal b o d i l y s t a t e , i . e . , i t w i l l be p o s s i b l e t o show i t w i t h o u t making any commitment about the typ e o f p e r c e p t i o n t h i s k i n d o f s t a t e i m p a i r s . F or example, suppose t h a t s c l e r o s i s causes a b n o r m a l l y poor t a c t u a l p e r c e p t i o n w i t h r e s p e c t t o some common t e s t : an a f f e c t e d person cannot t e s t r e l i a b l y the statement "The o b j e c t has two sharp p o i n t s " by sense o f to u c h i f the p o i n t s a r e an i n c h a p a r t ( o r l e s s ) . In t h o s e c i r c u m s t a n c e s he cannot d i s t i n - g u i s h t a c t u a l l y the o b j e c t ' s h a v i n g one sharp p o i n t from i t s h a v i n g two, a l - though the normal p e r c e i v e r can. (Whether o r n o t t h i s i s t r u e , i t w i l l s e r v e as an i l l u s t r a t i o n . ) And suppose t h a t one o f the two d i s p u t a n t s has s c l e r o s i s . I f the t e s t l e a d i n g t o the d i s p u t e i n v o l v e s t a c t u a l p e r c e p t i o n o f t h a t k i n d , then a case can be made f o r one person's d e f e r r i n g t o the o t h e r i f we can show n o n - c i r c u l a r l y t h a t the former has s c l e r o s i s ; i . e . , i f the i l l n e s s can be d i a g n o s e d w i t h o u t r e l y i n g on t a c t u a l p e r c e p t i o n , so t h a t , i n p r i n c i p l e , t h e p e r s o n a f f e c t e d can d i a g n o s e i t h i m s e l f . I f t h i s i s done, the n we have shown i n d i r e c t l y t h a t he i s v e r y p r o b a b l y an a b n o r m a l l y poor t a c t u a l p e r c e i v e r . I now wish t o g i v e a summary o f t h e g u i d e - l i n e s f o r r e s o l v i n g d i s p u t e s about t h e t r u t h / f a l s i t y o f a sta t e m e n t between one person/group o f peop l e and a n o t h e r . In t h e f o l l o w i n g p o i n t s t h e b a s i c soundness c o n d i t i o n s can be under- s t o o d i n t h e i r most g e n e r a l form (where no r e f e r e n c e i s made t o "normal p e r - c e i v e r s " ) , i . e . , (1) t h e t e s t - p r o c e d u r e s a r e f o l l o w e d f a u l t l e s s l y , (2) by someone h a v i n g the minimum p e r c e p t u a l a b i l i t y f o r the p r o c e d u r e s t o be r e l i - a b l e i n t h e environment i n q u e s t i o n . In j u d g i n g t h e soundness o f a v e r d i c t f o r some statement, we a p p l y f i r s t the e l i m i n a t i o n r u l e p r o v i d e d by the two b a s i c soundness c o n d i t i o n s : " R e j e c t ( o r a t l e a s t , do not r e l y on) any v e r d i c t r e a c h e d when e i t h e r ( o r both) o f the c o n d i t i o n s does not h o l d . " As we have seen, t he second o f thes e can be t e s t e d f o r d i r e c t l y , o r i n d i r e c t l y v i a known causes o f a l a c k / l o s s o f p e r c e p t u a l a b i l i t y r e n d e r i n g t h e t e s t u n r e l i a b l e f o r th e t e s t e r ( s ) c o n c e r n e d . (We l o o k e d a t t h e s p e c i a l form o f t h i s c o n d i t i o n where " a t l e a s t normal p e r c e p t i o n " i s r e q u i r e d , but t h e p o s s i b i l i t y o f i n d i r e c t 4< t e s t i n g need not be so r e s t r i c t e d . ) T h i s e l i m i n a t i o n r u l e a p p l i e s even when t h e r e i s no d i s p u t e , i . e . , when we have a group o f t h e same v e r d i c t s ( p e r - haps o n l y one v e r d i c t ) f o r some s t a t e m e n t , r e a c h e d u s i n g some one t e s t a num- ber o f times (perhaps o n c e ) . The v e r d i c t s may s t i l l be r e j e c t e d on t h e s e grounds. A group o f c o n c u r r i n g v e r d i c t s which pass t h i s t e s t become c a n d i - d a t e s f o r t h e t i t l e o f p r o b a b l y c o r r e c t v e r d i c t s . 1 Suppose we now have a d i s p u t e , i . e . , we have two groups o f v e r d i c t s f o r some s t a t e m e n t reached a f t e r u s i n g some one t e s t a number o f t i m e s , where a l l t he v e r d i c t s o f one group a r e " t r u e " and a l l t he v e r d i c t s o f the o t h e r group a r e " f a l s e " . The comments I s h a l l make a p p l y whether the d i s p u t e i s i n t e r p e r s o n a l o r i n t r a p e r s o n a l , i . e . , whether t h e v e r d i c t s a r e re a c h e d by d i f f e r e n t p e o p l e , o r by one person a t d i f f e r e n t t i m e s . A l t h o u g h we know t h a t one group o f v e r d i c t s must be c o r r e c t , we may f i n d t h a t none o f them i s b a s i - c a l l y sound, and so have no e p i s t e m o l o g i c a l r e a s o n s t o c l a i m t h e precedence o f one group o f v e r d i c t s o v e r t h e o t h e r . Then t h e m a t t e r remains u n r e s o l v e d . On th e o t h e r hand, i f one group o f v e r d i c t s i s unsound but t h e o t h e r b a s i c a l l y sound, then t h e l a t t e r a re more l i k e l y t o be c o r r e c t , and we have a n o n - a r b i - t r a r y r e s o l u t i o n o f t h e d i s p u t e . Where a l l t he v e r d i c t s appear t o be b a s i c a l l y sound, we may take note o f o r t r y t o e s t a b l i s h o t h e r soundness c o n d i t i o n s which are d e s i r a b l e r a t h e r than r e q u i r e d . E.g., i f t h e o r i g i n a l s tatement i s r e - t e s t e d u s i n g a t e s t i n d e p e n - dent o f the f i r s t , we may f i n d one o f t h e e a r l i e r groups o f v e r d i c t s t o be con- s i s t e n t l y c o n f i r m e d . I f t h i s r e - t e s t i n g i s b a s i c a l l y sound, i t p r o v i d e s a non- a r b i t r a r y r e s o l u t i o n o f t h e e a r l i e r d i s p u t e . Or we may r e - t e s t t he o r i g i n a l s t a t e m e n t by u s i n g f a r l e s s o f t h e k i n d o f p e r c e p t i o n used i n the o r i g i n a l t e s t , e.g., by moving t o a f a r more '''The v e r d i c t s , a l t h o u g h a l l b a s i c a l l y sound, need not be the soundest v e r - d i c t s . E.g., b a s i c a l l y sound v e r d i c t s r e a c h e d u s i n g a more r e l i a b l e t e s t may be deemed t o be sounder. 5( f a v o u r a b l e l o c a t i o n , so t h a t t h i s r e - t e s t r e q u i r e s l e s s p e r c e p t u a l a b i l i t y than does the o r i g i n a l . A g a i n , i f we f i n d one o f the e a r l i e r groups o f v e r - d i c t s t o be c o n s i s t e n t l y c o n f i r m e d i n t h i s way, and i f t h i s r e - t e s t i s b a s i - c a l l y sound, then i t p r o v i d e s a n o n - a r b i t r a r y r e s o l u t i o n o f the d i s p u t e . A n o t h e r i m p o r t a n t f e a t u r e we may l o o k f o r when we have a d i s p u t e where a l l the v e r d i c t s seem b a s i c a l l y sound i s t h e r a t i o o f the one group o f v e r - d i c t s t o t h e o t h e r . I f t h e r e i s good r e a s o n t o b e l i e v e t h a t i n a l l uses o f t h e t e s t t h e t e s t e r (whether one person o r more) does f o l l o w t h e i n s t r u c t i o n s c o r r e c t l y and does have t h e minimum p e r c e p t u a l a b i l i t y f o r the t e s t t o be " r e l i a b l e " i n the environment i n q u e s t i o n , then a l a r g e enough m a j o r i t y o f one o f the groups o f v e r d i c t s g i v e s us a n o n - a r b i t r a r y r e s o l u t i o n . How l a r g e t h e m a j o r i t y needs t o be depends on how you d e f i n e " r e l i a b l e " . I s h a l l e x p l a i n t h i s g e n e r a l p o i n t about a p o s s i b l e r e s o l u t i o n by s e t t i n g o u t t h e u s u a l , spe- c i a l form o f i t where ( a t l e a s t ) normal p e r c e p t i o n i s r e q u i r e d . Suppose we r e q u i r e a t l e a s t an 80% s u c c e s s - r a t e f o r an i n d i v i d u a l t o use a t e s t " r e l i a b l y " , i . e . , t h i s must be h i s r a t e o f r e a c h i n g t h e c o r r e c t v e r d i c t a f t e r f o l l o w i n g the t e s t - i n s t r u c t i o n s c o r r e c t l y . Then f o r some t e s t which i s r e l i a b l e f o r t h e normal p e r c e i v e r f o r some s t a t e m e n t , we e x p e c t the p r o p o r t i o n o f c o r r e c t : i n c o r r e c t v e r d i c t s t o be 4:1 o r b e t t e r ( i . e . >4 :1) . The s t a t e m e n t , " U s i n g p r o c e d u r e s , X, c o r r e c t l y i s a r e l i a b l e way o f t e s t i n g the s t a t ement, P, f o r t h e normal p e r c e i v e r " , may l e g i t i m a t e l y be c o n s t r u e d both i n t r a p e r s o n a l l y and i n t e r p e r s o n a l l y . I t g i v e s grounds f o r b e l i e v i n g both t h a t : i ) i t i s r e l i a b l e i n i t s many uses by any one normal p e r c e i v e r who f o l l o w s t h e i n s t r u c t i o n s c o r r e c t l y (where t h e s e uses t a k e p l a c e a t d i f f e r e n t t i m e s ) ; and t h a t i i ) i t i s r e l i a b l e i n i t s many uses by a group o f normal p e r - c e i v e r s who f o l l o w t h e i n s t r u c t i o n s c o r r e c t l y (whether o r not t h e s e uses t a k e p l a c e a t d i f f e r e n t t i m e s ) 5" p r o v i d e d we a r e p r e p a r e d t o make the f o l l o w i n g assumption: the sample s e t o f c a s e s (whether i n t e r p e r s o n a l o r not) i s a random sample and, t h e r e f o r e , l i k e l y t o be r e p r e s e n t a t i v e o f the t o t a l s e t o f such c a s e s . Here "the t o t a l s e t o f c a s e s " means a l l a c t u a l uses o f the t e s t by normal p e r c e i v e r s who f o l l o w t h e i n s t r u c t i o n s c o r r e c t l y , whether o r n o t t h e s e uses have o c c u r r e d a l r e a d y , a r e o c c u r r i n g , o r w i l l o c c u r . Assumptions about random sampling a r e used a g r e a t deal i n e x p e r i m e n t a l p s y c h o l o g y , but always w i t h the q u a l i f i c a t i o n t h a t by chance a random sample w i l l be u n r e p r e s e n t a t i v e a s m a l l , c a l c u l a b l e , p e r c e n - tage o f the t i m e . T h i s a p p l i e s t o o u r samples t o o . So, i n any random sample o f uses o f a r e l i a b l e t e s t , we l o o k f o r t h e c o r r e c t v e r d i c t ' s b e i n g r e a c h e d i n a t l e a s t 80% o f t h e uses i n t h i s sample, and e x p e c t t o be ' l e t down' v e r y r a r e l y . R e s o l v i n g a d i s p u t e i n t h i s way w i l l be a p p r o p r i a t e o n l y where a t l e a s t one o f the groups o f v e r d i c t s does i n v o l v e a number o f uses o f the t e s t , and where the r a t i o o f " t r u e " : " f a l s e " v e r d i c t s i s e i t h e r 1: >4 o r >4:1. Re- s o l v i n g i n f a v o u r o f t h e m a j o r i t y i s then not s i m p l y a r u l e o f e x p e d i e n c e . Where the r a t i o o f the v e r d i c t s i s 1: <4 o r <4:1, we must d e c i d e whether o r not the r a t i o i s c l o s e enough t o t h a t e x p e c t e d t o s u p p o r t r e s o l v i n g the d i s p u t e i n t h i s way. O b v i o u s l y , the f u r t h e r away from the e x p e c t e d s p l i t , t h e l e s s c o n f i d e n t i s our b e l i e f t h a t the m a j o r i t y o f v e r d i c t s a r e c o r r e c t . When t h i s happens we may, e.g., h y p o t h e s i z e t h a t t h e random sample o f uses i s not r e p r e s e n t a t i v e o f t h e t o t a l uses o f t h a t t e s t by normal p e r c e i v e r s who f o l l o w t h e i n s t r u c t i o n s c o r r e c t l y , o r , perhaps, t h a t i n some uses one o r both o f the b a s i c soundness c o n d i t i o n s d i d n o t i n f a c t h o l d . One o t h e r f a c t o r b e s i d e s t h a t o f t h e r a t i o o f the " t r u e " : " f a l s e " v e r - d i c t s a f f e c t s our c o n f i d e n c e i n the m a j o r i t y - v e r d i c t s , namely, the a c t u a l num- be r o f t e s t - u s e s i n the sample. The l a r g e r the sample, the l e s s l i k e l y t h a t the v e r d i c t - r a t i o here i s u n r e p r e s e n t a t i v e o f the v e r d i c t - r a t i o o f the t o t a l s e t o f t e s t - u s e s . 5; There may w e l l be o t h e r d e s i r a b l e soundness c o n d i t i o n s t o w e i g h t the c h o i c e between v e r d i c t s a l l o f which appear b a s i c a l l y sound, but the c o n c u r - rence o f t h e i ndependent t e s t s o r o f e a s i e r t e s t s , and t h e r e b e i n g a v a s t m a j o r i t y o f e i t h e r " t r u e " o r " f a l s e " v e r d i c t s a r e p r o b a b l y the most commonly sought c o n d i t i o n s . 53 9. T e s t i n g f o r the S a m e n e s s / D i f f e r e n c e Of C o l o u r o f P h y s i c a l O b j e c t s My q u e s t i o n s are asked i n the c o n t e x t o f a n o n - s o l i p s i s t i c p h y s i c a l ob- j e c t t h e o r y , i . e . , where i t i s assumed t h a t t h e r e a r e p h y s i c a l o b j e c t s , i n - c l u d i n g the b o d i e s o f o t h e r p e o p l e who do have p e r c e p t u a l e x p e r i e n c e s . A l s o my comments a r e r e s t r i c t e d t o the c o l o u r s o f p h y s i c a l o b j e c t s which a r e not the bodies o f any o f the p e r c e i v e r s i n v o l v e d i n v i e w i n g the o b j e c t s . F i n a l l y , I am d i s c u s s i n g the s a m e n e s s / d i f f e r e n c e o f the p r e s e n t c o l o u r o f p h y s i c a l ob- j e c t s , where the c o l o u r i s t h e c o l o u r the o b j e c t s have a t the time o f the a t - t r i b u t i o n o f s a m e n e s s / d i f f e r e n c e o f c o l o u r . I am not here l o o k i n g a t a t t r i - b u t i o n s which r e f e r t o the c o l o u r p h y s i c a l o b j e c t s have i n what i s deemed t o be a " s t a n d a r d environment" ( f o r t h o s e k i n d s o f o b j e c t s ) - - s o m e t i m e s r e f e r r e d t o as t h e i r ' r e a l ' c o l o u r . To b e g i n w i t h , I s h a l l make two p o i n t s about what i s r e q u i r e d i f we a r e t o have a concept o f "the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f two p h y s i c a l o b j e c t s " . F i r s t , f o r something t o be a q u a l i t y o f a p h y s i c a l o b j e c t I do not r e q u i r e t h a t i t be a q u a l i t y " i n the o b j e c t i t s e l f " , as Locke phrases i t . What t h e phrase " i n the p h y s i c a l o b j e c t i t s e l f " c o v e r s i s not a l t o g e t h e r c l e a r , but presumably a s i m p l e r e l a t i o n a l p r o p e r t y such as " b e i n g t o the l e f t o f . . . (some p h y s i c a l o b j e c t ) " i s not a p r o p e r t y which i s " i n the o b j e c t i t s e l f " . The c o n d i t i o n I do c o n s i d e r t o be n e c e s s a r y i f something i s t o count as a q u a l i t y o f a p h y s i c a l o b j e c t can b e s t be e x p r e s s e d i n terms o f statements a s c r i b i n g such q u a l i t i e s to p h y s i c a l o b j e c t s . N ecessary c o n d i t i o n : In a c o n s t a n t environment c o n t a i n i n g a p h y s i c a l ob- j e c t , c o n f l i c t i n g v e r d i c t s f o r a statement a s c r i b i n g t h e q u a l i t y t o the o b j e c t n e c e s s i t a t e one (group o f ) v e r d i c t ' s b e i n g i n c o r r e c t . (The environment i n c l u d e s t h e l o c a t i o n , but not the s t a t e o f the p e r c e i v e r . ) T h i s i s p a r t o f what i s meant by the statement's b e i n g g e n u i n e l y "about (a q u a l i t y o f ) a p h y s i c a l o b j e c t " , and any statement f o r which t h i s does not h o l d cannot be about a p a r t i c u l a r p h y s i c a l o b j e c t , no m a t t e r what i t s s u r f a c e grammar. A s i m p l e r e l a t i o n a l p r o p e r t y such as " b e i n g t o the l e f t o f . . . (some p h y s i c a l o b j e c t ) " , a l t h o u g h not " i n the o b j e c t i t s e l f " , can be t r e a t e d as a p r o p e r t y o f p h y s i c a l o b j e c t s i n t h a t statements a s c r i b i n g t h e p r o p e r t y t o o b j e c t s meet the i m p o r t a n t c o n d i t i o n s e t o u t above. The r e q u i r e m e n t i s i n t e n d e d n o t t o p r e c l u d e r e l a t i o n a l and d i s p o s i t i o n a l p r o p e r t i e s per se b e i n g t r e a t e d as genuine p r o p e r t i e s o f p h y s i c a l o b j e c t s . There i s a second p o i n t to do w i t h what i s i n v o l v e d i n the con c e p t o f "the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f two p h y s i c a l o b j e c t s " . T h i s i s about a req u i r e m e n t our s e n s e - e x p e r i e n c e must meet i f the e x p e r i e n c e i s to count as e x p e r i e n c e o f c o l o u r - q u a l i t i e s o f p h y s i c a l o b j e c t s . E a r l y i n the t h e s i s I made the p o i n t t h a t i f some i d e a s a re i d e a s o f the p h y s i c a l w o r l d , then they must be de t e r m i n e d by t h e p h y s i c a l w o r l d ( i n S e c t i o n 4 a b o v e ) . I f we a r e l e g i t i m a t e l y t o make c e r t a i n a t t r i b u t i o n s o f c o l o u r s t o c e r t a i n p h y s i c a l ob- j e c t s on the b a s i s o f the p e r c e i v e d c o l o u r s o f someone v i e w i n g the o b j e c t s , then t h e s e p e r c e i v e d c o l o u r s must be determined by thos e p h y s i c a l o b j e c t s . T h i s i s a c o n c e p t u a l r e q u i r e m e n t f o r t a k i n g i d e a s o f c o l o u r to be, a t l e a s t sometimes, i d e a s o f t h e p h y s i c a l w o r l d . A l s o , i f , a t l e a s t sometimes, on t h e b a s i s o f a d i f f e r e n c e i n p e r c e i v e d c o l o u r s when v i e w i n g a p a i r o f p h y s i c a l o b j e c t s , we a r e l e g i t i m a t e l y to c l a i m the o b j e c t s to be d i f f e r e n t c o l o u r s , then the d i f f e r e n c e i n the p e r c e i v e d c o l o u r s must be determined by the p h y s i - c a l o b j e c t s , g i v e n t h e i r environment. T h i s i s t o say t h e r e must be some d i f - f e r e n c e i n t h e p r o p e r t i e s o f t h e two o b j e c t s which a c c o u n t s f o r t h e d i f f e r e n c e i n p e r c e i v e d c o l o u r s . The p r o p e r t i e s need not be n o n - r e l a t i o n a l o r permanent. Some r e l a t i o n a l and d i s p o s i t i o n a l p r o p e r t i e s meet the c r u c i a l c o n d i t i o n f o r b e i n g c o n s i d e r e d p r o p e r t i e s o f p h y s i c a l o b j e c t s . I t i s u s e f u l to c a p t u r e t he p o i n t t h a t some r e l a t i o n a l p r o p e r t i e s o f the viewed p h y s i c a l o b j e c t s a r e r e l e v a n t t o t h e p e r c e i v e d c o l o u r s the view e r has, by s a y i n g t h a t the p e r c e i v e d c o l o u r s must be determined by the p h y s i c a l o b j e c t s , g i v e n . t h e i r environment. The r e q u i r e m e n t — t h a t i d e a s o f c o l o u r o f some p h y s i c a l o b j e c t s must be determined by thos e o b j e c t s , g i v e n t h e i r e n v i r o n m e n t — a l l o w s us to draw a t l e a s t one d i s t i n c t i o n t h a t we cannot a f f o r d t o i g n o r e . I t i s the b a s i s o f the d i s t i n c t i o n between the p e r c e i v e d c o l o u r o f a p h y s i c a l o b j e c t , and an h a l l u c i n a t i o n . A v i s u a l h a l l u c i n a t i o n o c c u r s p r e c i s e l y when one's p e r c e i v e d c o l o u r s a r e not determined by p a r t o f the ' e x t e r n a l ' p h y s i c a l w o r l d . Suppose t h a t you are p r e s e n t i n g and r e - p r e s e n t i n g p a i r s o f p h y s i c a l o b j e c t s t o a p e r - son to see i f he can c o n s i s t e n t l y d i s c r i m i n a t e between the two o b j e c t s i n each p a i r . So f a r as I know i t i s c o n c e i v a b l e ( w i t h o u t r e j e c t i n g any g i v e n f a c t ) f o r a person t o h a l l u c i n a t e i n such a way as t o d i s c r i m i n a t e o r match some o f h i s c o l o u r s e n s e - d a t a i n a p a t t e r n i s o m o r p h i c t o the p r e s e n t a t i o n s and r e - p r e s e n t a t i o n s o f p a i r s o f p h y s i c a l o b j e c t s . I am c e r t a i n l y not s u g g e s t i n g t h i s as a p r o b a b l e h y p o t h e s i s i f the person i n v o l v e d i n the d i s c r i m i n a t i o n t e s t g i v e s responses which are i s o m o r p h i c to the p r e s e n t a t i o n s and r e - p r e s e n - t a t i o n s o f the p h y s i c a l o b j e c t s . N o n e t h e l e s s t he p o i n t remains t h a t w i t h o u t t h i s r e q u i r e m e n t about the d e t e r m i n i n g o f h i s p e r c e i v e d c o l o u r s by the p h y s i - c a l o b j e c t s p r e s e n t e d i n the chosen environment, the person cannot be d i s - c r i m i n a t i n g p h y s i c a l o b j e c t s on the b a s i s o f t h e i r c o l o u r . Given t h a t t h i s r e q u i r e m e n t i s a n e c e s s a r y c o n d i t i o n f o r some o f our i d e a s o f c o l o u r to be i d e a s o f some viewed p h y s i c a l o b j e c t s , how can we d e c i d e whether o r n o t we i n f a c t have such i d e a s . C e r t a i n e m p i r i c a l t e s t s can sup- p o r t the c l a i m t h a t we can have p e r c e i v e d c o l o u r s t h a t a r e s y s t e m a t i c a l l y c o r - r e l a t e d w i t h p h y s i c a l o b j e c t s i n o u r p e r c e p t u a l environment, t e s t s l i k e the d i s c r i m i n a t i o n - t e s t mentioned above. We can p r e s e n t and r e - p r e s e n t p a i r s o f p h y s i c a l o b j e c t s t o a s i g h t e d person i n an environment t h a t o t h e r w i s e remains c o n s t a n t , and ask whether o r not he can d i s c r i m i n a t e t he two o b j e c t s o f each p a i r by c o l o u r . The o b j e c t s can be a l l o f t h e same shape and s i z e , but w i t h some i d e n t i f y i n g d e v i c e p e r c e i v a b l e o n l y by the t e s t e r , and the p a i r s can be p r e s e n t e d and r e - p r e s e n t e d i n a random o r d e r . I f the person t e s t e d d i s c r i - minates c o n s i s t e n t l y between t h e o b j e c t s o f c e r t a i n p a i r s , no m a t t e r when the p a i r s a re p r e s e n t e d , t h e n , s i n c e ex h y p o t h e s i t he o b j e c t s a re the same shape and s i z e (and same ' v i s u a l ' t e x t u r e , e t c . ) , t he p r o b a b l e h y p o t h e s i s i s t h a t t h e viewer i s d i s c r i m i n a t i n g between the o b j e c t s o f such p a i r s by c o l o u r . That i s t o s a y , h i s d i s c r i m i n a t i o n s a re made on the b a s i s o f h i s p e r c e i v e d c o l o u r s a t t h e time o f the p r e s e n t a t i o n s o f t h e s e p a i r s ; and t o a c c o u n t f o r t h e c o n s i s t e n c y o f h i s r e s p o n s e s , t h e p r o b a b l e h y p o t h e s i s i s t h a t some p r o - p e r t i e s o f the o b j e c t s p r e s e n t e d , g i v e n t h e i r environment, determines t h e s e p e r c e i v e d c o l o u r s he has. Of c o u r s e , f o r a p a t t e r n t o emerge i n the viewer ' s r e s p o n s e s , t h e r e needs t o be some o t h e r p a i r s o f o b j e c t s the members o f which he c o n s i s t e n t l y matches, o r c o n s i s t e n t l y h e s i t a t e s o v e r . I f h i s response t o a l l p r e s e n t a - t i o n s o f t h e p a i r s o f o b j e c t s i s t h a t the two o b j e c t s "have d i f f e r e n t c o l o u r s " , then t he f a c t t h a t he responds c o n s i s t e n t l y to the p r e s e n t a t i o n and r e - p r e s - e n t a t i o n o f each p a i r i s not as " s i g n i f i c a n t " as i t would o t h e r w i s e be. The use o f " s i g n i f i c a n t " here i s v e r y c l o s e t o t h a t used i n p s y c h o l o g i c a l e x p e r i - ments. Very c r u d e l y , the h i g h e r the s i g n i f i c a n c e o f a c o r r e l a t i o n , t he l e s s l i k e l y t h a t t h e c o r r e l a t i o n i s a mere c o i n c i d e n c e . In p s y c h o l o g y t h e r e a r e ways o f c a l c u l a t i n g what t h e " l e v e l o f s i g n i f i c a n c e " o f a c o r r e l a t i o n be- tween two v a r i a b l e s i s . For my purposes here i t i s enough t o p o i n t o u t t h a t t h e c o r r e l a t i o n between the p e r c e i v e r ' s r e s p o n s e s : "same c o l o u r " , "same", " d i f f e r e n t " , "same", " d i f f e r e n t " , " d i f f e r e n t " , . . . e t c . , and the p r e s e n - t a t i o n s o f t h e p a i r s o f o b j e c t s : "A & B", "C & D", "B & C", "C & D", "E & F", "B & C", . . . e t c . , p r o v i d e s b e t t e r s u p p o r t f o r the c l a i m t h a t the p e r c e i v e d c o l o u r s o f the person t e s t e d a r e determined by the p r o p e r t i e s o f the p h y s i c a l o b j e c t s p r e s e n t e d , than would the response " d i f f e r e n t c o l o u r s " made f o r e v e r y p r e s e n t a t i o n o f o b j e c t s . 5/ So w i t h the emergence o f such a p a t t e r n o f r e s p o n s e s , the s i m p l e s t hypo- t h e s i s i s t h a t the person's p e r c e i v e d c o l o u r s a re d e t e r m i n e d by the p r e s e n t e d p h y s i c a l o b j e c t s ( g i v e n t h e i r e n v i r o n m e n t ) , r a t h e r than t h a t t h e c o r r e l a t i o n between r e s p o n s e s and p a i r s o f o b j e c t s i s a mere c o i n c i d e n c e . By t e s t i n g o t h e r p e o p l e , i t may be found t h a t many, o r even a l l , o f the group t e s t e d g i v e c o n s i s t e n t l y one and t h e same response f o r t h i s o r t h a t p a i r o f o b j e c t s when p r e s e n t e d . Such c o r r e l a t i o n s a r e i n a sense j u s t b r u t e f a c t s about the w o r l d . And i n t h e f a c e o f t h e s e f a c t s , t h e v e r y p r o b a b l e h y p o t h e s i s t h a t p r o p e r t i e s o f the p r e s e n t e d p h y s i c a l o b j e c t s determine the p e r c e i v e d c o l o u r s o f t he vie w e r s so t h a t t h e i r i d e a s o f c o l o u r a re i d e a s o f t h e s e p h y s i c a l ob- j e c t s , i s enough t o make i t v e r y l i k e l y t h a t we can a r r i v e a t a c o h e r e n t con- c e p t o f " t h e c o l o u r o f a p h y s i c a l o b j e c t " . We have a l r e a d y a s o l i d base f o r the l o c u t i o n . For the moment I s h a l l f o c u s on the con c e p t o f "the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f two p h y s i c a l o b j e c t s " . The ne x t move towards making t h i s c o n c e p t c o h e r e n t i s t o e x p l a i n what c o n s t i t u t e s a m i s t a k e i n j u d g i n g t he sameness/ d i f f e r e n c e o f c o l o u r o f two p h y s i c a l o b j e c t s on the b a s i s o f one's p e r c e i v e d c o l o u r s on v i e w i n g them. To do t h i s we s h a l l need t o r e f e r t o the r e l e v a n t p r o p e r t i e s o f p h y s i c a l o b j e c t s , g i v e n the environments i n which t h e y a re b e i n g viewed, i . e . , t h o s e p r o p e r t i e s t h a t determine t he d i f f e r e n c e i n p e r c e i v e d c o l o u r s when a person d i s c r i m i n a t e s by c o l o u r between two p h y s i c a l o b j e c t s . As s t a t e d a l r e a d y , t h e s e p r o p e r t i e s may i n c l u d e r e l a t i o n a l p r o p e r t i e s o f t h e o b j e c t s . In a s i t u a t i o n l i k e the one d e s c r i b e d e a r l i e r where p h y s i c a l o b j e c t s o f t h e same s i z e , and shape, e t c . , a r e p r e s e n t e d i n p a i r s i n a random o r d e r t o v i e w e r s , a viewer who can c o n s i s t e n t l y d i s c r i m i n a t e between two o b j e c t s t h a t no-one e l s e can d i s c r i m i n a t e , i s t h e r e b y deemed a " f i n e r d i s c r i m i n a t o r " than t h e r e s t o f the p e o p l e . T h i s o f c o u r s e i m p l i e s t h a t h i s v e r d i c t — t h a t the two o b j e c t s d i f f e r i n c o l o u r - - i s c o r r e c t , whereas the v e r d i c t s o f the r e s t o f the people t e s t e d — t h a t the o b j e c t s a re the same c o l o u r — a r e wrong. What t h i s amounts t o i s t h a t whatever the r e l e v a n t d i f f e r e n c e i n the p r o p e r t i e s o f the two o b j e c t s , i . e . , whatever d i f f e r e n c e i n t h e i r p r o p e r t i e s d e t e r m i n e s the d i f f e r e n c e i n the " f i n e r d i s c r i m i n a t o r ' s " p e r c e i v e d c o l o u r s on v i e w i n g them, t h a t d i f f e r e n c e i s what makes t h o s e two o b j e c t s " d i f f e r e n t c o l o u r s " . Which p r o p e r t i e s a re r e l e v a n t , and j u s t how t h e s e p r o p e r t i e s d i f f e r i n those o b j e c t s , a r e e m p i r i c a l q u e s t i o n s . What i s not an e m p i r i c a l c l a i m , however, i s t h a t any o t h e r two p h y s i c a l o b j e c t s the r e l e v a n t p r o p e r t i e s o f which a r e q u a l i t a t i v e l y t he same as the r e l e v a n t p r o p e r t i e s o f the two o b j e c t s r e f e r r e d t o above, a l s o d i f f e r i n c o l o u r . (We can e x p e c t t he r e l e v a n t p r o p e r t i e s t o i n c l u d e t h e r e - l a t i o n a l p r o p e r t y g i v i n g the r e l a t i v e p o s i t i o n o f the p e r c e i v e r . ) The " f i n e r d i s c r i m i n a t o r ' s " d i f f e r e n c e i n p e r c e i v e d c o l o u r s on v i e w i n g such a p a i r o f ob- j e c t s must be d e t e r m i n e d by a d i f f e r e n c e i n the p r o p e r t i e s o f tho s e o b j e c t s , o t h e r w i s e t h e r e would be no grounds f o r deeming him t o be a f i n e r d i s c r i m i n a - t o r ( o f t h e c o l o u r s o f p h y s i c a l o b j e c t s ) . H i s v e r d i c t — t h a t such a p a i r o f o b j e c t s a r e d i f f e r e n t i n c o l o u r — i s c o r r e c t ; any one c l a i m i n g t h a t t h o s e two o b j e c t s , o r any o t h e r two o b j e c t s t he p r o p e r t i e s o f which d i f f e r i n the same r e s p e c t s , a re t h e same c o l o u r , w i l l be making a m i s t a k e . The f a c t t h a t not many, perhaps no-one e x c e p t the one p e r s o n , can d i s c r i m i n a t e by c o l o u r between t h e s e p a i r s o f p h y s i c a l o b j e c t s i s i r r e l e v a n t t o t h i s p o i n t . I t would a l s o c o n s t i t u t e a m i s t a k e t o c l a i m t h a t two p h y s i c a l o b j e c t s the r e l e v a n t p r o p e r t i e s o f which a r e q u a l i t a t i v e l y t he same a r e , i n f a c t , d i f f e r e n t i n c o l o u r . A m i s t a k e o f t h i s k i n d can be d e s c r i b e d as a c o n s i s t e n c y - e r r o r . I t would c o n s t i t u t e a m i s t a k e because o f the n e c e s s a r y c o n d i t i o n f o r something to count as a q u a l i t y o f a p h y s i c a l o b j e c t , v i z , "In a c o n s t a n t environment c o n t a i n i n g a p h y s i c a l o b j e c t , c o n f l i c t i n g v e r d i c t s f o r a statement a s c r i b i n g t h e q u a l i t y t o the o b j e c t n e c e s s i t a t e s one v e r d i c t ' s b e i n g i n c o r - r e c t . " Any p h y s i c a l o b j e c t i n a c o n s t a n t environment (which means t h a t the p e r c e i v e r ' s l o c a t i o n , among o t h e r t h i n g s , remains c o n s t a n t ) remains the same c o l o u r . The n e c e s s a r y c o n d i t i o n amounts t o a demand f o r c o n s i s t e n c y i n t h e s e v e r d i c t s . To meet the same demand, i t i s a l s o t r u e t h a t any two p h y s i c a l o b j e c t s i n q u a l i t a t i v e l y the same environment (which i n c l u d e s the n o n - r e l a - t i o n a l p r o p e r t i e s o f the o b j e c t s t h e m s e l v e s ) a r e the same c o l o u r . I t i s c o n c e i v a b l e t h a t some f e a t u r e s o f t h e i r environment a r e not r e l e v a n t t o t h e i r p r e s e n t c o l o u r . Whether o r not t h i s i s i n f a c t the c a s e , i t i s l e g i t i - mate t o c l a i m t h a t two p h y s i c a l o b j e c t s i n environments t h a t a r e r e l e v a n t l y the same have the same c o l o u r , o r , what amounts t o the same c l a i m , any two p h y s i c a l o b j e c t s the p r o p e r t i e s ( i n c l u d i n g the r e l a t i o n a l p r o p e r t i e s ) o f which are t h e same i n a l l the r e l e v a n t r e s p e c t s a r e t h e same c o l o u r . These c o n s i s t e n c y r e q u i r e m e n t s can l e g i t i m a t e l y be made even b e f o r e we have f i n a l l y a r t i c u l a t e d j u s t which are t h e r e l e v a n t p r o p e r t i e s . They a r e n o t e m p i r i c a l c l a i m s , but c l a i m s to do w i t h t he con c e p t o f "the s a m e n e s s / d i f f e r e n c e o f p r e - s e n t c o l o u r o f a p a i r o f p h y s i c a l o b j e c t s " , where the b a s i s o f t h i s c o n c e p t i s t h e p e r c e i v e d c o l o u r s some peopl e have on v i e w i n g t he o b j e c t s . A t the moment our t e s t s f o r the s a m e n e s s / d i f f e r e n c e o f p r e s e n t c o l o u r o f a p a i r o f o b j e c t s i n v o l v e s l o o k i n g a t them w i t h the naked eye, i d e a l l y when t h e o b j e c t s do not d i f f e r i n t h e i r shape, s i z e , e t c . . E v e n t u a l l y we may hope t o have a d i f f e r e n t k i n d o f t e s t which i n v o l v e s l o c a t i n g a r e l e v a n t d i f - f e r e n c e i n the p r o p e r t i e s o f the two o b j e c t s . ( C o n t r a r y t o the pessimism o f some p h i l o s o p h e r s , we a l r e a d y do have a g r e a t deal o f e m p i r i c a l knowledge about which p r o p e r t i e s a r e and which a r e not r e l e v a n t . ^ ) T h i s new t e s t w i l l not r e n d e r t h e common t e s t s i n v a l i d . P a r t o f i t s v i n d i c a t i o n w i l l be the * I t i s p o s s i b l e t h a t the e m p i r i c a l f i n d i n g s may be c o m p l i c a t e d by a " p l u - r a l i t y o f c a u s e s " a t work he r e . I do not wish t o dwell on t h i s p o s s i b i l i t y here ( a l t h o u g h the p o s s i b i l i t y i s d i s c u s s e d i n a l a t e r c o n t e x t , i n the s e c - t i o n on t r a n s p o s i t i o n o f c o l o u r s ) , nor c l a i m t h a t i t e m p i r i c a l l y i s the case w i t h r e g a r d t o the i s s u e mentioned h e r e . I s h a l l p o i n t o u t , however, t h a t t h i s p o s s i b i l i t y does not a f f e c t any o f the p o i n t s made i n t h i s s e c t i o n . c o n c u r r e n c e o f v e r d i c t s reached by a " r e l i a b l e " p e r c e i v e r ' s u s i n g i t and v e r d i e t s reached by a " r e l i a b l e " p e r c e i v e r ' s u s i n g the common t e s t s . I t w i l l n o t change the f a c t t h a t u l t i m a t e l y t h e b a s i s f o r the con c e p t o f sameness/ d i f f e r e n c e o f c o l o u r o f p h y s i c a l o b j e c t s i s the p e r c e i v e d c o l o u r s some peopl have when th e y view t h e o b j e c t s . We s h a l l not have t o d e c i d e on a g e n e r a l p r i o r i t y between t h e new t e s t and the v i s u a l d i s c r i m i n a t i o n t e s t s d e s c r i b e d e a r l i e r . They a r e not r i v a l s i n t h a t sense. (There may be some p a r t i c u l a r odd i n s t a n c e s where a p r i o r i t y must be d e c i d e d upon.) The v i s u a l d i s c r i m i - n a t i o n t e s t s u s i n g p a i r s o f p h y s i c a l o b j e c t s h a v i n g t h e same shape, s i z e , e t c . , depend f o r t h e i r v a l i d i t y upon t h e r e b e i n g p r o p e r t i e s o f t h e viewed o b j e c t s which d e t e r m i n e the s a m e n e s s / d i f f e r e n c e o f some v i e w e r s ' p e r c e i v e d c o l o u r s . 