UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Perception : the justification of perceptual beliefs Acock, Malcolm


The thesis is an enquiry into what provides the basis in justification for perceptual knowledge and beliefs. Thus, it is solely concerned with what has been called 'epistemic perception' Non-epistemic perception - perception in which, or as a result of which, no beliefs are acquired - is not discussed. The question of whether there is non-epistemic perception is not addressed In the early chapters of the thesis a major philosophical problem of perception is stated and "traditional" philosophical theories of perception are discussed with particular attention to how adequately these theories deal with the problem. In addition to emphasizing that the traditional theories are not satisfactory, this review illuminates a feature common to the theories and a natural way of stating the problem. This feature - the Cartesian doctrine of perception - is the thesis that perceptual awareness is the justificatory basis for perceptual knowledge and beliefs. Having established that the Cartesian doctrine is a tenet of the traditional theories, it is argued that the doctrine is unsatisfactory and that no theory that accepts it can be adequate. The criticisms made of the doctrine can be divided into two broad classes. First, there are arguments that rest on the actual occurrence or logical possibility of some phenomenon. For example, it is argued that because perception can occur without awareness (the logical possibility of subliminal perception, the occurrence of proprioception, etc.) the Cartesian doctrine cannot be correct. Further, it is argued that some phenomena (the optical "blind spot", stabilised retinal images, etc.) necessitate that even in those cases where perception is accompanied by-awareness, the awareness is not always the basis for the justification of perceptual beliefs and knowledge". Second, it is argued that awareness cannot be a relatum of the justification relation and that the Cartesian doctrine is thus ruled out a priori. Some attempts to argue the contrary are examined and rejected. Further, it is argued that the Cartesian doctrine can be replaced by the doxastic thesis - the claim that only beliefs can justify perceptual beliefs and knowledge. Some putative problems with the doxastic thesis are disposed of in arguing that the thesis can form a satisfactory element of a philosophical theory of perception. D.M. Armstrong's theory of perception is briefly examined and it is concluded that he appears to accept the Cartesian doctrine of perception. It is argued that, despite this, a theory could be developed which is very similar to Armstrong's except in that it rejects the Cartesian doctrine in favour of the doxastic thesis. It is argued that rejecting the Cartesian doctrine of perception is an instance of a larger general advance in episte-mology - an advance that has already been accomplished in philosophical accounts of knowledge and memory.

Item Media

Item Citations and Data


For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.