Aristotelian Substance Ontology
The Aristotelian view is clearly the best candidate for a reconciliation of substance and process, once we dispel the myth that the modern analytic view, even in its ‘thick’ version, is Aristotelian. Aristotelian scholars will tell you that the closest one can come to a concept of something that sustains properties in Aristotle is that which the Scholastics called prima materia, which is something that can only potentially exist without properties (Johansson 1989/2004: 27; Byrne 2018: 120-31: Sentesy 2020: 300). The idea that substance can be identified with prima materia ignores the fact that prima materia is a substance only in virtue of some unifying principle that gives it a certain function; only a unity of form and matter is properly speaking a being (ousia).
Now, this is not the time to go into the intricacies of Aristotelian hylomorphism, i.e. the details of how Aristotle portrayed the inner structure and workings of a substance. That is a subject that requires its own book-length study (or an entire series of books). Let it suffice to say that several modern authors claim to revive hylomorphism, for instance, Johnston (2006), Koslicki (2008), and Lowe (2011), while Aristotle-scholars like Marmodoro (2013) are questioning the Aristotelian lineage of their ideas. Perhaps the only thing that these authors have in common with each other and with Aristotle is the rough idea that substances have a unifying structure. However, as Johnston observes, the challenge has been to provide an account of what kind of structure gives the kind of unity that is characteristic of the things we identify as substances:
What it is for this hydrochloric acid molecule to be is for this positive hydrogen ion and this negative chlorine ion to be bonded together. [...] The idea that each complex item will have some such canonical statement true of it might be fairly called ‘Hylomorphism’. For it is the idea that each complex item admits of a real definition, or statement of its essence, in terms of its matter, understood as parts or components, and its form, understood as a principle of unity.
(Johnston 2006: 658)
What I have argued is that, in the scientific image, all bonds between every component part of any compound are characterised as interactions, wherefore it seems natural to suggest that interaction is the principle of unity we have been looking for. I have explained how we can think of interactions as a causal phenomenon and pointed out that the unities that are thus causally constituted persist in a thoroughly dynamic fashion. Now, obviously my suggestion does not converge with Aristotle’s ideas, because I am abstracting from scientific theories he did not have access to, but the dynamic aspect is at least compatible with what both Kosman (2013) and Sentesy (2020) argue, notably that Aristotle is moving towards an account of being as activity in Metaphysics.
I think we can see the dynamic aspects of Aristotelian substances without going into the details of his hylomorphism merely by looking at the way the Aristotelian tradition has typically characterised substances (as opposed to explained). The following seven claims represents a more or less complete list of these characteristics (for reference, see Loux 1998:107; Hoffman & Rosenkrantz 1997: 2-3):
- 1. Substances have attributes without themselves being attributes.
- 2. Substances are contingent beings.
- 3. Substances are spatio-temporal beings.
- 4. Substances are capable of change.
- 5. Substances are persistent beings.
- 6. Substances are independent beings.
- 7. Substances can affect each other.
These claims require some clarification. The first can be interpreted as saying that substances sustain properties but are separate from them, but only if one ignores everything said about the inner structure that provides the unity of form and matter. It could perhaps be formulated more precisely as: substances have attributes but cannot be reduced to mere attribute.
The second claim relates to the idea that things come into and go out of being, indicating that their existence is by no means a necessary affair. This may appear to contradict the sixth claim, that they are independent entities, i.e. the claim that every substance exists independently of any other substance, because if something comes into being it must be brought into being by something else that preceded it. However, it is relevant to distinguish between what could be called synchronic and diachronic dependence. Any particular substance is contingent in the sense that it comes into and goes out of being, and as such it is diachronic-ally dependent on (i) a previously existing ‘material cause’, i.e. a portion of matter capable of alteration, and (ii) an ‘efficient cause’ which provokes a change in that portion of matter, thus bringing a new unity of form and matter into being. However, once in existence, substances have an intrinsic nature independently of the nature of other synchronic-ally existing substances (which, according to the A view of time, are the only substances that exist). A person can continue to exist and be the person she is even if her entire family is destroyed (especially if she is unaware of this fact). A statue can survive the levelling of the city it has adorned. However, substances are not so autonomous as to the existence of other substances as to be unaffected by them when they interact. The contingency of substances is reflected not just in their coming into being but also in their destruction. Any substance can be destroyed by the influence of other substances. The independence of substances is thus clearly conditioned by causality; no substance comes into being without a cause, and no substance is immune to the causal powers of other substances that can change and/or destroy them. This conditionality of independence by causality is what constitutes the contingency of being. Independence is further related to persistence, because persistence is on the one hand a consequence of existential independence, but on the other is similarly conditioned by causality. The persistence of an object begins when it is created by a cause and ends by its destruction by a cause. Change is then related to most other claims. Change is an alteration in the properties of a persistent substance, produced by the influence of another persistent being. It is also the creation and/or destruction of a substance. The spatio-temporality of substances is a claim that is less obviously connected to other claims. It has mainly to do with the idea that time and space are boundary conditions upon all being but is also related to the idea that substances are contingent beings that can affect each other and thus share a common realm of existence. The spatio-temporality of substance is thus indirectly related to all other claims.
It is at this point we must observe that, while substances are contingent, prima materia is not. Well, it is controversial whether Aristotle really meant to attribute permanence to prima materia itself, since it is something that cannot exist on its own, or only to say that the total amount of substance can neither increase nor diminish. Particular unities of form and matter can be created and destroyed, but they can only be created by altering an already existing substance, and only be destroyed by being transformed to another kind of substance. It is in the persistence of substances when their attributes go out of existence, that makes substance more basic than attributes. It is because of the permanence of substance that change is not creation out of nothing, nor the annihilation of things.
Now, while the above characterisation of substances clearly implies that substances are dynamic in the sense that they can change, it is not as clear that they must continuously change. Mark Sentesy (2020) makes a convincing case for saying that Aristotle was at least moving towards a conception of substances as essentially activities. That is, not merely as objects possessing active powers, but as entities in which their potential is continuously being actualised. That is all well and good, but it is an account that still doesn’t bring Aristotle into harmony with the theories and findings of modern science.
Ultimately what I want to take away from this section is that the Aristotelian conception of substance is at least not obviously of something static and unchanging that merely sustains properties, but of something that can both change and survive that change. It is designed to answer the question of how things can always be different and yet be the same, thus fusing the Heraclitan and Parmenidean points of view. The modern analytic view ends up saying that they cannot be different and yet the same, which is kind of Parmenidean. And, as I will now explain, extant views on process end up saying that everything is always different and never the same, which is the Heraclitan opposite.