10. Smart, on C o l o u r s In the l i g h t o f the l a s t s e c t i o n I want now t o l o o k a t some p o i n t s made by Smart i n h i s paper, " C o l o u r s . " ^ C e n t r a l t o t h e s e p o i n t s i s h i s c o n c e p t o f a "normal p e r c e i v e r " . T h i s term he d e f i n e s i n two s t e p s : "A person A i s more normal t h a n B w i t h r e s p e c t t o a c e r t a i n type o f c o l o u r d i s c r i m i n a t i o n i f he can d i s c r i m i n a t e t h i n g s w i t h r e s p e c t to c o l o u r t h a t B cannot so d i s c r i m i n a t e . " He then d e f i n e s "normal p e r c e i v e r " as "one who i s a t l e a s t as normal i n r e - s p e c t o f any c o l o u r d i s c r i m i n a t i o n s as i s any o t h e r p e r c i p i e n t . Thus i f A can make d i s c r i m i n a t i o n s w i t h r e s p e c t to c o l o u r t h a t B cannot make then B i s 3 not a normal p e r c i p i e n t . " A normal p e r c e i v e r i n t h i s sense may be an i m a g i - nary person combining the a b i l i t i e s o f s e v e r a l a c t u a l p e o p l e . One o d d i t y about t h i s c o n c e p t i s t h a t no-one can a t any one time be b e t t e r a t c o l o u r - d i s c r i m i n a t i o n than someone who i s a normal p e r c e i v e r a t t h a t t i m e , but t h i s , though u n u s u a l , seems t o cause no s e r i o u s problem i n i t s e l f . I wish t o l o o k a t two s u g g e s t i o n s Smart makes as t o the meaning o f the term " r e d " . The f i r s t i s t h a t ' " t h i s i s r e d ' means r o u g h l y t h a t a normal human p e r c i p i e n t would not e a s i l y p i c k t h i s o u t o f a heap o f geranium p e t a l s 4 though he would e a s i l y p i c k i t out o f a heap o f l e t t u c e l e a v e s . " To b e g i n w i t h , Smart c l e a r l y a c c e p t s t h a t i f one p e r s o n can d i s c r i m i n a t e between two p h y s i c a l o b j e c t s , but a n o t h e r p e r s o n cannot, then t h i s shows t h a t t h e f i r s t person.has " s u p e r i o r a b i l i t y " t o t h a t o f the second. As I p o i n t e d o u t i n the l a s t s e c t i o n a n e c e s s a r y c o n d i t i o n f o r someone's d i s c r i m i n a t i n g two 1 J . J...C. Smart, " C o l o u r s , " P h i l o s o p h y , 36, 1961. 2 I b i d . , p. 136. 3 I b i d . , p. 137. 4 I b i d . , p. 139. T h i s s u g g e s t i o n he made f i r s t i n h i s paper " S e n s a t i o n s and B r a i n P r o c e s s e s , " P h i l o s o p h i c a l Review, 68, 1959. At t h i s s t a g e and f o r sim- p l i c i t y o n l y , I s h a l l s u b s t i t u t e "would match i t w i t h a heap o f geranium petals f o r "would no t e a s i l y p i c k t h i s out o f a heap. . .". T h i s does not a f f e c t t h e v a l i d i t y o f what f o l l o w s . 5 I b i d . , p. 137. p h y s i c a l o b j e c t s on the b a s i s o f a d i f f e r e n c e i n p e r c e i v e d c o l o u r s i s t h a t the p e r c e i v e d c o l o u r s and the d i f f e r e n c e between them be determined by the p h y s i - c a l o b j e c t s . I.e., t h e r e must be some d i f f e r e n c e i n the p r o p e r t i e s o f the two o b j e c t s which a c c o u n t s f o r the d i f f e r e n c e i n p e r c e i v e d c o l o u r s . The person i s not d i s p l a y i n g " s u p e r i o r a b i l i t y " a t d i s c r i m i n a t i n g t h e p h y s i c a l o b j e c t s by c o l o u r i f , f o r example, he i s h a l l u c i n a t i n g . S i n c e i t i s n e c e s s a r y here t o i n t r o d u c e t h e d i f f e r e n c e o f the r e l e v a n t d e t e r m i n i n g p r o p e r t i e s i n the two p h y s i c a l o b j e c t s , we are l o g i c a l l y o b l i g e d a l s o to acknowledge the two k i n d s o f e r r o r t o do w i t h the s a m e n e s s / d i f f e r e n c e o f the d e t e r m i n i n g p r o p e r t i e s a l o n g : c l a i m i n g t h a t two p h y s i c a l o b j e c t s are ( a t p r e s e n t ) the same c o l o u r when t h e i r p r o p e r t i e s are r e l e v a n t l y d i f f e r e n t , and c l a i m i n g t h a t two o b j e c t s a r e d i f f e r e n t c o l o u r s when t h e i r p r o p e r t i e s a r e r e l e v a n t l y t h e same. We can make sense o f the c l a i m t h a t a person who "can d i s c r i m i n a t e " between two ob- j e c t s t h e r e b y d i s p l a y s s u p e r i o r a b i l i t y o n l y i f we r e c o g n i z e t h a t h i s r e s u l t - i n g v e r d i c t t h a t the o b j e c t s a r e d i f f e r e n t c o l o u r s i s c o r r e c t , whereas the r e s u l t i n g v e r d i c t o f someone who cannot so d i s c r i m i n a t e w i l l be i n c o r r e c t - he w i l l c l a i m t h a t t h e o b j e c t s a r e t h e same c o l o u r when the p r o p e r t i e s o f the o b j e c t s a r e r e l e v a n t l y ' d i f f e r e n t . R e t u r n i n g now to Smart's f i r s t s u g g e s t i o n as to what " T h i s i s r e d " means, i t has two l i m i t a t i o n s as i t s t a n d s . The f i r s t i s t o do w i t h the f a c t t h a t the d i s c r i m i n a t o r y a b i l i t y o f what he c a l l s a normal p e r c e i v e r can v a r y . The second i s t o do w i t h the f a c t t h a t the s u g g e s t i o n i s t h a t we d e f i n e a p a r t i c u - l a r c o l o u r - t e r m , " r e d " , i n terms o f d i s c r i m i n a t o r y a b i l i t y a l o n e . I t i s use- f u l t o s e t o u t t h e s e l i m i t a t i o n s and see some o f the f e a t u r e s d e s i r a b l e f o r an a c c o u n t o f t h e c o l o u r s o f p h y s i c a l o b j e c t s . I s h o u l d s t a t e i m m e d i a t e l y t h a t the f i r s t l i m i t a t i o n i s based on what i s c o n c e i v a b l e i n my sense ( i . e . , w i t h o u t r e j e c t i n g any g i v e n f a c t ) r a t h e r than on what i s i n f a c t the case i n the w o r l d a t p r e s e n t . I have e v e r y sympathy w i t h not i n t e n d i n g one's a c c o u n t o f the meaning o f c o l o u r - t e r m s t o cope w i t h problems stemming from s i t u a t i o n s t h a t a r e l o g i c a l l y p o s s i b l e but not c o n c e i v a b l e ( n o t " e m p i r i c a l l y p o s s i b l e " ) . My major c o n c e r n t h r o u g h o u t t he t h e s i s i s to do w i t h what i s c o n c e i v a b l e , what i t i_s p o s s i b l e f o r humans t o know, and what p o s s i b l e problems may be e n c o u n t e r e d , i n t h e l i g h t o f the g i v e n f a c t s o f the w o r l d . On the o t h e r hand an a c c ount can be u n n e c e s s a r i l y r e s t r i c t e d i n t h a t i t cannot, as i t s t a n d s , cope w i t h s i t u a t i o n s t h a t ( e m p i r i c a l l y ) may o c c u r , even i f th e y a r e not ex- pect e d t o . An a c c o u n t which cannot deal w i t h s i t u a t i o n s t h a t do o c c u r i s c l e a r l y d e f e c t i v e , but an a c c o u n t which i s u n n e c e s s a r i l y l i m i t e d i n t h a t i t cannot, but some o t h e r c an, co v e r some c o n c e i v a b l e c a s e s t h a t do not a t t h i s time o c c u r and t h a t may n o t be e x p e c t e d t o o c c u r , i s f o r t h a t r e a s o n l e s s d e s i r a b l e than a more comprehensive a c c o u n t . The f i r s t l i m i t a t i o n I r e f e r t o i s to do w i t h a d r a s t i c r e d u c t i o n i n the normal p e r c e i v e r 1 s d i s c r i m i n a t o r y a b i l i t i e s . I am not s u g g e s t i n g t h a t t he s i t u a t i o n I d e s c r i b e i s one t h a t Smart i n t e n d e d to c o v e r but d i d n o t , but I do s u g g e s t t h a t i t i s more de- s i r a b l e t o c o v e r i t than n o t . Suppose t h e r e i s some environment which remains c o n s t a n t and which con- t a i n s a geranium p e t a l , a l e t t u c e l e a f , and some o t h e r p h y s i c a l o b j e c t , x, and t h a t normal p e r c e i v e r s ( i n Smart's sense) can e a s i l y d i s c r i m i n a t e x from the l e a f (by c o l o u r ) , but cannot d i s c r i m i n a t e x from the p e t a l . R e l y i n g on Smart's s u g g e s t i o n , i n t h i s s i t u a t i o n x i s r e d . Suppose now t h a t a t some l a t e r time normal p e r c e i v e r s have a f a r , f a r lower d i s c r i m i n a t o r y a b i l i t y ( e . g . , as the r e s u l t o f some d i s e a s e , o r i n t e r f e r e n c e from d r u g s , o r some mal- f u n c t i o n o f t h e s e n s o r y a p p a r a t u s o f s i g h t from some o t h e r c a u s e — a l l o f which a r e c o m p a t i b l e w i t h t h e i r b e i n g normal p e r c e i v e r s , s i n c e h i s d e f i n i t i o n o f "normal p e r c e i v e r " i s i n terms o f c o m p a r a t i v e d i s c r i m i n a t o r y a b i l i t y a l o n e ) and t h a t , as a m a t t e r o f f a c t , t h e y cannot now d i s c r i m i n a t e the l e a f from the p e t a l by c o l o u r . A f o r t i o r i t h e y cannot both d i s c r i m i n a t e x from t he l e a f and match i t w i t h t he p e t a l . Ex h y p o t h e s i I am su p p o s i n g t h a t the p e t a l and the l e a f a r e genuine examples o f a geranium p e t a l and a l e t t u c e l e a f , t y p i c a l o f t h o s e k i n d s o f o b j e c t s , and t h a t t h e environment (which i n c l u d e s t h e p e t a l and the l e a f ) has remained c o n s t a n t . In such a s i t u a t i o n , the normal per- c e i v e r s a r e no l o n g e r a b l e t o d i s c r i m i n a t e geranium p e t a l s from l e t t u c e l e a v e s — a c o n c e i v a b l e but unexpected c i r c u m s t a n c e . I f we keep the o r i g i n a l s u g g e s t i o n , then i n t h i s s i t u a t i o n x i s not r e d s i n c e i t i s not an o b j e c t which normal p e r c e i v e r s both match w i t h geranium p e t a l s and d i s c r i m i n a t e from l e t t u c e l e a v e s ( s i n c e ex h y p o t h e s i they cannot d i s c r i m i n a t e between the p e t a l s and the l e a v e s by c o l o u r ) . But t h i s would mean t h a t one and the same p h y s i c a l ob- j e c t , x, i n a c o n s t a n t environment i s both r e d and not r e d , and t h i s v i o l a t e s a n e c e s s a r y c o n d i t i o n f o r something t o count as a q u a l i t y o f some p h y s i c a l ob- j e c t , v i z , i n a c o n s t a n t environment c o n t a i n i n g t he p h y s i c a l o b j e c t i n ques- t i o n , c o n f l i c t i n g v e r d i c t s f o r statements a t t r i b u t i n g t h e q u a l i t y to t h e ob- j e c t n e c e s s i t a t e s one v e r d i c t ' s b e i n g i n c o r r e c t . ^ T h i s v i o l a t i o n i s not s u r - p r i s i n g g i v e n the r o l e the n o t i o n o f "a normal p e r c e i v e r " would have here and g i v e n t h a t the d i s c r i m i n a t o r y a b i l i t y o f a normal p e r c e i v e r can v a r y w i t h time, we can, i n f a c t , say more than t h a t t he v e r d i c t s a r e i n c o m p a t i b l e . The v e r - d i c t o f t h e l a t e r group o f normal p e r c e i v e r s would be unsound, s i n c e i n o r d e r t o reach a v e r d i c t about t h i s s o u n d l y , one must be a b l e t o judge a c c u r a t e l y the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f t h e l e a f and the p e t a l , and t h i s ex hypo- t h e s i t h e y cannot do. R e g a r d l e s s o f the sameness o f t h e i r p e r c e i v e d c o l o u r s when t h e y view t h e p e t a l and the l e a f , t he two p h y s i c a l o b j e c t s a re d i f f e r e n t c o l o u r s i f t h e i r p r o p e r t i e s a r e r e l e v a n t l y d i f f e r e n t . T h i s c o n c e i v a b l e c Some r e l a t i o n a l p r o p e r t i e s o f the o b j e c t a r e n o t f e a t u r e s o f the environment, v i z , t h o s e d e termined by the s t a t e o f the p e r c e i v e r , t he s t a t e o f the p e r c e i v e r b e i n g i t s e l f e x c l u d e d from the n o t i o n o f the environment. So, a l t h o u g h t h e s e r e l a t i o n a l p r o p e r t i e s may w e l l have changed i n t h i s example, t h i s does n o t mean the environment has not remained c o n s t a n t . s i t u a t i o n I s h o u l d p r e f e r t o d e a l w i t h r a t h e r than not. I t i s i n f a c t easy t o d e a l w i t h i n the way I i n d i c a t e above, by a r g u i n g t h a t the v e r d i c t s o f n o r - mal p e r c e i v e r s a t t h e l a t e r time a r e unsound s i n c e t h e y do not have t h e a b i l i t y t o t e s t the s t a t e m e n t "x i s r e d " i n the way s u g g e s t e d . To r e s o l v e the con- f l i c t o f v e r d i c t s i n t h i s way one must f i r s t have acknowledged t h a t f o r some- one's p e r c e i v e d c o l o u r s to be " i d e a s o f the p h y s i c a l w o r l d " (even i f the i d e a s do not "resemble" p r o p e r t i e s t h a t p h y s i c a l o b j e c t s have " i n themselves"), they must be d etermined by t h e p h y s i c a l w o r l d , and s e c o n d l y , when t h e p r o p e r t i e s o f a p a i r o f p h y s i c a l o b j e c t s are r e l e v a n t l y d i f f e r e n t , someone whose p e r c e i v e d c o l o u r s a r e t h e same when he views the o b j e c t s w i l l have an u n r e l i a b l e b a s i s f o r j u d g i n g the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f t h o s e o b j e c t s . In s h o r t , one must u n d e r s t a n d the r o l e p l a y e d by t h e r e l e v a n t p r o p e r t i e s o f t h e p h y s i - c a l o b j e c t s i n t h e i r b e i n g the s a m e / d i f f e r e n t c o l o u r . And s i n c e t h i s under- s t a n d i n g i s r e q u i r e d even f o r o r d i n a r y c a s e s o f u s i n g one's p e r c e i v e d c o l o u r s as a b a s i s on which t o judge the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f a p a i r o f p h y s i c a l o b j e c t s ( i . e . , f o r the c a s e s t h a t do now o c c u r ) , one may as w e l l make i t e x p l i c i t and then show how i t c o v e r s p r o b l e m - c a s e s , even i f the problems a r e n o t e x p e c t e d a c t u a l l y t o o c c u r . There i s one o t h e r l i m i t a t i o n t o Smart's s u g g e s t i o n as t o what " t h i s i s r e d " means, and i t i s a l i m i t a t i o n which a p p l i e s t o h i s second s u g g e s t i o n as w e l l . I s h o u l d make e x p l i c i t t h a t Smart does make p a s s i n g r e f e r e n c e t o the second l i m i t a t i o n e l s e w h e r e ( i n h i s P h i l o s o p h y and S c i e n t i f i c R e a l i s m ) , so he i s aware o f t h e problem. S t i l l , s i n c e the m a t t e r i s n o t mentioned i n the paper d i s c u s s e d i t w i l l be h e l p f u l t o d e s c r i b e i t c l e a r l y , as something t o be d e a l t w i t h . Smart's second s u g g e s t i o n i s t h a t we can r e g a r d such a phrase as "the c o l o u r o f tomatoes" as a d e f i n i t i o n o f " r e d " . 7 From the c o n t e x t o f the paper, i t i s c l e a r t h a t Smart means "the c o l o u r o f tomatoes as seen by a 7 S m a r t , " C o l o u r s , " p. 140. normal p e r c e i v e r ( i n h i s s e n s e ) " . T h i s , he c l a i m s , i s a " p e r f e c t l y good i n s t r u c t i o n " f o r someone who knows the word " c o l o u r " , but not the word " r e d " . I t i s much l e s s cumbersome t o e x p l a i n the second l i m i t a t i o n by r e f e r r i n g t o t h i s second s u g g e s t i o n o f Smart's s i n c e i t i n v o l v e s o n l y one k i n d o f p h y s i - c a l o b j e c t , v i z , tomatoes. A g a i n the l i m i t a t i o n i s to do w i t h s i t u a t i o n s which a r e , I b e l i e v e , c o n c e i v a b l e ( i n my s e n s e ) , a l t h o u g h they may not i n f a c t o c c u r a t t h i s time. L o o k i n g now a t Smart's second s u g g e s t i o n t h a t we r e g a r d "the c o l o u r o f tomatoes (as seen by normal p e r c e i v e r s ) " as a d e f i n i t i o n o f " r e d " , t h e r e a r e two d i f f e r e n t ways o f d e f i n i n g t h e term "tomato": so t h a t t h e r e i s no r e s t r i c - t i o n as to t h e a c t u a l p e r c e i v e d c o l o u r tomatoes p r e s e n t t o any one p e r c e i v e r , o r , so t h a t t h e r e i s some such r e s t r i c t i o n . To be more s p e c i f i c f o r my pur- pose h e r e , the term "tomato" can be d e f i n e d a) so t h a t no p e r c e i v e d c o l o u r a normal p e r c e i v e r has upon v i e w i n g a p h y s i c a l o b j e c t i n " s t a n d a r d " e n v i r o n - ments ( f o r t h a t k i n d o f o b j e c t ) can i n i t s e l f p r e c l u d e the o b j e c t ' s b e i n g a tomato; o r , b) so t h a t t h e r e i s a t l e a s t one p a r t i c u l a r c o l o u r w h ich, i f p e r - c e i v e d by a normal p e r c e i v e r when he views a p h y s i c a l o b j e c t i n one o f t h o s e " s t a n d a r d " e n v i r o n m e n t s , p r e c l u d e s the o b j e c t ' s b e i n g a tomato. Suppose we d e f i n e "tomato", o r r a t h e r , t o g i v e Smart's s u g g e s t i o n t he b e s t b a s i s , suppose we d e f i n e " r i p e tomato" i n t h e f i r s t o f t h e two ways, e.g., i n terms o f i t s shape, t e x t u r e , p l a n t p r o d u c i n g i t , i t s h a v i n g seeds i n s i d e i t , e t c . , but w i t h no r e f e r e n c e t o i t s p r e s e n t i n g any p a r t i c u l a r p e r - c e i v e d c o l o u r i n any p a r t i c u l a r k i n d o f s i t u a t i o n . Then the c o l o u r a normal p e r c e i v e r sees when he views such an o b j e c t i n a s t a n d a r d environment i s t o be c a l l e d " r e d " . But then i f a t some time t h e r e i s an i n s t a n c e o f the same normal p e r c e i v e r ' s s e e i n g a v e r y d i f f e r e n t c o l o u r when he views a tomato i n a s t a n d a r d environment, then t h a t c o l o u r t o o i s to be c a l l e d " r e d " . And t h i s 67 s i t u a t i o n i s , I t h i n k , c o n c e i v a b l e . For example, imagine a normal p e r c e i v e r s e e i n g a r i p e tomato which p r e s e n t s him w i t h a c o l o u r which the r e a d e r would c a l l " r e d " . I f t h e same normal p e r c e i v e r a t some time l a t e r sees a r i p e tomato and t h e r e b y p e r c e i v e s a c o l o u r t h a t he and the r e a d e r would c a l l " y e l - low", then t h a t c o l o u r i s t o be c a l l e d " r e d " , and " y e l l o w " becomes a redun- dant term. T h i s s i t u a t i o n c o u l d be brought about by tampering w i t h the p e r - c e p t u a l environment i n c l u d i n g t h e tomato, w i t h t o m a t o - p l a n t s , o r w i t h t he p e r c e i v e r , p r o v i d i n g t h a t a f t e r t h e changes the p e r c e i v e r would s t i l l be a normal p e r c e i v e r and the environment c o u l d s t i l l l e g i t i m a t e l y be d e s c r i b e d as s t a n d a r d f o r v i e w i n g such t h i n g s as r i p e tomatoes. The p r o d u c t i o n o f such i n - s t a n c e s c o u l d r e s u l t i n an a b s u r d l y reduced s t o c k o f c o l o u r - t e r m s , which would not be u s e f u l g i v e n t he g r e a t v a r i e t y o f d i f f e r e n t c o l o u r s many peopl e p e r - c e i v e . I am not s u g g e s t i n g t h a t t h i s p o s s i b i l i t y cannot be d e a l t w i t h , nor even t h a t Smart c o u l d not dea l w i t h i t . I am c l a i m i n g , however, t h a t i n o r d e r t o d e a l w i t h i t one must be p r e p a r e d t o make r e f e r e n c e t o t h e p a r t i c u l a r p e r - c e i v e d c o l o u r s , o r , i n Smart's p h r a s e , the " a c t u a l q u a l i a o f our [ c o l o u r ] sense- d a t a " , an i n d i v i d u a l has a t d i f f e r e n t t i m e s . He does a t one p o i n t c l a i m t h a t "the a c t u a l q u a l i a o f our [ c o l o u r ] s e n s e - d a t a m a t t e r not a t a l l so l o n g as t h e r e i s a one-one mapping o f the s e t o f s e n s e - d a t a produced i n me on t o the s e t o f s e n s e - d a t a produced i n you by v a r i o u s s t i m u l i . " ^ Smart makes t h i s c l a i m i n r e f e r e n c e t o i n t e r - s u b j e c t i v e d i f f e r e n c e s i n p e r c e i v e d c o l o u r s , but i t i s n o n e t h e l e s s m i s l e a d i n g a s . i t s t a n d s . ( T h i s i s the p o i n t he acknowledges i n h i s book, P h i l o s o p h y and S c i e n t i f i c Realism.) Even i f t h e r e i s always such 9 T h i s i s a b i t s i m p l i f i e d . T h i s one i n s t a n c e would not make the term " y e l l o w " redundant, s i n c e i t would s t i l - 1 be used f o r t h o s e shades 'of y e l l o w ' not i n -v o l v e d i n t h i s i n s t a n c e . S t r i c t l y s p e a k i n g , the term " y e l l o w " would be redun-d a n t i f i n s t a n c e s l i k e t h e one d e s c r i b e d o c c u r r e d f o r e v e r y shade p r e v i o u s l y c a l l e d " y e l l o w " by the p e r c e i v e r mentioned. 1 0 S m a r t , " C o l o u r s , " p. 129. 68 a mapping between my s e t o f p e r c e i v e d c o l o u r s and y o u r s e t , t he a c t u a l " q u a l i a " s t i l l m a t t e r i n t h a t t h e y may have t o be r e f e r r e d t o i n o r d e r t o s o r t out con- f u s i o n s r e s u l t i n g from c e r t a i n i n t r a - s u b j e c t i v e changes i n p e r c e i v e d c o l o u r s from one time t o a n o t h e r . The s i t u a t i o n d e s c r i b e d above and the c o n f u s i o n i n - v o l v e d i s j u s t such a c a s e . L o o k i n g back a t the s i t u a t i o n mentioned above and the p r o p o s a l we have to h a n d - - t h a t we d e f i n e " r e d " as the c o l o u r o f r i p e tomatoes (as seen by a nor- mal p e r c e i v e r ) " — t h e r e i s one amendment to the p r o p o s a l t h a t may seem a t f i r s t g l a n c e p r o m i s i n g . I t does n o t , i n f a c t , p r e v e n t t he k i n d o f r e d u c t i o n i n c o l o u r - t e r m s d e s c r i b e d e a r l i e r , but s i n c e i t i s an amendment t h a t r e f e r s o n l y t o the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f p h y s i c a l o b j e c t s and t o the sameness/ d i f f e r e n c e o f p e r c e i v e d c o l o u r s , l o o k i n g a t i t b r i e f l y w i l l h e l p show how we need a l s o t o r e f e r t o t h e p a r t i c u l a r p e r c e i v e d c o l o u r s i n v o l v e d . That i s t o say, i t w i l l h e l p t o show why, even w i t h the amendment, the p a r t i c u l a r p e r - c e i v e d c o l o u r s ( t h e " a c t u a l q u a l i a " ) s t i l l 'matter'. The amendment I have i n mind i s the i n t r o d u c t i o n o f s a m e n e s s / d i f f e r e n c e - o f - c o l o u r r e l a t i o n s h o l d i n g between u s u a l r i p e tomatoes and o t h e r p h y s i c a l o b j e c t s . For example, l e t us amend the p r o p o s a l t o r e a d : Red i s the c o l o u r o f a r i p e tomato when seen by a normal p e r c e i v e r i n a s t a n d a r d environment ( f o r tomatoes) p r o v i d i n g the p e r - c e i v e d c o l o u r i s the same as t h a t p r e s e n t e d t o t h e normal p e r c e i v e r ( i n s t a n - dard e nvironments) by a geranium p e t a l , a l e t t e r - b o x , a s t o p l i g h t , e t c . , and d i f f e r e n t from t h a t p r e s e n t e d t o t h e normal p e r c e i v e r ( i n s t a n d a r d environments) by a l e t t u c e l e a f , b l u e b e l l s , snow, e t c . . 1 1 ^ A g a i n , t h i s c o n t a i n s the same s i m p l i f i c a t i o n as t h a t r e f e r r e d t o i n f n . 9 i n t h i s s e c t i o n . "Being t he same c o l o u r as" can here be read as "be i n g t he same o r a v e r y s i m i l a r c o l o u r " , and " b e i n g a d i f f e r e n t c o l o u r from" as " b e i n g v e r y u n l i k e " , b ut s i n c e t h e s e p h r a s e s have n o t y e t been examined, I s h a l l not use them here. T h i s s i m p l i f i c a t i o n h o l d s f o r the r e s t o f t h i s s e c t i o n . I t w i l l n ot be h e l p f u l t o i n t e r p r e t t h i s amended p r o p o s a l so t h a t i t i s a suf- f i c i e n t and n e c e s s a r y c o n d i t i o n f o r the tomato's b e i n g r e d t h a t a l l o f a l o n g l i s t o f such r e l a t i o n s h o l d , i . e . , so t h a t i f even one o f them does n o t h o l d , then the tomato i s n o t r e d . T h i s would produce c o n t r a d i c t i o n s . For example, suppose a l l the r e l a t i o n s s p e c i f i e d h o l d f o r the p e r c e i v e d c o l o u r a normal p e r c e i v e r has when v i e w i n g a r i p e tomato i n some s t a n d a r d environment. Then, on t h i s p r o p o s a l , t he tomato i s r e d . But i f a t some l a t e r time any o f the p h y s i c a l o b j e c t s mentioned change ( e . g . , by d e v e l o p i n g f l o w e r s which we s h o u l d c a l l "geraniums", but which p r e s e n t a normal p e r c e i v e r w i t h a v e r y d i f f e r e n t p e r c e i v e d c o l o u r from t h a t seen when v i e w i n g e a r l i e r examples o f g e r a n i u m s ) , then some o f the s p e c i f i e d r e l a t i o n s do not h o l d . And i f i t i s a n e c e s s a r y (as w e l l as a s u f f i c i e n t ) c o n d i t i o n f o r t h e tomato's b e i n g r e d t h a t a l l t he s p e c i f i e d r e l a t i o n s ( o f s a m e n e s s / d i f f e r e n c e o f c o l o u r w i t h o t h e r o b j e c t s ) h o l d , t h e n , a t t h i s l a t e r t i m e , the tomato i s not r e d . But the p e r c e i v e d c o l o u r pre- s e n t e d by the tomato to a normal p e r c e i v e r c o u l d be q u a l i t a t i v e l y the same a t both t i m e s , and so too c o u l d the environment i n which i t was viewed. Given my use o f "environment", t o say here t h a t the environment remains c o n s t a n t i s to say t h a t t h e p a r t i c u l a r p h y s i c a l o b j e c t i n q u e s t i o n — t h e t o m a t o — r e m a i n s c o n s t a n t . We s h o u l d thus have a c o n t r a d i c t i o n s i n c e , i n t h i s s i t u a t i o n , one and t h e same p h y s i c a l o b j e c t i n a c o n s t a n t environment i s deemed t o be both r e d and n o t r e d , and t h i s v i o l a t e s the n e c e s s a r y c o n d i t i o n f o r something ( h e r e , " b e i n g red") t o count as a q u a l i t y (perhaps a r e l a t i o n a l p r o p e r t y ) o f some p h y s i c a l o b j e c t , i . e . , t he c o n d i t i o n t h a t " i n a c o n s t a n t environment, con- f l i c t i n g v e r d i c t s f o r statements a t t r i b u t i n g the q u a l i t y to a p h y s i c a l o b j e c t n e c e s s i t a t e s one (group o f ) v e r d i c t ' s b e i n g i n c o r r e c t . " ( T h i s c o n d i t i o n was f i r s t mentioned on p.53 above.) To t r y t o a v o i d such c o n t r a d i c t i o n s , we can i n t e r p r e t t h e amended p r o - posal as a s u f f i c i e n t , but not a n e c e s s a r y c o n d i t i o n , f o r the tomato's b e i n g 70 r e d . But f o r t h i s p r o p o s a l a l s o , t h e r e are some s i t u a t i o n s which I b e l i e v e 12 a r e c o n c e i v a b l e which i t would, t h e r e f o r e , be d e s i r a b l e t o deal w i t h , but which cannot be d e a l t w i t h by t h i s p r o p o s a l . The p r o p o s a l can r e s u l t i n a d r a s t i c r e d u c t i o n o f c o l o u r - t e r m s i f the f o l l o w i n g s i t u a t i o n i s c o n c e i v a b l e : t h a t a normal p e r c e i v e r ( i n Smart's sense) a t one time sees the c o l o u r c-|When v i e w i n g a tomato i n a s t a n d a r d environment, and a l l t h e s p e c i f i e d sameness/ d i f f e r e n c e - o f - c o l o u r r e l a t i o n s h o l d , and t h a t a t some o t h e r t i m e , b e i n g s t i l l a normal p e r c e i v e r , he sees the c o l o u r c^ when v i e w i n g a tomato i n a s t a n d a r d environment, and a l l the s p e c i f i e d s a m e n e s s / d i f f e r e n c e - o f - c o l o u r r e l a t i o n s h o l d , where c^ and are v e r y d i f f e r e n t c o l o u r s ( e . g . , what the r e a d e r would c a l l " r e d " and what he would c a l l " y e l l o w " ) . I f we r e l i e d on the p r o p o s a l i n t h i s s i t u a t i o n , t h e n both c-j and are t o be deemed t o be i n s t a n c e s o f the c o l o u r " r e d " , and a r e d u c t i o n o f c o l o u r - t e r m s can r e s u l t . Here i t would be the c o l o u r - t e r m " y e l l o w " ( f o r t h e r e a d e r ) t h a t would be i n danger o f be- coming redundant. ( I t would be redundant i f s i t u a t i o n s l i k e the one d e s c r i b e d o c c u r r e d f o r e v e r y shade p r e v i o u s l y c a l l e d " y e l l o w " by the r e a d e r . ) I f t h i s s i t u a t i o n i s c o n c e i v a b l e , even i f unexpected, then I c o n s i d e r i t d e s i r a b l e f o r an a c c o u n t o f the meaning o f c o l o u r - t e r m s , such as " r e d " , to be a b l e t o d e a l w i t h i t . T h i s can be done, but o n l y i f one i s p r e p a r e d t o make e x p l i c i t r e f e r - ence to the a c t u a l p e r c e i v e d c o l o u r s ( a s i d e from the terms c o v e r i n g them) p r e s e n t e d by c e r t a i n p h y s i c a l o b j e c t s i n c e r t a i n s i t u a t i o n s to c e r t a i n p e o p l e . I wish now to g l a n c e a t the a l t e r n a t i v e way o f c o n s t r u i n g Smart's sug- g e s t i o n f o r a d e f i n i t i o n o f " r e d " , by d e f i n i n g "tomato" i n sense ( b ) , i . e . , so t h a t t h e r e i s a t l e a s t one p a r t i c u l a r c o l o u r which, i f p e r c e i v e d by a nor- mal p e r c e i v e r when he views an o b j e c t i n a s t a n d a r d environment ( f o r tomatoes), p r e c l u d e s the o b j e c t ' s b e i n g a tomato. The phrase "the c o l o u r o f tomatoes", 12 " C o n c e i v a b l e " i s always t o be c o n s t r u e d i n the sense I use i t , i . e . , "con- c e i v a b l e w i t h o u t r e j e c t i n g any g i v e n f a c t " , and i s t o be d i s t i n g u i s h e d from " l o g i c a l l y p o s s i b l e " which i s not q u a l i f i e d i n t h i s way. Smart c l a i m s , can be taken as a d e f i n i t i o n o f " r e d " ; i t i s "a p e r f e c t l y good i n s t r u c t i o n " f o r someone who knows the word " c o l o u r " but not the word " r e d " . F i r s t o f a l l i t i s c l e a r t h a t i f we take the s u g g e s t i o n to be t h a t we g i v e the phrase as a p u r e l y v e r b a l i n s t r u c t i o n to a s i g h t e d p e r s o n , then the i n - s t r u c t i o n w i l l be u n h e l p f u l , even i f t h e s i g h t e d person r e c e i v i n g t h i s i n s t r u c - t i o n i s a normal p e r c e i v e r . To make use o f the v e r b a l i n s t r u c t i o n , he must be a b l e t o then l o o k a t tomatoes and see the p e r c e i v e d c o l o u r t h e y p r e s e n t . But t h i s he cannot do u n t i l he can i d e n t i f y some p h y s i c a l o b j e c t s as tomatoes ( r i p e t o m a t o e s ) , and g i v e n the way the term "tomato" i s here d e f i n e d , he can- not do t h i s u n t i l he knows which p e r c e i v e d c o l o u r s p r e c l u d e an o b j e c t ' s b e i n g a tomato, and so p r e c l u d e i t s b e i n g r e d . In s h o r t , the v e r b a l i n s t r u c t i o n would be u s e f u l o n l y t o someone who has no need o f i t . So I s h a l l c o n s t r u e the s u g g e s t i o n i n a d i f f e r e n t w a y and drop the r e f e r - ences t h a t Smart makes t o "the phrase 'the c o l o u r o f tomatoes'". I s h a l l sup- pose t h a t the i n s t r u c t i o n i s to be g i v e n o s t e n s i v e l y , by p o i n t i n g t o an example o f a tomato, so t h a t , t a u t o l o g o u s l y , the o b j e c t i n d i c a t e d does not have any c o l o u r w h ich, i n i t s e l f , p r e c l u d e s a p h y s i c a l o b j e c t ' s b e i n g a tomato, and so p r e c l u d e s i t s b e i n g r e d . The i d e a l case here i s when the i n s t r u c t i o n i s g i v e n by a normal p e r c e i v e r t o a normal p e r c e i v e r i n a s t a n d a r d environment ( f o r t o m a t o e s ) . A g a i n t h e r e are s i t u a t i o n s where t h e r e would be problems w i t h the p r o p o s a l , and i f t h o s e s i t u a t i o n s a r e c o n c e i v a b l e , then even i f Smart d i d not i n t e n d h i s a c c o u n t t o d e a l w i t h them, i t i s s t i l l more d e s i r a b l e t o do so than not. Suppose t h a t a normal p e r c e i v e r o s t e n s i v e l y d e f i n e s " r e d " f o r a n o t h e r normal p e r c e i v e r by p o i n t i n g t o a tomato i n a s t a n d a r d environment, and sup- pose t h a t the i n s t r u c t o r here p e r c e i v e s some c o l o u r c-j and t h a t the o t h e r p e r - c e i v e r sees c (where c-, and c may o r may not be the same c o l o u r ) . The i n - a i a s t r u c t o r can a l s o i n d i c a t e p h y s i c a l o b j e c t s which p r e s e n t p e r c e i v e d c o l o u r s which i n themselves p r e c l u d e the o b j e c t s ' b e i n g tomatoes (and r e d ) . As an example o f t h i s , suppose the i n s t r u c t o r p o i n t s t o an o b j e c t which p r e s e n t s him w i t h t he c o l o u r i n t h a t environment and p r e s e n t s the o t h e r p e r c e i v e r w i t h c ^ (which may o r may not be t h e same as c^). S i n c e t h e y a re both normal p e r - c e i v e r s ( i n Smart's s e n s e ) , they d i s c r i m i n a t e between the same p a i r s o f p h y s i - c a l o b j e c t s , and s i n c e c-j and c^ a r e d i f f e r e n t c o l o u r s , so too are c g and c^. In f a c t , a t the time o f t h e s e showings the s a m e n e s s / d i f f e r e n c e - o f - c o l o u r r e - l a t i o n s h o l d i n g between the p e r c e i v e d c o l o u r o f the tomato and the p e r c e i v e d c o l o u r s p r e s e n t e d by o t h e r o b j e c t s a r e t h e same f o r both p e r c e i v e r s ; e.g., any o b j e c t i n a c e r t a i n environment which p r e s e n t s the i n s t r u c t o r w i t h the same p e r c e i v e d c o l o u r as t h a t p r e s e n t e d by the tomato here w i l l l i k e w i s e p r e s e n t the o t h e r p e r c e i v e r w i t h t he c o l o u r he p e r c e i v e s when he views the tomato here- i n t h i s s i t u a t i o n , the l a t t e r w i l l c o n c l u d e t h a t c i s r e d and t h a t c, , among a -b' 3 o t h e r s , i s n o t r e d . But i f the f o l l o w i n g i s c o n c e i v a b l e a c o n t r a d i c t i o n can a r i s e . Suppose t h a t a t some time l a t e r i n the same environment the i n s t r u c t e d p e r c e i v e r views the 'tomato' and p e r c e i v e s a c o l o u r he e a r l i e r c o n c l u d e d from h i s i n s t r u c t i o n was not r e d , a c o l o u r , i n f a c t , which he b e l i e v e d p r e c l u d e d an o b j e c t ' s b e i n g a tomato, e.g., the c o l o u r c^. And on v i e w i n g the o b j e c t s which p r e v i o u s l y p r e s e n t e d t o him the p e r c e i v e d c o l o u r c^ and which were shown to him as p r e s e n t i n g examples o f a c o l o u r which p r e c l u d e s an o b j e c t ' s b e i n g a tomato (and r e d ) , he now p e r c e i v e s the c o l o u r c , which he thought e a r l i e r was the c o l o u r r e d . The two c o l o u r s c Q and c^ have, i n t h i s environment, ' i n t e r - changed'. I f the i n s t r u c t o r ' s p e r c e i v e d c o l o u r s i n t h i s environment have not 'inter-changed' and he r e p e a t s h i s i n s t r u c t i o n s a t the l a t e r t i m e , then t he other p e r c e i v e r w i l l be l e f t w i t h two c o n t r a d i c t i o n s : f i r s t he w i l l c o n c l u d e t h a t c a i s r e d and c^, among o t h e r s , i s a c o l o u r p r e c l u d i n g an o b j e c t ' s b e i n g a tomato, and i f i t i s c o n c e i v a b l e f o r a normal p e r c e i v e r t o see one c o l o u r a t one time and a n o t h e r " v e r y d i f f e r e n t " c o l o u r a t a n o t h e r time when v i e w i n g one 13 and the same p h y s i c a l o b j e c t i n a c o n s t a n t environment , then something more The environment, w i t h my d e f i n i t i o n o f the term, does i n c l u d e t he p h y s i c a l o b j e c t i n q u e s t i o n but does not i n c l u d e t he s t a t e o f the p e r c e i v e r . 