SOURCE: "Substance and Form in Aristotle," in Journal of Philosophy, Vol. LIV, No. 22, October 24, 1957, pp. 688-99.

In the following essay, Sellars reviews the nature of substance, form, and matter as discussed by Aristotle, noting ways in which Categories, particularly statements regarding the theory of predication, can help one understand the concepts expressed in Metaphysics.

I

In Categories 2 b 4 ff., Aristotle writes, "Everything except primary substance is either predicated of primary substances or is present in them, and if these last did not exist, it would be impossible for anything else to exist."¹ By "everything except primary substances" he presumably means, in this context, everything which is either a secondary substance, or belongs in one of the other categories. And he is telling us that while items other than primary substances may legitimately be said to exist, their existence is essentially bound up with the fact that they are...