A colleague asked me yesterday what exactly the division of matter and form explained about, say, vocal chords. The basic answer is that it explains how they could both be beings and come to be. It also explains why, when we consider them qua bodies, they are not alive. But all this is to say that matter and form are answers to questions that no one is asking. In fact, we find it terribly difficult to take the Parmenidean problem seriously enough to look for a solution. This is not to say the Parmenidean problem should be dismissed, but it rings hollow to us, and so Aristotle’s solution to it seems superfluous.
A deeper problem is that composition of matter and form was only designed to explain things so far as they come to be, and so it runs into problems when we try to use it to explain things that don’t come to be. But all the main physical theories demand the existence of physical things that don’t come to be, and so matter and form can only be a partial account of physical things. This was less of a problem on the ancient/ medieval theory, since they thought the non-generated beings were the celestial bodies, and so the matter-form schema was easy enough to translate over to them. But the Newtonian idea of absolute space or the contemporary idea of EM waves as purely formal do not admit of the same simple translation. Again, an idea like inertia seems to mean that every body participates in the sort of eternal action that was once only imputed to the celestial bodies, which means we should broaden the quondam account of the celestial bodies to include all bodies. In fact, even our idea of gravitational action of gravity requires this (remember that, for Aristotle, if a body reached the center of the universe its impelling tendency would cease, but gravitational attraction does not cease when the bodies are in contact). But no one has even suggested the outlines of a coherent account of such corruptible/eternal composition.
But even of we could figure out the problem of the physical first mobiles being somehow distributed throughout things, a more pressing problem for us is the fact that the human person is neither wholly physical, nor is he exhaustively explained by natural generation. Direct creation is also a necessary principle of his existence, and creation is not any sort of motion or generation. An adequate understanding of a person will therefore require understanding him in opposition to hylemorphic composition. But we cannot do this in the most simplistic way, sc. by denying that the person is a hylemorphic composite. Persons are hylemorphic composites, but they aren’t only this. But what are we saying here? Isn’t this just a dressed up way of saying that persons are, like, totally sorta hylemorphic?