PLATONIC IDEAS

While Parmenides presented his philosophy in poetic metre, Plato's prefered medium is the display of dialectic in dramatic form. This presents certain problems when we set out to identify what does and does not count as Plato's own philosophy: positions are given as characters, or characters as positions, and their implications are worked out in live discussion, with all its digressions, illustrations and false starts. A degree of caution must therefore be exercised when we attribute a theory to Plato, in the sense “Plato held that …” That said, the problems addressed in his dialogues form the corpus of Platonic philosophy, both in his work and, as we shall see, in Neoplatonism. When, therefore, in what follows we attribute a position or a thesis, we are attributing it to “Platonism” although we shall take care to note what justification there might be for attributing these positions to Plato. The resulting problems will therefore form the basis of this outline of key elements of Platonism for the idealist tradition.

The first such problem concerns Parmenides' conclusions regarding what is not, or not-being. Plato engages it in the Sophist, which argues that not-being takes two forms: first, there is to me on, absolute not-being or “what is not”. The Eleatic Stranger, who takes Socrates' usual role as the primary interlocutor in the dialogue, presents Theaetetus with Parmenides' argument that “he who undertakes to say ‘not-being’ [me on] says nothing at all” (Soph. 237e), but adds an important qualification: things can be said of “what is not” despite the fact that it is “no thing”.