Aristotle on The Relation between Matter and Body: A Continuing Philosophical Problem

Helen Lang

Villanova University

In the Metaphysics, Aristotle argues that substance can be identified in three ways: (1) form, i.e., what is actual, separable, and prior; (2) matter, i.e., what is potential and provides the possibility for change and individuation; and (3) the combination of form and matter, i.e., natural things, the most commonly recognized substances. In the Physics, he first defines nature as a source of being moved and being at rest and then defines natural things as primarily form, although a reference to matter must be included in the definition. He lists and examines further topics universally required by nature: motion, the continuous, the infinite, place, void and time. There is a striking omission from this list of topics universally involved in natural things: body. Although body appears often, for example in the definitions of place and the infinite, it is not examined in the Physics. Given the specific inclusion of matter within the science of physics and the association, especially in later philosophy, of body with matter, this omission seems surprising. At first glance, it is addressed by the de Caelo, which opens [I, 1]: “Clearly the science of nature concerns itself for the most part with both bodies and magnitude, their properties and movements, . . .”. Indeed the four books of the de Caelo provide an extensive analysis of body, beginning with its definition as perfect magnitude. But magnitude is not substance and so cannot be either form, or matter or their combination; rather, magnitude -- and so body as perfect magnitude -- is a kind of quantity and quantity is a predicate, or accident, of substance. Consequently, body cannot be directly identified with substance, not even substance in the sense of matter. The relation among these terms, form, matter, natural things, and body, is not immediately clear in Aristotle’s physics and requires some consideration. In the Prior Analytics, Aristotle distinguishes universals, which signify a thing’s essence, from “properties”, which are predicates of individuals. A property, unlike other kinds of predicates, is a predicate that belongs to every individual of a given kind and to no individual not of that kind. In Aristotle’s example, “grammatical” is a property of humans. Furthermore, properties can be “counterpredicated”, i.e., moved from the predicate position to become a subject and thereby found a further investigation. I shall argue that body is a property of natural things as substance; therefore, it can be “counterpredicated” and found an investigation, such as that found in the de Caelo. In this paper, I shall consider natural things as substance, i.e., as a combination of form and matter, and body as a property; I shall argue that matter plays a special role in making the “counterpredication” of body possible. Consequently, a complex relation obtains between body and the combination of form and matter, especially matter. Indeed, here we shall find a special role for prime matter. This relation, I shall suggest in conclusion, becomes central first to Stoic philosophy and then to late Scholasticism.