73 i s needed f o r the d e f i n i t i o n not to run i n t o t r o u b l e i n r e g a r d t o such a s i t u - a t i o n . As both the e a r l i e r and the l a t e r t i m e , the s a m e n e s s / d i f f e r e n c e - o f c o l o u r r e l a t i o n s between the person's p e r c e i v e d c o l o u r when he views the 'tomato' and h i s p e r c e i v e d c o l o u r when he views some o t h e r o b j e c t a r e the same. I t has been e x p l a i n e d e a r l i e r i n the t h e s i s t h a t i n o r d e r f o r p e r c e i v e d c o l o u r s t o be e p i s t e m o l o g i c a l l y t r u s t w o r t h y f o r a s c r i b i n g s a m e n e s s / d i f f e r e n c e - o f - c o l o u r t o a p a i r o f p h y s i c a l o b j e c t s , o r f o r a s c r i b i n g a p a r t i c u l a r c o l o u r t o a p a r t i c u l a r o b j e c t , the p e r c e i v e d c o l o u r s must be determined by the p h y s i - c a l o b j e c t s i n q u e s t i o n . We may hope e v e n t u a l l y t o d i s c o v e r p r e c i s e l y which p r o p e r t i e s ( r e l a t i o n a l and n o n - r e l a t i o n a l ) o f a p h y s i c a l o b j e c t are r e l e v a n t t o the p e r c e i v e d c o l o u r i t d e termines f o r a v i e w e r , and then to produce t e s t s f o r the r e l e v a n t s a m e n e s s / d i f f e r e n c e o f t h e s e p r o p e r t i e s i n two ( o r more) p h y s i c a l o b j e c t s . But t h i s i n i t s e l f would not s o l v e the c o n t r a d i c t i o n s r e - f e r r e d t o above, s i n c e t h o s e c o n f l i c t i n g c l a i m s a r e not m erely about the same- n e s s / d i f f e r e n c e o f c o l o u r o f v a r i o u s p a i r s o f p h y s i c a l o b j e c t s , but are about the p a r t i c u l a r c o l o u r s o f the o b j e c t s i n q u e s t i o n . A l l t h a t such a t e s t would do would be t o c o n f i r m t h a t the person has a genuine c o n f l i c t o f c l a i m s , s i n c e i t would e n a b l e him t o check t h a t the r e l e v a n t p r o p e r t i e s o f t h e 'tomato' have i n d e e d remained c o n s t a n t (as they d i d , s i n c e ex h y p o t h e s i the environment r e - mained c o n s t a n t ) . I c o n c l u d e t h a t the most p r o m i s i n g a c c o u n t o f the e p i s t e m o l o g y o f c o l o u r - s t a t e m e n t s w i l l acknowledge the r o l e o f the r e l e v a n t " d e t e r m i n i n g " p r o p e r t i e s o f p h y s i c a l o b j e c t s ( i . e . , t h o s e p r o p e r t i e s r e l e v a n t to the d e t e r m i n a t i o n o f someone's p e r c e i v e d c o l o u r s on v i e w i n g the o b j e c t s ) , and w i l l p e r m i t r e f e r e n c e t o the a c t u a l p e r c e i v e d c o l o u r s ( t h e 'actual q u a l i a o f c o l o u r s e n s e - d a t a " , i n Smart's language) a s i d e from the terms t h a t w i l l be deemed t o c o v e r them. I t w i l l a l s o i n c l u d e c e r t a i n a p r i o r i s t atements about the i n c o m p a t i b i l i t y o f some c o l o u r s , and a c l o s e r i n v e s t i g a t i o n i n t o the r o l e o f the p e r c e i v e r ' s s t a t e i n 74 c o l o u r - p e r c e p t i o n o f p h y s i c a l o b j e c t s . 75 11. T r a n s p o s i t i o n o f C o l o u r s Between P e r c e i v e r s Smart c l a i m s t h a t a person " c o u l d never be s u r e " t h a t he saw the same c o l o u r as some o t h e r p e r s o n , and i t seems to be i n response t o t h i s t h a t he c l a i m s t h a t " t he a c t u a l q u a l i a o f our [ c o l o u r ] s e n s e - d a t a m a t t e r n o t a t a l l so l o n g as t h e r e i s a one-one mapping o f the s e t o f s e n s e - d a t a produced i n me on t o t h e s e t o f s e n s e - d a t a produced i n you by v a r i o u s s t i m u l i .v" What Smart has i n mind here a r e i n t e r - s u b j e c t i v e d i f f e r e n c e s between the c o l o u r s seen by d i f f e r e n t p e o p l e . I s h a l l e x p l a i n i n S e c t i o n 12 t h a t t h e r e a re th e o - r e t i c a l r e a s o n s why such d i f f e r e n c e s would "matter". In t h i s s e c t i o n I s h a l l argue t h a t the m o t i v a t i o n f o r c l a i m i n g t h a t they do not m a t t e r i s dubious i n t h a t the 'problem' i t i s i n t e n d e d t o a v o i d — t h a t one can "never be s u r e " t h a t one sees t h e same c o l o u r as an o t h e r p e r s o n - - i s not an i n s o l u b l e problem. I t i s commonly h e l d t h a t t h e r e a re s p e c i a l problems t o do w i t h the " l o g - i c a l p o s s i b i l i t y " o f a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s i n the c o l o u r - v i s i o n o f d i f f e r e n t p e r c e i v e r s . The c e n t r a l c l a i m i s t h a t s i n c e t h i s i s l o g i - i c a l l y p o s s i b l e , we cannot be s u r e t h a t two o r more peopl e who can d i s c r i m i - n a t e by c o l o u r between t h e same p a i r s o f p h y s i c a l o b j e c t s d o , i n f a c t , see the same p e r c e i v e d c o l o u r s i n each s i t u a t i o n , s i n c e a s y s t e m a t i c t r a n s p o s i t i o n l o g i c a l l y c o u l d not be d e t e c t e d . I s h a l l r e f e r t o t h i s c o r e as the "Transpo- s i t i o n Argument". To un d e r s t a n d t h e T r a n s p o s i t i o n Argument a d i s t i n c t i o n must be drawn be- tween s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s between two p e o p l e , and what I s h a l l c a l l " o v e r - l a p p i n g " t r a n s p o s i t i o n . T h i s can be done most c l e a r l y by making use o f a few symbols. We have s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s between two p e o p l e when and o n l y when: t h e r e i s a s e t o f d i f f e r e n t c o l o u r s , C^, Cg, C» . . . C , and a n o t h e r s e t , c . , c 0 , c 0 . . . c , which i s one-one c o r r e l a t e d i n l d. $ n ^ S m a r t , p. 129. 76 such t h a t where the one person p e r c e i v e s c o l o u r C^, the o t h e r person p e r c e i v e s c o l o u r C p and a l s o where t h e l a t t e r person p e r c e i v e s c^, the former p e r c e i v e s 0^ and where t h e r e i s no case where one person sees one c o l o u r and the o t h e r person a d i f f e r e n t c o l o u r where not a l l o f t h e above h o l d s . There can, o f c o u r s e , be cases where both people see the same c o l o u r s . As a s i m p l e example, "suppose you see the Union Jack as p u r p l e , y e l l o w and green w h i l e I see i t as r e d , w h i t e and b l u e . In o t h e r words, when you see a p r o p e r Union Jack you get the same s e n s e - d a t a as I get when I see a p u r p l e , y e l l o w and green Union J a c k . Suppose a l s o t h a t the r e v e r s e h o l d s , and t h a t you see the p u r p l e , y e l l o w and green "Union Jack" as though i t were a p r o p e r r e d , w h i t e and b l u e one." Ther e i s o v e r l a p p i n g t r a n s p o s i t i o n o f c o l o u r s between two people when and o n l y when: t h e r e i s some case where one per s o n sees one c o l o u r and t h e o t h e r person a d i f f e r e n t c o l o u r , but where the d i f f e r e n t c o l o u r s a r e not one- ' one c o r r e l a t e d i n the way s e t o u t i n the paragraph above. T h i s k i rid o f t r a n s - p o s i t i o n i s always i n p r i n c i p l e d e t e c t a b l e i n t h a t t h e r e would always be some case where one person sees two d i f f e r e n t c o l o u r s and the o t h e r sees two samples o f the same c o l o u r , i . e . , where one person makes a d i s c r i m i n a t i o n by c o l o u r which the o t h e r does n o t . T h i s does n o t mean t h a t one per s o n has t o be o v e r - a l l a f i n e r d i s c r i m i n a t o r than the o t h e r , s i n c e i t may be t h a t f o r each o f them t h e r e i s some ca s e where he does and the o t h e r does not make a d i s c r i m i - n a t i o n by c o l o u r . What I g i v e above i s the minimum t h a t i s g u a r a n t e e d , and i t w i l l be h e l p f u l t o a l a t e r p o i n t t o s k e t c h v e r y b r i e f l y how t h i s i s guaran- t e e d : (1) I f t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n o f c o l o u r s between two p e o p l e , 2 I b i d . and P^, t h e n , by d e f i n i t i o n , t h e r e i s a t l e a s t one c a s e where P^ sees one c o l o u r , c a > and where P£ sees some d i f f e r e n t c o l o u r , c^; (2) and, a l s o by d e f i n i t i o n , c^ and c, are not s y s t e m a t i c a l l y t r a n s p o s e d , a D i . e . , i t i s n o t t r u e t h a t [(where Pj sees c a , ?2 a ^ w a y s s e e s a n d (where ?2 sees c^, P^ always sees c g)J ; (3) and s i n c e the whole c o n j u n c t i o n i n (2) above i s f a l s e , then e i t h e r (a) t h e r e i s a c a s e where: [ ( P , sees O and ( P 0 sees c )] 1 a' 2 m where c ?c. m b o r (b) t h e r e i s a c a s e where: [(P2 sees c^) and ( P ^ sees c ^ ) ] where c /c : n a' (4) i f ( a ) , then t h e r e a r e s i t u a t i o n s where P, sees c t h r o u g h o u t , but where x a P2 sees sometimes c^ and sometimes c m ; i f ( b ) , then t h e r e a r e s i t u a t i o n s where ?^ sees c^ t h r o u g h o u t , but where P T sees sometimes c and sometimes c . 1 a n In t h i s g e n e r a l form o f the argument, r e p l a c i n g " s i t u a t i o n s " by some more p r e c i s e p h r a s e , e.g., "when c o n f r o n t i n g p h y s i c a l o b j e c t s some o f t y p e X and some o f type Y", i s unwarranted. We have no i n f o r m a t i o n about the k i n d o f case where t h e t r a n s p o s i t i o n o f c o l o u r s o c c u r s . So i t i s always l o g i c a l l y p o s s i b l e t o d e t e c t t h a t t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n . I t w i l l be i m p o r t a n t i n t h i s s e c t i o n to keep c l e a r the d i s t i n c - t i o n between d e t e c t i n g t h a t t h e r e i s a t r a n s p o s i t i o n ( o f one o r the o t h e r k i n d ) between two p e r c e i v e r s , and d e t e c t i n g which c o l o u r s are t r a n s p o s e d ( i n the sense t h a t a f t e r t h i s d e t e c t i o n , one knows by a c q u a i n t a n c e which c o l o u r s are t r a n s p o s e d ) . The above argument i n i t s e l f does not show t h a t which c o l o u r s a r e t r a n s p o s e d i s a l s o d e t e c t a b l e . The d i s t i n c t i o n between s y s t e m a t i c and o v e r l a p p i n g t r a n s p o s i t i o n i s u s u a l l y drawn by w r i t e r s on the t o p i c ( a l t h o u g h the l a b e l s may d i f f e r ) , but not o f t e n i n a p r e c i s e f a s h i o n . However, the d i s t i n c t i o n does need t o be made p r e c i s e i f we a r e t o l o c a t e the s u s p e c t p a r t o f the T r a n s p o s i t i o n Argument. The c o n f u s i o n i n the argument , 1ies i n the statement "where.one person sees one c o l o u r , t he o t h e r sees a d i f f e r e n t c o l o u r . " As i t stands t h i s i s u n c l e a r . O b v i o u s l y we s h a l l n o t c a p t u r e t he n o t i o n o f s y s t e m a t i c t r a n s p o s i t i o n i f "where" i s i n t e r p r e t e d i n a c r u d e l y l i t e r a l s e n s e, f o r example, as "on the p h y s i c a l o b j e c t s o r p a r t s o f them where one per s o n sees . . .". With no time r e f e r e n c e a case can be c o n s t r u c t e d which meets t h i s s y s t e m a t i c t r a n s p o s i t i o n c r i t e r i o n which i s i n d i s t i n g u i s h a b l e from o v e r l a p p i n g t r a n s p o s i t i o n . Rather the "where" needs t o be read as " i n the same c o n d i t i o n s " o r " i n the same s i t u a - t i o n " . A t t h i s p o i n t i t i s i m p o r t a n t t o make use o f a d i s t i n c t i o n I have a l - ready drawn between t h e s t a t e o f t h e p e r c e i v e r and t h e environment i n which a p e r c e p t i o n takes p l a c e . The l a t t e r i n c l u d e s a l l q u a l i t a t i v e f e a t u r e s o f t h e s i t u a t i o n e x c e p t the s t a t e o f t h e p e r c e i v e r . I say " q u a l i t a t i v e f e a t u r e s " here meaning t h a t the time o f the p e r c e p t i o n and the l o c a t i o n o f the environment as a whole a r e not i n themselves p a r t o f what I c a l l "the environment". The l o c a - t i o n o f t h e p e r c e i v e r , however, i s i n c l u d e d . "In the same s i t u a t i o n " , t h e n , can be i n t e r p r e t e d i n two d i f f e r e n t ways: a) " i n the same environment", o r , b) " i n t h e same environment and g i v e n t h a t t he two p e r c e i v e r s a re i n q u a l i t a t i v e l y t h e same s t a t e " , and each o f them c r e a t e s problems f o r the T r a n s p o s i t i o n Argument. I f we ta k e ( a ) , then t he concept o f a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s i s u n p r o b l e m a t i c ; c l e a r l y such a c o n s i s t e n t , symmetrical t r a n s p o s i t i o n o f c o l o u r s between two pe o p l e i s l o g i c a l l y p o s s i b l e i n any environment. But I deny t h a t i t i s l o g i c a l l y i m p o s s i b l e t o d e t e c t such a t r a n s p o s i t i o n . There a r e here two p o s s i b l e bases f o r d e t e c t i n g t h a t a s y s t e m a t i c t r a n s p o s i t i o n h o l d s . The weaker o f the two can be e x p l a i n e d f a i r l y s i m p l y ; the s t r o n g e r b a s i s , a l - though a l l the m a t e r i a l r e q u i r e d has a l r e a d y been c o v e r e d , i s worth e x p l a i n i n g i n more d e t a i l . The F i r s t B a s i s and I t s Use The b a s i s o f t h e f i r s t s o l u t i o n i s the c l a i m : " E x p e r i e n c e s and b r a i n s t a t e s ( o r , b r a i n p r o c e s s e s ) a re ' c o r r e l a t e d 1 , so t h a t f o r any two d i f f e r e n t e x p e r i e n c e s , t h e r e w i l l be two d i f f e r e n t b r a i n s t a t e s . " In t h i s s e c t i o n , I s h a l l r e f e r t o t h i s as s i m p l y ' . ' t h e c o r r e l a t i o n - c l a i m " . I f t h i s c l a i m i s c o r - r e c t , then one has enough to d e t e c t s y s t e m a t i c t r a n s p o s i t i o n . Immediately I must p o i n t o u t t h a t the phrase " c o r r e l a t e d w i t h " here i s b e i n g used so as t o p e r m i t the e x p e r i e n c e s t o be i d e n t i c a l w i t h the b r a i n s t a t e s . Some/writers use the phrase so t h a t "A: i s c o r r e l a t e d w i t h B" e n t a i l s t h a t A and B a r e d i s - t i n c t , but t h i s e n t a i l m e n t does not h o l d i n my usage here. On the c o n t r a r y , i t i s t r u e t o say t h a t "both the d u a l i s t and the i d e n t i t y t h e o r i s t agree t h a t t h e r e i s a c o r r e l a t i o n . . ... between mental s t a t e s and p h y s i c a l s t a t e s " , where " c o r r e l a t i o n " i s b e i n g used " n e u t r a l l y w i t h o u t p r e j u d g i n g which s i d e i s c o r - r e c t . " Of c o u r s e , someone h o l d i n g an i d e n t i t y - t h e s i s about e x p e r i e n c e s and b r a i n s t a t e s w i l l make a l s o the f o l l o w i n g c l a i m : "For any two q u a l i t a t i v e l y the same e x p e r i e n c e s , t h e r e w i l l be two q u a l i t a t i v e l y the same b r a i n s t a t e s . " T h i s I have no t i n c l u d e d i n t h e " c o r r e l a t i o n - c l a i m " above, and t h i s i s i n t e n - t i o n a l . However, t h e o m i s s i o n s h o u l d hot be c o n s t r u e d as a v e i l e d i n d i c a t i o n t h a t many people who a c c e p t the c o r r e l a t i o n - c l a i m do n o t , as a m a t t e r o f f a c t , a c c e p t t h i s f u r t h e r c l a i m . The p o i n t i s the c o r r e l a t i o n - c l a i m as g i v e n does not i n i t s e l f e n t a i l the f u r t h e r c l a i m above, a t l e a s t , not w i t h o u t begging the q u e s t i o n a g a i n s t the p o s s i b i l i t y o f "a p l u r a l i t y o f c a u s e s " f o r a c e r t a i n ( k i n d o f ) e f f e c t . T hat i s t o say, i f a " p l u r a l i t y o f c a u s e s " i s l o g i c a l l y p o s s i b l e , then i t i_s_ l o g i c a l l y p o s s i b l e f o r someone t o a c c e p t the c o r r e l a t i o n - c l a i m (as g i v e n ) and t o a c c e p t as l o g i c a l l y p o s s i b l e t h a t " F o r two q u a l i t a t i v e l y t h e same e x p e r i e n c e s , t h e r e may be two q u a l i t a t i v e l y d i f f e r e n t b r a i n s t a t e s I s h a l l not t a c k l e the i s s u e about the p o s s i b i l i t y o f a p l u r a l i t y o f causes h e r e ; i n s t e a d I s h a l l a t t h i s p o i n t omit r e f e r e n c e t o the c l a i m : " F o r any two q u a l i t a t i v e l y t h e same e x p e r i e n c e s , t h e r e w i l l be two q u a l i t a t i v e l y t h e same b r a i n s t a t e s . " I t i s n o t , i n any c a s e , r e q u i r e d f o r the l o g i c a l p o s s i b l i t y o f d e t e c t i n g c a s e s o f s y s t e m a t i c t r a n s p o s i t o n u s i n g the c o r r e l a t i o n - c l a i m as the b a s i s . J S a u l A. K r i p k e , "Naming and N e c e s s i t y , " Semantics o f N a t u r a l Language, 2nd ed., Donald Davidson and G i l b e r t Harman ( D o r d r e c h t , H o l l a n d , 1972), p. 355. 80 L e t me e x p l a i n how the c o r r e l a t i o n - c l a i m , i f t r u e , can be made t o f u n c - t i o n h e re. Suppose, t o b e g i n w i t h t h a t t h e r e a re two ( s i g h t e d ) p e o p l e who a t the time o f v i e w i n g any p a r t o f any c o n s t a n t environment have q u a l i t a t i v e l y the same b r a i n s t a t e s . I t f o l l o w s from the c o r r e l a t i o n - c l a i m t h a t a t the time o f v i e w i n g they see q u a l i t a t i v e l y t h e same c o l o u r s , and s i n c e ex hypothesi t h i s i s t r u e f o r any p a r t o f any c o n s t a n t environment t h e y view, i t f o l l o w s t h a t t h e r e i s no_ t r a n s p o s i t i o n ( o f e i t h e r k i n d ) h o l d i n g between them. Suppose l a t e r t h a t a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s does h o l d between them; l e t us say t h a t p e r c e i v e r P^'s c o l o u r - v i s i o n remains unchanged and t h a t Pg's has changed, so t h a t the t r a n s p o s i t i o n now h o l d s . By v i e w i n g p h y s i c a l o b j e c t s i n environments which have remained c o n s t a n t and i n which Pg has viewed p r i o r t o the change i n h i s c o l o u r - v i s i o n , Pg can d e t e c t t h a t the c o l o u r - c h a n g e has o c c u r r e d , and t h a t he has n o t g a i n e d n o r l o s t d i s c r i m i n a t o r y a b i l i t y (ex h y p o t h e s i h i s d i s c r i m i n a t o r y a b i l i t y w i l l n ot have changed s i n c e h i s c o l o u r - v i s i o n b e f o r e and a f t e r t he change are s y s t e m a t i c a l l y t r a n s p o s e d ) ; i n s h o r t , he can d e t e c t t h a t a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s has o c c u r r e d ' w i t h i n ' the l i f e - s p a n o f h i s c o l o u r - v i s i o n . He a l s o , o f c o u r s e , can d e t e c t which c o l o u r s a r e t r a n s p o s e d , i . e . , he can know by a c q u a i n t a n c e which c o l o u r s a r e t r a n s p o s e d . And i f the c o r r e l a t i o n - c l a i m i s t r u e , then i n one o f the c o n s t a n t environments where he now sees a p a r t i c u l a r p h y s i c a l o b j e c t to be a d i f f e r e n t c o l o u r from t h e c o l o u r he saw b e f o r e t he change, then when he views t h a t ob- j e c t h i s b r a i n s t a t e now w i l l be d i f f e r e n t from h i s b r a i n s t a t e when he viewed the o b j e c t b e f o r e the t r a n s p o s i t i o n ; and so a l s o i t w i l l be d i f f e r e n t from P^'s b r a i n s t a t e when he ( P j ) now views t h a t p h y s i c a l o b j e c t i n t h a t c o n s t a n t en- viro n m e n t , s i n c e P^'s c o l o u r - v i s i o n remains unchanged. Now I know the c l a i m t h a t i t i s l o g i c a l l y i m p o s s i b l e t o d e t e c t t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i - t i o n o f c o l o u r s between two peop l e i s made i n r e g a r d t o a permanent, l i f e - l o n g t r a n s p o s i t i o n o f c o l o u r s between them, but what I have d e s c r i b e d above does p r o v i d e enough to d e t e c t i t even i n such a permanent c a s e . The key i s t h a t 81 i f t h e c o r r e l a t i o n - c l a i m i s t r u e , can l e g i t i m a t e l y produce the g e n e r a l i z a - t i o n : " I n t h o s e c o n s t a n t environments where h i s ̂ ' s ) change i n c o l o u r - v i s i o n i s i n e f f e c t when he views c e r t a i n p h y s i c a l o b j e c t s , i f two o t h e r p e r c e i v e r s view the p h y s i c a l o b j e c t s i n q u e s t i o n , and t h e i r b r a i n s t a t e s a t the time o f v i e w i n g d i f f e r one from the o t h e r i n p r e c i s e l y the same way as P2's b r a i n s t a t e s d i f f e r b e f o r e and a f t e r h i s change i n c o l o u r - v i s i o n , then P2 can c o n c l u d e t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s between th e s e o t h e r two p e o p l e . " A l s o he w i l l know by a c q u a i n t a n c e which c o l o u r s a r e t r a n s p o s e d , and he can l e g i t i m a t e l y g e n e r a l i z e t o t h e e f f e c t t h a t f o r system- a t i c t r a n s p o s i t i o n i n v o l v i n g t h e s e two b r a i n s t a t e s on v i e w i n g t h e s e p h y s i c a l o b j e c t s i n t h i s and t h i s c o n s t a n t environment, t h i s and t h i s c o l o u r s , which he knows by a c q u a i n t a n c e , a r e t r a n s p o s e d . The f i r s t o f t h e s e two g e n e r a l i z a t i o n s can be used i n t h e f o l l o w i n g way. Suppose t h e r e i s a t h i r d p e r c e i v e r , Pg, who, i n t h o s e c o n s t a n t environments where P2's change i n c o l o u r - v i s i o n i s i n e f f e c t and on v i e w i n g the p h y s i c a l o b j e c t s i n q u e s t i o n , has a b r a i n s t a t e q u a l i t a t i v e - l y t h e same as P^'s a f t e r h i s ̂ ' s ) change. I f t h i s i s t r u e f o r a l l c o n s t a n t environments where P2 1s change i s i n e f f e c t , then a t the times o f t h e s e view- i n g s , Pg's b r a i n s t a t e and P ^ s b r a i n s t a t e d i f f e r i n p r e c i s e l y t he same way as the b r a i n s t a t e s o f P^ b e f o r e and a f t e r h i s change i n c o l o u r - v i s i o n . And s i n c e , ex h y p o t h e s i , t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n between P^'s c o l o u r - v i s i o n b e f o r e the change and h i s c o l o u r - v i s i o n a f t e r the change, t h e r e i s a l s o a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s h o l d i n g between and Pg. T h i s t r a n s - p o s i t i o n c o u l d t h e r e f o r e be d e t e c t e d even i f i t was permanent f o r both P^ and Pg. And I s h o u l d make e x p l i c i t t h a t the c l a i m t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n here c o u l d be made j u s t i f i a b l y by both P^ and Pg u n l e s s t h e r e i s some argument why i n g e n e r a l a person s h o u l d not be r e l i e d upon when j u d g i n g t h e d i f f e r e n c e o f some o f t h e p e r c e i v e d c o l o u r s he has a t d i f f e r e n t times i n h i s e x p e r i e n c e s . So f a r as I know no-one has c l a i m e d t h a t the T r a n s p o s i t i o n Argument e i t h e r depends upon, o r i s a way o f r e v e a l i n g t he u n r e l i a b i l i t y o f a person's judgements as t o the d i f f e r e n c e o f some o f t h e c o l o u r s he p e r c e i v e s , w i t h o r w i t h o u t the q u a l i f i c a t i o n t h a t he p e r c e i v e s t he c o l o u r s i n q u e s t i o n a t d i f f e r e n t t i m e s . In any c a s e , we cannot r e j e c t a l t o g e t h e r r e l i a n c e on someone e l s e ' s judgements about t h e s a m e n e s s / d i f f e r e n c e o f h i s p e r c e i v e d c o l o u r s w i t h - o u t undermining t h e g e n e r a l l y a c c e p t e d c l a i m t h a t o v e r l a p p i n g t r a n s p o s i t i o n j_s d e t e c t a b l e . And we s h o u l d need t o r e - s p e c i f y what counts as o v e r l a p p i n g t r a n s p o s i t i o n i f we are t o guarantee t h a t t he d e t e c t a b i l i t y o f i t never de- pends upon someone's j u d g i n g the d i f f e r e n c e o f c o l o u r s p e r c e i v e d a t d i f f e r e n t t i m e s . I do n o t see any o b v i o u s reason f o r deeming the judgements i n q u e s t i o n to be i n g e n e r a l u n r e l i a b l e , but i f an argument t o t h i s e f f e c t i s put fo r w a r d and the c o r r e s p o n d i n g r e v i s i o n o f what counts as o v e r l a p p i n g t r a n s p o s i t i o n i s made, then t h e c r u c i a l d i f f e r e n c e between s y s t e m a t i c and o v e r l a p p i n g t r a n s p o - s i t i o n i s not a t a l l what many w r i t e r s on the s u b j e c t b e l i e v e . I f the c o r r e l a t i o n - c l a i m i s t r u e , t h e n s i n c e what I have d e s c r i b e d above i s l o g i c a l l y p o s s i b l e , i t i s l o g i c a l l y p o s s i b l e t o d e t e c t t h a t t h e r e i s a s y s - t e m a t i c t r a n s p o s i t i o n between two p e o p l e . 4 T h i s i s t r u e even i f t h e t r a n s p o - s i t i o n i s permanent. In f a c t , i t i s t r u e even i f permanency i s made a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n . P j and P^ were a b l e t o d e t e c t t h a t t h e r e was such a t r a n s p o s i t i o n between them even though i t was permanent. ( I f we d i d make permanency a d e f i n i t i v e f e a t u r e , then we s h o u l d need t o make a t r i v i a l change i n the d e s c r i p t i o n o f P^'s change i n c o l o u r - v i s i o n . I n s t e a d o f s a y i n g t h e r e was a s y s t e m a t i c t r a n s p o s i t i o n between h i s c o l o u r - v i s i o n b e f o r e and h i s v i s i o n a f t e r t he change, we s h o u l d say t h e r e was a ' s y s t e m a t i c t r a n s - p o s i t i o n ' between h i s c o l o u r - v i s i o n b e f o r e and a f t e r the change, i . e . , t h e d i f f e r e n c e between h i s c o l o u r - v i s i o n i n the two phases i s p r e c i s e l y t h a t o f 4 T h i s c l a i m i s about " s y s t e m a t i c t r a n s p o s i t i o n " w i t h i t s f i r s t i n t e r p r e t a t i o n where the phrase " i n t h e same s i t u a t i o n " i s i n t e r p r e t e d t o mean " i n t he same environment". ( S e e p . 78 above.) s y s t e m a t i c t r a n s p o s i t i o n e x c e p t f o r t h e one f e a t u r e — b e i n g permanent.) In the l a s t s e c t i o n I r e f e r r e d t o Smart's c l a i m t h a t "we c o u l d never be 5 s u r e t h a t you see the same c o l o u r s as I do." I f t h e r e i s what I c a l l a s y s - t e m a t i c t r a n s p o s i t i o n , t h e n , Smart c l a i m s "the d i f f e r e n c e between us w i l l be 6 u n d e t e c t a b l e . " T h i s , however, i s j u s t f a l s e , s i n c e Smart makes c l e a r e l s e - where t h a t he does a c c e p t the c o r r e l a t i o n - c l a i m about b r a i n p r o c e s s e s and ex- p e r i e n c e s , and so the above p o s s i b i l i t y o f d e t e c t i o n i s open t o him. In h i s paper " S e n s a t i o n s and B r a i n P r o c e s s e s " 7 , he c l a i m s " s e n s a t i o n s a r e n o t h i n g o v e r and above b r a i n p r o c e s s e s " and "when I say t h a t a s e n s a t i o n i s a b r a i n p r o c e s s o r t h a t l i g h t n i n g i s an e l e c t r i c d i s c h a r g e , I am u s i n g " i s " i n the sense o f s t r i c t i d e n t i t y . " He i s ^ u s i n g " s e n s a t i o n " i n i t s broad s e n s e , where i t i s not r e s t r i c t e d t o " s e n s a t i o n o f t o u c h " . The example he d i s c u s s e s i s t h a t o f an a f t e r - i m a g e . H i s t h e s i s then c l e a r l y e n t a i l s what I have c a l l e d the " c o r r e l a t i o n - c l a i m " , v i z , " E x p e r i e n c e s and b r a i n s t a t e s ( o r , b r a i n p r o - c e s s e s ) a r e ' c o r r e l a t e d ' , so t h a t f o r any two d i f f e r e n t e x p e r i e n c e s , t h e r e w i l l be two d i f f e r e n t b r a i n s t a t e s . " Smart h i m s e l f c o n s i d e r s t he use o f t h e term " c o r r e l a t i o n " t o be i n a c c u r a t e , s i n c e t he two s e t s o f e n t i t i e s , s e n s a - t i o n s and b r a i n p r o c e s s e s , a r e n o t , i n h i s t h e s i s , d i s t i n c t . But the a m b i g u i t y o f " c o r r e l a t i o n " here has a l r e a d y been e l i m i n a t e d ; I have used the term so t h a t i t i s n e u t r a l as t o whether t h e two s e t s o f e n t i t i e s a r e i d e n t i c a l o r d i s t i n c t . I t i s i m p o r t a n t t o r e a l i z e t h a t the comments above about Smart's view ar e made with r e g a r d t o t h e f i r s t i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " . In t h i s i n t e r p r e t a t i o n the term "where" i n . t h e s e n t e n c e "where one person 5 S m a r t , p. 129. 6 I b i d . . 7 J . J . C. Smart, " S e n s a t i o n s and B r a i n P r o c e s s e s , " P h i l o s o p h i c a l Review, 68, 1959. p Smart, " S e n s a t i o n s and B r a i n P r o c e s s e s , " p. 145. 