On Aristotle’s Theory of Substance

That which ‘is’ in the primary sense is substance. – Aristotle, Metaphysics Zeta

No philosopher in history worked harder on the theory of substance than Aristotle. As a matter of fact, not only did the debate over substance begin with his works on the subject, but it is arguably the case that his account is the de facto starting point of any attempt to work out a theory of substance. Accordingly, we will start our discussion of the nature of substance with his view as well. What is Aristotle’s theory of substance? It cannot be stressed enough that this is a difficult question to answer. Not only does he seem to say a number of different things in the various texts in which he takes up the topic, but even worse, what he does say is unclear and seems to involve serious inconsistencies. Consider what he says at the beginning of Metaphysics Zeta: There are several senses in which a thing may be said to ‘be’, as we pointed out previously in our book on the various senses of words; for in one sense the ‘being’ meant is ‘what a thing is’ or a ‘this’, and in another sense it means a quality or quantity or one of the other things that are predicated as these are. While ‘being’ has all these senses, obviously that which ‘is’ primarily is the ‘what’, which indicates the substance of the thing (1028a10-14).1 This passage should make it clear that understanding Aristotle’s view on the nature of substance is a challenge to say the least. Even so, it seems that we can say this. Simply stated, Aristotle’s clearest conception of the nature of substance is that x is a substance iff x is a this-such (1033b20-25). This is just the starting point. For it should be obvious that this analysis immediately raises the question what is it for some x to be a this-such? We need to ask, in other words, what we are to understand the substance-qua-a-this-such notion to tell us exactly. What follows is far from an exhaustive treatment of his substance-qua-a-this-such concept. Instead, to help us make sense of this theory of substance, it will be helpful to note what he believes are (at least some of) the necessary conditions for some x—e.g., a hedgehog—to be a substance. As the block-quoted passage above should make clear, Aristotle thinks that the question ‘what is a substance?’ is synonymous with what he calls “the primary question,” namely, the question ‘what is being?’ (1028b2-4). As such, he begins his investigation in the first book of his corpus, his Categories, trying to answer this question. In so doing, he delimits the fundamental categories of all things in existence (or possible existence) (1b10ff.). According to Aristotle, there are ten basic or primitive kinds of (abstract and concrete) entities that constitute reality. The first of these is the existent in question, namely, substance (Gk. ousia). He takes it that

