Abstract

Few notions are more central to Aquinas’s thought than those of matter and form. Although he invokes these notions in a number of different contexts, and puts them to a number of different uses, he always assumes that in their primary or basic sense they are correlative both with each other and with the notion of a “hylomorphic compound”—that is, a compound of matter (hyle) and form (morphe). Thus, matter is an entity that can have form, form is an entity that can be had by matter, and a hylomorphic compound is an entity that exists when the potentiality of some matter to have form is actualized.1 What is more, Aquinas assumes that the matter of a hylomorphic compound explains certain of its general characteristics, whereas its form explains certain of its more specific characteristics. Thus, the matter of a bronze statue explains the fact that it is bronze, whereas its form explains the fact that it is a statue. Again, the matter of a human being explains the fact that it is a material object, whereas its form explains the specific type of material object it is (namely, human). My aim in this chapter is to provide a systematic introduction to Aquinas’s primary or basic notions of matter and form. To accomplish this aim, I focus on the two main theoretical contexts in which he deploys them—namely, his theory of change and his theory of individuation. In both contexts, as we shall see, Aquinas appeals to matter and form to account for relations of sameness and difference holding between distinct individuals.