84 p e r c e i v e s c o l o u r C^, the o t h e r person p e r c e i v e s c o l o u r C p . , ." i s i n t e r - p r e t e d t o mean " i n t h e same environment". The second i n t e r p r e t a t i o n , i n which t h e term "where" i s i n t e r p r e t e d t o mean " i n t h e same environment and g i v e n t h a t t h e two p e r c e i v e r s are i n q u a l i t a t i v e l y t he same s t a t e " , makes the co n c e p t o f s y s t e m a t i c t r a n s p o s i t i o n i n c o h e r e n t f o r Smart, g i v e n h i s t h e s i s about the i d e n t i t y o f s e n s a t i o n s and b r a i n p r o c e s s e s . I f we t a k e h i s i d e n t i t y - t h e s i s t o be t r u e then i t i s not l o g i c a l l y p o s s i b l e t o have a s y s t e m a t i c t r a n s - p o s i t i o n a t work when the two p e r c e i v e r s a r e i n the same ( i . e . , c o n s t a n t ) en- vironment, and i n q u a l i t a t i v e l y the same s t a t e . I f t h e y a r e i n q u a l i t a t i v e l y the same s t a t e , then t h e y l o g i c a l l y cannot be hav i n g d i f f e r e n t v i s u a l e x p e r i - e nces. In t h e same environment and i n the same s t a t e , t h e y l o g i c a l l y cannot be p e r c e i v i n g d i f f e r e n t c o l o u r s . So g i v e n Smart's i d e n t i t y - t h e s i s , t h e o n l y n o n - c o n t r a d i c t o r y c o n c e p t o f s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s i s i n i t s f i r s t i n t e r p r e t a t i o n , and a g a i n , g i v e n h i s i d e n t i t y - t h e s i s , s y s t e m a t i c t r a n s - p o s i t i o n i n t h a t sense l o g i c a l l y c o u l d be d e t e c t e d . I r e t u r n now t o the g e n e r a l argument i n t h i s s e c t i o n b e f o r e remarks s p e c i f i c a l l y about Smart were made. I t has a l r e a d y been e s t a b l i s h e d t h a t g i v e n t h e f i r s t i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " , i t i s always l o g i c a l l y p o s s i b l e t o d e t e c t t h a t i t h o l d s between two p e o p l e . I want now t o loo k a t a p o s s i b l e o b j e c t i o n to t h e e f f e c t t h a t a l t h o u g h and P^ may d e t e c t t h a t t h e y have a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s , t h e y l o g i c a l l y cannot d e t e c t which c o l o u r s a r e t r a n s p o s e d (so t h a t they know by a c q u a i n t a n c e which c o l o u r s a re t r a n s p o s e d ) . But t h i s i s m i s l e a d i n g as i t s t a n d s . Suppose t h a t t h e o n l y two c o l o u r s t r a n s p o s e d a r e and C p i . e . , suppose t h a t i n any con- s t a n t environment where P^ sees C^, P^ sees c ^ , and a l s o t h a t i n any c o n s t a n t environment where P^ sees c^, P^ sees C^. S t i l l assuming the c o r r e l a t i o n - c l a i m (about e x p e r i e n c e s and b r a i n s t a t e s ) t o be t r u e , i t i_s c o n t i n g e n t l y poss- i b l e to d e t e c t t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n by showing t h a t a t the 85 a p p r o p r i a t e v i e w i n g t i m e s , and Pg have d i f f e r e n t b r a i n s t a t e s l i k e the b r a i n s t a t e s o f ?2 b e f o r e and a f t e r h i s change, w i t h o u t t h e r e b y g i v i n g P-̂  and Pg the r i g h t t o c l a i m to know which c o l o u r s a re t r a n s p o s e d . Very s i m p l y , P^ may never have had the b r a i n s t a t e Pg has a t a v i e w i n g when the t r a n s p o s i t i o n i s i n e f f e c t , and i n t h a t case he w i l l n o t know by a c q u a i n t a n c e which c o l o u r s a r e t r a n s p o s e d . ( M u t a t i s mutandis f o r Pg.) But t h i s same p o i n t i s t r u e a l s o o f o v e r l a p p i n g t r a n s p o s i t i o n . I t i s c o n t i n g e n t l y p o s s i b l e t o d e t e c t t h a t t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n o f c o l o u r s between two peopl e w i t h o u t t h e r e b y g i v i n g the two peopl e the r i g h t to c l a i m t o know which c o l o u r s a re t r a n s p o s e d . T h i s can b e s t be seen i f we lo o k back a t the s h o r t argument show- i n g t h a t i t i s always l o g i c a l l y p o s s i b l e t o d e t e c t t h a t t h e r e i s a case o f o v e r l a p p i n g t r a n s p o s i t i o n (on pp. 76-77 ab o v e ) . The f e a t u r e d i s t i n c t i v e o f o v e r l a p p i n g t r a n s p o s i t i o n guarantees t h a t t h e r e must be some s i t u a t i o n i n which one o f t h e p e r c e i v e r s d i s c r i m i n a t e s some items by c o l o u r , and the o t h e r does not. L e t us ta k e one o f t h e two p o s s i b l e c o n c l u s i o n s o f t h a t argument: " t h e r e are some s i t u a t i o n s where P^ sees c a t h r o u g h o u t , but where P2 sees sometimes c^ and sometimes c m (where c ^ c ^ , and c ^ c m ) ( T h e f o l l o w i n g remarks can be made, m u t a t i s mutandis, about the a l t e r n a t i v e c o n c l u s i o n . ) I t i s p o s s i b l e f o r P^ to d e t e c t t h a t t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n (by o b s e r v i n g the d i f - f e r e n c e i n d i s c r i m i n a t i o n ) even i f he has never p e r c e i v e d the c o l o u r s c^ and c^; l i k e w i s e i t i s p o s s i b l e f o r P2 to d e t e c t t h a t t h e r e i s such a t r a n s p o s i t i o n even i f he has never p e r c e i v e d t h e c o l o u r c . So i t i s c o n t i n g e n t l y p o s s i b l e f o r them t o d e t e c t t h a t t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n w i t h o u t t h e r e b y h a v i n g t he r i g h t to c l a i m to know by a c q u a i n t a n c e which c o l o u r s a re t r a n s p o s e d . Both i n the case o f s y s t e m a t i c and o v e r l a p p i n g t r a n s p o s i t i o n , i t i s l o g i c a l l y p o s s i b l e f o r a person t o d e t e c t t h a t t h e r e i s a t r a n s p o s i t i o n o f c o l o u r s be- tween h i m s e l f and a n o t h e r p e r s o n , even i f he has never p e r c e i v e d and w i l l never p e r c e i v e the c o l o u r s the o t h e r person p e r c e i v e s i n v i e w i n g s where the t r a n s p o s i t i o n i s i n e f f e c t . Being a c q u a i n t e d w i t h t h o s e c o l o u r s i s not a ne- c e s s a r y c o n d i t i o n f o r the l o g i c a l p o s s i b i l i t y o f d e t e c t i n g t h a t t h e r e i s a t r a n s p o s i t i o n ( o f e i t h e r k i n d ) . The problem o f knowing (by a c q u a i n t a n c e ) which c o l o u r s a r e t r a n s p o s e d i s t o do w i t h one person's not hav i n g a n o t h e r person's v i s u a l e x p e r i e n c e s , and not to do w i t h how c o n s i s t e n t o r symmetrical the t r a n s p o s i t i o n i s . The d i s - t i n c t i o n between o v e r l a p p i n g and s y s t e m a t i c t r a n s p o s i t i o n i s not c r u c i a l h e r e . Assuming the c o r r e l a t i o n - c l a i m t o be c o r r e c t , t h e n o f c o u r s e d e t e c t i n g t h a t t h e r e i s a t r a n s p o s i t i o n ( o f e i t h e r k i n d ) may g i v e the p a i r o f p e r c e i v e r s w i t h the t r a n s p o s i t i o n t h e r i g h t t o c l a i m t o know which c o l o u r s a r e transposed.; e.g., when a p e r c e i v e r knows which b r a i n s t a t e ( s ) i s ( a r e ) c o r r e l a t e d w i t h t he c o l o u r ( s ) t h e o t h e r p e r s o n sees when t h e t r a n s p o s i t i o n i s a c t u a l l y i n e f f e c t , he may know t h a t he has been i n the b r a i n s t a t e ( s ) h i m s e l f , and he may know which c o l o u r ( s ) he saw when i n the s t a t e ( s ) . But i n any c a s e , i f the c o r r e - l a t i o n between e x p e r i e n c e s and b r a i n s t a t e s does h o l d , i t i s s u r e l y always l o g i c a l l y p o s s i b l e t o ensure t h a t both p e r c e i v e r s do know which c o l o u r s a r e t r a n s p o s e d s i m p l y by d e l i b e r a t e l y changing t h e i r b r a i n s t a t e s t o the on e ( s ) i n v o l v e d i n the t r a n s p o s i t i o n . T h i s c o u l d always be done i n a way t h a t would not v i o l a t e t he permanency f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n , i f permanency i s made a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n . The i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " b e i n g used here i s t h a t o f an ' i n t e r - c h a n g e ' o f c o l o u r s i n c e r t a i n c o n s t a n t environments when the two p e r c e i v e r s i n q u e s t i o n view c e r t a i n p h y s i c a l o b j e c t s i n tho s e environments. Now t h i s t r a n s p o s i t i o n can remain permanent w i t h o u t making i t i m p o s s i b l e to produce i n the one per- c e i v e r t he b r a i n s t a t e ( s ) c o r r e l a t e d w i t h t he c o l o u r ( s ) t he o t h e r p e r c e i v e r sees when the t r a n s p o s i t i o n i s a c t u a l l y i n e f f e c t , s i m p l y because we can p r o - duce t h a t b r a i n s t a t e i n the f i r s t p e r c e i v e r when he i s not v i e w i n g any p h y s i - c a l o b j e c t , e.g., when h i s eyes a r e c l o s e d . For the purpose here t h e r e i s 87 n o t h i n g wrong i n tampering w i t h h i s b r a i n d i r e c t l y , and i f h i s eyes are c l o s e d , then no m a t t e r what h i s v i s u a l e x p e r i e n c e s t h e y cannot a f f e c t the c l a i m t h a t the s y s t e m a t i c t r a n s p o s i t i o n i s permanent, s i n c e t h a t c l a i m i s o n l y t o do w i t h c e r t a i n d i f f e r e n c e s i n the e x p e r i e n c e s o f t h e two peopl e when the y v i ew c e r - t a i n p h y s i c a l o b j e c t s i n c e r t a i n c o n s t a n t e n v i ronments. B e f o r e l e a v i n g t h i s i n v e s t i g a t i o n i n t o the l o g i c a l p o s s i b i l i t y o f d e t e c t - i n g t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n (and which c o l o u r s are t r a n s p o s e d ) i f one a c c e p t s the c o r r e l a t i o n - c l a i m , t h e r e i s one more p o i n t t o n o t i c e . T h i s i s t h a t the remarks made about the i m p o s s i b i l i t y o f Smart's making use o f the second i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " are g e n e r a l i z a b l e f o r a l l p h i l o s o p h e r s who a c c e p t any v e r s i o n o f the c o r r e l a t i o n - c l a i m . In the second i n t e r p r e t a t i o n the term "where" i n the s e n t e n c e "where one person p e r c e i v e s c o l o u r s C p the o t h e r person p e r c e i v e s c o l o u r C p . . ." i s i n t e r p r e t e d t o mean " i n the same environment and g i v e n t h a t the two p e r c e i v e r s are i n q u a l i - t a t i v e l y t h e same s t a t e " . I f t h e c o r r e l a t i o n - c l a i m i s t r u e , t h e n t h i s second i n t e r p r e t a t i o n i s not c o h e r e n t . For my i n v e s t i g a t i o n i t i s more i m p o r t a n t t h a t i t be c o n c e i v a b l e ( i . e . , w i t h o u t r e j e c t i n g any g i v e n f a c t ) , r a t h e r than merely l o g i c a l l y p o s s i b l e , t o d e t e c t a case o f permanent s y s t e m a t i c t r a n s p o s i t i o n . If_ the c o r r e l a t i o n - c l a i m i s t r u e , then i t w i l l be c o n c e i v a b l e t o d e t e c t a case o f s y s t e m a t i c t r a n s p o s i - t i o n i f i t i s c o n c e i v a b l e f o r someone to do what I have d e s c r i b e d as d o i n g - u n d e rgoing a ' t r a n s p o s i t i o n ' w i t h i n h i s c o l o u r - v i s i o n w i t h o u t n e c e s s a r i l y ( l o g i c a l l y o r c a u s a l l y ) l o s i n g h i s a b i l i t y t o judge the d i f f e r e n c e o f t h e r e l e v a n t p e r c e i v e d c o l o u r s b e f o r e and a f t e r the c h a n g e — a n d t h e r e b y t o d e t e c t ( t h e r e l e v a n t f e a t u r e s o f ) the c o r r e l a t e d b r a i n s t a t e s , and produce e v e n t u a l l y g e n e r a l i z a t i o n s l i k e t h e one d e s c r i b e d above. (See pp.80-81 above.) My use o f " c o n c e i v a b l e " does not r e q u i r e t h a t , e.g., we can e x p e c t someone a c t u a l l y t o be a b l e t o g i v e an adequate d e s c r i p t i o n o f the b r a i n s t a t e s ; i t i s r e q u i r e d o n l y t h a t no g i v e n f a c t p r o h i b i t s t h i s . Given my use o f " c o n c e i v a b l e " , t h e r e 88 i s one f a i r l y o b v i o u s query I s h a l l answer.here. I t may be t h o u g h t . t h a t i t i s n o t c o n c e i v a b l e (in.my sense) t h a t someone s h o u l d be a b l e t o d e s c r i b e t h e b r a i n s t a t e s a d e q u a t e l y s i n c e t h i s would take a l o n g t i m e , and l o n g b e f o r e the d e s c r i p t i o n o f a s t a t e was completed, the s t a t e would have changed. But t h i s need n o t c o n s t i t u t e a genuine problem. I f i t i s c o n c e i v a b l e t o r e c o r d the s t a t e i n some way m e c h a n i c a l l y , then the f a c t t h a t i t would take a l o n g time f o r a human t o g i v e an adequate v e r b a l d e s c r i p t i o n o f i t i s i r r e l e v a n t to my q u e s t i o n . There i s a n o t h e r q u e s t i o n about c o n c e i v a b i l i t y h e r e , v i z , whether o r not i t i s c o n c e i v a b l e t o d e t e c t which c o l o u r s a r e t r a n s p o s e d . Of c o u r s e f o r t h i s t o be c o n c e i v a b l e i t i s n e c e s s a r y t h a t d e t e c t i o n t h a t t h e r e i s a case o f s y s - t e m a t i c t r a n s p o s i t i o n be a l s o c o n c e i v a b l e . I t i s c o n c e i v a b l e t o d e t e c t which c o l o u r s a r e s y s t e m a t i c a l l y t r a n s p o s e d i f i t i s c o n c e i v a b l e to d e t e c t t h a t t h e r e i s s y s t e m a t i c t r a n s p o s i t i o n , and i f i t i s c o n c e i v a b l e t o produce the r e l e v a n t b r a i n s t a t e s i n the two p e r c e i v e r s w i t h o u t b r e a k i n g t h e permanency f e a t u r e (assuming t h i s f e a t u r e t o be made d e f i n i t i v e o f " s y s t e m a t i c t r a n s p o - s i t i o n " ) . The second o f t h e s e two r e q u i r e m e n t s seems u n p r o b l e m a t i c . I have sugg e s t e d t h a t the o b v i o u s t h i n g t o do, once one knows which b r a i n s t a t e s a r e the ones i n v o l v e d , i s t o produce tho s e s t a t e s f o r t h e p e r c e i v e r s when the per- c e i v e r s a r e not v i e w i n g any p h y s i c a l o b j e c t s o f t h e i r environment ( e . g . , when t h e i r eyes a r e c l o s e d ) . O b v i o u s l y the b r a i n s t a t e s can o c c u r i n humans, s i n c e t h e y were d i s c o v e r e d t o o c c u r ; so i t seems s a f e t o c l a i m t h a t i t i s c o n c e i v - a b l e t o produce them i n t e n t i o n a l l y when the eyes o f the p e r c e i v e r s a r e c l o s e d . The f i r s t o f the two r e q u i r e m e n t s i s o f c o u r s e what I was d i s c u s s i n g i n the p r e v i o u s p a r a g r a p h . At t h i s p o i n t I s h a l l not say any more about the q u e s t i o n o f whether o r not i t i s c o n c e i v a b l e t o d e t e c t t h a t t h e r e i s a permanent system- a t i c t r a n s p o s i t i o n o f c o l o u r s between two p e o p l e . The q u e s t i o n i s v e r y impor- t a n t f o r my programme and I s h a l l d i s c u s s i t i n some d e t a i l , but I s h a l l do t h i s a f t e r c a r e f u l l y s e t t i n g o u t below the second b a s i s f o r d e t e c t i n g t h a t a 89 (permanent) systematic transposition holds. I have described the f i r s t basis— the reliance on the correlation-claim about brain states and experiences—as being weaker than the second. What I mean by this is that the correlation- claim by i t s e l f does not bring to light the most important points relevant to this detection. The second basis does, and thereby provides the material rele- vant to the question of the conceivability of such a detection. The Second Basis I shall explain now what this second basis i s . The conclusion of sec- tion 4 of the thesis was that: "It is a necessary condition of ideas (of per- ception) of the physical world that they are "determined by" the physical world." (The phrase "of perception" was to distinguish these ideas from what Locke calls "ideas of reflection".) We are concerned now only with perceived colours, to be precise with perceived colours a person has upon viewing some particular physical object(s) in a constant environment. After a l l , the basis I am here setting out is to do with the detectability of systematic transpo- sition where "systematic transposition" is given the f i r s t interpretation— in which the term "where" in the sentence "where one person perceives colour C|, the other person perceives colour c-j, . . ." is interpreted to mean "in the same (constant) environment". If, then, some of our perceived colours are ideas of certain physical objects (other than the perceiver's body), then i t is a necessary condition that these ideas be "determined by" the physical ob- jects in question. This, of course, is not to assume that the ideas "resemble any property in the physical objects themselves (i.e., any non-relational pro- perty of the physical objects)". The claim is not empirical; i t does not state that we do have perceived colours that are determined by physical objects in this way. Rather the claim makes explicit a necessary condition for ideas to count as ideas of certain physical objects in the environment around us, even i f the ideas do not resemble a non-relational property of them. For example, i t i s t h i s n e c e s s a r y c o n d i t i o n t h a t d i s t i n g u i s h e s such i d e a s from p e r c e i v e d c o l o u r s t h a t a person has d u r i n g an h a l l u c i n a t i o n . I t i s i n c l u d e d i n the con- c e p t o f a ( v i s u a l ) h a l l u c i n a t i o n t h a t t h e person's v i s u a l e x p e r i e n c e s , i n c l u d - i n g h i s p e r c e i v e d c o l o u r s , a r e not determined by p h y s i c a l o b j e c t s around him as they must be i f h i s e x p e r i e n c e s a r e t o c o n s t i t u t e a case o f genuine ( v i s u a l ) p e r c e p t i o n o f t h e p h y s i c a l w o r l d i n h i s environment. B e f o r e e x p l a i n i n g what i s c o n t a i n e d i n t h i s n o t i o n o f " d e t e r m i n i n g " , t h e r e i s one o t h e r p o i n t t o make about l o o k i n g a t p h y s i c a l o b j e c t s i n a con- s t a n t environment. N e c e s s a r i l y i t i n v o l v e s u s i n g "the sense o f s i g h t " . I t i s p a r t o f the meaning o f the phrase " v i e w i n g p h y s i c a l o b j e c t s ( o t h e r than one's own body) i n the environment around one" t h a t the sense o f s i g h t i s b e i n g used. A l s o , i t i s a d e f i n i t i v e f e a t u r e o f a human's u s i n g h i s sense o f s i g h t t h a t h i s sense-organs o f s i g h t a r e , a t t h a t t i m e , f u n c t i o n i n g , and a human's s e n s e - organs o f s i g h t a r e h i s eyes. S t r i c t l y s p e a k i n g the d e f i n i t i v e f e a t u r e i s t h a t one eye i s f u n c t i o n i n g a t the t i m e , but f o r s i m p l i c i t y I s h a l l speak o f both e y e s . I am not here e q u a t i n g " f u n c t i o n i n g eyes" w i t h " p r o p e r l y f u n c t i o n - i n g e y e s " ; some k i n d s o f m a l f u n c t i o n s do not p r o h i b i t t he eyes' f u n c t i o n i n g a l - t o g e t h e r . The eyes a r e f u n c t i o n i n g when they a r e open and r e c e i v i n g t he appro- p r i a t e " i n p u t " , whatever t h a t t u r n s out t o be, from p a r t s o f the p e r c e i v e r ' s environment, which means he i s r e c e i v i n g " i n p u t " from a p a r t o f t h e p h y s i c a l Q w o r l d . A l s o , s i n c e v i e w i n g the p h y s i c a l w o r l d around one n e c e s s a r i l y i n v o l v e s u s i n g t h e e y e s , and so n e c e s s a r i l y i n v o l v e s some f e a t u r e s o f one's p h y s i c a l s t a t e , we can g i v e sense t o the c o n c e p t o f the p h y s i c a l e n d - s t a t e f o r t h a t per- c e p t i o n . T h i s c o n c e p t a p p l i e s s i n c e the p h y s i c a l s t a t e is i n v o l v e d and per- c e p t i o n s do o c c u r , i . e . , t h e y a re 'completed'. The f a c t t h a t we can g i v e sense 9 " F u n c t i o n i n g e yes" i s b e i n g c o n s t r u e d n o n - d i s p o s i t i o n a l l y t o mean "bei n g open, b e i n g d i r e c t e d i n t h e a p p r o p r i a t e d i r e c t i o n , and r e c e i v i n g t he appro- p r i a t e 'input' (whatever t h a t i n p u t i s ) " . 91 t o the con c e p t does not i n i t s e l f t e l l us what the e n d - s t a t e w i l l be i f i t i s e m p i r i c a l l y t r u e t h a t p a r t s o f the p h y s i c a l w o r l d do determine a p e r c e i v e r ' s i d e a s . I t does not t e l l us, e.g., i f the e n d - s t a t e i s something o t h e r than a s t a t e o f t h e ey e s . A g a i n , s i n c e t he use o f t h e eyes i s n e c e s s a r i l y i n v o l v e d i n v i e w i n g t h e p h y s i c a l w o r l d we can g i v e sense t o the n o t i o n o f c e r t a i n v a r i - a t i o n s i n the p e r c e i v e r ' s p h y s i c a l s t a t e " a f f e c t i n g " t he i d e a s he has, s i n c e we can g i v e sense t o the n o t i o n o f c e r t a i n v a r i a t i o n s i n the s t a t e o f h i s eyes " a f f e c t i n g " h i s i d e a s . T h e r e may be o t h e r v a r i a t i o n s i n h i s p h y s i c a l s t a t e t h a t would " a f f e c t " h i s i d e a s , depending, e.g., on what the p h y s i c a l e n d - s t a t e i s . We have seen t h a t i d e a s o f some p a r t o f the p h y s i c a l w o r l d must be d e t e r - mined by t h a t p a r t . Ideas o f some p h y s i c a l o b j e c t must be determined by t h a t p h y s i c a l o b j e c t g i v e n i t s environment. The phrase " g i v e n i t s environment" i s not an a r b i t r a r y way o f ' s p e l l i n g o u t ' what " t h a t p a r t o f the p h y s i c a l w o r l d " amounts t o he r e . I t must be remembered t h a t we are d e a l i n g s t i l l w i t h a physi- c a l o b j e c t ' s p r e s e n t c o l o u r (as opposed t o , e.g., " i t s r e a l c o l o u r " where t h i s p hrase r e f e r s t o i t s p r e s e n t c o l o u r i n some s p e c i a l l y s e l e c t e d e n v i r o n m e n t ) , and i t s p r e s e n t c o l o u r w i l l be, i n a sense, environment-dependent. D e s c r i b i n g the p a r t o f the p h y s i c a l w o r l d as "the s p e c i f i e d p h y s i c a l o b j e c t g i v e n i t s environment" w i l l be seen t o be u s e f u l once we move on to making e m p i r i c a l c l a i m s about a per s o n ' s v i e w i n g a p h y s i c a l o b j e c t . Some r e l a t i o n a l p r o p e r t i e s o f an o b j e c t i n a c e r t a i n environment may, i n f a c t do, a f f e c t i t s p r e s e n t c o l o u r , t he p o i n t b e i n g t h a t o t h e r f e a t u r e s o f the environment ( b e s i d e s the n o n - r e l a t i o n a l p r o p e r t i e s o f the o b j e c t ) may a f f e c t i t s p r e s e n t c o l o u r , e.g., a change i n the k i n d o f l i g h t i n g used i n the environment, o r a change i n the p o s i t i o n o f the p h y s i c a l o b j e c t i n r e g a r d t o the so u r c e o f l i g h t . So i f a p e r c e i v e r ' s i d e a s a r e id e a s o f the p a r t o f the p h y s i c a l w o r l d , then they a r e det e r m i n e d by the s p e c i f i e d p h y s i c a l o b j e c t g i v e n i t s environment. Now t o say t h a t X determines Y i s a l r e a d y t o say something about a c e r - t a i n r e g j j n a n t j / i n the o c c u r r e n c e s o f X and Y, a c e r t a i n l a w l i k e n e s s : " I f X det e r m i n e s Y, then whenever X o c c u r s , Y w i l l o c c u r . " O t h e r w i s e i t i s g r a t u i - t o u s t o say X d e t e r m i n e s Y r a t h e r t h a n , e.g., t h a t on a number o f o c c a s i o n s Y has f o l l o w e d X. The r e g u l a r i t y i s p a r t o f what i s i n c l u d e d i n the con c e p t o f " d e t e r m i n i n g " . So i f a c e r t a i n p h y s i c a l o b j e c t g i v e n i t s environment d e t e r - mines a c e r t a i n i d e a i n a p e r c e i v e r (when he views the o b j e c t ) , then whenever the same s i t u a t i o n o c c u r s a g a i n , i t w i l l d e termine an i d e a which i s q u a l i t a - t i v e l y the same as the f i r s t . The phr a s e "the same s i t u a t i o n " , however, covers more than t he o b j e c t and the r e s t o f the environment. S i n c e t he person's view- i n g t h e o b j e c t n e c e s s a r i l y i n v o l v e s h i s u s i n g h i s e y e s , some f e a t u r e s o f h i s p h y s i c a l s t a t e c o n s t i t u t e p a r t o f "the s i t u a t i o n " . I have s t a t e d a l r e a d y t h a t i t would be an e m p i r i c a l c l a i m what o t h e r p a r t s o f the p e r c e i v e r ' s body are i n - v o l v e d , and what v a r i a t i o n s i n h i s p h y s i c a l s t a t e a f f e c t h i s p e r c e i v e d c o l o u r s when he views the o b j e c t r e f e r r e d t o . What i s not an e m p i r i c a l c l a i m i s the f o l l o w i n g : r f whenever t h e r e i s "the same s i t u a t i o n " t he o b j e c t , g i v e n i t s e n v i r o n m e n t , i s t o dete r m i n e q u a l i t a t i v e l y t he same i d e a , t h e n t he ways i n which v a r i a t i o n s i n the p e r c e i v e r ' s p h y s i c a l s t a t e a f f e c t h i s i d e a s must a l s o have the same r e g u l a r i t y . For a r a t h e r crude d e s c r i p t i o n o f t h i s p o i n t (before I go on to r e f i n e i t ) , suppose X i s the p h y s i c a l o b j e c t g i v e n i t s environment ( i . e . , t h e o b j e c t v i e w e d ) , Y i s the i d e a ( s ) the p e r c e i v e r has on v i e w i n g the o b j e c t , and Z i s the p e r c e i v e r ' s p h y s i c a l s t a t e . I f "X d e t e r m i n e s Y" i n v o l v e s both X's e f f e c t s on Z, and Z's e f f e c t s on Y, then t o ensure a l a w l i k e r e g u l a r i t y o f t he form "In the same s i t u a t i o n , the same X determines the same Y", both X's e f f e c t s on Z, and Z's e f f e c t s on Y need t o have a l a w l i k e r e g u l a r i t y . The d e s c r i p t i o n above ( i n terms o f X, Y, and Z) o f what i s i n v o l v e d i n the n o t i o n o f a p a r t o f t h e p h y s i c a l w o r l d ' s d e t e r m i n i n g a p e r c e i v e r ' s i d e a ( s ) needs t o be r e f i n e d . In p a r t i c u l a r , I need t o c l a r i f y what Z i s . T h i s w i l l be done by making use o f the co n c e p t s o f "the i n p u t ('through' the e y e s ) " , "the ' r o u t e ' o f the i n p u t i n the p e r c e i v e r ' s body", and "the p h y s i c a l end- s t a t e " . F u n c t i o n i n g eyes (as I have c l a r i f i e d t h e phrase) a r e n e c e s s a r i l y i n - v o l v e d , but what the p h y s i c a l e n d - s t a t e i s c o u l d be d i s c o v e r e d o n l y i f p a r t s o f t h e p h y s i c a l w o r l d do a c t u a l l y determine i d e a s a p e r c e i v e r has on v i e w i n g , and then we i n v e s t i g a t e e m p i r i c a l l y what the p h y s i c a l e n d - s t a t e i s . Without t h e s e e m p i r i c a l f i n d i n g s we need to remember t h a t t h e e n d - s t a t e c o u l d be some s t a t e o f the p e r c e i v e r ' s eyes so t h a t the ' r o u t e ' o f the i n p u t c o l l a p s e s i n t o n o t h i n g . Even so t h e r e w i l l be some e n d - s t a t e even i f t h a t s t a t e i s the o n l y change i n p h y s i c a l s t a t e brought about by the person's v i e w i n g t h e p a r t o f the p h y s i c a l w o r l d r e f e r r e d t o . I s h a l l go on t o c l a i m l a t e r t h a t p a r t s o f the p h y s i c a l w o r l d do determine i d e a s a person has on v i e w i n g i t , and t h a t the end- s t a t e has been d i s c o v e r e d t o be a b r a i n s t a t e and t h a t t he i n p u t has been d i s - c o v e r e d t o be e l e c t r o - m a g n e t i c waves. F i r s t , however, I s h a l l c l a r i f y i n some d e t a i l the d e s c r i p t i o n I gave ( i n terms o f X,Y, and Z) o f what i s i n v o l v e d i n the c o n c e p t o f a p a r t o f the p h y s i c a l w o r l d ' s d e t e r m i n i n g a p e r c e i v e r ' s i d e a s . The c o r e o f t h a t f i r s t d e s c r i p t i o n i s : I f "X de t e r m i n e s Y" i n v o l v e s both X's e f f e c t s on Z, and Z's e f f e c t s on Y, then t o ensure a l a w l i k e r e g u l a r i t y o f the form "In t h e same s i t u a t i o n , t he same X determines the same Y", both X's e f f e c t s on Z, and Z's e f f e c t s on Y need t o have a l a w l i k e r e g u l a r i t y . Here I s h a l l c l a r i f y what Z i s , i . e . , I s h a l l e x p l a i n what i s meant by "the p e r c e i - v e r ' s p h y s i c a l s t a t e " i n t h i s c o n t e x t . F i r s t I g i v e two c l a i m s t h a t c a p t u r e the l a w l i k e r e g u l a r i t y r e q u i r e d i f we are t o g i v e sense t o "a p a r t o f the p h y s i c a l w o r l d ' s d e t e r m i n i n g a p e r c e i v e r ' s i d e a ( s ) when he views t h a t p a r t " : i ) On two o c c a s i o n s o f a p e r c e i v e r ' s v i e w i n g a p h y s i c a l o b j e c t , i f he views t h e same p h y s i c a l o b j e c t i n a c o n s t a n t environment, and h i s p h y s i c a l s t a t e i s the same on both o c c a s i o n s , then he w i l l have t h e same i d e a ( s ) ; i i ) On two o c c a s i o n s o f a p e r c e i v e r ' s v i e w i n g a p h y s i c a l o b j e c t , i f he views the same p h y s i c a l o b j e c t i n a c o n s t a n t environment, and has on each oc - c a s i o n a d i f f e r e n t i d e a ( o r s e t o f i d e a s ) , then h i s p h y s i c a l s t a t e i s d i f f e r e n t on each o c c a s i o n . 1 ^ (There are o t h e r c l a i m s to do w i t h t h i s r e g u l a r i t y , but f o r o u r purposes t h e s e two a r e the i m p o r t a n t ones. Our i n v e s t i g a t i o n here i s to h e l p e v e n t u a l l y w i t h t h e q u e s t i o n o f whether o r n o t s y s t e m a t i c t r a n s p o s i t i o n , i n i t s f i r s t i n t e r - p r e t a t i o n , i s d e t e c t a b l e ; and i n i t s f i r s t i n t e r p r e t a t i o n , the term "where" i n "where one person p e r c e i v e s c o l o u r , the o t h e r person p e r c e i v e s c o l o u r c^, ..." i s i n t e r p r e t e d t o mean " i n a c o n s t a n t environment".) I s h a l l use c l a i m ( i i ) above as the v e h i c l e f o r e x p l a i n i n g what i s meant here by " h i s p h y s i c a l s t a t e i s d i f f e r e n t on each o c c a s i o n " . A t f i r s t g l a n c e the e x p l a n a t i o n l o o k s more c o m p l i c a t e d than i t r e a l l y i s ; the u n d e r l y i n g n o t i o n w i l l be seen t o be q u i t e s i m p l e , what i s meant by " h i s p h y s i c a l s t a t e i s d i f f e r e n t on each oc - c a s i o n " as i t i s used i n c l a i m ( i i ) above i s : There i s a d i f f e r e n c e i n the p e r c e i v e r ' s p h y s i c a l s t a t e on each o c c a s i o n a t some time ( t e m p o r a l l y ) p r i o r t o t h e b e g i n n i n g o f the p h y s i c a l end- s t a t e , where a) t h i s d i f f e r e n c e i n p h y s i c a l s t a t e i s not i t s e l f caused by_ the i n p u t , and where b) t h i s d i f f e r e n c e i n p h y s i c a l s t a t e a f f e c t s ( i n a l a w l i k e f a s h i o n ) the i d e a s t h e p e r c e i v e r a c t u a l l y h a s — i n t h a t i f t h e r e was not t h i s d i f - f e r e n c e and t h e s t a t e s were o t h e r w i s e l e f t unchanged, t h e p e r c e i v e r would have q u a l i t a t i v e l y the same i d e a on both o c c a s i o n s . There i s one c o r o l l a r y I s h a l l s t a t e h e r e : I f t h e r e i s g e n u i n e l y a ' r o u t e ' the i n p u t ' t r a v e l s ' i n the p e r c e i v e r ' s body, i . e . , i f the p h y s i c a l e n d - s t a t e i s not s i m p l y the i n i t i a l change ^ T h e s e c l a i m s and a l l the p o i n t s f o l l o w i n g a p p l y l i k e w i s e t o cases where a d i f f e r e n t p e r c e i v e r views t h e p h y s i c a l o b j e c t on each o f t h e two o c c a s i o n s . I t i s s l i g h t l y l e s s cumbersome, however, t o r e f e r t o o n l y one p e r c e i v e r h e r e . 95 ( i n the s t a t e o f the eyes) brought about by the v i e w i n g , then the d i f - f e r e n c e i n the p e r c e i v e r ' s s t a t e r e f e r r e d t o - - t h e d i f f e r e n c e t h a t i s n o t caused by_ the i n p u t from the viewed p a r t o f the p h y s i c a l w o r l d , but which a f f e c t s the i d e a s the p e r c e i v e r a c t u a l l y h a s — w i l l o b t a i n i m m e d i a t e l y p r i o r t o the b e g i n n i n g o f the time t a k e n by the i n p u t t o ' t r a v e l i t s r o u t e ' i n the p e r c e i v e r ' s body, o r a t some time d u r i n g t he time taken by the i n p u t t o ' t r a v e l i t s r o u t e ' (from the e y e s ) , but i n any case tempo- r a l l y p r i o r t o the b e g i n n i n g o f the p h y s i c a l e n d - s t a t e . The d i f f e r e n c e c o u l d be im m e d i a t e l y p r i o r t o the p e r i o d o f time r e f e r r e d t o i f i t was a d i f f e r e n c e i n the s t a t e o f the p e r c e i v e r ' s eyes a f f e c t i n g h i s i d e a s . A l s o , even though the d i f f e r e n c e must o b t a i n p r i o r to the b e g i n n i n g o f the p h y s i c a l e n d - s t a t e , i t can be a d i f f e r e n c e i n s t a t e i n t h a t p a r t o f h i s body where the e n d - s t a t e w i l l o c c u r ; e.g., i f the e n d - s t a t e i s l o c a t e d i n a c e r t a i n p a r t o f the b r a i n , t he d i f f e r e n c e i n s t a t e can be a d i f f e r e n c e i n the s t a t e o f t h a t p a r t o f t h e b r a i n i m m e d i a t e l y p r i o r t o the b e g i n n i n g o f t h e e n d - s t a t e . Very c r u d e l y , the u n d e r l y i n g n o t i o n o f the e x p l a n a t i o n and i t s c o r o l l a r y i s t h i s : i f t h e r e i s a l a w l i k e r e g u l a r i t y i n the p a r t o f the environment's d e t e r m i n i n g the p e r c e i v e r ' s i d e a ( s ) , then a d i f f e r e n c e i n h i s i d e a s on two o c - c a s i o n s can be acco u n t e d f o r o n l y i f t h e r e i s a d i f f e r e n c e i n the d e t e r m i n i n g f a c t o r s , and s i n c e , ex h y p o t h e s i , the o b j e c t viewed and i t s environment remain c o n s t a n t , the d i f f e r e n c e i n the d e t e r m i n i n g f a c t o r s must be some d i f f e r e n c e i n the p e r c e i v e r ' s s t a t e " p r i o r t o " h i s h a v i n g the i d e a s , where t h i s d i f f e r e n c e a f f e c t s h i s c o l o u r - v i s i o n . A l l t h i s i s p a r t o f what i s c o n t a i n e d i n the con- c e p t o f a p a r t o f t h e p h y s i c a l w o r l d ' s d e t e r m i n i n g a p e r c e i v e r ' s i d e a s when he views a p h y s i c a l o b j e c t i n t h a t p a r t . I t i s r e q u i r e d t o ensure the l a w l i k e r e g u l a r i t y t he con c e p t o f " d e t e r m i n i n g " i n v o l v e s . A s i m p l e diagram h e l p s to c l a r i f y t h e temporal r e f e r e n c e s made i n t h e c o r o l l a r y t o the e x p l a n a t i o n o f " h i s p h y s i c a l s t a t e i s d i f f e r e n t on each o c c a s i o n " as t h i s sentence i s used i n c l a i m ( i i ) (on pp. 93-94 above.) P e r c e i v e r views o b j e c t : 'A . A- Input to the B e g i n n i n g o f eyes Time d u r i n g which the i n - p h y s i c a l end- put ' t r a v e l s ' i t s 'r o u t e ' s t a t e (The diagram h e r e , o f c o u r s e , does n o t r e p r e s e n t t he l e n g t h s o f time p r o p o r t i o n a t e l y . ) S e v e r a l p o i n t s can now be made about the " d i f f e r e n c e i n p h y s i c a l s t a t e " b e i n g r e f e r r e d t o , some about the g e n e r a l e x p l a n a t i o n , some s p e c i f i c a l l y about t h e c o r o l l a r y . F i r s t t h e r e a re two s i m p l e p o i n t s to do w i t h the g e n e r a l e x p l a - n a t i o n . Some d i f f e r e n c e s i n p h y s i c a l s t a t e which a f f e c t a person's p e r c e p t i o n s may h o l d f o r a l o n g time. They may h o l d p r i o r t o the two v i e w i n g s , and some may h o l d f o r a l o n g time a f t e r t h e b e g i n n i n g o f t h e e n d - s t a t e , but they need not do so to be e f f e c t i v e i n the r e q u i r e d way. A l s o , t h e p h y s i c a l e n d - s t a t e can v a r y i n d u r a t i o n (which i s why i n the diagram the e n d - s t a t e i s g i v e n no s p e c i f i c temporal d u r a t i o n ) . I t w i l l a l s o h e l p t o g i v e a b r i e f word as t o why, i f t h e p h y s i c a l w o r l d ' s d e t e r m i n i n g the i d e a s i s t o o c c u r , t h e r e must be a d i f f e r e n c e p r i o r t o the b e g i n n i n g o f t h e p h y s i c a l e n d - s t a t e (as " d i f f e r e n c e i n p h y s i c a l s t a t e " i s b e i n g used i n c l a i m ( i i ) a b ove). I f a d i f f e r e n c e i n t h e e n d - s t a t e s was the o n l y d i f f e r e n c e i n v o l v e d i n the two v i e w i n g s , then t h e same i n p u t ( s i n c e i n both ca s e s t he p e r c e i v e r i s v i e w i n g t he same o b j e c t i n a con- s t a n t environment) can on two o c c a s i o n s a f f e c t a p e r c e i v e r i n e x a c t l y the same p h y s i c a l s t a t e d u r i n g the time t he i n p u t ' t r a v e l s i t s r o u t e ' and y e t two d i f - f e r e n t p h y s i c a l e n d - s t a t e s r e s u l t . ^ I t would n o t be t r u e t h a t both t he i n - put's e f f e c t s on h i s p h y s i c a l s t a t e and the e f f e c t s o f h i s p h y s i c a l s t a t e on ^ T h e p h y s i c a l e n d - s t a t e must not be c o n f u s e d w i t h the l o c a t i o n o f i t . There can be a d i f f e r e n c e i n t h a t p a r t o f the p e r c e i v e r ' s body p r i o r t o the b e g i n - n i n g o f t h e e n d - s t a t e , where t h i s d i f f e r e n c e a f f e c t s h i s a c t u a l i d e a s . 