Aristotle on Unity and Being

Abstract

In this paper I will discuss what Aristotle has to say on the relation between τὸ ἕν and τὸ ὄν. Stated briefly the relation is that τὸ ἕν and τὸ ὄν are (a) transcendental predicates: each applies in all the categories; (b) convertible predicates: each implies the other and adds nothing to the other. For Met. 1003b23–4 claims that being and unity are one and the same thing in that they are implied in each other, τὸ ὂν καὶ τὸ ἕν ταὐτὸν καὶ μία φύσις τῶι ἀκολουθεîν ἀλλήλοις. This is clearly meant to apply in every category, since the convertibility claim is functioning as a premiss in an argument whose conclusion is that there are exactly as many types of being as of unity. At Met. 1061a17–18 there is an equally explicit statement of convertibility, καὶ γὰρ εἰ μὴ ταὐτὸν ἄλλο δ' ἐστίν, ἀντιστρέφει γε· τό τε γὰρ ἓν καὶ ὄν πως, τό τε ὄν ἔν. I will try to say more precisely what these claims mean, and come to some view on their philosophical plausibility.There are a number of reasons for discussing these topics. First, it is a prolegomenon to a comprehensive discussion of all those predicates which came to be thought of as convertible and transcendental.