So we say: There are many ways to reply to this argument. Yet the one who cites it has already placed two premises before bringing the proof itself. We shall begin by examining those two premises, so that our reply corresponds precisely to the argument—out of fairness and commitment to the truth. We shall therefore deal with the first premise first, starting where he started, even though additional criticisms may be raised concerning the form of the argument rather than its matter; these we shall postpone.

We say, then: His statement that “things which differ in their individual realities yet agree in some constitutive factor must be such that either the point of agreement follows necessarily from the point of difference, or the reverse, or it is incidental to it, or the reverse” can be addressed as follows. Existing things—whether alike or unlike—may share a common feature, as do individual members of a species or different species within a genus: two human beings, a human being and a horse, two grains of wheat, two silver coins, and the like. In each case it is said that there is something in which they concur and something in which they diverge. Thus one may say: the two men share humanity, while each is distinguished from the other by his own individuation and particular identity; or one may claim: two Necessary Existents share sheer existence, while each is set apart from the other by its own individuation, and so on.

The point, however, is that their agreement in a common element—humanity, for example—does not mean that there is outside the mind a single, self-subsisting entity that both literally share; no rational person would hold such a view. They themselves know this to be false, and that the five universals—genus, species, differentia, proprium, and generic accident—do not exist extra-mentally as absolute universals conditioned solely by universality. There is no external, free-floating universal ‘animal’ that is so conditioned