97 h i s i d e a s had the l a w l i k e r e g u l a r i t y i n v o l v e d i n the p h y s i c a l w o r l d ' s d e t e r - m i n i n g h i s i d e a s . There a r e a l s o a c o u p l e ; o f p o i n t s worth m e n t i o n i n g which a re s p e c i f i - c a l l y about t he c o r o l l a r y . The t i m e t h e i n p u t t a k e s t o ' t r a v e l i t s r o u t e ' may be s h o r t , perhaps so s h o r t t h a t we s h o u l d n o t n o r m a l l y t h i n k o f the ' r o u t e - t r a v e l l i n g ' as t a k i n g time a t a l l but r a t h e r speak o f "the time" a t which the p e r c e i v e r both views the o b j e c t and has the r e s u l t i n g i d e a s . But we must r e - member t h a t t h e r e i s always a p e r i o d o f ti m e i n v o l v e d . For example, i f the p e r c e i v e r ' s eyes a l t e r e d d u r i n g h i s v i e w i n g o f an o b j e c t , i t would be impor- t a n t t o know whether the a l t e r a t i o n o c c u r r e d b e f o r e o r a f t e r t he i n p u t ' l e f t ' the eyes. I f the a l t e r a t i o n p o s t - d a t e d the ' d e p a r t u r e ' , by however l i t t l e , t h e a l t e r a t i o n would not count as p r o d u c i n g "a d i f f e r e n c e i n p h y s i c a l s t a t e " f o r purposes o f my a n a l y s i s . I t has not been s p e c i f i e d t h a t the d i f f e r e n c e i n p h y s i c a l s t a t e o c c u r on the ' r o u t e ' , and t h i s i s the second p o i n t I wish to make about the c o r o l - l a r y . I t i s t r u e , o f c o u r s e , t h a t t h e d i f f e r e n c e must make some r e l e v a n t d i f - f e r e n c e to the 'r o u t e ' a t t h e a p p r o p r i a t e t i m e , but i t i s s t i l l u s e f u l not t o r e q u i r e t h a t i t be on the ' r o u t e ' f o r the f o l l o w i n g r e a s o n . There may be some d i f f e r e n c e s i n p h y s i c a l s t a t e s t h a t a r e easy t o d e t e c t , t h a t d e t e r m i n e a d i f - f e r e n c e i n a p e r c e i v e r ' s i d e a s i n a c o n s t a n t environment, but which may not u s e f u l l y be d e s c r i b e d as b e i n g d i f f e r e n c e s i n a p a r t o f the person's s e n s o r y a p p a r a t u s o f s i g h t , even though t h e d i f f e r e n c e s a f f e c t t h a t a p p a r a t u s . Indeed, t h e r e a r e such c a s e s . I und e r s t a n d t h a t a s e v e r e o b s t r u c t i o n o f b i l e - - t h e cause o f j a u n d i c e - - c a n a f f e c t a person's i d e a s ( o f c o l o u r ) i n a c o n s t a n t en- viro n m e n t , y e t most people would not wish t o r e f e r to the b i l e d u c t as p a r t o f t he person's s e n s o r y a p p a r a t u s o f s i g h t . 98 The Use o f the Second B a s i s L e t us r e t u r n now to the q u e s t i o n f o r which t h i s second b a s i s i s p r o v i - ded. We a r e a s k i n g i f s y s t e m a t i c t r a n s p o s i t i o n , i n i t s f i r s t i n t e r p r e t a t i o n , i s d e t e c t a b l e ; i n the f i r s t i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " t he term "where" i n t h e sentence "where one person p e r c e i v e s c o l o u r C^V the o t h e r person p e r c e i v e s c o l o u r c-j, . . ." i s i n t e r p r e t e d t o mean " i n a c o n s t a n t en- vironment". As b e f o r e , I s h a l l ask f i r s t i f i t i s l o g i c a l l y p o s s i b l e t o d e t e c t i t , and a f t e r w a r d s ask about c o n c e i v a b i l i t y . Suppose t h a t a s y s t e m a t i c t r a n s p o s i t i o n does h o l d between two p e r c e i v e r s , P-j and P^. Given t h e f i r s t i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " , t h i s means t h e r e a re some con- s t a n t environments i n which P 1 sees c o l o u r C| ( f o r a p a r t o f the environment v i e w e d ) , and P^ sees c o l o u r c^ ( f o r the same p a r t ) , where C ^ c ^ , and t h e r e i s no c o n s t a n t environment where P-j sees C| ( f o r a p a r t viewed) but where Pg does not see c.| ( f o r t he same p a r t ) , and no^ c o n s t a n t environment where P^ sees c-j but where P^ does not see . When the s y s t e m a t i c t r a n s p o s i t i o n i s i n e f f e c t , t h e n , t h e environment i s c o n s t a n t , o r , as Smart d e s c r i b e d the environment here, 13 the " s t i m u l i " are c o n s t a n t , and f o r both v i e w e r s , t h e i r p e r c e i v e d c o l o u r s are i d e a s o f a p a r t o f t h a t environment, and so a r e determined by ( t h a t p a r t o f ) the environment. S i n c e , ex h y p o t h e s i , the environment i s c o n s t a n t , by a p p e a l - i n g t o what I have c a l l e d "the second b a s i s " , we know t h a t a t t h e times when th e two p e r c e i v e r s a c t u a l l y view the p a r t o f the environment i n q u e s t i o n t h e r e i s a d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e . To be p r e c i s e : t h e r e i s a d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e s (on o c c a s i o n s when t h e y view the p a r t o f the e n v i r o n - ment i n q u e s t i o n ) a t some time p r i o r t o the b e g i n n i n g o f the r e s p e c t i v e p h y s i - c a l e n d - s t a t e s , where (a) t h i s d i f f e r e n c e i n p h y s i c a l s t a t e i s not i t s e l f caused by_ the i n p u t , and where (b) t h i s d i f f e r e n c e i n p h y s i c a l s t a t e s a f f e c t s ( i n a l a w l i k e f a s h i o n ) the i d e a s the p e r c e i v e r s a c t u a l l y h a v e - - i n t h a t i f t h e r e was not t h i s d i f f e r e n c e and t h e i r s t a t e s were o t h e r w i s e l e f t u n a l t e r e d , 1 3 S m a r t , " C o l o u r s , " p. 129. 99 the p e r c e i v e r s would see q u a l i t a t i v e l y the same i d e a ( s ) ( o f c o l o u r ) on t h e s e 14 o c c a s i o n s . Even i f the s y s t e m a t i c t r a n s p o s i t i o n between P-̂  and Pg i s perma- nen t , i t i s l o g i c a l l y p o s s i b l e t o d e t e c t t h a t t h e r e i s a s y s t e m a t i c t r a n s p o - s i t i o n h o l d i n g between them, s i n c e we can make use o f an o t h e r p e r c e i v e r , P^, as we d i d e a r l i e r i n the s e c t i o n (when we were u s i n g t he " f i r s t b a s i s " f o r t a c k l i n g t he T r a n s p o s i t i o n Argument). Very b r i e f l y h e r e , i t w i l l be l o g i c a l l y p o s s i b l e f o r P^ t o view the p a r t o f the environment i n q u e s t i o n on d i f f e r e n t o c c a s i o n s where, on some o f t h e s e o c c a s i o n s , h i s p h y s i c a l s t a t e - - i n the sense s p e c i f i e d above (p.94 ) — i s q u a l i t a t i v e l y t h e same as P-^'s, and where on o t h e r o c c a s i o n s h i s p h y s i c a l s t a t e i s q u a l i t a t i v e l y the same as Pg's. P ? w i l l then e x p e r i e n c e the d i f f e r e n c e i n p e r c e i v e d c o l o u r s r e s u l t i n g from t h i s d i f f e r e n c e i n p h y s i c a l s t a t e , and i t w i l l be l o g i c a l l y p o s s i b l e f o r him (and o t h e r s ) t o d e t e c t t h i s d i f f e r e n c e i n p h y s i c a l s t a t e and produce the g e n e r a l i z a t i o n t h a t any two p e r c e i v e r s ( o r one p e r c e i v e r a t d i f f e r e n t t i m e s ) w i t h t h i s d i f f e r e n c e i n p h y s i c a l s t a t e w i l l have a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s between them. I f permanency i s made a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n , then the r e l e v a n t g e n e r a l i z a t i o n he (and o t h e r s ) w i l l make w i l l be t h a t any two p e r c e i v e r s h a v i n g permanently t h i s d i f f e r e n c e i n p h y s i c a l s t a t e w i l l have a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s h o l d i n g between them. The g e n e r a l i z a t i o n c o u l d then be a p p l i e d t o p e r c e i v e r s P^ and Pg. So i t would be l o g i c a l l y p oss- i b l e t o d e t e c t t h a t a (permanent) s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s h o l d s between two p e r c e i v e r s ; and i t would be d e t e c t a b l e by the p a i r o f p e r c e i v e r s a c t u a l l y i n v o l v e d . W i l l i t be l o g i c a l l y p o s s i b l e t o d e t e c t which c o l o u r s a r e t r a n s p o s e d (so as t o know by a c q u a i n t a n c e which c o l o u r s a r e t r a n s p o s e d ) ? Of c o u r s e , 9 " i v e n t h e r o l e he has, can d e t e c t which c o l o u r s a re t r a n s p o s e d s i n c e i t i s l o g i c a l l y 1 4 T h i s e x p l a n a t i o n o f " d i f f e r e n c e i n p h y s i c a l s t a t e " as used here i s f i r s t g i v e n on p.94 above. p o s s i b l e f o r him to be i n the s t a t e o f P^, a t one t i m e , and i n the s t a t e o f Pg, a t a n o t h e r t i m e , and t o view the p a r t o f t h e environment r e f e r r e d t o w h i l s t i n t h e s e s t a t e s and a c t u a l l y have the d i f f e r e n t p e r c e i v e d c o l o u r s . However, t h e i n t e r e s t i n g q u e s t i o n h e r e , as i t was e a r l i e r i n t h e s e c t i o n , i s whether o r not P^ and Pg can know which c o l o u r s a re t r a n s p o s e d , and i n p a r t i c - u l a r , whether o r n o t t h e y c a n know i f permanency i s made a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n . ( I f the t r a n s p o s i t i o n happens t o be permanent but permanency i s n o t a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n , then i t w i l l be l o g i c a l l y p o s s i b l e f o r P^ and Pg t o d e t e c t which c o l o u r s a re t r a n s - posed between them s i m p l y because i t w i l l be l o g i c a l l y p o s s i b l e f o r each t o undergo t h e r e l e v a n t change i n p h y s i c a l s t a t e - - a s Pg d i d - - and so a c t u a l l y have t h e t r a n s p o s e d p e r c e i v e d c o l o u r s . T h i s w i l l be l o g i c a l l y p o s s i b l e even i f t h e i r t r a n s p o s i t i o n happens t o be permanent, j u s t so l o n g as permanency i s not a d e f i n i t i v e f e a t u r e o f s y s t e m a t i c t r a n s p o s i t i o n . ) I t has been shown e a r l i e r i n the s e c t i o n t h a t d e t e c t i n g t h a t t h e r e i s a s y s t e m a t i c t r a n s p o s i t i o n by r e f e r e n c e t o a person h a v i n g t he r o l e o f Pg does n o t t h e r e b y guarantee de- t e c t i o n o f which c o l o u r s a re t r a n s p o s e d . But i t was a l s o shown t h a t t h i s i s not a problem s p e c i f i c a l l y t o do w i t h s y s t e m a t i c t r a n s p o s i t i o n ; t h e same p o i n t was shown t o be t r u e o f d e t e c t i n g t h a t t h e r e i s an o v e r l a p p i n g t r a n s p o s i t i o n . What t h i s means i s , a l t h o u g h the q u e s t i o n ( o f whether o r not i t i s l o g i c a l l y p o s s i b l e f o r the p e r c e i v e r s i n v o l v e d t o d e t e c t which c o l o u r s a re s y s t e m a t i c a l l y t r a n s p o s e d ) i s worth a s k i n g , i t would be a m i s t a k e t o c o n s t r u e i t as a demand t h a t must be met f o r cases o f s y s t e m a t i c t r a n s p o s i t i o n i f thos e c a s e s a re 'to be on a p a r w i t h 1 c a s e s o f o v e r l a p p i n g t r a n s p o s i t i o n . T h a t i s t o say, i t would be a m i s t a k e t o make the demand as though i n c a s e s o f o v e r l a p p i n g t r a n s p o s i t i o n , by v i r t u e o f the f e a t u r e t h a t makes them cases o f o v e r l a p p i n g t r a n s p o s i t i o n , t h e demand i s guar a n t e e d t o be met. As has been shown, the f e a t u r e t h a t makes them c a s e s o f o v e r l a p p i n g t r a n s p o s i t i o n does not guarantee t h a t which c o l o u r s a r e t r a n s p o s e d i s d e t e c t a b l e . B e a r i n g t h i s i n mind, l e t us ask whether i t i s l o g i c a l l y p o s s i b l e i n a case o f (permanent) s y s t e m a t i c t r a n s p o s i t i o n f o r the p e r c e i v e r s i n v o l v e d t o d e t e c t which c o l o u r s a re t r a n s p o s e d . I t s h o u l d be remembered t h a t I am not a s k i n g t h i s q u e s t i o n i n vacuo, but w i t h r e g a r d t o the c l a i m s o f t h e "second b a s i s " . One p o i n t mentioned e a r l i e r i n the s e c t i o n — i n c o n n e c t i o n w i t h t he " f i r s t b a s i s " f o r t a c k l i n g t he T r a n s p o s i t i o n A r g u m e n t — i s r e l e v a n t here. I f i t i s l o g i c a l l y p o s s i b l e f o r one o f t h e two p e r c e i v e r s i n v o l v e d t o have h i s eyes c l o s e d , and so not " f u n c t i o n i n g " (as I have used t h i s t e r m ) , and y e t to have the p e r c e i v e d c o l o u r i n q u e s t i o n , and know t h a t i t i s the a p p r o p r i a t e p e r c e i v e d c o l o u r , t h e n i t w i l l be l o g i c a l l y p o s s i b l e f o r him t o d e t e c t which c o l o u r s a r e t r a n s p o s e d w i t h o u t b r e a k i n g t h e permanency c o n d i t i o n o f t h e s y s - t e m a t i c t r a n s p o s i t i o n . The c o n d i t i o n w i l l n ot be broken i n such a case because t h e i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " here i s i n terms o f what t h e two p e r c e i v e r s see when t h e y view some p a r t o f some c o n s t a n t environment, and t h i s i s n o t a f f e c t e d by c l a i m s about t h e p e r c e i v e d c o l o u r s t he two peopl e have sometimes when t h e i r eyes are not f u n c t i o n i n g . One p o s s i b i l i t y here i s t o make use o f the concept o f a " p h y s i c a l e n d - s t a t e o f a v i e w i n g " , but to do so I need t o say a l i t t l e more about the c o n c e p t . The p o i n t s here w i l l be i n q u i t e an a b s t r a c t form, s i n c e t h e y w i l l be t o do w i t h e x p l a i n i n g the c o n c e p t r a t h e r than making e m p i r i c a l c l a i m s about what the e n d - s t a t e a c t u a l l y i s and what the ' i n p u t ' a c t u a l l y i s f o r cases o f v i e w i n g by humans. (The l a t t e r w i l l appear below i n t h i s s e c t i o n , i n the c o n t e x t o f a s k i n g about the c o n c e i v a b i l i t y o f d e t e c t i n g s y s t e m a t i c t r a n s p o s i t i o n , g i v e n t h e "second b a s i s " . ) W i t h o ut g o i n g i n t o undue d e t a i l , t h e n , the f o l l o w i n g a re the i m p o r t a n t p o i n t s . Suppose t h a t a p e r c e i v e r views some p h y s i c a l o b j e c t i n a c e r t a i n e n vironment, and t h a t t h e i d e a ( o f c o l o u r ) d e t e r m i n e d by t h a t o b j e c t ( g i v e n i t s environment) i s the i d e a , X . 1 3 F i r s t , the p h y s i c a l e n d - s t a t e o f t h a t view- i n g o f t h a t o b j e c t i s d e termined by the i n p u t r e s u l t i n g f r o m . t h a t v i e w i n g (whatever t h a t i n p u t t u r n s o u t t o b e ) . S e c o n d l y , the p h y s i c a l e n d - s t a t e f o r t h i s v i e w i n g i s t h a t p h y s i c a l s t a t e , which t h e p e r c e i v e r does have, which i s " s u f f i c i e n t " f o r h i s h a v i n g the i d e a X i n t h i s v i e w i n g , where " s u f f i c i e n t " i s t o be e x p l a i n e d i n the f o l l o w i n g way. For our purpose here what i n t e r e s t s me i s t h a t the person had the i d e a X r a t h e r than some o t h e r i d e a ; I am not p r i - m a r i l y i n t e r e s t e d i n more g e n e r a l s e t s o f c o n t r a s t s , e.g., t h a t the p e r s o n i s s i g h t e d r a t h e r than b l i n d . So l e t us take as g i v e n t h a t the person i s s i g h t e d and awake, which means t a k i n g as g i v e n those f e a t u r e s o f h i s p h y s i c a l s t a t e t h a t are c o n d i t i o n s f o r h i s b e i n g s i g h t e d and awake. A l s o , i f t h e r e a r e some ge n e r a l c o n d i t i o n s f o r a person's h a v i n g " f u n c t i o n i n g eyes" (which i s a non- d i s p o s i t i o n a l c o n c e p t , as I have used i t ) , where t h e s e c o n d i t i o n s (a) a r e r a t h e r d i f f e r e n t from (perhaps j u s t more s p e c i f i c than) tho s e c o n d i t i o n s need- ed f o r t h e person t o be s i g h t e d and awake; and (b) can be s p e c i f i e d w i t h o u t t h e r e b y s p e c i f y i n g the c o n d i t i o n s f o r t h e p e r c e i v e r ' s h a v i n g a p a r t i c u l a r i d e a ( s a y , X ) , o r some p a r t i c u l a r s e t o f i d e a s , then t h e s e c o n d i t i o n s t o o may be t a k e n as g i v e n f o r t h e purpose t o hand. In f a c t , take as g i v e n a l l c o n d i t i o n s o f h i s p h y s i c a l s t a t e r e q u i r e d f o r the p e r s o n t o view the p h y s i c a l o b j e c t , where t h e s e c o n d i t i o n s as s p e c i f i e d a r e n o t i n t hemselves c o n d i t i o n s f o r the p e r c e i v e r ' s h a v i n g a c e r t a i n i d e a , say, X. The s e t o f t h e s e c o n d i t i o n s can be c a l l e d "the v i e w i n g - c o n d i t i o n s o f a p e r s o n ' s p h y s i c a l s t a t e " . In b r i e f t h e n , f o r o u r example where t h e person views a c e r t a i n p h y s i c a l o b j e c t and has as a r e s u l t the i d e a ( o f c o l o u r ) X, the p h y s i c a l e n d - s t a t e i s : t h e l a s t s e t o f changed f e a t u r e s he has, which i s d e t e r m i n e d by the i n p u t o f h i s i n i t i a l 15 We s h o u l d e x p e c t a whole c o n f i g u r a t i o n o f i d e a s ( o f c o l o u r ) t o be d e t e r - mined by any p h y s i c a l o b j e c t when viewed, but t h i s would make the f o l l o w i n g p o i n t s v e r y cumbersome. So I have s i m p l i f i e d by w r i t i n g as though j u s t one i d e a ( o f c o l o u r ) i s d e t e r m i n e d i n t h e example I l o o k a t . T h i s does no t a f f e c t t h e soundness o f the p o i n t s . 103 p e r c e p t i o n o f t h e o b j e c t , where the s e t i s s u f f i c i e n t f o r the p e r c e i v e r ' s h a v i n g t he i d e a X, t a k i n g i t as a l r e a d y g i v e n t h a t what I c a l l t h e v i e w i n g - c o n d i t i o n s h o l d f o r t h e person's p h y s i c a l s t a t e ( a t t h e time o f v i e w i n g ) . T here w i l l always be some change i n p h y s i c a l s t a t e when a person views a p h y s i c a l o b j e c t i n h i s environment, s i n c e i t i s a n e c e s s a r y c o n d i t i o n o f such v i e w i n g t h a t the person have f u n c t i o n i n g eyes a t the ti m e , where one o f the t h i n g s i n c l u d e d i n the n o t i o n o f " f u n c t i o n i n g eyes" i s t h a t t h e eyes a r e b e i n g a f f e c t e d by the a p p r o p r i a t e i n p u t (whatever t h a t t u r n s out t o b e ) . T h i s has been mentioned a l r e a d y . I t w i l l n ot be p o s s i b l e t o d e c i d e a p r i o r i what the e n d - s t a t e i s f o r a v i e w i n g ( o r f o r any o t h e r p e r c e p t i o n o f t h e " e x t e r n a l w o r l d " ) ; i t i s l o g i c a l l y p o s s i b l e t h a t t h e e n d - s t a t e f o r such a vi e w i n g i s some changed s t a t e brought about i n the eyes. Only e m p i r i c a l i n - v e s t i g a t i o n c o u l d show o t h e r w i s e . What does not r e q u i r e e m p i r i c a l s u p p o r t i s the f o l l o w i n g c l a i m : " I f a p e r c e i v e r , on two o c c a s i o n s , has q u a l i t a t i v e l y t h e same p h y s i c a l e n d - s t a t e , he h a s / w i l l have q u a l i t a t i v e l y the same i d e a ( s ) . " T h i s a g a i n i s p a r t o f what i s c o n t a i n e d i n the concept o f t h e p h y s i c a l ob- j e c t ' s d e t e r m i n i n g the per s o n ' s i d e a ( s ) on h i s v i e w i n g t h a t o b j e c t . The c l a i m , as i t s t a n d s , i s i n t e n t i o n a l l y n e u t r a l as t o whether o r not the p h y s i c a l end- s t a t e i s i d e n t i c a l w i t h t h e e x p e r i e n c e (hence the o p t i o n s "has" o r " w i l l b e " ) . Even though i t i s n e u t r a l i n t h i s way, i t s t i l l must be t r u e i f , i n the case o f a v i e w i n g , b o t h t he e f f e c t s o f t h e p a r t o f t h e p h y s i c a l w o r l d viewed on p e r c e i v e r ' s p h y s i c a l s t a t e , and the e f f e c t s o f t h e p e r c e i v e r ' s p h y s i c a l s t a t e on h i s i d e a s ( i f t h e r e a re any e f f e c t s o f t h i s second k i n d ) , a re t o have the l a w l i k e r e g u l a r i t y r e q u i r e d b y . t h e c o n c e p t o f a p a r t o f t h e p h y s i c a l w o r l d ' s d e t e r m i n i n g t h e person's i d e a s (on v i e w i n g t h a t p a r t ) . I t i s i m p o r t a n t t o n o t i c e a l s o t h a t the c l a i m t h a t the p h y s i c a l e n d - s t a t e i s " s u f f i c i e n t " f o r t h e person t o have t h e i d e a ( s ) he has i s l i k e w i s e n e u t r a l w i t h r e g a r d t o t h e i s s u e o f whether o r not the i d e a i s i d e n t i c a l w i t h t he p h y s i c a l e n d - s t a t e . 104 The c o n c e p t o f the p h y s i c a l e n d - s t a t e o f a v i e w i n g ( o f a p a r t o f the p h y s i c a l world) i s u s e f u l when a s k i n g i f the two people i n v o l v e d i n a systema- t i c t r a n s p o s i t i o n o f c o l o u r s l o g i c a l l y can d e t e c t which c o l o u r s a r e tr a n s p o s e d w i t h o u t b r e a k i n g t he permanency c o n d i t i o n o f t h e t r a n s p o s i t i o n . I t s u s e f u l - ness l i e s i n the c l a i m ( g i v e n a b ove): " I f a p e r c e i v e r on two o c c a s i o n s has q u a l i t a t i v e l y t h e same p h y s i c a l e n d - s t a t e , he h a s / w i l l have q u a l i t a t i v e l y t he same i d e a ( s ) ( m u t a t i s mutandis f o r two p e r c e i v e r s , r a t h e r than one a t two d i f - f e r e n t t i m e s ) . " I have s a i d t h a t the p h y s i c a l e n d - s t a t e o f a person's v i e w i n g a c e r t a i n p h y s i c a l o b j e c t and hav i n g as a r e s u l t the i d e a ( o f c o l o u r ) X, i s determined by the i n p u t r e s u l t i n g from t he v i e w i n g (whatever t h a t i n p u t t u r n s o u t to b e ) . However, i f q u a l i t a t i v e l y the same p h y s i c a l s t a t e as t h a t p h y s i c a l e n d - s t a t e can be brou g h t about i n a person w i t h o u t i t s b e i n g d e t e r m i n e d by a p a r t o f t h e p h y s i c a l w o r l d (when v i e w e d ) , then i t i s l o g i c a l l y p o s s i b l e f o r two p e o p l e i n v o l v e d i n a s y s t e m a t i c t r a n s p o s i t i o n t o d e t e c t which c o l o u r s a re t r a n s p o s e d w i t h o u t b r e a k i n g t he permanency c o n d i t i o n o f the t r a n s p o s i t i o n . The c r u c i a l p o i n t i s t h a t i f a s y s t e m a t i c t r a n s p o s i t i o n h o l d s between two p e o p l e , then on o c c a s i o n s when the t r a n s p o s i t i o n i s a c t u a l l y i n e f f e c t i n whatever en- v i r o n m e n t ^ ) t h a t o c c u r s , t he two peop l e w i l l have d i f f e r e n t p e r c e i v e d c o l o u r s , and so t h e i r p h y s i c a l e n d - s t a t e s f o r thos e v i e w i n g s w i l l be d i f f e r e n t . Now i f i t i s l o g i c a l l y p o s s i b l e t o produce i n one o f the peop l e t h e p h y s i c a l e n d - s t a t e had by the o t h e r when the t r a n s p o s i t i o n i s i n e f f e c t , where t h i s e n d - s t a t e i s produced when the person concerned i s n o t v i e w i n g any p a r t o f t h e p h y s i c a l w o r l d ( e . g . , when h i s eyes a r e c l o s e d ) , then the person b e i n g a l t e r e d w i l l have the p e r c e i v e d c o l o u r the o t h e r person has when the t r a n s p o s i t i o n i s i n e f f e c t , and he w i l l have i t w i t h o u t b r e a k i n g the permanency c o n d i t i o n o f the t r a n s p o - s i t i o n . S i n c e t he t r a n s p o s i t i o n i s about c e r t a i n s y s t e m a t i c d i f f e r e n c e s t h a t o c c u r when the two people view a c e r t a i n p a r t o f the p h y s i c a l w o r l d (when t h a t p a r t i s kept c o n s t a n t ) , what happens when th e y a r e not v i e w i n g any p a r t o f the p h y s i c a l w o r l d w i l l not ' i n t e r f e r e w i t h ' the t r a n s p o s i t i o n . More s p e c i f i c p o i n t s about the p o s s i b i l i t y o f p r o d u c i n g q u a l i t a t i v e l y the same p h y s i c a l e n d - s t a t e i n t h i s way can be made when.asking about t h e c o n c e i v a b i l i t y o f d e t e c t i n g s y s t e m a t i c t r a n s p o s i t i o n s o f c o l o u r s , s i n c e i n t h a t c o n t e x t I s h a l l make use o f c e r t a i n e m p i r i c a l f a c t s ( e . g . , as t o what the p h y s i c a l e n d - s t a t e a c t u a l l y i s f o r s i g h t e d humans). Here I s h a l l p o i n t out o n l y t h a t t h e r e i s n o t h i n g i n . t h e "second b a s i s " t h a t i s i n c o n s i s t e n t w i t h the n o t i o n o f "a p l u r a l i t y o f c a u s e s " f o r some e v e n t / s t a t e . The l a w l i k e r e g u l a r i t i e s r e f e r r e d t o i n the "second b a s i s " a r e , v e r y c r u d e l y , o f the form "Same cause, same e f f e c t " , " D i f f e r e n t e f f e c t , d i f f e r e n t cause". And t h e i d e a t h a t t h e r e may be "a p l u r a l i t y o f c a u s e s " f o r a p h y s i c a l e n d - s t a t e (which i s s u f f i c i e n t f o r a c e r t a i n e x p e r i e n c e ) i s f a r from o r i g i n a l . I t goes back a t l e a s t as f a r as D e s c a r t e s . He, o f c o u r s e , makes e x p l i c i t t h a t he does not a c c e p t t he i d e n t i t y - t h e s i s (about e x p e r i e n c e s and the p h y s i c a l e n d - s t a t e s ) , but he a p p a r e n t l y does a c c e p t t h a t t h e r e can be more than one cause f o r a p h y s i c a l e n d - s t a t e . . . , when I f e e l p a i n i n my f o o t , my knowledge o f p h y s i c s t e a c h e s me t h a t t h i s s e n s a t i o n i s communicated by means o f nerve s d i s p e r s e d t hrough the f o o t , which, b e i n g extended l i k e c o r d s from t h e r e t o the b r a i n , when t h e y a re c o n t r a c t e d i n the f o o t , a t t h e same time con- t r a c t the inmost p o r t i o n s o f t h e b r a i n which i s t h e i r e x t r e m i t y and p l a c e o f o r i g i n , and then e x c i t e a c e r t a i n movement which n a t u r e has e s t a b l i s h e d i n o r d e r t o cause the mind t o be a f f e c t e d by a s e n s a t i o n o f p a i n r e p r e s e n t e d as e x i s t i n g i n the f o o t . But because t h e nerves must pass t h r o u g h the t i b i a , t h e t h i g h , t he l o i n s , the back and t h e neck, i n o r d e r t o reach from the l e g t o t h e b r a i n , i t may happen t h a t a l t h o u g h t h e i r e x t r e m i t i e s - w h i c h a r e i n the f o o t a r e n o t a f f e c t - ed, but o n l y c e r t a i n ones o f t h e i r i n t e r v e n i n g p a r t s which pass by t h e l o i n s o r the neck', t h i s a c t i o n w i l l e x c i t e the same movement i n the b r a i n t h a t might have been e x c i t e d t h e r e by a h u r t r e c e i v e d i n the f o o t , i n consequence o f which the mind w i l l n e c e s s a r i l y f e e l i n the f o o t the same p a i n as i f i t had r e c e i v e d a h u r t . And the same h o l d s good o f a l l the o t h e r p e r c e p t i o n s o f our s e n s e s . 6 ( I t i s n o t s u g g e s t e d , o f c o u r s e , t h a t D e s c a r t e s ' d e s c r i p t i o n o f what the Rene D e s c a r t e s , " M e d i t a t i o n s on F i r s t P h i l o s o p h y , V I," The P h i l o s o p h i c a l Works o f D e s c a r t e s , t r a n s . , E l i z a b e t h S. Haldane and G. R. T. Ross (London, 1911), I, pp. 196-197. 106 p h y s i c a l e n d - s t a t e i s i n h i s example, i s a c c u r a t e . ) S i n c e , t h e n , i t i s l o g i - c a l l y p o s s i b l e t h a t a p h y s i c a l e n d - s t a t e can have s e v e r a l d i f f e r e n t c a u s e s , i t i s l o g i c a l l y p o s s i b l e t h a t an e n d - s t a t e may be brought about i n a person when he i s not v i e w i n g the p h y s i c a l w o r l d . In t h i s c a s e , i t i s l o g i c a l l y p o s s i b l e f o r the two peop l e i n v o l v e d i n a case o f s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s t o d e t e c t which c o l o u r s a re t r a n s p o s e d w i t h o u t b r e a k i n g t he permanency o f t h e t r a n s p o s i t i o n . In r e g a r d t o t h e l o g i c a l p o s s i b i l i t y o f d e t e c t i n g s y s t e m a t i c t r a n s p o s i - t i o n by r e l y i n g on the "second b a s i s " , i t remains t o be s t a t e d t h a t the second i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " i s i n c o h e r e n t . In the second i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " the term "where" i n the se n t e n c e "where one person p e r c e i v e s c o l o u r C p the o t h e r person p e r c e i v e s c o l o u r C p . . . " i s i n t e r p r e t e d t o mean " i n the same environment and g i v e n t h a t t he two p e r c e i v e r s a re i n q u a l i t a t i v e l y t he same s t a t e " . To say here t h a t t h e y a r e i n q u a l i t a t i v e l y t h e same s t a t e means: On v i e w i n g some p h y s i c a l o b j e c t i n some c o n s t a n t environment, t h e r e i s no d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e s i m m e d i a t e l y p r i o r t o o r d u r i n g t h e i r v i e w i n g s , but p r i o r t o the b e g i n n i n g s o f t h e i r e n d - s t a t e s (where t h i s d i f f e r e n c e i s not caused by the i n p u t o f t h e v i e w i n g s ) . Making use now o f the "second b a s i s " , when two people view a p a r t o f t h e p h y s i - c a l w o r l d and have i d e a s o f t h a t p a r t o f the p h y s i c a l w o r l d , then n e c e s s a r i l y t h o s e i d e a s a r e de t e r m i n e d by t h a t p a r t o f t h e w o r l d . And f o r the i d e a s t o be determined i n t h i s way when peop l e view t h a t p a r t o f the p h y s i c a l w o r l d (which i n v o l v e s t h e i r h a v i n g " f u n c t i o n i n g e yes" a t t h a t t i m e ) , t h e r e needs to be a l a w l i k e r e g u l a r i t y i n the e f f e c t s o f the p h y s i c a l w o r l d on the p h y s i c a l s t a t e s o f t h e p e r c e i v e r s , and between the e f f e c t s o f t h e i r p h y s i c a l s t a t e s on t h e i r i d e a s . So i n a case where two people view the same p a r t o f t h e same ( c o n s t a n t ) e n v i r o n m e n t , and are i n the same p h y s i c a l s t a t e (as c l a r i f i e d a b o v e ) , t h e 107 d e t e r m i n i n g f a c t o r s o f t h e i r r e s p e c t i v e i d e a s are the same, and so t h e y w i l l have ( q u a l i t a t i v e l y ) t h e same i d e a s . I t i s n o t l o g i c a l l y p o s s i b l e t h a t t h e y s h o u l d both view the same p a r t o f a c o n s t a n t environment, have i d e a s o f t h a t p a r t o f t h e p h y s i c a l w o r l d , be i n the same p h y s i c a l s t a t e (as c l a r i f i e d above), and y e t have ( q u a l i t a t i v e l y ) d i f f e r e n t i d e a s . But t h a t i s p r e c i s e l y what i s r e q u i r e d f o r t h e second i n t e r p r e t a t i o n o f " s y s t e m a t i c t r a n s p o s i t i o n " h e r e , and t h e r e f o r e the c o n c e p t o f s y s t e m a t i c t r a n s p o s i t i o n , g i v e n t h i s second i n - t e r p r e t a t i o n , i s i n c o h e r e n t . I t remains t o be asked i f s y s t e m a t i c t r a n s p o s i t i o n i s c o n c e i v a b l y d e t e c t - a b l e on the "second b a s i s " . Here p r o p o s a l s a r e r e s t r i c t e d by the g i v e n f a c t s o f t h e w o r l d , but so a l s o i s the problem. That i s t o say, I am here i n t e r e s t e d o n l y i n c o n c e i v a b l e c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n , where " s y s t e m a t i c t r a n s - p o s i t i o n " i s g i v e n i t s f i r s t i n t e r p r e t a t i o n ( i n which the term "where" i n t h e sentence "where one person p e r c e i v e s c o l o u r C^, the o t h e r person p e r c e i v e s c o l o u r C j , . . ." i s i n t e r p r e t e d to mean " i n a c o n s t a n t e n v i r o n m e n t " ) . To ask i f c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n a r e c o n c e i v a b l y d e t e c t a b l e , we must ask e x p l i c i t l y i f t h e r e a r e c o n c e i v a b l e c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n , and then i f t h e y are c o n c e i v a b l y d e t e c t a b l e . I f we r e a c h a n e g a t i v e answer f o r the f i r s t o f t h e s e two q u e s t i o n s , then s y s t e m a t i c t r a n s p o s i t i o n ( f i r s t i n t e r p r e t a - t i o n ) i s i t s e l f i n c o n c e i v a b l e , and the q u e s t i o n about the c o n c e i v a b i l i t y o f d e t e c t i n g i t e v a p o r a t e s . There must be a k i n d o f e q u i t y about the s e t t i n g up t h e q u e s t i o n , and i n r e s t r i c t i n g the means f o r answering i t . I t i s l e g i t i m a t e t o ask about the c o n c e i v a b i l i t y o f d e t e c t i o n p r o v i d i n g what i s meant i s the d e t e c t i o n o f c o n c e i v a b l e c a s e s . I f i t i s b e i n g asked i f l o g i c a l l y p o s s i b l e c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n can be d e t e c t e d , where the c a s e s can be i n f a c t p r o h i b i t e d by the g i v e n f a c t s o f t h i s w o r l d , then one i s e n t i t l e d t o c a l l upon what i s l o g i c a l l y p o s s i b l e , w i t h o u t r e g a r d t o g i v e n f a c t s , i n d e s c r i b i n g how t h e y can be d e t e c t e d . What would be i n e q u i t a b l e would be t o demand the 108 c o n c e i v a b i l i t y o f d e t e c t i o n o f c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n t h a t a r e me r e l y l o g i c a l l y p o s s i b l e , but n o t c o n c e i v a b l e ( i . e . , c a s e s p r o h i b i t e d by some g i v e n f a c t ) . My major i n t e r e s t i n : t h i s t h e s i s i s w i t h q u e s t i o n s t o do w i t h c o n c e i v a b i l i t y r a t h e r than t o do w i t h m e r e l y l o g i c a l p o s s i b l i t y . I am p r i m a r i l y concerned w i t h t he p o t e n i a l knowledge humans can a c q u i r e i n t h i s w o r l d , and w i t h the p o t e n t i a l hazards i n v o l v e d . In r e g a r d t o my p r e s e n t q u e s t i o n , c o n c e i v a b l e c a s e s o f s y s t e m a t i c t r a n s p o s i t i o n a r e al1 the cases t h a t I am o b l i g e d to: c o n s i d e r . For s y s t e m a t i c t r a n s p o s i t o n t o be c o n c e i v a b l e , i t must be c o n c e i v a b l e t h a t t h e r e a r e some c o n s t a n t environments i n which p e r c e i v e r P j sees c o l o u r ( f o r a p a r t o f the environment v i e w e d ) , and a n o t h e r p e r c e i v e r Pg sees c o l o u r Cj ( f o r t h e same p a r t when v i e w e d ) , where C ^ C p and t h e r e i s no c o n s t a n t environment where Pj s e e s ( f o r a p a r t viewed) b u t where Pg does n o t s e e c ^ ( f o r t h e same p a r t ) , "and no c o n s t a n t environment w h e r e Pg sees c^ b u t w h e r e P j does not see C^. T h i s i n v o l v e s i t s b e i n g c o n - c e i v a b l e f o r humans t o have i d e a s o f a c e r t a i n p a r t o f t h e p h y s i c a l w o r l d on v i e w i n g i t , i . e . , i d e a s d e termined by t h a t p a r t o f t h e phys- i c a l w o r l d . As noted above ( i n S e c t i o n 9) t h e r e i s much e m p i r i c a l e v i - dence t h a t t h i s o f t e n a c t u a l l y happens. I t was e x p l a i n e d how i n an e n v i - ronment o t h e r w i s e c o n s t a n t , a t e s t e r c o u l d p r e s e n t t o any number o f s i g h t e d p e o p l e many p a i r s o f p h y s i c a l o b j e c t s h a v i n g the same shape, same s i z e , same ' v i s i b l e ' t e x t u r e , so as t o be i n d i s t i n g u i s h a b l e to the view e r s on any o t h e r b a s i s than t h a t o f p e r c e i v e d c o l o u r s , a l t h o u g h the t e s t e r , from h i s p o s i t i o n , c o u l d see some i d e n t i f y i n g f e a t u r e o f the o b j e c t s . By p r e s e n t i n g and r e - p r e s e n t i n g t h e p a i r s , the t e s t e r can a c q u i r e e v i d e n c e o f a " s i g n i f i c a n t c o r - r e l a t i o n " (as t h i s phrase i s used i n p s y c h o l o g y ) between t h e p a i r s o f ob- j e c t s and the p e r c e i v e d c o l o u r s seen by each v i e w e r . ( P r o v i d i n g the p a i r s were p r e s e n t e d c a r e f u l l y , t h i s e v i d e n c e c o u l d be a c q u i r e d v i a sameness/ d i f f e r e n c e - o f - p e r c e i v e d - c o l o u r judgements g i v e n by the view e r s i n r e s p e c t o f the pairs of objects, presented.) Evidence f o r a " s i g n i f i c a n t correlation" could be a c q u i r e d w i t h o u t p r e s u p p o s i n g t h a t the p e r c e i v e d c o l o u r s f o r each vie w e r were q u a l i - t a t i v e l y t h e same f o r each o b j e c t p r e s e n t e d ; the t e s t can be s e t up so as t o p r o v i d e e v i d e n c e t h a t t h e r e i s a s i g n i f i c a n t c o r r e l a t i o n between the p r e s e n t a - t i o n o f c e r t a i n p a i r s o f o b j e c t s and the p e r c e i v e d c o l o u r s o f each ( r a t h e r than a l l ) v i e w e r s t e s t e d . ^ With a v e r y h i g h degree o f c o r r e l a t i o n , i t i s c o r r e s p o n d i n g l y v e r y p r o b a b l e t h a t the c o r r e l a t i o n i s not a c o i n c i d e n c e . The s i m p l e s t h y p o t h e s i s f o r an ov e r w h e l m i n g l y h i g h c o r r e l a t i o n i s t h a t the p r e s e n t - ed o b j e c t s , g i v e n t h e i r environment, determine t h e p e r c e i v e d c o l o u r s o f t h e v i e w e r s . And i t i s i m p o r t a n t to note t h a t t h e r e can be overwhelming e v i d e n c e f o r t h i s h y p o t h e s i s even i f i t i s n o t as y e t c l e a r p r e c i s e l y which f e a t u r e s o f the o b j e c t s and t h e i r environment are the d e t e r m i n i n g f a c t o r s o f t h e p e r c e i v e d c o l o u r s . Given t h a t we are r e f e r r i n g t o p e r c e i v e d c o l o u r s t h a t a r e i d e a s o f a c e r t a i n p a r t o f the p h y s i c a l w o r l d when we r e f e r t o a case o f s y s t e m a t i c t r a n s - p o s i t i o n , and g i v e n a l s o t h a t i n such a case t he p e r c e i v e d c o l o u r s a r e d i f f e r - e n t f o r two v i e w e r s , even though the environment i s c o n s t a n t , t h e n , by u s i n g the c l a i m s o f the. "second b a s i s " , t h e r e must be a d i f f e r e n c e , between one per- son's v i e w i n g and t h e o t h e r ' s , i n t h e o n l y o t h e r d e t e r m i n i n g f a c t o r o f t h e i r p e r c e i v e d c o l o u r s , v i z , t h e i r p h y s i c a l s t a t e s . So f o r s y s t e m a t i c t r a n s p o s i t i o n to be c o n c e i v a b l e , t h e r e must be a t l e a s t one p a i r o f d i f f e r e n t p h y s i c a l s t a t e s such t h a t i n some c o n s t a n t environment two v i e w e r s , one i n each s t a t e , w i l l p e r c e i v e d i f f e r e n t c o l o u r s on v i e w i n g some p a r t o f t h a t environment. I a c c e p t t h a t t h e r e a r e i n f a c t such p a i r s o f p h y s i c a l s t a t e s , a l t h o u g h o f c o u r s e I can- not g i v e a l o n g l i s t o f them s i n c e I l a c k the e m p i r i c a l knowledge r e q u i r e d . A p p a r e n t l y , b e i n g w i t h and w i t h o u t a f a i r l y s e v e r e o b s t r u c t i o n o f b i l e c o n s t i - t u t e s such a p a i r . 