Matter

Lots of people know of Aristotle's and Aquinas's theories that matter is the substratum of change, that it is 'pure potentiality', that it cannot exist without form, and so forth. Henry of Ghent, Scotus, and Ockham have a very different view of matter.

Roughly speaking, matter is the basic stuff that all material substances are ultimately composed of. For instance, although animals are composed of organic tissue, tissue is composed of cells, and so forth, at rock bottom there’s a fundamental kind of stuff that all material substances are ultimately made from. This basic stuff is called ‘matter’, and the earth is filled with it.

Matter is not, as we might imagine today, just another name for atoms or quarks or whatever other sort of particle we think is the fundamental building block of material bodies. Matter cannot be broken down into fundamental ‘particles’ or indivisible parts. It’s more like an amorphous kind of stuff that can always be divided into smaller and smaller parts, similar to the way that a line can always be divided into shorter segments.

But matter is ‘amorphous’ in the sense that it does not have any form itself — it is not, that is, itself a composite of matter and form. Rather, matter is a purely receptive sort of material that can be made into different kinds of material substances.

This is not to say that matter is a ‘bare substrate’, as it were, that has no features of its own. On the contrary, matter is real stuff; it has parts (as I’ve already indicated), and it exists in space. Ockham even thinks matter is extended in three dimensions. (Scotus denies that matter is extended, but he still thinks it exists in particular places, perhaps similar to the way that electrons have no dimensions but still exist here or there.)

Further matter has specific features. It is the foundation for relations, and it has the capacity to take on substantial forms. More precisely, there is a discrete power that exists in matter to receive each different kind of substantial form. So there is a power p1 to receive the form of fire, a power p2 to receive the form of water, and so forth for every substantial form that matter can receive. (Matter has no powers to receive accidental forms.)

Nor is matter just ‘pure potentiality’ — i.e., a mere abstraction of the potential in material substances to be transformed into different substances. Henry, Scotus, and Ockham all believe that God could create a lump of matter without any forms, so matter is at least the sort of thing that in principle can exist all by itself.

Aquinas denies all this, I think. He explicitly says that matter cannot exist without form, and even God cannot create matter all by itself, without a form. Matter does not have any features of its own except that it is a 'pure potentiality'. (I don't know if Aquinas thinks matter has parts or exists in places. I wouldn't think so, but I don't know.)

Still, it’s difficult to imagine what a lump of matter is like, even on the views of Henry, Scotus, and Ockham. As I’ve already hinted, the best we can do is imagine an amorphous blob. But even that’s not quite right, and there’s a reason for this. Medieval Aristotelians believe that we can only know things through their forms, so we cannot imagine something that doesn’t have some particular form.

But just because we can’t imagine it does not mean that it’s not there. As our authors see it, matter must exist because we see material substances coming to be and passing away all the time, and given the hypothesis that change requires a recipient, there must be something there that gains and loses the forms that constitute those material substances.

(Besides, say Henry, Scotus, and Ockham, God isn't limited to knowledge by forms, and he has a proper 'idea' of matter -- and that means that matter has a nature; i.e., it has essential properties that define just like every other kind of entity.)