Is Plato a Coherentist? The Theory of Knowledge in Republic V–VII

Abstract

Although many scholars take a foundationalist approach to the theory of knowledge in Republic V–VII, few if any have responded to a growing number of coherentist interpretations, which hold that, for Plato, justification rests not on a first principle but rather on the coherence of a sufficiently large number of beliefs. This paper argues that the structure of knowledge in the Republic analogies is incompatible with the coherentist reading. Plato’s analogies provide ample evidence that he holds something, at the very least, approximating a foundationalist first principle. In addition, this paper puts forward a Platonic solution to the regress problem. It argues that the form of the good is plausibly self-justifying. Because the form of the good serves as the “measure” by which the philosopher is able to determine the goodness, fittingness, and truth of all that he encounters (517b), it seems reasonable to conclude that the philosopher’s ultimate source of justification – what it is that puts an end to the search for explanations and serves as an explanation of his claim to know the form of the good – is nothing other than the form of the good itself.