17 F o r more d e t a i l s , see S e c t i o n 9 above. 110 The q u e s t i o n I wish t o ask, t h e n , i s : Is i t c o n c e i v a b l e t o d e t e c t t h a t t h e r e i s a case o f s y s t e m a t i c t r a n s p o s i t i o n between two p e r c e i v e r s whose p h y s i - c a l s t a t e s ex h y p o t h e s i a re a p a i r which do as a m a t t e r o f f a c t r e s u l t i n a s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s ? A (conceivable) case o f s y s t e m a t i c t r a n s - p o s i t i o n o f c o l o u r s h o l d i n g between two people i s d e t e c t a b l e i f : i t i s con- c e i v a b l e f o r some t h i r d p e r s o n , whose p h y s i c a l s t a t e i s l i k e t h a t o f one o f t h e two p e r c e i v e r s i n a l l the r e l e v a n t r e s p e c t s , t o change so as to be i n a p h y s i c a l s t a t e l i k e t h a t o f the o t h e r p e r c e i v e r i n a l l r e l e v a n t r e s p e c t s , with- o u t n e c e s s a r i l y — l o g i c a l l y o r c a u s a l T y — c h a n g i n g h i s d i s c r i m i n a t o r y a b i l i t i e s and w i t h o u t l e a v i n g him unable t o judge the s a m e n e s s / d i f f e r e n c e o f t h e p e r - c e i v e d c o l o u r s i n q u e s t i o n . A c r u c i a l q u e s t i o n , t h e n , i s whether o r not i t i s c o n c e i v a b l e t o d i s c o v e r which f e a t u r e s o f a p e r c e i v e r ' s p h y s i c a l s t a t e a re r e l e v a n t t o h i s c o l o u r - v i s i o n when v i e w i n g p a r t s o f the p h y s i c a l w o r l d , and s p e c i f i c a l l y , which d i f f e r e n c e s i n p h y s i c a l s t a t e w i l l r e s u l t i n a d i f f e r e n c e i n p e r c e i v e d c o l o u r s when v i e w i n g some p a r t o f some c o n s t a n t environment. There are a t l e a s t two k i n d s o f grounds f o r c l a i m i n g t h a t c e r t a i n f e a - t u r e s (and the v a r i o u s combinations' o f them) o f a person's p h y s i c a l s t a t e a r e i r r e l e v a n t t o h i s c o l o u r - v i s i o n . One way t o a c q u i r e t he grounds i s to v a r y t h e s e f e a t u r e s ( s i n g l y and i n c o m b i n a t i o n s ) i n many ways t o see ( v i a t he p e r - c e i v e r ' s r e p o r t s ) i f any o f t h e s e changes r e s u l t s i n some change i n h i s p e r - c e i v e d c o l o u r s when he i s v i e w i n g some p a r t o f some c o n s t a n t environment. I f none o f them does r e s u l t i n a change and i f a g r e a t many v a r i a t i o n s have been undergone by t h e p e r c e i v e r , t h e r e a re grounds f o r c l a i m i n g t h a t t h e s e f e a t u r e s 18 a r e i r r e l e v a n t . A n o t h e r way o f a c q u i r i n g e v i d e n c e about i r r e l e v a n t f e a t u r e s i s so s i m p l e i t may be o v e r l o o k e d . ( a l t h o u g h I have mentioned e a r l i e r , i n ex- p l a i n i n g t he "second b a s i s " ) . C o l o u r - v i s i o n o f p a r t s o f the e x t e r n a l w o r l d i s 'There i s no s u g g e s t i o n here t h a t we t e s t f o r a l l c o n c e i v a b l e v a r i a t i o n s . I l l j u s t t h a t , v i s i o n , i . e . , a s e n s o r y a c t i v i t y i n v o l v i n g the sense o f s i g h t . By the d e f i n i t i o n o f "the sense o f s i g h t " one f e a t u r e t h a t i s ; r e l e v a n t i s t h a t o f h a v i n g eyes ( a c t u a l l y , a t l e a s t one eye) t h a t can f u n c t i o n when open and the p e r c e i v e r i s v i e w i n g p a r t o f the p h y s i c a l w o r l d . T h a t i s t o s a y , on an o c c a s i o n o f such a v i e w i n g , the person has " f u n c t i o n i n g . e y e s " (as I have used t h i s p h r a s e ) , eyes v i a which the p a r t o f the p h y s i c a l w o r l d viewed determines the v i s u a l i d e a s i n the person c o ncerned (which i s s a y i n g more, o f c o u r s e , than t h a t t h e p e r s o n c o ncerned has v i s u a l i d e a s a t a c e r t a i n t i m e ) . F u n c t i o n - i n g eyes are r e l e v a n t t o the sense o f s i g h t i n t h a t i f a person never has them, he i s b l i n d , i . e . , deemed to be w i t h o u t the sense o f s i g h t . Given t h a t h a v i n g f u n c t i o n i n g eyes i s r e l e v a n t ( s i n c e r e q u i r e d f o r ) v i e w i n g c o l o u r s o f p h y s i c a l o b j e c t s , so too a r e s t a t e s o f any s e n s o r y a p p a r a t u s i n v o l v e d i n t h e f u n c t i o n i n g o f the e y e s . And here we have a way o f d e c i d i n g t h a t some f e a t u r e s a r e n o t i n v o l v e d ( n o t r e l e v a n t ) which i s r a t h e r d i f f e r e n t from t h a t o f v a r y i n g t h e f e a t u r e i n q u e s t i o n t o see i f a person's p e r c e i v e d c o l o u r s i n some c o n s t a n t environment a r e r e p o r t e d to change. One may d i s c o v e r f i r s t what the i n p u t v i a the eyes i s , and t h e n , c r u d e l y s p e a k i n g , one may o b s e r v e t h e ' r o u t e ' o f t h e i n p u t , i f i t has a ' r o u t e ' . The n a t u r e o f the i n p u t ( r e s u l t i n g from v i e w i n g the p h y s i c a l world)as i t moves through t h e person's body has been d i s c o v e r e d t o be e l e c t r o - m a g n e t i c waves, and they have been d i s c o v e r e d t o pass v i a the nerve then a p p r o p r i a t e l y l a b e l l e d "the o p t i c a l nerve" t o a c e r t a i n p a r t o f t h e b r a i n . One r e s u l t o f such t r a c i n g b e g i n n i n g w i t h the s e n s o r y organ t h a t i s d e f i n i t i v e o f (human) v i e w i n g o f p h y s i c a l o b j e c t s i s t h a t one has some grounds f o r c l a i m - i n g , e.g., t h a t the p e r c e i v e r ' s f o o t i s n o t i n v o l v e d i n t h i s , t h a t i t s s i z e i s not r e l e v a n t t o t h e s e n s o r y a c t o f v i e w i n g , and t h a t the l e n g t h o f the p e r - c e i v e r ' s f i n g e r - n a i l s i s n o t r e l e v a n t , e t c . . Of c o u r s e t h e r e are some r i s k s i n v o l v e d h e r e . The c l a i m s are e m p i r i c a l and depend on the a c c u r a c y o f t h e t r a c i n g mentioned. A l s o t h e r e may be some, perhaps many, p a r t s o f the body 112 which are not on t h e ' r o u t e ' o f t h e e l e c t r o - m a g n e t i c waves, where a v e r y small number o f c o n c e i v a b l e s t a t e s o f t h o s e p a r t s do_ a f f e c t some p a r t o f the ' r o u t e ' , and so i n d i r e c t l y a f f e c t a person's c o l o u r - v i s i o n ; e.g., a s e v e r e o b s t r u c t i o n o f b i l e . S t i l l , t h e c l a i m s , about c e r t a i n f e a t u r e s o f a person's p h y s i c a l s t a t e s b e i n g i r r e l e v a n t t o c o l o u r - v i s i o n , made on t h e s e grounds have some s u p p o r t , and the s u p p o r t does not i n v o l v e v a r y i n g the f e a t u r e s i n ques- t i o n ( t h e s i z e o f the f o o t , the l e n g t h o f t h e f i n g e r - n a i l s ) . The two k i n d s o f g r o u n d s — t r a c i n g the e l e c t r o - m a g n e t i c waves from t h e e y e s , and v a r y i n g t h e f e a t u r e s i n q u e s t i o n — a r e n o t e x c l u s i v e . Some f e a t u r e s may be c l a i m e d to be i r r e l e v a n t ( t o c o l o u r - v i s i o n ) on both grounds, e.g., the l e n g t h o f t h e person's f i n g e r - n a i l s . C l a i m i n g t h a t c e r t a i n f e a t u r e s o f a person's p h y s i c a l s t a t e a r e i r r e l e - v ant t o h i s c o l o u r - v i s i o n , by t r a c i n g the ' r o u t e ' o f the e l e c t r o - m a g n e t i c waves from the f u n c t i o n i n g e y e s , i s v e r y u s e f u l f o r c a s e s o f s y s t e m a t i c t r a n s - p o s i t i o n where one o r both o f t h e p e r c e i v e r s i n v o l v e d have some f e a t u r e ( s ) t h a t cannot c o n c e i v a b l y be changed i n the f o l l o w i n g way: a t h i r d person i n e x a c t l y the same p h y s i c a l s t a t e ( i n the s p e c i f i e d sense) cannot c o n c e i v a b l y change ( o r be changed) so as to be i n e x a c t l y t h e same p h y s i c a l s t a t e as t h e o t h e r p e r c e i v e r . S y s t e m a t i c t r a n s p o s i t i o n may be c o n c e i v a b l y d e t e c t a b l e , n o n e t h e l e s s , i f t h e f e a t u r e s o f t h e s t a t e t h a t cannot c o n c e i v a b l y be changed are f e a t u r e s which can j u s t i f i a b l y be c l a i m e d t o be i r r e l e v a n t t o v i e w i n g t h e c o l o u r s o f p h y s i c a l o b j e c t s , on the b a s i s o f t h e i r i r r e l e v a n c e t o t h e t r a c e d ' r o u t e ' o f t h e e l e c t r o - m a g n e t i c waves from the f u n c t i o n i n g eyes. In t h i s c a s e s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s , h o l d i n g between p e r c e i v e r s and Pg, can c o n c e i v a b l y be d e t e c t e d by h a v i n g a t h i r d p e r c e i v e r , who i s l i k e P^ i n a l l the r e l e v a n t r e s p e c t s , change h i s p h y s i c a l s t a t e so as t o be l i k e Pg i n a l l the r e l e v a n t r e s p e c t s , and by h a v i n g him view a p a r t o f a c o n s t a n t environment where P^ and Pg's c o l o u r s a r e t r a n s p o s e d , both b e f o r e and a f t e r h i s ( P ? ' s ) 11.3 change i n p h y s i c a l s t a t e , so t h a t he w i l l be aware o f . t h e change i n h i s c o l o u r - v i s i o n . U s i n g the "second b a s i s " , he can then j u s t i f i a b l y g e n e r a l i z e t h a t , s i n c e the environment, ex hypothesi;, remained c o n s t a n t , the change i n h i s p e r c e i v e d c o l o u r s was the r e s u l t o f the change i n h i s p h y s i c a l s t a t e , and t h a t any p a i r o f p e r c e i v e r s whose s t a t e s d i f f e r ( i n r e g a r d to f e a t u r e s r e l e - vant t o c o l o u r - v i s i o n ) as h i s d i d b e f o r e and a f t e r the change, see d i f f e r e n t c o l o u r s when v i e w i n g t he p a r t o f the environment r e f e r r e d t o . And s i n c e Pg can c o n c e i v a b l y d i s c o v e r t h a t h i s d i s c r i m i n a t o r y a b i l i t i e s have not changed, he can j u s t i f i a b l y c l a i m t h a t such a p a i r o f p e r c e i v e r s would have a system- a t i c t r a n s p o s i t i o n o f c o l o u r s h o l d i n g between them. P e r c e i v e r s P^ and Pg i n the case d e s c r i b e d above would be e n t i t l e d t o c l a i m t h a t a s y s t e m a t i c t r a n s - p o s i t i o n h o l d s between them i n t h e s e c i r c u m s t a n c e s . A l s o ?2 W""H know which c o l o u r s a r e t r a n s p o s e d between P^ and Pg, and between any o t h e r p a i r o f p e r c e i v e r s l i k e t h i s p a i r i n t h e r e l e v a n t r e s p e c t s . Assuming t h e t r a n s p o s i t i o n between P-̂  and Pg t o be permanent, i s i t c o n c e i v - a b l e f o r them t o d e t e c t which c o l o u r s a r e t r a n s p o s e d between them? Here one can make use o f t h e c o n c e p t o f the p h y s i c a l e n d - s t a t e s f o r t h e v i e w i n g s Pg made b e f o r e and a f t e r h i s change i n s t a t e . Pg was f i r s t l i k e ( i n the r e l e - vant r e s p e c t s ) P^, and a f t e r t he change, l i k e Pg. I t w i l l be c o n c e i v a b l e f o r P^ t o d e t e c t which c o l o u r Pg has when the t r a n s p o s i t i o n i s i n e f f e c t i f i t i s c o n c e i v a b l e t o produce i n P^ the p h y s i c a l e n d - s t a t e i n q u e s t i o n ( t h e e a r l i e r o f Pg d i f f e r e n t e n d - s t a t e s ) w i t h o u t P^'s v i e w i n g any p a r t o f t h e p h y s i c a l w o r l d a t a l l a t the tim e , e.g., when h i s eyes are c l o s e d and so not f u n c t i o n i n g . I f t h i s can c o n c e i v a b l y be done then P^ can d e t e c t which c o l o u r s a r e t r a n s p o s e d w i t h o u t b r e a k i n g t h e permanency c o n d i t i o n o f t h e t r a n s p o s i t i o n . ( M u t a t i s mutandis f o r Pg's d e t e c t i n g which c o l o u r s a r e t r a n s p o s e d . ) To answer the q u e s t i o n o f whether o r not a l l c o n c e i v a b l e c a s e s o f system- a t i c t r a n s p o s i t i o n a re c o n c e i v a b l y d e t e c t a b l e r e q u i r e s a g r e a t deal more e m p i r i c a l knowledge about v i s u a l p e r c e p t i o n than I have, p r o b a b l y more than any one has.. The q u e s t i o n i s n o t w i t h o u t an answer, but to t r y t o answer i t w i t h o u t an adequate knowledge o f t h e r e l e v a n t c a u s a l laws i s v i r t u a l l y t o i g n o r e the c o n d i t i o n o f c o n c e i v a b i l i t y , v i z , "without r e j e c t i n g any g i v e n f a c t " . Someone i n the f i e l d o f m e d i c i n e o r t h e p s y c h o l o g y o f p e r c e p t i o n w i l l have f a r more r e l e v a n t knowledge h e r e . Always, o f c o u r s e , t h e r e w i l l remain the p o s s i b i l i t y o f d i s c o v e r i n g unexpected e m p i r i c a l t r u t h s , perhaps c a u s a l laws, which a l t e r one's c l a i m s , but t h i s i s j u s t t h e s t a n d a r d r e s e r v a t i o n •, about any c l a i m whose t r u t h depends upon t h a t o f some e m p i r i c a l s t a t e m e n t ( s ) . I r e a l i z e t h a t q u e s t i o n s about c o n c e i v a b i l i t y a r e n o t as e a s i l y s e t t l e d as t h o s e about the l o g i c a l p o s s i b i l i t y o f some s i t u a t i o n , but I argue t h a t my n o t i o n o f c o n c e i v a b i l i t y has the g r e a t e r u t i l i t y when we a r e i n v e s t i g a t i n g what i s e s s e n t i a l l y an e p i s t e m o l o g i c a l problem, t h a t o f what i s i n the power o f human b e i n g s t o know. I t i s c l e a r t h a t t h e r e i s a c o n n e c t i o n between what I have c a l l e d t h e " f i r s t b a s i s " and t h e "second b a s i s " f o r t a c k l i n g the T r a n s p o s i t i o n Argument. The second b a s i s i s t o do w i t h what i s c o n t a i n e d i n t h e concept o f a p a r t o f the p h y s i c a l w o r l d ' s d e t e r m i n i n g a p e r c e i v e r ' s i d e a s when t h a t person views t h a t p a r t o f t h e w o r l d . The f i r s t b a s i s i n v o l v e s a t l e a s t one e m p i r i c a l c l a i m v i z , t h a t i n the case o f a person's v i e w i n g a p a r t o f the p h y s i c a l w o r l d , t h e p h y s i c a l e n d - s t a t e (as I have used t h i s phrase) i s a b r a i n s t a t e . The two bases c o n n e c t i n the f o l l o w i n g way. I t can be seen by examining the second b a s i s t h a t i n o r d e r f o r t h e r e t o be t h e l a w l i k e r e g u l a r i t i e s i n v o l v e d i n t h e c o n c e p t o f a p a r t o f the p h y s i c a l w o r l d ' s d e t e r m i n i n g a person's i d e a on(View- i n g t h a t p a r t , t h e s e two c l a i m s (among o t h e r s ) must be t r u e : (a) I f two p e r - c e i v e r s have d i f f e r e n t i d e a s ( o r s e t s o f i d e a s ) , then t h e i r p h y s i c a l end- s t a t e s a r e d i f f e r e n t ; (b) I f two p e r c e i v e r s have the same p h y s i c a l e n d - s t a t e , then t h e y have ( q u a l i t a t i v e l y ) the same i d e a s . I f t h e s e c l a i m s a r e combined w i t h the e m p i r i c a l c l a i m t h a t the p h y s i c a l e n d - s t a t e i n the case o f v i s u a l ex- p e r i e n c e s i s a b r a i n s t a t e , then we a r r i v e a t the " c o r r e l a t i o n - c l a i m " , v i z , " V i s u a l e x p e r i e n c e s and b r a i n s t a t e s a r e ' c o r r e l a t e d ' , so t h a t f o r any two d i f - f e r e n t v i s u a l e x p e r i e n c e s , t h e r e w i l l be two d i f f e r e n t b r a i n s t a t e s " , and a l s o we a r r i v e a t the c l a i m t h a t " I f two people have the same b r a i n s t a t e s , then th e y w i l l have the same v i s u a l e x p e r i e n c e s " (a c l a i m used a l o n g w i t h the c o r - r e l a t i o n - c l a i m i n the e a r l y p a r t o f the s e c t i o n ) . The second b a s i s i s , i n a sense, more i m p o r t a n t than the f i r s t i n a n o t h e r way to o . By making permanency a c o n d i t i o n o f s y s t e m a t i c t r a n s p o s i t i o n , we t h e r e b y make i t l i k e l y t h a t the cause o f the d i f f e r e n c e i n p e r c e i v e d c o l o u r s when two peop l e w i t h a s y s t e m a t i c t r a n s p o s i t i o n view the same p a r t o f some c o n s t a n t environment i s some perma- nent d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e s , where " d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e s " i s t o be c o n s t r u e d as i t i s i n the second b a s i s , and not as " d i f f e r e n t p h y s i c a l e n d - s t a t e s a t the time o f v i e w i n g " . There w i l l , o f c o u r s e , be d i f - f e r e n t e n d - s t a t e s a l s o , but the e n d - s t a t e s a re temporary s t a t e s , and the cause o f a permanent t r a n s p o s i t i o n can r e a s o n a b l y be e x p e c t e d t o be o f a permanent n a t u r e . F i n a l l y , i n r e g a r d t o t h e two bases, the c l a i m s made i n both o f them are n e u t r a l w i t h r e g a r d t o an i d e n t i t y - t h e s i s about v i s u a l e x p e r i e n c e s and the p h y s i c a l e n d - s t a t e s . ( T h i s has been e x p l a i n e d i n the s e c t i o n a t a p p r o p r i a t e p o i n t s . ) T h i s s e c t i o n c o n t a i n s the p o i n t s needed t o deal w i t h the f r e q u e n t o b j e c - t i o n t h a t "we can never be s u r e " i f two p e o p l e , i n some c o n s t a n t environment, see t he same c o l o u r s when v i e w i n g t he same p a r t o f t h a t environment. T h i s i s 'the o t h e r s i d e o f the c o i n ' t o t h a t o f showing t h a t some p e r c e i v e r s see d i f - f e r e n t c o l o u r s ( i n some c o n s t a n t e n v i r o n m e n t ) . For a l l c o n c e i v a b l e cases where no t r a n s p o s i t i o n o f c o l o u r s , s y s t e m a t i c o r o v e r l a p p i n g , h o l d s between two p e r c e i v e r s i n any c o n s t a n t environment, i s i t c o n c e i v a b l e t o d e t e c t t h a t no t r a n s p o s i t i o n h o l d s ? For any c o n c e i v a b l e p h y s i c a l s t a t e (as t h i s phrase i s used i n the "second b a s i s " ) i t i s c o n c e i v a b l e t h a t more than one person have t h a t s t a t e , and so a f o r t i o r i i t i s c o n c e i v a b l e f o r more than one person's s t a t e t o be the same i n r e s p e c t s r e l e v a n t t o c o l o u r - v i s i o n . I cannot t h i n k o f r e a s o n s why i t s h o u l d be i n c o n c e i v a b l e t o d e t e c t the t o t a l o r p a r t i a l s i m i - l a r i t y o f s t a t e s h e r e . I t i s , of. c o u r s e , no o b j e c t i o n t h a t as y e t we do n o t know a l l t h e r e i s t o know about which f e a t u r e s a re r e l e v a n t to c o l o u r - v i s i o n and how d i f f e r e n c e s i n thes e f e a t u r e s a f f e c t c o l o u r - v i s i o n . I f i t i s con- c e i v a b l e t o a c q u i r e enough knowledge t o make w e l l s u p p o r t e d e m p i r i c a l c l a i m s about t h e s e t h i n g s , t h a t i s a l l t h a t i s r e q u i r e d . I t i s n o t a ' d e f e c t ' t h a t a m i s t a k e may be made; the p o s s i b i l i t y o f e r r o r remains as i t does f o r a l l e m p i r i c a l s t a t e m e n t s . 117 12. A s c r i b i n g P a r t i c u l a r C o l o u r s t o P h y s i c a l O b j e c t s I want now t o l o o k a t e r r o r s t h a t can be made i n a s c r i b i n g a p a r t i c u l a r c o l o u r such as r e d o r green t o a p h y s i c a l o b j e c t , f o r making sense o f mis- t a k e s about such c o l o u r - s t a t e m e n t s shows t h a t we can make sense o f the second soundness c o n d i t i o n ' s not h o l d i n g f o r t h e s e s t a t e m e n t s . Someone who q u i t e o f t e n reaches a wrong v e r d i c t i n c e r t a i n environments i s someone f o r whom the second soundness c o n d i t i o n does not h o l d i n t h e s e c o n d i t i o n s ; he i s not r e l i - a b l e . There a r e two ways i n which one can e r r about the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f one p h y s i c a l o b j e c t a t d i f f e r e n t t i m e s : someone may c l a i m on the b a s i s o f h i s p e r c e i v e d c o l o u r s t h a t a p h y s i c a l o b j e c t i n a c o n s t a n t e n v i r - onment i s d i f f e r e n t c o l o u r s a t d i f f e r e n t t i m e s , o r someone may c l a i m on the b a s i s o f h i s p e r c e i v e d c o l o u r s t h a t some p h y s i c a l o b j e c t remains the same c o l o u r when i n f a c t i t s p r o p e r t i e s change r e l e v a n t l y so t h a t i t s c o l o u r too i n f a c t i s d i f f e r e n t a t d i f f e r e n t t i m e s . In n e i t h e r case does the p e r c e i v e r have the p e r c e p t u a l a b i l i t y t o t e s t r e l i a b l y the statement "The o b j e c t i n q u e s t i o n remains the same c o l o u r d u r i n g the s p e c i f i e d time p e r i o d " by s i m p l y v i e w i n g the o b j e c t i n the e n v i r o n m e n t ( s ) th r o u g h o u t t h a t time p e r i o d . T h i s i n i t s e l f s u g g e s t s t h a t m i s t a k e s can be made i n a s c r i b i n g a p a r t i - c u l a r c o l o u r such as red t o a p h y s i c a l o b j e c t . I f we l o o k a t the f i r s t o f the two examples mentioned i n t h e paragraph above, a s i m i l a r s t r u c t u r e w i l l g i v e us a case o f c o n f l i c t i n g v e r d i c t s about the a s c r i p t i o n o f some p a r t i c u l a r c o l o u r , o f an i n c o n s i s t e n c y i n f a c t , and t h e r e b y we g i v e sense t o the n o t i o n o f a m i s t a k e i n making such an a s c r i p t i o n . Suppose a p e r c e i v e r views some p h y s i c a l o b j e c t i n a c o n s t a n t environment and d e c l a r e s sometimes t h a t the statement "The o b j e c t i s r e d " i s t r u e , sometimes t h a t i t i s f a l s e ( e . g . , p e r - haps h i s p e r c e p t i o n i s a f f e c t e d by v a r i o u s b o d i l y changes because o f some drugs t a k e n ) . G i v e n t h a t t h e environment i s c o n s t a n t , t h e v e r d i c t s a r e i n c o n s i s t e n t . The p e r c e i v e r , t h e n , does not have enough p e r c e p t u a l a b i l i t y to t e s t r e l i a b l y 113 i n t h a t environment the statement "The o b j e c t i s r e d " , j u s t as i n t h a t e n v i r o n - ment he does not have enough p e r c e p t u a l a b i l i t y t o t e s t r e l i a b l y the statement "The o b j e c t has remained t h e same c o l o u r d u r i n g the s p e c i f i e d time p e r i o d " by s i m p l y v i e w i n g the o b j e c t t h r o u g h o u t t h a t time. The i m p o r t a n t p o i n t here i s t h a t h a v i n g the p e r c e p t u a l a b i l i t y to d e t e c t r e l i a b l y the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f the o b j e c t t h r o u g h o u t the time p e r i o d i s a l l t h a t i s needed t o know t h a t t h e p e r c e i v e r i s making some m i s t a k e s i n h i s v e r d i c t s about the ob- j e c t ' s b e i n g r e d . One need not know i f t h e o b j e c t i s i n f a c t r e d . I t i s enough to know t h a t i t has remained the same c o l o u r . There i s a problem i f we t r y t o do the same k i n d o f t h i n g w i t h the second example g i v e n o f the second soundness c o n d i t i o n ' s n o t h o l d i n g f o r a p e r c e i v e r who i s t e s t i n g t he statement "The o b j e c t remains the same c o l o u r " , v i z , where someone c l a i m s on the b a s i s o f the c o l o u r s he p e r c e i v e s t h a t the o b j e c t remains the same c o l o u r when i t s p r o p e r t i e s change r e l e v a n t l y so t h a t i t s c o l o u r too i s i n f a c t d i f f e r e n t a t d i f f e r e n t t i m e s . A t l e a s t , t h e r e i s a problem i f we remove a s i m p l i f i c a t i o n employed i n the s e c t i o n on Smart's paper and acknow- led g e t h a t one c o l o u r - t e r m such as " r e d " i s p e r m i t t e d t o c o v e r s e v e r a l d i f f e r - e n t c o l o u r s . F or the second example, i f we t r y t o produce a ca s e w i t h a s i m i - l a r s t r u c t u r e but about m i s t a k e s i n the a s c r i p t i o n o f a p a r t i c u l a r c o l o u r , we f i n d t h a t one c o u l d n o t know t h a t t h e p e r c e i v e r has made some m i s t a k e ( s ) i f a l l one had was the p e r c e p t u a l a b i l i t y t o judge r e l i a b l y the s a m e n e s s / d i f - f e r e n c e o f c o l o u r o f the o b j e c t t h r o u g h o u t the time p e r i o d i n v o l v e d . To b e g i n w i t h i t w i l l not do t o d e s c r i b e t he case ( w i t h a s t r u c t u r e s i m i l a r t o t h a t o f the example g i v e n i n t h i s paragraph) s i m p l y as: on the b a s i s o f the c o l o u r s he p e r c e i v e s someone t h r o u g h o u t t he time p e r i o d always reaches t he v e r d i c t " t r u e " f o r the statement a s c r i b i n g the c o l o u r r e d t o the o b j e c t when i n f a c t the p r o p e r t i e s o f the o b j e c t change r e l e v a n t l y so t h a t i t i s d i f f e r e n t c o l o u r s a t d i f f e r e n t t i m e s . I t w i l l n ot do because t h i s case as d e s c r i b e d need not 119 i n v o l v e the p e r c e i v e r ' s making any mi s t a k e i n h i s a s c r i p t i o n o f the c o l o u r r e d . T h a t t h e . o b j e c t changes c o l o u r i s c o n s i s t e n t w i t h i t s r e m a i n i n g r e d t h r o u g h o u t , and so i s c o n s i s t e n t w i t h the p e r c e i v e r ' s v e r d i c t s ' b e i n g a l l c o r - r e c t . To make t h i s p o i n t c l e a r i t w i l l h e l p t o i n t r o d u c e a d i s t i n c t i o n between two meanings o f "the s a m e / d i f f e r e n t c o l o u r " : i ) where two p h y s i c a l o b j e c t s a r e "the same c o l o u r " when they a re e x a c t l y the same c o l o u r , and where they a r e " d i f f e r e n t c o l o u r s " i n a]J_ cases where t h e y a r e not e x a c t l y the same colour ( r e g a r d l e s s o f whether o r not some commonly used c o l o u r - t e r m can be used t o co v e r both c o l o u r s ) ; i i ) where two p h y s i c a l o b j e c t s a r e "the same c o l o u r " when some one commonly used c o l o u r - t e r m can be " l e g i t i m a t e l y " used t o r e f e r t o the c o l o u r o f each. Sense ( i ) i s the meaning the phrases have i n , e.g., S e c t i o n 9 above, and now sense ( i i ) becomes i m p o r t a n t . Two o b j e c t s which are "the same c o l o u r " i n b e i n g " c o v e r e d by the same c o l o u r - t e r m " may be " d i f f e r e n t c o l o u r s " i n t h e o t h e r se n s e . For c l a r i t y I s h a l l speak o f two o b j e c t s ' -being "the same/ d i f f e r e n t c o l o u r " when I mean " e x a c t l y t he s a m e / d i f f e r e n t c o l o u r " as i n sense ( i ) above. I s h a l l speak o f two o b j e c t s ' b e i n g "the s a m e / d i f f e r e n t c o l o u r ^ " when I mean they a r e "both l e g i t i m a t e l y c o v e r e d by some commonly used c o l o u r - term" as i n sense ( i i ) above. When I w r i t e about o r d e r i n g p h y s i c a l o b j e c t s by c o l o u r , I s h a l l e x p l a i n what i s meant by " l e g i t i m a t e l y c o v e r e d by some one c o l o u r - t e r m " . Here i t i s n e c e s s a r y t o acknowledge o n l y t h a t two p h y s i c a l ob- j e c t s which are the same c o l o u r ^ may not be e x a c t l y the same c o l o u r . T h i s p o i n t does n o t a f f e c t t h e case d e s c r i b e d i n the second paragraph where con- f l i c t i n g v e r d i c t s a r e reached f o r a statement a s c r i b i n g the c o l o u r r e d t o a p h y s i c a l o b j e c t i n a c o n s t a n t environment (where the r e l e v a n t p r o p e r t i e s o f the o b j e c t , t h e r e f o r e , remain t h e same t h r o u g h o u t ) , but i t does a f f e c t the c a s e b e i n g d e a l t w i t h now. I t i s i n f a c t because o f t h i s p o i n t t h a t the f i r s t attempted d e s c r i p t i o n o f the case w i l l not do: the case where, on the b a s i s o f the c o l o u r s he p e r - c e i v e s , someone th r o u g h o u t the time p e r i o d i n q u e s t i o n always reaches the v e r - d i c t " t r u e " f o r the statement a s c r i b i n g the c o l o u r r e d to the o b j e c t when i n f a c t t he o b j e c t has d i f f e r e n t c o l o u r s a t d i f f e r e n t t i m e s , need not c o n s t i t u t e a case where the p e r c e i v e r makes some m i s t a k e ( s ) i n h i s v e r d i c t s s i n c e t he ob- j e c t ' s r e m a i n i n g r e d (and so r e m a i n i n g the same colour^.) i s c o m p a t i b l e w i t h i t s b e i n g d i f f e r e n t c o l o u r s ( i . e . , n ot e x a c t l y the same c o l o u r ) a t d i f f e r e n t t i m e s . There i s an asymmetry o f a s o r t a t work here: t o c l a i m t h a t a p h y s i - c a l o b j e c t i s d i f f e r e n t c o l o u r s ^ a t d i f f e r e n t times when i n f a c t the e n v i r o n - ment and so the c o l o u r o f the p h y s i c a l o b j e c t remains the same th r o u g h o u t con- s t i t u t e s a m i s t a k e ; b u t t o c l a i m t h a t an o b j e c t i s t h e same colour^, a l l t he time when i n f a c t t he r e l e v a n t p r o p e r t i e s v a r y i n such a way t h a t i t i s d i f - f e r e n t c o l o u r s a t d i f f e r e n t times need not c o n s t i t u t e a m i s t a k e . For our de- s c r i p t i o n t o be t h a t o f a ca s e where some m i s t a k e ( s ) about the a s c r i p t i o n o f a p a r t i c u l a r c o l o u r i s made, i t i s not enough t h a t t he p e r c e i v e r always r e a c h the v e r d i c t " t r u e " f o r the statement a s c r i b i n g the c o l o u r r e d t o the o b j e c t when i n f a c t the c o l o u r o f the o b j e c t i s d i f f e r e n t a t d i f f e r e n t t i m e s . We need t o s p e c i f y a l s o t h a t e i t h e r t h e o b j e c t i s i n f a c t d i f f e r e n t colours^, with- i n the time p e r i o d i n q u e s t i o n , o r , i f the o b j e c t i s i n f a c t the same c o l o u r ^ t h r o u g h o u t , t h a t c o l o u r i s n o t r e d . T h i s does ensure t h a t a m i s t a k e about t h e a s c r i p t i o n o f a p a r t i c u l a r c o l o u r i s b e i n g made, but i t i s no l o n g e r d e t e c t a b l e s i m p l y by v i r t u e o f h a v i n g the p e r c e p t u a l a b i l i t y to d e t e c t r e l i a b l y t h e same- n e s s / d i f f e