UBC Theses and Dissertations

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UBC Theses and Dissertations

Democritus and Epicurus : soul, thought, and theory of knowledge Darcus, Shirley Muriel Louise


This thesis seeks to present a clear account of the teachings of Democritus and Epicurus on the soul (mind), thought, and the source of knowledge through an examination of the extant remains of their works and the reports of their teachings made by other authors. Democritus believed that the soul was a substance like fire but not fire itself. He taught that the mind and the soul were identical. The soul (mind) was distributed throughout the whole body and was the seat of both thought and sensation. Thought was a "change" caused by idols entering the body and its nature was dependent upon the condition of the body itself. Democritus believed that all sensible qualities had no objective existence; they were empty "affections" (πάθη) of the senses — only the atoms and void existed in reality. Democritus postulated two forms of knowledge: "bastard" cognition which was equivalent to sensation; "genuine" cognition which could grasp the realities of the atoms and void. Although Democritus considered the evidence of the senses unreliable, he did use the senses as the starting point for gaining "genuine" knowledge. He also believed that the mind, by using sensible objects, could grasp the realities lying within the objects themselves but there is no clear evidence on how he thought this happened. Epicurus taught that the soul was composed of four very subtle elements; one like air, one like fire, one like wind and a fourth nameless element. The soul had two parts, the animus located in the breast and the anima distributed throughout the body. All four elements of the soul were present in both the animus and anima. The fourth element present in the anima caused sensation to take place in the sense-organs themselves. Epicurus believed that the mind was stirred in some way with each impression made upon the sense-organs. The mind was also struck directly by idols too fine to affect the senses. Epicurus taught that all sense-impressions were true; sensation was a criterion of truth. A second criterion of truth was the prolepsis. This was a general concept of a class of objects which was derived from sensation and stored within the mind. Epicurus believed that error arose not because the sense-impression was false, but because the mind formed an incorrect opinion of the nature of the sensible object. One had to pay attention to a "clear view" (ένάργημα) of the sensible object to determine the truth of any opinion formed by the mind. In the case of objects which could not be perceived close at hand, any opinion of their nature which was not contradicted by the senses could be accepted as true. Epicurus believed that all sense-impressions were true but the "clear" (έναργής) sensations were more valuable for determining the exact nature of the sensible object. Besides the forms of thought caused by sensation, Epicurus believed that the mind was capable of reasoning. This activity of the mind played an important role in determining the nature of imperceptible things. Epicurus taught that the mind used "signs" provided by sensible objects to form hypotheses about τά ӓϭηλα and that it checked these hypotheses with the evidence of the senses. If the hypothesis was confirmed or not contradicted by sensation, it could be accepted as true. Epicurus believed it was by this method that a knowledge of the atoms and the void could be obtained. The έπιβολή τής όιανοιας, which the later Epicureans added as a criterion of truth, appears to have been used by Epicurus to refer to the apprehension by the mind of idols too fine to affect the senses. There is also evidence that the έπιβολή of the mind signified the selection by the mind of concepts existing within it. The έπιβολή was important, not for any role in establishing the nature of τα άσηλα, but as a special form of sensation.

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