Aristotle on Metaphysics(2004) - Bibotu.com

308 CRITICISM OF PLATO’S THEORY OF FORMSAbove all, however, Plato argues that changeless essences and forms areseparate, i.e. separate in the sense of distinct from changing things:PL7. Essences are not identical with, and they are distinct from,changing things.We will return to this central claim in a moment (see §4 of this chapter).The claim that changeless essences and forms are separate and distinct fromchanging things is central to Plato’s theory of forms, especially as <strong>Aristotle</strong>understands this theory. For it is this claim that <strong>Aristotle</strong> especially fastenson in his criticism of Plato’s theory of forms.But although Plato’s separation of essences tends to attract most of<strong>Aristotle</strong>’s attention, it is important to recognize that Plato’s theory is,exactly, a theory of essence:PL8. The changeless forms have an essence. This means that theform F is F in virtue of itself, not in virtue of its relation to otherthings. And the changeless forms are the only things that have anessence.In general, the changeless forms are what they are in virtue of themselvesand not in virtue of their relation to other things. This stands directlyopposed to Plato’s claim about changing things, which says that changingthings are what they are not in virtue of themselves, but in virtue of theirrelation to changeless forms. But changeless forms do not so much haveessences, rather they are essences, i.e. essences conceived as separate anddistinct from changing things:PL9. A changeless form is identical with its essence—it is an essence.So the changeless forms are essences, and they are the only essences. It isalso worth emphasizing Plato’s basic view that:PL10. Essences are changeless.This is a view that he shares with <strong>Aristotle</strong>. For it is indeed evident thatessences are changeless, i.e. this is part of the very notion of essence. Ingeneral, the essence of a thing, x, is what we search for when we ask, ‘Whatis this thing, x?’, i.e. when we search for the definition of this thing, x. Butsuppose that x has an essence, i.e. there is something, E, that it is to be thisthing, x. Then evidently x will be E for as long as x exists. For example,