r e n c e o f c o l o u r o f the o b j e c t t h r o u g h o u t t he time p e r i o d . In t h i s r e s p e c t t h i s case o f some e r r o r ( s ) about the a s c r i p t i o n o f a p a r t i c u l a r c o l o u r d i f f e r s from the f i r s t case o f t h i s mentioned. We have a t any r a t e one s i t u a t i o n i n which a p e r c e i v e r ' s making an e r r o r i n a s c r i b i n g a p a r t i c u l a r c o l o u r can.be d e t e c t e d by someone hav i n g the p e r - c e p t u a l a b i l i t y t o d e t e c t r e l i a b l y the s a m e n e s s / d i f f e r e n c e o f c o l o u r o f p h y s i c a l o b j e c t s i n t h e environment i n v o l v e d , v i z , where the p e r c e i v e r , on the b a s i s o f the c o l o u r s he p e r c e i v e s , d e c l a r e s sometimes t h a t the s tatement "The p h y s i c a l o b j e c t i n q u e s t i o n i s r e d " i s t r u e , sometimes t h a t i t i s f a l s e , where- as i n f a c t the environment remains c o n s t a n t . But an e r r o r i n c o n s i s t e n c y i n a s c r i b i n g a p a r t i c u l a r c o l o u r t o a p h y s i c a l o b j e c t , which i s what t h i s case amounts t o , i n i t s e l f t e l l s us n o t h i n g about what c o n s t i t u t e s a c o r r e c t v e r - d i c t f o r a s t a t e m e n t about such an a s c r i p t i o n , and s u r e l y , t o use the n o t i o n o f an e r r o r i n o r d e r t o g i v e sense t o the second soundness c o n d i t i o n f o r such s t a t e m e n t s , we need an u n d e r s t a n d i n g o f what c o n s t i t u t e s a c o r r e c t v e r d i c t here as w e l l as a more f u l l - b l o o d e d n o t i o n o f an i n c o r r e c t v e r d i c t . Then t h e r e i s some c o n t e n t to the p o i n t t h a t the second soundness c o n d i t i o n does not h o l d f o r such a statement when the p e r c e i v e r has not the a b i l i t y r e q u i r e d t o r e a c h c o r r e c t v e r d i c t s r e l i a b l y i n the e n v i r o n m e n t ( s ) i n v o l v e d . And once t h i s i s done, we can c l a i m t h a t statements about a s c r i p t i o n s o f p a r t i c u l a r c o l o u r s t o p h y s i c a l o b j e c t s a r e o b j e c t i v e , s i n c e i t i s easy t o g i v e sense t o the f i r s t soundness c o n d i t i o n here. E.g., the f i r s t c o n d i t i o n does not h o l d i f t he p e r c e i v e r l o o k s a t the wrong p h y s i c a l o b j e c t ( s ) . In i n v e s t i g a t i n g the n o t i o n o f an e r r o r i n a s c r i b i n g a p a r t i c u l a r c o l o u r to a p h y s i c a l o b j e c t a t p r e s e n t , t h e r e i s one s e t o f a p r i o r i t r u t h s we s h o u l d b e ar i n mind--the a p r i o r i s tatements about the i n c o m p a t i b i l i t y o f c e r t a i n c o l o u r s . E.g., i t i s commonly a c c e p t e d as b e i n g a p r i o r i t r u e t h a t "No p h y s i - c a l o b j e c t can be both green and r e d i n the same p a r t a t the same ti m e . " Two p o i n t s need to be made e x p l i c i t i m m e d i a t e l y . In the f i r s t p l a c e , what a r e b e i n g r e f e r r e d t o a r e the paradigm cases o f green and r e d , and a c o l o u r t h a t i s " r e d d i s h green" ( i f t h i s c o u l d d e s c r i b e some c o l o u r ) does no t count as a counter-example t o the c l a i m . Of c o u r s e , the n o t i o n o f a " b o r d e r - l i n e c o l o u r " between, e.g., r e d and green has not been d i s c u s s e d , but i t i s a p o i n t t o remem- ber here. S e c o n d l y , the i n c o m p a t i b i l i t y - c l a i m r e f e r s t o the p e r c e p t u a l q u a l i t i e s 122 a p h y s i c a l o b j e c t has a t any one tim e , as opposed t o the c o l o u r i t i s deemed to have by r e f e r e n c e t o " s t a n d a r d c o n d i t i o n s " which may not be i n f o r c e a t some t i m e s . For example, a banana may have a t p r e s e n t the p e r c e p t u a l q u a l i t y g r e y as a r e s u l t o f i t s b e i n g viewed a t a d i s t a n c e i n the dusk. S t i l l , most • peopl e would c l a i m t h a t i t s " r e a l c o l o u r " i s y e l l o w , i . e . , i n what a r e deemed to be " s t a n d a r d c o n d i t i o n s " f o r v i e w i n g bananas i t has the p e r c e p t u a l q u a l i t y y e l l o w . I t can be t r u e , t h e n , t h a t a t p r e s e n t the banana i s p e r c e p t u a l l y grey, and a l s o a t p r e s e n t i t s " r e a l c o l o u r " i s y e l l o w . There i s no c o n f l i c t h e r e , and t h i s does n o t count as a counter-example, e.g., t o the a p r i o r i incompat- i b i l i t y c l a i m : "No p h y s i c a l o b j e c t can be both gre y and y e l l o w a t the same time i n the same p l a c e . " The a p r i o r i i n c o m p a t i b i l i t y - c l a i m s s t a t e t he impos- s i b i l i t y o f a p h y s i c a l o b j e c t ' s h a v i n g as p e r c e p t u a l q u a l i t i e s two v e r y d i f - f e r e n t c o l o u r s s i m u l t a n e o u s l y (and on the same p a r t ) . I t f o l l o w s t h a t i f some- one does c l a i m t h a t a p h y s i c a l o b j e c t i s s i m u l t a n e o u s l y r e d and green (on the same p a r t ) , h i s c l a i m i s a p r i o r i f a l s e . T h i s k i n d o f e r r o r reduces t o a case o f b e i n g i n c o n s i s t e n t . To c l a i m t h a t t he p h y s i c a l o b j e c t i s red i s t o p r e c l u d e i t s b e i n g , a t t h a t t i m e , g r e e n . So the person i s c l a i m i n g t h a t t h e o b j e c t i s a c o l o u r which p r e c l u d e s i t s b e i n g green and t h a t i t i_s gre e n . T h i s i s a c o n s i s t e n c y - e r r o r o f the k i n d d e s c r i b e d a t the b e g i n n i n g o f the s e c t i o n . We know t h a t e i t h e r h i s a s c r i p t i o n o f red o r o f green ( o r both) i s i n c o r r e c t , i . e . , we know he has made a m i s t a k e . But we need more than what i s g i v e n here t o know which a s c r i p t i o n ( i f e i t h e r ) i s c o r r e c t . I have a l r e a d y acknowledged t h a t d i f f e r e n c e s i n the s t a t e s o f two p e r - c e i v e r s can r e s u l t i n t h e i r h a v i n g d i f f e r e n t p e r c e i v e d c o l o u r s when th e y view a p a r t o f some c o n s t a n t environment, so t h a t t h e r e i s a case o f o v e r l a p p i n g o r s y s t e m a t i c t r a n s p o s i t i o n o f c o l o u r s between the p e r c e i v e r s . I have argued t h a t i t may w e l l be c o n c e i v a b l e t o d e t e c t such d i f f e r e n c e s i n p e r c e i v e d colours, and t o d e t e c t i n o t h e r c a s e s t h a t no t r a n s p o s i t i o n h o l d s J For none o f t h i s 123 was t h e n o t i o n o f "a c o r r e c t v e r d i c t " about the p a r t i c u l a r p r e s e n t c o l o u r o f a p h y s i c a l o b j e c t r e q u i r e d . T h i s c o n c e p t I s h a l l now examine, and i n d o i n g s o , I s h a l l l o o k a t the r e l a t e d concept o f "a s t a t e g i v i n g r i s e t o p e r c e i v e d c o l o u r s t h a t a r e e p i s t e m o l o g i c a l l y t r u s t w o r t h y f o r r e a c h i n g such c o r r e c t v e r - d i c t s ( i . e . , v e r d i c t s about the p a r t i c u l a r p r e s e n t c o l o u r o f an o b j e c t ) " . Some s t a t e s o f p e r c e i v e r s a r e such t h a t t h e y produce h a l l u c i n a t i o n s so t h a t i f t h e p e r s o n i s asked t o l o o k a t a p a r t i c u l a r p h y s i c a l o b j e c t he i s , a t t h a t t i m e , i n c a p a b l e o f d o i n g so. Such a case l a c k s a n e c e s s a r y c o n d i t i o n f o r h i s p e r c e i v e d c o l o u r s ' b e i n g e p i s t e m o l o g i c a l l y t r u s t w o r t h y f o r a s c r i b i n g a p a r t i c u l a r c o l o u r t o t h e p h y s i c a l o b j e c t , s i n c e h i s p e r c e i v e d c o l o u r s a r e not determined by the o b j e c t ( g i v e n i t s e n v i r o n m e n t ) . In t h i s i n s t a n c e h i s s t a t e i n t e r f e r e s r a d i c a l l y w i t h h i s p e r c e p t i o n s o f the p h y s i c a l w o r l d , but t h e r e can be ' i n t e r f e r e n c e ' o f a l e s s r a d i c a l k i n d . The p o i n t i s t h a t a l t h o u g h a p e r - son's p e r c e i v e d c o l o u r s must be de t e r m i n e d by the p h y s i c a l o b j e c t , g i v e n i t s e n vironment, i f the p e r c e i v e d c o l o u r s a r e t o be " i d e a s o f ( t h a t p a r t o f ) the p h y s i c a l w o r l d " , t h i s i s n o t s u f f i c i e n t t o e n s u r e t h a t t h e i d e a s a r e e p i s t e m o - l o g i c a l l y t r u s t w o r t h y . Even when the i d e a s a re so d e t e r m i n e d , a p e r c e i v e r ' s s t a t e may ' i n t e r f e r e w i t h ' h i s p e r c e p t i o n so t h a t h i s p e r c e i v e d c o l o u r s a r e m i s l e a d i n g . E.g., presumably t h i s i s t h e us u a l s i t u a t i o n when i n a c o n s t a n t environment one per s o n cannot a l t h o u g h a n o t h e r can d i s c r i m i n a t e by c o l o u r be- tween two p h y s i c a l o b j e c t s h a v i n g r e l e v a n t l y d i f f e r e n t p r o p e r t i e s . The f i r s t p e r s o n ' s p e r c e i v e d c o l o u r s a r e m i s l e a d i n g f o r t h e purpose o f t e s t i n g t h e stat e m e n t "The two o b j e c t s a re the same c o l o u r " . By r e l y i n g on h i s p e r c e i v e d c o l o u r s he w i l l r each the v e r d i c t " t r u e " , and t h a t w i l l be i n c o r r e c t . In r e - gar d t o an a s c r i p t i o n o f a p a r t i c u l a r c o l o u r t o a p h y s i c a l o b j e c t , t he r o l e I t would be a mi s t a k e t o ta k e t h i s c l a i m t o be r e a l l y a weak one A g r e a t deal o f s u p p o r t i s o f f e r e d i n the l a s t s e c t i o n . The phrase "may w e l l be con- c e i v a b l e " r e f l e c t s m e r e l y my l a c k o f the d e t a i l e d e m p i r i c a l knowledge r e q u i r e d t o show t h a t i t c l e a r l y i s c o n c e i v a b l e . 124 o f the p e r c e i v e r ' s s t a t e w i l l be found, i n f a c t , t o be c e n t r a l t o the v e r y c o n c e p t o f such an a s c r i p t i o n , so t h a t the c o n c e p t i s a n t h r o p o c e n t r i c . To c o r r e c t l y a t t r i b u t e t h e p r e s e n t c o l o u r , say, r e d , t o a p h y s i c a l ob- j e c t s o l e l y on the b a s i s o f the p e r c e i v e d c o l o u r o f a person v i e w i n g i t , I am n o t s u g g e s t i n g t h a t the o b j e c t must have a p r o p e r t y " i n i t s e l f , which r e - sembles one o r o t h e r o f a c e r t a i n group o f p e r c e i v e d c o l o u r s " . No p o i n t made so f a r and none f o l l o w i n g r e q u i r e s t h i s . R ather than spend time examin- i n g what t h i s f e a t u r e , which i s not r e q u i r e d , amounts t o , I s h a l l s e t out and argue f o r what i_s r e q u i r e d f o r us to have a v i a b l e c o n c e p t o f a p h y s i c a l ob- j e c t ' s " b e i n g now r e d " . I t w i l l become c l e a r t h a t the c o n c e p t can be a n t h r o - p o c e n t r i c w i t h o u t a f f e c t i n g t h e o b j e c t i v i t y o f the s t a t e m e n t s about such a s - c r i p t i o n s . The a c c o u n t I o f f e r o f a p h y s i c a l o b j e c t ' s b e i n g ( a t p r e s e n t ) r e d does not r e s t on a s i m p l e appeal t o the p e r c e i v e d c o l o u r s t h e m a j o r i t y o f s i g h t e d p e o p l e now a l i v e would have i f t h e y viewed t h e o b j e c t . Such an ap- peal can g i v e r i s e t o c o n t r a d i c t i o n s which I a v o i d . I t w i l l be c l e a r e s t t o s t a t e the c e n t r a l c l a i m o f the a c c o u n t and then t o e x p l a i n i t and i n d i c a t e how i t overcomes c e r t a i n problems t h a t some o t h e r a c c o u n t s e n c o u n t e r . What i s g i v e n below i s a statement o f what i t i s f o r a p h y s i c a l o b j e c t t o be now r e d . A f t e r w a r d s I s h a l l e x p l a i n how t o d e r i v e from i t t e s t s t o be used i n p r a c t i c e , f o r d e c i d i n g whether o r n o t some p h y s i c a l o b j e c t i s a t p r e s e n t r e d . As a r e m i n d e r , the a c c o u n t i s o f what i t i s f o r a p h y s i c a l o b j e c t t o be a t p r e s e n t r e d , as opposed t o what i t i s f o r t h e " r e a l c o l o u r " o f a p h y s i c a l ob- j e c t t o be r e d , where by " r e a l c o l o u r " i s meant i t s p r e s e n t c o l o u r i n some s p e c i a l l y chosen e n v i r o n m e n t ( s ) . The l a t t e r c o n c e p t i s i n f a c t p a r a s i t i c upon the f o r m e r , as I s h a l l e x p l a i n . THE CENTRAL CLAIM: A p h y s i c a l o b j e c t i s now r e d i f and o n l y i f ( g i v e n i t s p r e s e n t environment) i t would determine f o r an o v e r w h e l m i n g l y l a r g e p a r t o f the time when viewed by a l l s t a n d a r d - s t a t e p e r c e i v e r s one 125 o r o t h e r o f the p e r c e i v e d c o l o u r s deemed t o be samples o f r e d - p r o v i d i n g t h a t i f the p h y s i c a l o b j e c t i s the body o f a s i g h t e d per- son, h i s p e r c e p t i o n s a r e not i n c l u d e d i n the t o t a l o f s t a n d a r d - s t a t e p e r c e p t i o n s . L e t me s t a t e i m m e d i a t e l y t h a t t h i s w i l l t u r n out t o be a n o n - c i r c u l a r a c c o u n t o f a p h y s i c a l o b j e c t ' s b e i n g now r e d . A l s o , the r i d e r a t the end i s not an a r b i t r a r y manoeuvre. I t w i l l be e a s i e s t t o e x p l a i n f i r s t t he c e n t r a l c l a i m w i t h o u t t h i s r i d e r , and then t o s t a t e b r i e f l y why the r i d e r i s r e q u i r e d . A t t h i s s t a g e i t i s enough t o remember t h a t the a c c o u n t can c o v e r the c o l o u r o f a p h y s i c a l o b j e c t which happens to be t h e body o f a s i g h t e d p e r s o n ; a l l t h a t i s needed f o r t h e c a s e t o be on a p a r w i t h o t h e r c a s e s i s t h a t t h i s p h y s i c a l o b j e c t have t h e same r o l e as any o t h e r viewed o b j e c t , i . e . , f o r the person's body t o be the o b j e c t viewed by o t h e r p e o p l e . But I s h a l l g i v e the reason f o r t h i s a t a more a p p r o p r i a t e p o i n t i n the s e c t i o n . While I examine the cen- t r a l c l a i m w i t h o u t the r i d e r , I s h a l l have i n mind the c e n t r a l c l a i m as i t ap- p l i e s t o p h y s i c a l o b j e c t s which a r e not the b o d i e s o f any s i g h t e d p e r s o n . Given t h e p h y s i c a l s t a t e s o f v i e w e r s o f a p h y s i c a l o b j e c t , i f t h e i r p e r c e i v e d c o l o u r s on l o o k i n g a t a p h y s i c a l o b j e c t a r e not d e t e r m i n e d by t h a t o b j e c t ( g i v e n i t s environment) i n a l a w l i k e and r e g u l a r f a s h i o n , then the con- c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " does no t have a s o l i d b a s i s a t a l l . I have argued e a r l i e r t h a t t h e r e are c o r r e l a t i o n s between v i e w e r s ' p e r c e i v e d c o l o u r s and p r e s e n t e d p h y s i c a l o b j e c t s t h a t c o n s t i t u t e e m p i r i c a l e v i d e n c e t h a t v i e w e r s ' p e r c e i v e d c o l o u r s a r e d e termined by the o b j e c t s viewed ( g i v e n t h e i r e n v i r o n m e n t ) . But a l t h o u g h t h i s i s r e q u i r e d f o r t h e c o n c e p t t o be v i a b l e , more than t h i s i s needed. As i t s t a n d s t h i s r e q u i r e m e n t can be met i n , e.g., a s i t u a t i o n where a number o f v i e w e r s l o o k a t some one p h y s i c a l o b j e c t i n a c o n s t a n t environment and have d i f f e r e n t p e r c e i v e d c o l o u r s because t h e i r p h y s i - c a l s t a t e s a r e r e l e v a n t l y d i f f e r e n t . T h i s i s t o s a y , t h i s r e q u i r e m e n t about 126 the p e r c e i v e d c o l o u r s ' b e i n g determined by the viewed o b j e c t says n o t h i n g about how s i m i l a r o r how d i f f e r e n t t he p e r c e i v e d c o l o u r s o f the vie w e r s need t o be, but t h e r e i s a re q u i r e m e n t about t h i s f o r "the c o l o u r o f a p h y s i c a l o b j e c t " t o be a v i a b l e c o n c e p t . Very c r u d e l y t o b e g i n w i t h , t h e r e q u i r e m e n t i s t h a t t h e r e be a k i n d o f u n i f o r m i t y i n the p e r c e i v e d c o l o u r s humans have on v i e w i n g a c e r t a i n p h y s i c a l o b j e c t i n a c e r t a i n c o n s t a n t environment. Without t h i s u n i f o r m i t y i t i s g r a t - u i t o u s to a t t r i b u t e p a r t i c u l a r c o l o u r s t o p a r t i c u l a r p h y s i c a l o b j e c t s ( g i v e n t h e i r e n v i r o n m e n t ) . I t i s r e q u i r e d because o f t h e r o l e the v i e w e r s ' p e r c e i v e d c o l o u r s have i n g i v i n g the meaning o f "the c o l o u r o f a p h y s i c a l o b j e c t " . The phrase i s d e f i n e d i n terms o f the p e r c e i v e d c o l o u r s o f c e r t a i n v i e w e r s . So, b e a r i n g i n mind t h a t the p e r c e i v e d c o l o u r s do not "resemble" p r o p e r t i e s " i n the o b j e c t s t h e m s e l v e s " , i f t h e r e i s no u n i f o r m i t y i n p e o p l e ' s p e r c e i v e d c o l o u r s on v i e w i n g p a r t i c u l a r p h y s i c a l o b j e c t s , t h e r e i s no b a s i s f o r deeming a p a r t i c u l a r p h y s i c a l o b j e c t t o be one c o l o u r r a t h e r than a n o t h e r . ( I n t h i s s i t u a t i o n we c o u l d r e t a i n our c o l o u r - t e r m s as they a p p l y to our c o l o u r sense- d a t a . T h i s has n o t been den i e d . ) In t he c e n t r a l c l a i m on pp. 124 -125 I have made the l o g i c a l l y f i r s t step o f the a c c o u n t d e c i d i n g t h a t c e r t a i n p e r c e i v e d c o l o u r s a r e t o count as samples o f " r e d " . A common c o l o u r - t e r m such as " r e d " i s used t o c o v e r q u i t e a number o f d i f f e r e n t c o l o u r s (which a re n o n e t h e l e s s deemed t o be t h e same c o l o u r ^ ) . In d e c i d i n g which p e r c e i v e d c o l o u r s w i l l be c a l l e d samples o f " b l u e " , which, samples o f " r e d " , e t c . , t h e r e a r e o b v i o u s l y d e c i s i o n s about c o n v e n t i o n s i n - v o l v e d . Such and such a group we s h a l l choose t o c a l l " r e d " , some o t h e r group "blue", and which group r e c e i v e s which l a b e l i n t h i s f i r s t s t e p o f the ac c o u n t i s a r b i t r a r y . On the o t h e r hand, how v a r i o u s c o l o u r s a r e combined t o c o n s t i t u t e such a group i s not e n t i r e l y a r b i t r a r y . Members o f such a group 2 T h i s i n c l u d e s the terms " b l a c k " and " w h i t e " . are r e l a t e d t o one a n o t h e r so as to form a small " o r d e r e d s e r i e s " , each c o l o u r "more l i k e " i t s n e i g h b o u r s than any o t h e r i n t h e s e r i e s . (I s h a l l s ay more about t h e s e small " s e r i e s " a f t e r t h i s s e c t i o n . ) Two p o i n t s need to be made, o r r a t h e r r e p e a t e d , h e r e . In the f i r s t p l a c e , suppose t h a t someone has p e r c e i v e d the d i f f e r e n t c o l o u r s t h a t a r e co v e r e d by the term " r e d " and t h a t when he p e r c e i v e d them he was informed t h a t t h o s e c o l o u r s a re c o v e r e d by t h a t term. T h i s w i l l p r o v i d e a b a s i s f o r h i s use o f the term " r e d " o n l y i f he can q u i t e r e l i a b l y r e c o g n i z e o t h e r samples o f t h o s e c o l o u r s i n the f u t u r e . T h i s i s t r u e ; a t l e a s t , i t i s i f we ar e t a l k i n g o f a person's d e s c r i b i n g a p h y s i c a l o b j e c t as red s i m p l y on the b a s i s o f h i s p r e s e n t p e r c e i v e d c o l o u r s as he views the o b j e c t . But as I p o i n t e d o u t e a r l y i n the t h e s i s Ayer i s c o r r e c t when he argues t h a t each p e r - son i s o b l i g e d u l t i m a t e l y to r e l y on h i s a b i l i t y t o i d e n t i f y and r e - i d e n t i f y c e r t a i n elements o f h i s e x p e r i e n c e i f he i s t o make any e m p i r i c a l knowledge c l a i m s a t a l l . S e c o n d l y , i t may be o b j e c t e d t h a t we cannot make t h i s l o g i - c a l l y f i r s t s t e p d e c i d i n g t h a t c e r t a i n p e r c e i v e d c o l o u r s a r e t o count as samples o f " r e d " s i n c e , i f we do, we can never i n p r i n c i p l e know t h a t two people a r e u s i n g t h e c o l o u r - t e r m s such as " r e d " i n t h e same way, i . e . , t h a t t h e y a re both u s i n g the same term to c o v e r much the same group, o r much "the same range", o f c o l o u r s . T h i s problem, however, has a l r e a d y been f a c e d i n the p r e v i o u s s e c t i o n . To do our b e s t t o ensure t h a t two peop l e use the term " r e d " t o r e f e r t o much the same group o f c o l o u r s , we can make use o f a con- s t a n t environment ( o r s e v e r a l ) w h e r e the r e l e v a n t p e r c e i v e d c o l o u r s a re d e t e r - mined by v a r i o u s p h y s i c a l o b j e c t s which are easy t o i n d i c a t e . T h i s i s a s i m p l i f i c a t i o n , o f c o u r s e ; the person i n s t r u c t i n g the o t h e r one w i l l assume t h a t t h e y each have q u a l i t a t i v e l y t he same p e r c e i v e d c o l o u r s when each o f them s t a n d s i n the a p p r o p r i a t e p o s i t i o n and views the o b j e c t ( s ) i n d i c a t e d . T h i s assumption may be f a l s e — a s an advocate o f the T r a n s p o s i t i o n Argument 1 2 8 w i l l h a s t e n to p o i n t o u t . T h i s has never been d e n i e d i n t h i s t h e s i s , but i t has been d e n i e d t h a t such a d i f f e r e n c e i n the p e r c e i v e d c o l o u r s o f two pe o p l e must be o b v i o u s l y i n p r i n c i p l e u n d e t e c t a b l e . I f t h e i r p e r c e i v e d c o l o u r s a r e determined by the o b j e c t ( s ) viewed ( g i v e n i t s environment) and y e t are d i f - f e r e n t f o r each v i e w e r , t h e n s i n c e ex h y p o t h e s i t h e environment remains con- s t a n t , the d i f f e r e n c e must be the r e s u l t o f a d i f f e r e n c e i n the p e r c e i v e r s ' s t a t e s a t the time o f v i e w i n g . I t has been argued i n t h e p r e v i o u s s e c t i o n t h a t i t j_s, t h e r e f o r e , l o g i c a l l y p o s s i b l e , and may w e l l be c o n c e i v a b l e , t o d e t e c t such a d i f f e r e n c e i n p e r c e i v e d c o l o u r s , e s p e c i a l l y i f we c o n t i n u e t o a c q u i r e and make use o f knowledge as t o which d i f f e r e n c e s i n v i e w e r s ' s t a t e s a r e r e l e v a n t t o the c o l o u r s t h e y p e r c e i v e i n a c e r t a i n environment. E q u a l l y , i f we have grounds f o r c l a i m i n g t h a t two v i e w e r s ' s t a t e s a r e the same i n a l l r e l e v a n t r e s p e c t s , we have grounds f o r c l a i m i n g t h a t t h e y do p e r c e i v e t h e same c o l o u r s i n a c o n s t a n t environment. I t i s c l e a r from what I have a l r e a d y w r i t t e n i n t h i s s e c t i o n t h a t I r e - j e c t t h e i d e a t h a t mere v e r b a l agreement about which p a r t i c u l a r p e r c e i v e d c o l o u r s most peop l e have when they view o b j e c t s i n c o n s t a n t environments i s an adequate b a s i s f o r the con c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " . I f t h e r e i s no g e n e r a l u n i f o r m i t y about t h e s e p e r c e i v e d c o l o u r s , then such c l a i m s as "The so-and-so (which i s a p h y s i c a l o b j e c t ) i s r e d " a r e v e r y m i s l e a d i n g . E i t h e r t h e y a r e c l a i m s about j u s t t h e sp e a k e r ' s c o l o u r s e n s e - d a t a i n a p a r t i - c u l a r s i t u a t i o n , o r , a t most, t h e y a re a b b r e v i a t i o n s f o r statements about an isomorphism i n the p a t t e r n o f the s a m e n e s s / d i f f e r e n c e r e l a t i o n s h o l d i n g be- tween the p e r c e i v e d c o l o u r s d e t e r m i n e d i n viewers by the o b j e c t r e f e r r e d to and the p e r c e i v e d c o l o u r s d e t e r m i n e d i n viewers by o t h e r o b j e c t s i n o t h e r e n v i r o n - ments. On the f i r s t o f t h e s e a l t e r n a t i v e s , someone's c l a i m i n g "The so-and-so i s r e d " amounts t o h i s c l a i m i n g "I have c o l o u r s e n s e - d a t a o f such-and-such a k i n d i n t h i s s i t u a t i o n . " Even i f i t i s s p e c i f i e d t h a t h i s c o l o u r s e n s e - d a t a 129 a r e d e t e r m i n e d by the o b j e c t g i v e n i t s environment, t h a t i n t h i s environment he always has c o l o u r s e n s e - d a t a o f t h i s k i n d o f v i e w i n g t h a t o b j e c t , and t h a t o t h e r p e o p l e can d i s c o v e r which c o l o u r s e n s e - d a t a he i s h a v i n g , i t s t i l l does not w a r r a n t the a s c r i p t i o n o f a p a r t i c u l a r c o l o u r , such as r e d , t o the o b j e c t i f t h e r e i s no s t r o n g tendency f o r viewers o f t h a t o b j e c t i n t h a t environment t o p e r c e i v e one o r o t h e r o f a r e l a t i v e l y s m a l l group ( o r " s e r i e s " ) o f c o l o u r s . The p o i n t i s t h a t s p e a k i n g o f a p h y s i c a l o b j e c t ' s b e i n g c o l o u r e d has c u r r e n c y o n l y i n s o f a r as t h e r e i s a r e l a t i o n s h i p between p e r c e i v e r s v i e w i n g p h y s i c a l o b j e c t s and t h e i r r e s u l t i n g p e r c e i v e d c o l o u r s , more s p e c i f i c a l l y i n s o f a r as the o b j e c t s determine t h e v i e w e r s ' p e r c e i v e d c o l o u r s . Speaking o f a p h y s i c a l o b j e c t , g i v e n i t s environment, ha v i n g one p a r t i c u l a r c o l o u r r a t h e r than some o t h e r p a r t i c u l a r c o l o u r has c u r r e n c y o n l y i f , i n the p e r c e i v e d c o l o u r s d e t e r - mined i n v i e w e r s by t h a t o b j e c t i n i t s environment, t h e r e a r e some p e r c e i v e d c o l o u r s r a t h e r than o t h e r s . A t the v e r y l e a s t t h e r e needs t o be a s t r o n g t e n - dency f o r t h e r e t o be some p e r c e i v e d c o l o u r s r a t h e r than o t h e r s . That i s t o say, more i s r e q u i r e d f o r the con c e p t o f "the ( p r e s e n t ) c o l o u r o f a p h y s i c a l o b j e c t " than s i m p l y t h a t p h y s i c a l o b j e c t s d e t e r m i n e p e r c e i v e d c o l o u r s i n peopl e who a r e v i e w i n g them; t h e r e a l s o needs t o be some g e n e r a l u n i f o r m i t y among t h e p e r c e i v e d c o l o u r s p e o p l e have i n v i e w i n g one and the same o b j e c t i n 3 a c o n s t a n t environment. I s a i d e a r l i e r i n t h i s paragraph t h a t i f t h e r e i s no such g e n e r a l u n i f o r m i t y , then a t b e s t statements l i k e "The so-and-so (which i s a p h y s i c a l o b j e c t ) i s r e d " are a b b r e v i a t i o n s f o r statements about an isomor- phism i n the p a t t e r n o f the s a m e n e s s / d i f f e r e n c e o f the p e r c e i v e d c o l o u r s p e o p l e have on v i e w i n g v a r i o u s p h y s i c a l o b j e c t s . L e t me c l a r i f y b r i e f l y what I mean 3 I m y s e l f do not f i n d i t a t a l l b i z a r r e t o c l a i m t h a t p h y s i c a l o b j e c t s c o u l d be c o l o u r e d w i t h o u t each p h y s i c a l o b j e c t ( i n any one environment) b e i n g some one p a r t i c u l a r c o l o u r , s i n c e , f o r p h y s i c a l o b j e c t s t o be c o l o u r e d fewer f a c t s need t o o b t a i n than a r e needed f o r each p h y s i c a l o b j e c t ( i n any one e n v i r o n - ment) t o be some p a r t i c u l a r c o l o u r . For the f i r s t o f t h e s e a l l t h a t i s r e - r e q u i r e d i s t h a t p h y s i c a l o b j e c t s determine p e r c e i v e d c o l o u r s i n people who ar e v i e w i n g them. by t h i s . So f a r the f a c t s assumed to h o l d a r e t h a t t he spea k e r ' s p e r c e i v e d c o l o u r s a re det e r m i n e d by "the so-and-so" ( g i v e n i t s e n v i r o n m e n t ) , t h a t i n t h i s environment he always has c o l o u r s e n s e - d a t a o f t h i s k i n d on v i e w i n g t h a t o b j e c t , and t h a t o t h e r p e o p l e can d i s c o v e r which p e r c e i v e d c o l o u r s he has. In a d d i t i o n , suppose t h a t the s a m e n e s s / d i f f e r e n c e o f h i s p e r c e i v e d c o l o u r s on v i e w i n g t h i s and o t h e r o b j e c t s i n d i f f e r e n t environments i s i s o m o r p h i c t o the s a m e n e s s / d i f f e r e n c e o f the p e r c e i v e d c o l o u r s o f o t h e r people when th e y view the same o b j e c t s as he does i n the same environments as those i n which he views them. Even w i t h t h i s I deny t h a t t h e r e i s an adequate b a s i s f o r a s c r i b - i n g p a r t i c u l a r c o l o u r s to p h y s i c a l o b j e c t s , u n l e s s t h e r e i s a l s o a ge n e r a l u n i - f o r m i t y among the p e r c e i v e d c o l o u r s v i e w e r s have when l o o k i n g a t some one ; p h y s i c a l o b j e c t i n a c o n s t a n t environment. I f t h e r e i s no such g e n e r a l u n i - f o r m i t y , then when t h e o r i g i n a l speaker ( o r anyone e l s e ) c l a i m s t h a t "The so- and-so i s r e d " t h i s means a t b e s t t h a t "The p e r c e i v e d c o l o u r the so-and-so de t e r m i n e s i n me when I view i t i n t h i s environment i s l i k e t h e p e r c e i v e d c o l o u r d e t e r m i n e d i n me by the such-and-such i n t h i s environment, but u n l i k e t h e p e r c e i v e d c o l o u r d e t e r m i n e d i n me by t h i s and t h i s o b j e c t i n t h a t e n v i r o n - ment, e t c . , e t c . , and t h e r e i s a g e n e r a l u n i f o r m i t y , an isomorphism, i n t h e p a t t e r n o f the s a m e n e s s / d i f f e r e n c e r e l a t i o n s h o l d i n g between the c o l o u r s people p e r c e i v e i n t h e s e v a r i o u s environments when th e y view t h e s e v a r i o u s o b j e c t s . " Some w r i t e r s c l a i m t h a t , s u p p o s i n g t h i s isomorphism between the p e r c e i v e d c o l o u r s o f vie w e r s . g e n e r a l l y to h o l d , i t i s " i m p o s s i b l e " t o d e t e c t i f the pa r - t i c u l a r p e r c e i v e d c o l o u r s people have i n v i e w i n g some one o b j e c t i n a c o n s t a n t environment v a r y a g r e a t deal from one person t o a n o t h e r , and t h a t i n any c a s e such d i f f e r e n c e s do n o t m a t t e r . In e f f e c t , t h i s does "reduce" statements such as "The so-and-so i s r e d " to state m e n t s o f t h e form g i v e n above (about the i s o - morphism o f . t h e s a m e n e s s / d i f f e r e n c e o f p e r c e i v e d c o l o u r s o f people when t h e y view v a r i o u s p h y s i c a l o b j e c t s i n v a r i o u s e n v i r o n m e n t s ) . But I r e j e c t both o f 131 t h e s e c l a i m s ; I argued i n the l a s t s e c t i o n t h a t i t i s not l o g i c a l l y i m p o s s i b l e , n o t even c l e a r l y i n c o n c e i v a b l e , t o d e t e c t d i f f e r e n c e s i n the p e r c e i v e d c o l o u r s o f d i f f e r e n t v i e w e r s i n a c o n s t a n t environment. And i n t h i s s e c t i o n I have argued t h a t the p a r t i c u l a r p e r c e i v e d c o l o u r s o f vie w e r s a re i m p o r t a n t i n t h a t i f t h e p e r c e i v e d c o l o u r s o f viewers i n a c o n s t a n t environment d i f f e r a g r e a t d e a l , then we do not have an adequate b a s i s f o r the c o n c e p t o f "the ( p a r t i - c u l a r ) c o l o u r o f a p h y s i c a l o b j e c t " . There needs t o be some g e n e r a l u n i f o r m i t y i n the p e r c e i v e d c o l o u r s o f vie w e r s i n a c o n s t a n t environment. I t i s not the " i m p o s s i b i l i t y " o f d e t e c t i n g d i f f e r e n c e s i n p e r c e i v e d c o l o u r s among vie w e r s t h a t g i v e s r i s e t o t h e " r e d u c t i o n " o f statements a s c r i b i n g p a r t i c u l a r c o l o u r s t o p h y s i c a l o b j e c t s to the ki n d s o f statements d e s c r i b e d above, s i n c e , I have argued, such d i f f e r e n c e s a r e open t o d e t e c t i o n . What would l e a d t o the " r e - d u c t i o n " would be the e m p i r i c a l d i s c o v e r y t h a t t h e r e i s not a g e n e r a l u n i - f o r m i t y among the p e r c e i v e d c o l o u r s o f d i f f e r e n t v i e w e r s i n a c o n s t a n t e n v i r o n - ment, and t h i s " r e d u c t i o n " would amount t o l o s i n g the co n c e p t o f "the ( p a r t i - c u l a r ) c o l o u r o f a p h y s i c a l o b j e c t " . In summary, g i v e n t h a t our p e r c e i v e d c o l o u r s do not "resemble" p r o p e r - t i e s " i n the o b j e c t s t h e m s e l v e s " , i f t h e r e i s no g e n e r a l u n i f o r m i t y i n people's p e r c e i v e d c o l o u r s on v i e w i n g p a r t i c u l a r p h y s i c a l o b j e c t s i n a c o n s t a n t e n v i r o n - ment, then t h e r e i s no b a s i s f o r deeming a p a r t i c u l a r p h y s i c a l o b j e c t to be one c o l o u r r a t h e r than a n o t h e r . The c o n c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " i s r e l a t i o n a l and e s s e n t i a l l y i n v o l v e s r e f e r e n c e t o c e r t a i n human v i s u a l ex- p e r i e n c e s . In a sense, al1 the s t r u c t u r a l f e a t u r e s o f how we c l a s s i f y p h y s i - c a l o b j e c t s by t h e i r p a r t i c u l a r c o l o u r s must, t h e r e f o r e , be found w i t h i n t h i s range o f human v i s u a l e x p e r i e n c e s i f the con c e p t i s t o be v i a b l e . And so I r e j e c t Smart's c l a i m t h a t i n o r d e r t o a s c r i b e p a r t i c u l a r c o l o u r s to p h y s i c a l o b j e c t s , "the a c t u a l q u a l i a o f our [colour] s e n s e - d a t a m a t t e r not a t a l l so l o n g as t h e r e i s a one-one mapping o f the s e t o f s e n s e - d a t a produced i n me on t o the s e t o f s e n s e - d a t a produced i n you by v a r i o u s s t i m u l i . " H In the next s e c t i o n I s h a l l l o o k more c l o s e l y at.what t h i s r e q u i r e m e n t about a g e n e r a l u n i f o r m i t y i n v i e w e r s ' p e r c e i v e d c o l o u r s i n v o l v e s , and i n d o i n g so I s h a l l examine the n o t i o n o f a " s t a n d a r d - s t a t e p e r c e i v e r " r e f e r r e d t o i n t h e c e n t r a l c l a i m on pp. 124-125. Smart, " C o l o u r s , " p. 129. 