Over lunch on Sunday, Brian B asked me to explain my disagreement with Ed Feser and others over Aquinas’ hylomorphism. Here is a pithier statement than the ones I’ve already posted.
I will assume with Aquinas that human beings after death continue to exist as disembodied souls until the general resurrection. The question I and others have posed is how the persistence of individual souls after death is conceivable on the Aristotelian hylomorphic principles to which Thomas subscribes. Why should this be a problem? The problem is that the following propositions, each of which is a doctrinal commitment of Thomas, are collectively logically inconsistent: they cannot all be true.
a) Designated matter in material substances both individuates their forms and accounts for the substances’ numerical difference. Thus Peter and Paul are two and not one because of the difference in their designated matter. And their forms are individuated by designated matter as well. This implies that (i) Peter’s substantial form is numerically different from Paul’s, and that (ii) neither form is an individual form without the matter that individuates it.
b) The souls of living things are substantial forms of their bodies: anima forma corporis. Peter and Paul are living things; hence their souls are individual substantial forms of their bodies. To put it more precisely, Peter and Paul are form-matter composites. The psychic or soulic component in each is the individual substantial form, and the material component in each is the parcel of designated matter. Each component needs the other to be what it is: the psychic-formal component needs the material component for its individuation, and the material component needs the psychic component for its animation. And neither component can exist without the other: each exists only together with the other. Thus the whole of which they are proper parts is not a whole compounded of parts that can exist on their own, as substances in their own right, but a whole the parts of which are mere ‘principles’ in scholastic jargon and thus not substances in their own right. This implies that the hylomorphic whole, which is a substance in its own right, is ontologically prior to the morphic and hyletic parts which are not substances in their own right. Bear in mind that a primary substance, by definition, is a basic entity that is metaphysically capable of independent existence.
c) The souls of humans, unlike those of non-human animals, are subsistent: they are metaphysically capable of independent existence. So the souls of Peter and Paul will continue to exist after their bodily death in a disembodied intermediate state prior to their re-embodiment in the general resurrection.
The triad is inconsistent because (a) and (b) taken together entail the negation of (c). Indeed any two of the propositions, taken together, entails the negation of the remaining one.
In a nutshell: it cannot be the case that souls depend on material bodies for their existence and individuation but continue to exist as individual souls after bodily death in a bodiless state.
What Thomists want to say is that SOMEHOW a substantial form that achieves individuation ‘here below’ pre-mortem by marriage with a hunk of matter, thereby animating said hunk of matter, continues to exist as a disembodied individual soul ‘up yonder’ post-mortem AFTER the individuating factor has been removed. That makes no sense. What would make sense is that the individual soul cease to exist after the death of the body. Bear in mind that the soul on an Aristotelian hylomorphic mereological analysis is a mere ‘principle’ of the hylomorphic composite entity and not itself a substance.
The conclusion to be drawn from this is that despite the Angelic Doctor’s noble attempt to stay as close as possible to The Philosopher (philosophus), he is in the end a substance dualist of sorts, though not quite along Platonic, Augustinian, or Cartesian lines.
There was a time when I thought that, with respect to the soul, Thomas was an Aristotelian ‘on earth,’ but a Platonist ‘in heaven.’ (I may have picked up that line from Anthony Kenny.) But then the problem of the SOMEHOW, the problem of how a human soul can go from a mere non-subsistent ‘principle’ to a subsistent upon the removal of the soul’s individuating factor, becomes insoluble. I now think that it would be better to say that, with respect to the soul, the doctor angelicus was a Platonist in both the sublunary and superlunary spheres, both ‘on earth’ and ‘in heaven,’ and this in consequence of his Christian theological commitments which exercise ‘veto power’ over his philosophical assertions.