Abstract

There is a mystery right at the heart of Plato ’s famous doctrine of the three parts of the soul, as this doctrine is presented in the Republic, Phaedrus and Timaeus: just what is a soul ‘part’? Republic IV tells us a way to distinguish soul parts, namely by the Principle of Opposites : since ‘the same thing will not do or undergo opposites in the same respect, in relation to the same thing, at the same time’, whenever we find a thing that does or undergoes opposites in the same respect, in relation to the same thing, at the same time, we must partition it in such a way that each of the parts does or undergoes only one of the opposites in question. But this raises more questions than it answers: are these parts themselves simple? is the Principle of Opposites the only way to determine parts? what is there to being a soul-part other than being distinguished by the Principle of Opposites —is it to desire and pursue one of the characteristic pleasures identified at Republic 580d-81c, namely, the pleasures of truth for the reasoning part of the soul, of honour and victory for the spirited part, and of food-sex-drink, and as a means to these, money, for the appetitive part?