133 13. S t a n d a r d - S t a t e P e r c e i v e r s The next s t a g e i s t o i n v e s t i g a t e who would count as a s t a n d a r d - s t a t e p e r c e i v e r , s i n c e t h i s n o t i o n i s c e n t r a l t o my account o f what i t i s f o r a p h y s i c a l o b j e c t t o be, e.g., r e d . One c r u c i a l p o i n t here i s t h a t the a c c o u n t o f what c o n s t i t u t e s a s t a n d a r d - s t a t e must s a f e g u a r d the n e c e s s a r y c o n d i t i o n f o r " b e i n g ( a t p r e s e n t ) r e d " to count as a p r o p e r t y o f a p h y s i c a l o b j e c t i n some p e r c e p t u a l o r p o t e n t i a l p e r c e p t u a l environment, v i z , "In a c o n s t a n t en- vironment c o n t a i n i n g a p h y s i c a l o b j e c t , c o n f l i c t i n g v e r d i c t s f o r a statement a s c r i b i n g the p r o p e r t y t o the o b j e c t n e c e s s i t a t e one (group o f ) v e r d i c t ' s b e i n g i n c o r r e c t . " T h i s i s t o s a y , i f my a c c o u n t o f which p h y s i c a l o b j e c t s a r e r e d i s t o be v i a b l e , I need t o p r e v e n t c o n t r a d i c t i o n s a r i s i n g as a r e s u l t o f i t . The a c c o u n t must not produce c o n f l i c t i n g v e r d i c t s as t o whether o r not some p h y s i c a l o b j e c t , g i v e n i t s e n v i r o n m e n t , i s a t p r e s e n t r e d . I t was p o i n t - ed o u t e a r l i e r t h a t t h i s n e c e s s a r y c o n d i t i o n h o l d s f o r r e l a t i o n a l as w e l l as f o r n o n - r e l a t i o n a l p r o p e r t i e s o f a physical o b j e c t i n a c o n s t a n t environment. E.g., i n a c o n s t a n t environment a c o n f l i c t o f v e r d i c t s f o r the s tatement "The t a b l e i s t a l l e r than the a r m c h a i r " ( g i v e n , o f c o u r s e , t h a t the s t a t e - ment i s r e n d e r e d unambiguous) n e c e s s i t a t e s one v e r d i c t ' s b e i n g i n c o r r e c t j u s t as i t would i f a c o n f l i c t a r o s e o v e r the s tatement "The t a b l e - s u r f a c e i s r e c t a n g u l a r . " I have a l r e a d y c l a i m e d t h a t i f t h i s n e c e s s a r y c o n d i t i o n i s not met, then no m a t t e r what the s u r f a c e grammar o f t h e statement i n q u e s t i o n , i t i s n o t g e n u i n e l y about a p r o p e r t y o f a p h y s i c a l o b j e c t i n the environment i n q u e s t i o n . I t i s , f o r example, t h e c o r e o f the d i s t i n c t i o n between c l a i m - i n g on the b a s i s o f what you now s e e , "The book-cover i s r e d " and c l a i m i n g "I now 'seem t o see' a r e d book-cover." In the l a t t e r case t h e r e i s no genuine c o n f l i c t i f someone e l s e ( o r you a t a n o t h e r time) i n the same ( i . e . , c o n s t a n t ) environment c l a i m s on the b a s i s o f h i s p e r c e i v e d c o l o u r s "The book- c o v e r i s b l u e . " The formulae "I seem t o s e e " , "I seem to h e a r " , e t c . , a r e t r a d i t i o n a l l y used t o make c l a i m s which are n o t about the p h y s i c a l w o r l d ( o t h e r than one's own body) . In a c o n s t a n t environment an i n d i v i d u a l ' s c l a i m can change as a r e s u l t o f changes i n h i s p e r c e i v e d c o l o u r s from "I seem t o see a red book-cover" t o "I seem to see a b l u e book-cover", and s t i l l t h e r e i s no genuine c o n f l i c t h ere. I f t h e r e i s good re a s o n f o r the p e r c e i v e r t o suppose t h a t the change i n h i s p e r c e i v e d c o l o u r s i s the r e s u l t s o l e l y o f a change i n h i s b o d i l y s t a t e , he may w e l l choose t o make c l a i m s o n l y about what he "seems t o s e e " , s i m p l y because t h i s commits him to much l e s s . The account I o f f e r w i l l ensure t h i s n e c e s s a r y c o n d i t i o n f o r red to count as a p r o p e r t y o f a p h y s i c a l o b j e c t . The c o n c e p t o f a p h y s i c a l o b j e c t ' s b e i n g red e s s e n t i a l l y i n v o l v e s r e f e r - ence t o v i e w e r s ' p e r c e i v e d c o l o u r s — i n my a c c o u n t , t o the p e r c e i v e d c o l o u r s o f " s t a n d a r d - s t a t e " v i e w e r s . One p o i n t t h a t I can make imme d i a t e l y i s t h a t I am n o t b a s i n g the a c c o u n t on an appeal t o "the p e r c e i v e d c o l o u r s o f the m a j o r i t y o f p e r c e i v e r s a l i v e a t the time o f the a s c r i p t i o n o f red t o the p h y s i c a l ob- j e c t i n q u e s t i o n " . Suppose t h a t people agree t o use the term " r e d " t o c o v e r much the same group ( o r " s e r i e s " ) o f c o l o u r s . ( T h i s c o u l d be c hecked, i f my e a r l i e r p o i n t s about the T r a n s p o s i t i o n Argument a r e c o r r e c t . ) In f a c t , f o r the r e s t o f t h i s s e c t i o n l e t t h i s assumption be t r u e and known t o be so. Then i f "So-and-so (some p h y s i c a l o b j e c t ) i s r e d " means s i m p l y "So-and-so would de- termine now i n the m a j o r i t y o f p e r c e i v e r s a l i v e one o r o t h e r o f the c o l o u r s deemed to be r e d " , c o n t r a d i c t i o n s can a r i s e . I f the m a j o r i t y o f p e r c e i v e r s undergo some change i n p h y s i c a l s t a t e which a f f e c t s t h e i r c o l o u r - v i s i o n , then a t a n o t h e r time the same o b j e c t i n the same ( i . e . , c o n s t a n t ) environment c o u l d d e t e r m i n e i n the m a j o r i t y o f p e r c e i v e r s v e r y d i f f e r e n t c o l o u r s , so t h a t on t h i s a c c o u n t the o b j e c t i s now not r e d . There would be a c o n t r a d i c t i o n t h a t i n a c o n s t a n t environment one and the same p h y s i c a l o b j e c t i s both r e d and not r e d . *As a r e m inder, t h i s r e s t r i c t i o n remains i n f o r c e . The r i d e r t o the c e n t r a l c l a i m o f what i t i s f o r a p h y s i c a l o b j e c t t o be r e d has not y e t been e x p l a i n e d . In t he a c c o u n t I o f f e r t he r e f e r e n c e i s t o the p e r c e i v e d c o l o u r s o f a l l " s t a n d a r d - s t a t e " v i e w e r s — a l l who have l i v e d , a r e a l i v e , o r w i l l l i v e . The "g e n e r a l u n i f o r m i t y " o f p e r c e i v e d c o l o u r s on v i e w i n g p h y s i c a l o b j e c t s , which we r e q u i r e f o r the c o n c e p t o f "the c o l o u r o f a p h y s i c a l o b j e c t " , s h o u l d be found i n the p e r c e i v e d c o l o u r s o f t h i s group o f p e o p l e . Why do I s p e c i f y " s t a n d a r d - s t a t e " ? The n a t u r e o f t h e human s e n s o r y a p p a r a t u s o f s i g h t i s r e l e - vant not o n l y t o how humans t e s t s t a t e m e n t s a s c r i b i n g a p a r t i c u l a r c o l o u r t o a p h y s i c a l o b j e c t , b ut to the v e r y c o n c e p t o f "the c o l o u r o f a p h y s i c a l ob- j e c t " . For example, c o n s i d e r some animal h a v i n g a s e n s o r y a p p a r a t u s o f s i g h t v e r y u n l i k e t h a t o f humans, e.g., a f l y . A p p a r e n t l y the eye o f a f l y i s v e r y u n l i k e a human eye. Even i f we knew a g r e a t d e a l about the v i s u a l e x p e r i e n c e s o f f l i e s , t h o s e e x p e r i e n c e s a r e j u s t not r e l e v a n t t o the con c e p t b e i n g ' s et o u t ' h e r e . (Perhaps we c o u l d s t a r t work on a new con c e p t s p e c i f i c a l l y t o do w i t h t he c o l o u r - v i s i o n o f f l i e s , but i t would be a d i f f e r e n t c o n c e p t from t h a t b e i n g d i s c u s s e d here.) Of c o u r s e , i t i s easy enough t o d i s r e g a r d t h e v i s u a l e x p e r i e n c e s o f f l i e s and l i z a r d s when we g i v e an ac c o u n t o f what i t i s f o r a p h y s i c a l o b j e c t t o be, e.g., r e d , but the i n t e r e s t i n g q u e s t i o n i s whether o r not t h e r e a r e grounds f o r r u l i n g some v i s u a l e x p e r i e n c e s o f human beings t o be l i k e w i s e i r r e l e v a n t t o such an a c c o u n t . There i s a g r e a t d e a l o f u n i f o r m i t y i n the s e n s o r y a p p a r a t u s o f s i g h t i n humans, but can t h e r e be " d e v i a t i o n s " t h a t would r e n d e r a person's p e r c e i v e d c o l o u r s i r r e l e v a n t t o s e t t i n g out such an a c c o u n t ? Or, as I p r e f e r t o f o r m u l a t e i t , i s i t c o n c e i v a b l e f o r a human b e i n g t o have a p h y s i c a l s t a t e which r e n d e r s h i s p e r c e i v e d c o l o u r s i r r e l e v a n t t o p r o v i d i n g such an account? T h i s q u e s t i o n does n o t s p e c i f y t h a t the p h y s i - c a l s t a t e be a s t a t e o f the s e n s o r y a p p a r a t u s o f s i g h t , a l t h o u g h the s t a t e must a f f e c t t h i s a p p a r a t u s so as to have some e f f e c t on the p e r c e i v e d c o l o u r s he has on v i e w i n g some p a r t s o f the p h y s i c a l w o r l d . And by " p h y s i c a l s t a t e " i n t h i s q u e s t i o n , I am r e f e r r i n g t o something o t h e r than the p h y s i c a l 136 2 end-states of the perceptions "affected". If there are any such physical states I shall deem them to be non-standard. It is tempting to reject the question outright as absurd, to say that the visual experiences of a l l human beings are relevant to setting out the concept of a physical object's being red, and that only a state that would render the person not a human being at a l l could be "non-standard" as I am using this term. This response, I think, is an oversimplification of what the ..anthropocentric nature of the concept i s . The question is not settled that easi ly. E.g . , perhaps i t w i l l be possible one day to provide a r t i f i c i a l l y manufactured replacements for at least some of the parts of a person's sen- sory apparatus of sight i f those parts are damaged in some way. It would not be surprising i f in the early stages of developing such replacements, manu- factured parts were produced which permitted a person to have perceived colours on viewing the physical world, but which nonetheless functioned in some "radical ly different" way from the sensory apparatus of sight of most hu- man beings. At least, I think we need to examine quite closely the possibi- l i t y of there being human beings in a non-standard state. At this point I wish to distinguish two different questions. They are related, but nonetheless different. 1) Which human beings are standard-state humans? I.e., the perceived colours of which group of viewers constitute the basis of the concept of "a physical object's being red"? Or, in which group of viewers shall we look for the "general uniformity" of perceived colours (when viewing certain physical objects) which is the basis of the concept of "a physical object's being red"? 2) Can this or that person, or group of people, test rel iably in a certain 2 These last two points about the use of "physical state" I am not explaining here since they have been explained in detail in the context of the "second basis" for tackling the Transposition Argument. 137 environment a statement a s c r i b i n g the c o l o u r r e d t o some p a r t i c u l a r p h y s i c a l o b j e c t i n t h a t environment? At the moment I am a s k i n g q u e s t i o n ( 1 ) . As a temporary rough guide o n l y , t h e two q u e s t i o n s r e l a t e i n the f o l l o w i n g way. There w i l l be a v e r y s t r o n g t e n - dency f o r s t a n d a r d - s t a t e v i e w e r s t o be r e l i a b l e i n the sense r e f e r r e d t o i n ( 2 ) . However, t h e r e need not be such a s t r o n g tendency f o r people who a r e r e l i a b l e i n t h a t way t o be s t a n d a r d - s t a t e v i e w e r s . (One o f the reasons f o r t h i s i s t h a t t h e r e may be ways o f t e s t i n g a sta t e m e n t a s c r i b i n g t h e c o l o u r r e d t o a p h y s i c a l o b j e c t o t h e r than by s i m p l y v i e w i n g t he o b j e c t and r e a c h i n g a v e r d i c t s o l e l y on t h e b a s i s o f one's p e r c e i v e d c o l o u r s . ) In o r d e r f o r a st a t e , to be a non-standard s t a t e , i t must a f f e c t the p e r - son's p e r c e i v e d c o l o u r s on v i e w i n g some p h y s i c a l o b j e c t s . That i s t o s a y , t h e r e must be some ways i n which we can change t h i s s t a t e , l e a v i n g the r e s t o f h i s s t a t e c o n s t a n t , which w i l l r e s u l t i n d i f f e r e n t p e r c e i v e d c o l o u r s on view- i n g some p h y s i c a l o b j e c t s from the p e r c e i v e d c o l o u r s he had ( o r would have had) on v i e w i n g t h e s e o b j e c t s i n the same environments b e f o r e such a change i n s t a t e . S t r i c t l y s p e a k i n g , what i s meant by " l e a v i n g t h e r e s t o f h i s s t a t e c o n s t a n t " i s " l e a v i n g c o n s t a n t whatever f e a t u r e s o f h i s s t a t e can c o n c e i v a b l y be l e f t c o n s t a n t , g i v e n t h a t the s p e c i f i e d change i n h i s s t a t e has o c c u r r e d " . E.g., t h e r e may be some f e a t u r e s not mentioned i n the d e s c r i p t i o n o f the changes t o be made, but which c a u s a l l y must change i f t h a t s p e c i f i e d change i n 3 s t a t e o c c u r s . In answer t o q u e s t i o n ( 1 ) , I s u g g e s t t h a t t h e r e a r e a t l e a s t two k i n d s o f r e a s o n s f o r deeming a p h y s i c a l s t a t e which a f f e c t s a person's p e r c e i v e d c o l o u r s on v i e w i n g some p h y s i c a l o b j e c t s t o be non - s t a n d a r d : 3 I f the k i n d o f "change" t h a t would produce d i f f e r e n t p e r c e i v e d c o l o u r s i s i n f a c t i n c o n c e i v a b l e ( i . e . , one person c o u l d not c o n c e i v a b l y change i n t h i s way), then the p o i n t can be s t a t e d i n terms o f two people and how t h e i r s t a t e s d i f f e r i n c e r t a i n r e s p e c t s , r a t h e r than i n terms o f one person and how h i s s t a t e changes. 1 3 8 a) I t i s the s t a t e o f some p a r t o f h i s s e n s o r y a p p a r a t u s o f s i g h t where t h i s p a r t i s i n appearance " r a d i c a l l y d i f f e r e n t " from t h a t o f the v a s t m a j o r i t y o f v i e w e r s . b) I t i s a s t a t e o f ( o r a s t a t e which a f f e c t s the s t a t e o f ) h i s s e n s o r y a p p a r a t u s o f s i g h t such t h a t the f u n c t i o n i n g o f some p a r t o f t h a t s e n - s o r y a p p a r a t u s i s " r a d i c a l l y d i f f e r e n t " from the f u n c t i o n i n g o f t h a t p a r t i n the v a s t m a j o r i t y o f v i e w e r s . (These two p o s s i b i l i t i e s a r e not e x c l u s i v e . ) I s h a l l make some remarks about (b) s i n c e t h i s i s the more i n t e r e s t i n g o f t h e two. As they are s t a t e d , (a) and (b) amount t o g u i d e - l i n e s f o r d e c l a r i n g some s t a t e s o f humans t o be n o n - s t a n d a r d ; they a r e not s u f f i c i e n t l y p r e c i s e t o be more than t h a t . P a r t l y t h i s i s because I do not have the d e t a i l e d em- p i r i c a l knowledge t o g i v e a l o t more i n f o r m a t i o n about t h e s e two p o s s i b i l i - t i e s , a l t h o u g h I s h a l l say something about ( b ) . A l s o , t h e i r b e i n g r a t h e r im- p r e c i s e makes them more u s e f u l r a t h e r than the r e v e r s e , s i n c e t h e r e a r e no r i g i d r e s t r i c t i o n s as t o what can l e g i t i m a t e l y be deemed t o be a n o n - s t a n d a r d s t a t e . Even the most knowledgeable i n t h e s e m a t t e r s may f i n d t h i s an advan- tage i f t h e y e n c o u n t e r some ' p e c u l i a r ' s t a t e not p r e v i o u s l y thought o f . L o o k i n g a t (b) above, the f u n c t i o n i n g o f p a r t o f a person's s e n s o r y ap- p a r a t u s o f s i g h t c o u l d count as b e i n g " r a d i c a l l y d i f f e r e n t " from t h a t o f t h e v a s t m a j o r i t y o f v i e w e r s f o r two d i f f e r e n t r e a s o n s : t h a t the p h y s i c a l ob- j e c t s ' p r o p e r t i e s ( i n c l u d i n g t h e i r r e l e v a n t r e l a t i o n a l p r o p e r t i e s ) which de- t e r m i n e h i s p e r c e i v e d c o l o u r s i n l o o k i n g a t them are d i f f e r e n t from the p r o - p e r t i e s d e t e r m i n i n g the p e r c e i v e d c o l o u r s o f the v a s t m a j o r i t y o f v i e w e r s ; o r , even though the p r o p e r t i e s d e t e r m i n i n g . h i s p e r c e i v e d c o l o u r s a r e the same as t h o s e d e t e r m i n i n g the p e r c e i v e d c o l o u r s o f the v a s t m a j o r i t y o f v i e w e r s , t h e r e a r e n o n e t h e l e s s some v a r i a t i o n s i n t h i s s e t o f d e t e r m i n i n g p r o p e r t i e s t h a t f o r him r e s u l t i n v e r y d i f f e r e n t v i s u a l e x p e r i e n c e s from tho s e o f the v a s t m a j o r i t y . 1 3 9 (I s h a l l g i v e a t l e a s t one k i n d o f case t h a t c o u l d be an example o f t h i s l a s t s i t u a t i o n . ) For both t h e s e s i t u a t i o n s what I mean i s t h a t i n some c o n s t a n t environments t h e r e i s one o r o t h e r o f t h e s e d i f f e r e n c e s i n how h i s s e n s o r y ap- pa r a t u s o f s i g h t f u n c t i o n s . T h e r e f o r e , s i n c e we a r e r e f e r r i n g t o c o n s t a n t en- vi r o n m e n t s , t h e r e i s some d i f f e r e n c e between h i s s t a t e and the s t a t e s o f the v a s t m a j o r i t y o f vie w e r s t h a t r e s u l t s i n the d i f f e r e n c e i n how h i s and t h e i r 4 s e n s o r y a p p a r a t u s o f s i g h t f u n c t i o n s . We may deem the one vi e w e r ' s p h y s i c a l s t a t e t h a t r e s u l t s i n t h i s d i f f e r e n c e i n f u n c t i o n i n g t o be a non - s t a n d a r d s t a t e . I s h a l l d e s c r i b e i n g e n e r a l terms the f i r s t o f t h e two reaso n s f o r c l a i m i n g t h a t a person's s e n s o r y a p p a r a t u s o f s i g h t f u n c t i o n s i n a r a d i c a l l y d i f f e r e n t way from t h o s e o f the v a s t m a j o r i t y o f v i e w e r s . Suppose t h a t t he p r o p e r t i e s o f a p h y s i c a l o b j e c t ( i n c l u d i n g t h e i r r e l e v a n t r e l a t i o n a l ones) t h a t d e t e r m i n e f o r the v a s t m a j o r i t y o f vie w e r s t h e i r p e r c e i v e d c o l o u r a r e the p r o p e r t i e s A, B, C, D. These are the p r o p e r t i e s some v a r i a t i o n s o f which w i l l produce d i f f e r e n t p e r c e i v e d c o l o u r s i n many v i e w e r s ; e.g., suppose t h a t a p h y s i c a l o b j e c t h a v i n g t he p r o p e r t i e s A-|, B-j, Cg, Dg determines i n most viewers a p e r c e i v e d c o l o u r d i f f e r e n t from t h a t determined by an o b j e c t w i t h the p r o p e r t i e s Ag, Bg, Cg, D-j. A l s o , and more i m p o r t a n t h e r e , i f the pro- p e r t i e s a r e a l l t he same f o r two p h y s i c a l o b j e c t s b e i n g viewed ( e . g . , both ob- j e c t s have the p r o p e r t i e s A-j, B^, Cg, D 2 ) , then f o r the v a s t m a j o r i t y o f view e r s t h e p e r c e i v e d c o l o u r t he one o b j e c t d e termines w i l l be the same as t h a t d e t e r m i n e d by the o t h e r o b j e c t . Suppose now t h a t we d i s c o v e r t h a t f o r one v i e w e r t h e p r o p e r t i e s t h a t d e t e r m i n e h i s p e r c e i v e d c o l o u r s a r e p r o p e r t i e s A, C, E, F, so t h a t some v a r i a t i o n s i n t h e s e p r o p e r t i e s between two p h y s i c a l 4 T h i s i s so because o f the " l a w l i k e r e g u l a r i t y " t h a t must h o l d between the environment's e f f e c t , on a vi e w e r ' s p h y s i c a l s t a t e , and the vi e w e r ' s p h y s i c a l s t a t e on h i s p e r c e i v e d c o l o u r s , i f t h o s e p e r c e i v e d c o l o u r s a r e t o be d e t e r - mined by some p a r t o f t h a t environment. (See the "second b a s i s " f o r t a c k l i n g the T r a n s p o s i t i o n Argument, S e c t i o n 11.) 140 o b j e c t s c o n s i s t e n t l y produce a d i f f e r e n c e between h i s p e r c e i v e d c o l o u r on v i e w i n g the one o b j e c t and h i s p e r c e i v e d c o l o u r on v i e w i n g the o t h e r o b j e c t , and a l s o so t h a t i f a l l t h e s e p r o e p r t i e s — A , C, E, F — a r e the same f o r two p h y s i c a l o b j e c t s b e i n g viewed, then t he p r o p e r t i e s determine i n him the same p e r c e i v e d c o l o u r on v i e w i n g t h e one o b j e c t as on v i e w i n g t he o t h e r o b j e c t . I f any such s i t u a t i o n i s c o n c e i v a b l e , then t h e r e w i l l be some b i g d i f - f e r e n c e s between the one person's c o l o u r - v i s i o n and t h a t o f most v i e w e r s . E.g., suppose t h a t t h e r e a re two p h y s i c a l o b j e c t s which, g i v e n t h e i r e n v i r o n - ments, have t h e same A, B, C, D, p r o p e r t i e s , i . e . , whatever p a r t i c u l a r A- f e a t u r e one o b j e c t has ( e . g . , A^) the o t h e r o b j e c t has t o o , e t c . . Then f o r the v a s t m a j o r i t y o f v i e w e r s one o b j e c t w i l l d etermine t h e same p e r c e i v e d c o l o u r as t h a t d e t e r m i n e d by the o t h e r o b j e c t . In f a c t , we can say more than t h i s . We can c l a i m t h a t i f the two o b j e c t s a r e t h e same i n r e s p e c t o f t h e s e p r o p e r t i e s t h e y a re i n f a c t the same c o l o u r . But c o n s i d e r now the one view e r whose p e r c e i v e d c o l o u r s a r e determined by t h e p r o p e r t i e s A, C, E, F, o f p h y s i - c a l o b j e c t s . Two o b j e c t s t he same i n r e s p e c t o f the s e t o f p r o p e r t i e s A, B, C, D, may n o n e t h e l e s s d i f f e r i n r e s p e c t o f t h e s e t o f p r o p e r t i e s A, C, E, F ( t h e i r E and/or F p r o p e r t i e s may d i f f e r ) , and d i f f e r i n such a way as t o de- te r m i n e i n the one viewer v e r y d i f f e r e n t p e r c e i v e d c o l o u r s . In f a c t , t h e y c o u l d c o n s i s t e n t l y determine i n t h a t one view e r p e r c e i v e d c o l o u r s t h a t a r e so d i f f e r e n t t h e y c o u l d n o t be samples o f the same c o l o u r ^ . T h i s i s how d i f - f e r e n t t he c o l o u r - v i s i o n o f t h e one view e r and the m a j o r i t y can be as a r e - s u l t o f the d i f f e r e n c e between how h i s and t h e i r s e n s o r y a p p a r a t u s o f s i g h t f u n c t i o n s . A l t h o u g h I have made i t c l e a r t h a t I do not have the d e t a i l e d e m p i r i c a l knowledge r e q u i r e d t o g i v e s p e c i f i c and c l e a r l y c o n c e i v a b l e examples o f such a s i t u a t i o n , I t h i n k we must be c a u t i o u s about assuming t h a t t h e r e a r e no such c o n c e i v a b l e examples. We are s t i l l a c q u i r i n g knowledge about v i s u a l p e r c e p t i o n , but we know a l r e a d y t h a t humans respond v i s u a l l y t o a c e r t a i n 141 'range' o f the s t i m u l u s . The s t i m u l u s i s r a d i a n t energy, which o r i g i n a t e s a t a p r i m a r y s o u r c e , as t h e sun o r a l i g h t b u l b . The energy sometimes comes d i r e c t l y t o the eye, but more commonly i t r e a c h e s the eye a f t e r r e f l e c t i o n from some o b j e c t . . . . Newton, i n 1704, r e p o r t e d t h a t a p r i s m breaks up a band o f w h i t e l i g h t i n t o a spectrum o f c o l o u r s , r a n g i n g from r e d t o v i o l e t . T h at i s , the p r i s m spreads o u t the mixed waves t h a t comprise the w h i t e beam i n t o a sheath o f waves, each element o f which i s homogeneous w i t h r e s p e c t t o w a v e l e n g t h . These wavelengths have been measured w i t h much p r e c i s i o n ; the ones t h a t c o r r e s p o n d t o the v i s u a l spectrum run from about 380 m i l l i m i c r o n s [(thousandths o f a m i l l i o n t h o f a meter)] a t the v i o l e t end t o 720 a t the r e d e n d . 5 The s p e c t r a l l i m i t s g i v e n are t o some e x t e n t a r b i t r a r y s i n c e "the spectrum 'peters o u t ' a t each end". There i s o f c o u r s e a g r e a t deal o f v a r i e t y i n the v i s u a l mechanisms o f o t h e r a n i m a l s , and a p p a r e n t l y "many o f t h e s e respond t o s l i c e s o f t h e e l e c t r o - m a g n e t i c spectrum d i f f e r e n t from t h a t which a f f e c t s our e y e s . I do not know whether o r n o t ' b u r i e d ' i n t h e s e k i n d s o f f a c t s i s the i n f o r m a t i o n needed to c o n s t r u c t some c o n c e i v a b l e examples o f t h e k i n d de- s c r i b e d . A c o n c e i v a b l e case can be one d e l i b e r a t e l y brought about ( i . e . , by d e l i b e r a t e l y changing someone's p h y s i c a l s t a t e ) , a l l t h a t i s r e q u i r e d i s t h a t the change does n o t l e a v e t h e s u b j e c t non-human. I must l e a v e the i s s u e un- s e t t l e d , but I t h i n k I have g i v e n enough t o e x p l a i n what I have i n mind. I mentioned t h a t the f u n c t i o n i n g o f p a r t o f a person's s e n s o r y a p p a r a t u s o f s i g h t c o u l d count as b e i n g " r a d i c a l l y d i f f e r e n t " from t h a t o f the v a s t m a j o r i t y o f v i e w e r s f o r a n o t h e r reason a l s o , where, even though the s e t o f p r o p e r t i e s ( o f p h y s i c a l o b j e c t s ) d e t e r m i n i n g h i s p e r c e i v e d c o l o u r s i s the same as t h a t d e t e r m i n i n g the p e r c e i v e d c o l o u r s o f t h e v a s t m a j o r i t y o f v i e w e r s , t h e r e a r e n o n e t h e l e s s some v a r i a t i o n s i n t h i s s e t o f d e t e r m i n i n g p r o p e r t i e s Robert S . Woodworth and H a r o l d S c h l o s b e r g , E x p e r i m e n t a l P s y c h o l o g y , 3rd ed. (London, 1954), pp. 362-363. ^ I b i d . , p. 363. b u n d l e , p. 55. 142 t h a t f o r him r e s u l t i n v e r y d i f f e r e n t v i s u a l e x p e r i e n c e s from t h o s e o f the v a s t m a j o r i t y . For t h i s k i n d o f case i t w i l l be e a s i e s t t o f o c u s on examples o f the k i n d o f t h i n g I have i n mind. My i n t e r e s t i s i n d i f f e r e n c e s f u n c t i o n - i n g a f f e c t i n g c o l o u r - v i s i o n . A v e r y small number o f humans now (about 3 i n 100,000) a r e a b l e to make v e r y few d i s c r i m i n a t i o n s by c o l o u r . A s e r i e s o f d i s c r i m i n a t i o n t e s t s w i l l r e v e a l a small number o f d i f f e r e n t p e r c e i v e d c o l o u r s t h e y have when vi e w i n g i n environments where the v a s t m a j o r i t y o f viewers have v e r y many d i f f e r e n t p e r c e i v e d c o l o u r s . T h i s much can be t e s t e d f o r even w i t h o u t knowing which p a r t i c u l a r p e r c e i v e d c o l o u r s the small number o f people have. Given t h a t ex h y p o t h e s i i n the d i s c r i m i n a t i o n t e s t s the small number o f p e o p l e and the v a s t m a j o r i t y view o b j e c t s i n c o n s t a n t e n v i r o n m e n t s , the d i f f e r e n c e i n t h e i r v i s u a l e x p e r i e n c e s , i n p a r t i c u l a r i n the number o f d i f f e r e n t p e r c e i v e d c o l o u r s t h e y have, must be the r e s u l t o f some r e l e v a n t d i f f e r e n c e i n t h e i r p h y s i c a l s t a t e s a t the time o f v i e w i n g . The r e t i n a o f the human eye c o n t a i n s two k i n d s o f r e c e p t o r s , rods and cones. The 3 i n 100,000 view e r s r e f e r r e d t o have o n l y rod v i s i o n . That i s to say, h a v i n g o n l y rod v i s i o n has been e m p i r i c a l l y d i s c o v e r e d t o change one's c o l o u r v i s i o n d r a s t i - c a l l y ; i n f a c t , the s e n s o r y a p p a r a t u s o f a viewer h a v i n g o n l y rod v i s i o n i s " r a d i c a l l y d i f f e r e n t " i n i t s f u n c t i o n i n g from t h a t o f the m a j o r i t y o f v i e w e r s i n t h a t some v a r i a t i o n s i n the p r o p e r t i e s ( o f p h y s i c a l o b j e c t s ) t h a t d e t e r - mine the p e r c e i v e d c o l o u r s o f v i e w e r s r e s u l t i n v e r y d i f f e r e n t v i s u a l e x p e r i - ences o f c o l o u r i n him from the e x p e r i e n c e s o f the v a s t m a j o r i t y v i e w i n g the same o b j e c t s . The term used by p s y c h o l o g i s t s t o r e f e r t o people w i t h t h i s very r a r e f e a t u r e o f t h e human eye i s "monochromats". The p s y c h o l o g i s t s ' c l a i m s about monochromats go beyond what I have g i v e n h e r e . As w e l l as l o c a t i n g the cause o f t h e i r s e v e r e l y l i m i t e d number o f d i f f e r e n t p e r c e i v e d c o l o u r s , i t i s commonly c l a i m e d t h a t "they cannot d i s t i n g u i s h any e x c e p t the s o - c a l l e d n e u t r a l o c o l o u r s ( g r e y s , b l a c k and w h i t e ) . " Even t h e l i t t l e I have s a i d about 143 monochromats r e v e a l s a p r o m i s i n g e m p i r i c a l programme f o r d i s c o v e r i n g which p a r t i c u l a r p e r c e i v e d c o l o u r s t h e y do have--by i s o l a t i n g t h e common cause, by t r y i n g t o i s o l a t e t h e f u n c t i o n s o f t h e rods and t h e c o n e s , and by t r y i n g t o i s o l a t e , i n p e o p l e who have b o t h , t h e f u n c t i o n o f the r o d s . (There i s a l s o n o t t o be f o r g o t t e n t h e p o s s i b i l i t y o f making use o f t h e n o t i o n o f t h e p h y s i - c a l e n d - s t a t e - - t h e b r a i n s t a t e o f a monochromat when he views v a r i o u s p a r t s o f h i s e nvironment. T h i s may w e l l be a n o t h e r l e v e l o f c o m p l e x i t y a l t o g e t h e r from t h e programme j u s t o u t l i n e d , but i f i t i s c o n c e i v a b l e t o d e t e c t t h e r e l e v a n t b r a i n s t a t e s and b r i n g them about i n o t h e r humans, t h e n f o r my i n q u i r y t h i s s o l u t i o n i s as l e g i t i m a t e as t h e o t h e r . ) Given t h a t t h e v a s t m a j o r i t y o f v i e w e r s now do n o t have o n l y r o d v i s i o n , and g i v e n t h a t h a v i n g o n l y r o d v i s i o n r e s u l t s i n c o l o u r - v i s i o n " r a d i c a l l y d i f f e r e n t " from t h a t o f v i e w e r s w i t h cones as w e l l , t h e n t h e p h y s i c a l s t a t e o f h a v i n g o n l y rods ( o r , o n l y r o d s f u n c t i o n - i n g ) i s a l i k e l y c a n d i d a t e f o r the l a b e l " non-standard s t a t e " as I am u s i n g t h i s p h r a s e . I.e., i t will be a n o n - s t a n d a r d s t a t e i f t h e r e a r e v e r y few monochromats among t h e group o f a l l v i e w e r s . And i f t h i s i s t r u e , t h e n viewers i n such a s t a t e a r e n o t p a r t o f t h e group o f v i e w e r s whose p e r c e i v e d c o l o u r s c o n s t i t u t e the b a s i s o f t h e c o n c e p t o f "a p h y s i c a l o b j e c t ' s b e i n g r e d " ("red" b e i n g our sample c o l o u r - t e r m ) . I t h i n k t h e above example s e r v e s t o show t h a t even i f t h e same s e t o f p r o p e r t i e s ( o f p h y s i c a l o b j e c t s ) d e t e r m i n e t h e p e r c e i v e d c o l o u r s i n t h e mono- chromats and i n t h e m a j o r i t y o f v i e w e r s , t h e r e can s t i l l be grounds f o r c l a i m - i n g t h a t the f u n c t i o n i n g o f t h e s e n s o r y a p p a r a t u s o f s i g h t o f t h e monochromats i s r a d i c a l l y d i f f e r e n t from t h a t o f t h e m a j o r i t y . I do n o t a c t u a l l y c l a i m t h a t t h e s e t o f p r o p e r t i e s i s the same f o r both groups o f v i e w e r s s i n c e I do n o t have enough e m p i r i c a l knowledge t o be s u r e . W i t h out g o i n g i n t o d e t a i l , i t w i l l be c l e a r t h a t the same p o i n t s can be made about v i e w e r s h a v i n g o n l y I b i d . , p. 124. 144 two k i n d s o f cones (some 2-3% o f w h i t e m a l e s ) . T h i s has been d i s c o v e r e d t o be a cause o f a r a d i c a l d i f f e r e n c e between the c o l o u r - v i s i o n o f t h e s e v i e w e r s and t h a t o f people who have t h r e e k i n d s o f cones. ( P e o p l e w i t h o n l y two k i n d s o f cones a r e t h o s e u s u a l l y r e f e r r e d t o as b e i n g " c o l o u r - b l i n d " . P s y c h o l o g i s t s sometimes p r e f e r t o c a l l them " d i c h r o m a t s " t o remove the a m b i g u i t y between t h i s group o f people and t h e monochromats.) The p h y s i c a l s t a t e o f h a v i n g o n l y two k i n d s o f cones i s a l s o l i k e l y t o c o u n t as a n o n - s t a n d a r d s t a t e . Here a g a i n the v i e w e r s a r e l i k e l y not t o be p a r t o f the group o f v i e w e r s whose c o l o u r - v i s i o n c o n s t i t u t e s t h e b a s i s f o r the c o n c e p t o f "the c o l o u r o f a p h y s i - c a l o b j e c t " . What o t h e r s t a t e s would count as n o n - s t a n d a r d I can o n l y i n d i c a t e gene- r a l l y . Some i l l n e s s e s and i n j u r i e s can b r i n g w i t h them a change i n p h y s i c a l s t a t e t h a t r a d i c a l l y changes a person's c o l o u r - v i s i o n so t h a t i t i s v e r y un- l i k e t h a t o f o t h e r v i e w e r s , e.g., a p p a r e n t l y j a u n d i c e can do t h i s . So i f a v e r y s m a l l p r o p o r t i o n o f a l l v i e w e r s have j a u n d i c e , i t ' w i l l count as a non- s t a n d a r d s t a t e . I t would be d e s i r a b l e t o g i v e o t h e r s p e c i f i c examples o f con- c e i v a b l e n o n - s t a n d a r d s t a t e s human b e i n g s c o u l d be i n , c o n c e i v a b l e non-standard s t a t e s b e i n g a l l t h a t I am c o n c e r n e d w i t h . However, as I have s a i d b e f o r e , t o g i v e such s p e c i f i c examples one would need a g r e a t deal o f e m p i r i c a l knowl- edge about t h e s e n s o r y a p p a r a t u s o f s i g h t , how i t f u n c t i o n s , what causes changes i n i t s f u n c t i o n i n g , e t c . . Without t h a t knowledge one cannot be reason- a b l y sure t h a t the examples g i v e n do not depend upon r e j e c t i n g some g i v e n f a c t , and i f an example d i d depend upon t h i s , i t would not be c o n c e i v a b l e (as I use t h a t t e r m ) . However, I do not t h i n k the small number o f sample c a s e s o f non- s t a n d a r d s t a t e s p r e v e n t s o u r u n d e r s t a n d i n g the r o l e o f "a s t a n d a r d - s t a t e v i e w e r " i n r e l a t i o n t o c o l o u r - c o n c e p t s ( a p p l i e d to p h y s i c a l o b j e c t s )