1 Two things. First, the reference ‘1028a10-14’ tells us that the passage comes from Metaphysics Book Zeta (i.e., Book VII), Chapter 1, lines 10-14. Second, compare this translation by Ross with another translation of the very same passage: “That which is is spoken of in many ways, as we have previously expounded in our discussion of the ways in which things are spoken of. For, on the one hand, it means what something is and an item with thisness, and, on the other, a quality or quantity or each of the other items that are predicated in this way. Now, given that that which is is spoken of in as many ways as this, it is patently the case that the primary thing-that-is is what something is, which picks out the substance” (Aristotle, Metaphysics, trans. H. Lawson-Tancred [NY: Penguin Books, 1998], Book Zeta, Chapter 1 [p.167]). substance is the first category given that substance is “neither said of a subject nor in another subject” (2a14, italics mine). This, however, is not true of any other category, e.g., property, quantity, relation, etc. Rather, a substance is the particular or individuated thing of which properties, quantities, relations, etc., are predicated and of which all of the other nine categories are ultimately existentially dependent. He calls the this highlighted by these characteristics ‘primary substance.’ While these considerations point to the ‘this’ portion of his substance-qua- a-this-such analysis, he also understands being to exist in another sense: that is, the “such.” He dubs this ‘secondary substance’. The species (and he further adds the genera of the species) indicates another important characteristic of substance, namely, certain qualifications (3b10-23). This is important given that secondary substance picks out the class to which every individual substance belongs, thereby seemingly continuing to “carve up the world at its joints.” Consequently, we learn this. A substance, on the one hand, is an individual entity; on the other, a substance is the species to which an individual belongs. What, then, are we to make of these two senses, primary and secondary substance? This is important if for no other reason than a number of Aristotle scholars have argued that they are inconsistent concepts. It may turn out that they are inconsistent. Whether that is so is a question that we will leave aside. Even so, Aristotle must have thought that they are compatible. It is important to see if we can understand how he might have understood their being compatible notions. I think that his discussion in another important book can clarify this. Let us turn to take a brief look. In Metaphysics Zeta, one of Aristotle’s most difficult to understand texts, he highlights other considerations that seem to clarify the apparent inconsistency of these basic existents. He is primarily interested in this book with four candidates that might constitute substances: substratum, essence, genus, and universals. In the final analysis, it is only the first two that he believes can actually make sense of the ‘this-such’ idea of a substance (1038b1-2).2 According to the first, a substance is a substratum (Gk. hypokeimenon). In this sense, x is a substance iff x “stands under” the properties had by the thing that x is. As such, on this conception, substances are—to use the Lockean locution—“bare particulars.”3 Aristotle says that this is the “truest sense” of substance since it underlies all the properties (1028b35-1029a1). Yet, he asks: what is the substratum? Is it matter (Gk. hule¯)? Is it a form (Gk. morphe¯)? Or might it actually be a sort of compound or complex of both matter and form? After an analysis of the issues that follow from these considerations, he notes that each of these individually (or combined) cannot be what a substratum is. Even so, he seems definitely committed to the idea that the hypokeimenon is in fact the individuator—the this—of a primary substance. This is important since he takes it as an uncontroversial fact that substances are separable and individual. (In the end, it does seem that he is committed to the view that matter (again, hule¯) is what constitutes the substratum. For he seems to think that hule¯ is the “raw” material from which primary substances are formed). After his discussion of the substance-qua-a-substratum theory, he turns consider whether a substance is to be understood as an essence. He notes that an essence quite simply, “is what it is said to be in virtue of itself’ (1029b14). According the substance-qua-an- essence theory, x is a substance if x is a thing that has a certain essence e that makes it the sort of thing it is such that without e, x would cease to be. This is an important idea since a thing’s

2 He denies universals since these are in fact predicated of objects and are common. As for genus, he does not seem explicitly to offer defeaters for it. 3 For Locke’s bare particular theory of substance, see his An Essay Concerning Human Understanding, Vol. 1, Chapters XXIII and XXIV. accidental properties—e.g., a hunk of clay having the property being orb-shaped—it seems are dependent upon the substance whereas it seems that the essence of a thing merely is what the substance is (the such) and not dependent (at least not in the same way) upon the substance (1031a15-18). Given this brief (very brief) summation of Aristotle’s discussion in the Categories and Metaphysics Zeta, it seems that he saw substance (at least those kind that we have sense experiences of everyday) to be a ‘this-such’. As I have noted, this is explainable in terms of a substratum, i.e., an individual thing, that has a certain essence, i.e., essential properties, that makes up what that thing is. As I noted above, he seems to see this all working out in terms of what is known as the hylomorphic composition theory of substance. A substance is a this-such in the sense that it is a unified, unique complex in which there is “raw” matter (substratum), form (the essence), and the compound of both. Given this, we can now restate Aristotle’s theory of substance-qua-a-this-such as follows: x is a substance iff x is a hylomorphic compound of a particular hunk of matter having a certain form. One final note. In addition to the fact that this substance-qua-hylomorphic-compound theory tells us that a substance is particular, unified entity, Aristotle draws our attention to some other characteristics that are true of substances. First, substances do not admit of degrees. That is just to say that something cannot be more or less a substance. Rather, a substance either is or is not. Second, substances can admit of what he calls “contraries,” namely, the having of opposing properties. For instance, a substance may have a property F at some time t and have its opposite property G at some time t+1, e.g., Socrates can have the property of being healthy at one point yet have the property of being ill at another point. Finally, given that substances can have contraries, substances are enduring entities. To say that a substance s is an enduring entity is to say that s is capable of surviving change, that is, s can persist over time and through change as one and the same thing. A substance is numerically identical with itself through change.†

† © 2009, Richard G. Graziano.