Abstract

Some subordinate issues dealt with are: Plato's notion of cognitive faculties, the nature of the Forms, the nature of the phenomenal world and the 'theory of flux' associated with it, the concept of "The Good", and the consistency and significance of the Sun, Cave and Divided Line similes. The final chapter contains observations concerning Plato's psychological-foundational approach to epistemology, and its crucial differences from an analytical approach focussing on propositional knowledge and belief. Since this thesis indicates the importance of empirical knowledge, it supports the view that the Forms have a much more limited epistemological role than some interpretations claim. This is argued in the main text; the significance of the beginning of Parmenides, and of passages pertaining to the population of the noetic realm of Forms is discussed in appendices. ;In fact, a systematic doctrine of cognition is presented in the Republic, and is exposited in this dissertation. The principle of gnosis as direct cognitive apprehension provides the foundation for the whole structure. There are close parallels between the intellectual and empirical applications of human thought, and a common psychological basis and epistemological principle . Plato's theory of learning and developing intellectual understanding is shown to require this. ;What is gnosis and its relation to episteme? The thesis developed in this study is that gnosis is direct cognitive apprehension, or knowledge by acquaintance, and is for Plato the fundamental principle of all knowing, whether epistemic or not. Plato's epistemology is foundational, based on a knowable particular which possesses qualities, or 'is' such-and-such. In knowledge, the intellect apprehends the object and understands what it is. This knowledge by acquaintance is for Plato the basic sine qua non of knowing, not reducible to anything more fundamental. Moreover, the principle is the same in epistemic knowledge of the Forms and in perceptual apprehension of physical objects. ;The nature of the Forms as knowable particulars is revealed in Republic Book V's proof of their existence. The proof is based on the nature of being, and being is treated predicatively. The proof requires that both sensible particulars and Forms are knowable, though only the Forms are an adequate basis for knowledge and understanding of certain qualities in themselves. Here Plato reveals episteme and doxa as precisely defined technical terms. The purity of the epistemic gnosis is guaranteed by the way in which the objects of episteme are what they are. But there is a gnostic element in doxa as well; hence the concept of doxa is not identical to that of 'belief.' Doxa, however, is not simply gnosis of its proper objects, as episteme is. But Plato's epistemology indicates in detail the scope of gnosis in doxa. ;In an initial survey of Plato's use of crucial epistemic terms it is shown that Plato is consistently restrictive in applying the term episteme. This fact supports the traditional view of Plato as a rigorous rationalist. It is also shown that Plato applies the term gnosis or its cognates in cases which cannot be episteme, such as practical science and perceptual awareness. These are often thought to be relegated to mere opinion in Plato's epistemology, at least in its middle period. This interpretation is rejected. Gnosis is knowledge, though conceptually distinct from episteme. ;Plato's understanding of the foundations of knowledge and belief is the subject of this study. Its exposition concentrates on the central books of the Republic because this is the source of the greatest detail and clarity. However, continuity of Plato's views on this matter is assumed and, to some extent, argued for; earlier and later works are examined in cases where they provide better illumination