Defining ‘Substance’ Using Grounding

If my account in my previous post of fundamentality is right, the distinction between what is fundamental and what is derived is not going to enable us to distinguish substances from proper parts and accidents. However, we still might try to use grounding to explicate the difference. Perhaps we could say that in some sense the existence of the proper parts or accidents is grounded by the existence and essential nature of the whole substance. What I have in mind is to exclude the contingent and accidental characteristics of the substance from the grounds, leaving only the existence and essential nature of the substance.

In what sense do substances (and their essences) explain the existence of the dependent things (accidents and proper parts)?

(a) The essence is a partial explanation (along with relevant causal and material factors) of the actual existence of the accident/part.

(b) The existence and essence of the substance grounds the possibility of the existence of the accident/part.

Option (a) involves a somewhat controversial claim: that the sum of the essence of a particular thing and the immediate total cause of some effect in that thing is the ground of the effect. This would have to remain true after the efficient cause has ceased to exist. And what if the cause is non-necessitating (e.g., stochastic)? This does not seem promising.

In option (b), we would have to expand on what is meant by ‘the possibility’ of the existence of an accident. We can’t just mean metaphysical possibility tout court, since that is probably ungrounded, or grounded by God or the modal structure of reality. Could it mean something like the immediate, real potentiality of the accident’s existence? Or of the accident’s persistence, assuming that it was caused some time ago?

And, do we mean that the possibility of the accident’s existence is grounded by the actual existence of the substance, or just by its essence (whether actualized or not)? I’m going to advocate for the view that accidents can outlive their substances, so I would prefer the second option. The essence of the substance continues to ground the existence/persistence of the accident, even after the substance has ceased to exist.

If we take option (b), we could define substances as fundamental things whose immediate potentiality for existence is not grounded by the essence of any other thing.

S1. A substance is a fundamental particular thing whose immediate possible existence is not even partially grounded by the essence of any other thing.

A1. An accident is a fundamental particular thing that is neither a substance nor a proper part of a substance nor composed of such.

Three potential problems

• What about God? Doesn’t God’s essence at least partially ground the possible existence of everything else? We could simply exclude God by brute force –“by another thing except God.”

• Origins essentialism

Would a substance be dependent in this way on its original generators, at the moment of its generation, or even thereafter?

• Proper parts of the substance. Is the substance dependent on the essences of its material parts? If these are essential parts, then this would not be a problematic sort of dependence.

Before I go any farther, I will need to say something about essences.

Are there individual essences in Aristotle’s theory? Should there be?

Clearly not in Aristotle. He’s explicit that individuals are not definable as such. All definitions are of universals or types.

If we accept individual real definitions, we will confront the issue of origins essentialism. If the origin of a substance is essential to it as an individual, how can we impute ontological independence to it? Won’t a child become a mere accident of its parents?

This is why I think it’s better to say that the definition of an individual is the definition of its infima species, a universal or type.

In Metaphysics Zeta 4 (1030a), Aristotle asserts that accidents (and probably proper parts of substances) don’t have essences or definitions in the strictest sense. However, they do have quasi-essences or quasi-definitions. I’ll ignore this subtlety for the moment.

Now back to the problem of origins essentialism.

We could avoid this by insisting that something is a substance if it is not essentially such as to have its potential existence wholly grounded by the essence of something else (except perhaps God).

S1.1. A substance is a fundamental particular thing whose essence does not entail that the immediate possible existence of members of the kind is partially grounded by the essence of any other thing.

What about a substance’s matter and substantial form? We could again deny that the relationship is one of grounding. Or, perhaps neither matter nor form have an essence.

S2. A substance is a fundamental particular thing with an essence, whose essence does not entail that the immediate possible existence of members of the kind is partially grounded by the essence of any other thing (except God and its essential parts).

I think this definition is not wrong, but it isn’t completely satisfying, either, because it’s unclear what immediate possible existence means in this context. We can shed some light on this by turning next to ontological dependence. Parts and accidents depend for their immediate possible existence on the whole substance because their essences include the substance. In my next post, I will consider how to use Fine’s notion of ontological dependence to define ‘substance’.