Hi @dga471,
You’re a Ph.D. student in physics. I’d just like to ask you this: what facts about the world do you think Aristotelian Thomism successfully explains, that rival metaphysical theories (including rival Scholastic theories of nature) fail to explain? It really seems to me that you’re going to quite extraordinary lengths to defend a centuries-old metaphysical account which is almost certainly wrong. I have to ask you: what’s the attraction of A-T? The reason why I’m asking is that I studied it myself for several years as a young man, before concluding that it really didn’t gel with science or common sense. What’s worse, the attempts of its leading exponents to explain away difficulties with their theory struck me as lame and evasive. So I’m mystified as to why you find it appealing.
This is assuming that H and O are present “as parts”. Are they? I’m not sure all Thomists would agree. They might think of H and O as present only “in power” in H2O. And there seems to be no contradiction between something being simple and having a lot of powers: to take an extreme example, God is simple yet omnipotent.
If Thomists can’t agree about a simple case like water, then what can they agree about? In any case, the claim that H and O as present only “in power” in H2O makes no sense. The power of a thing cannot be present where the thing itself is not, because the power of a thing is inseparable from the thing itself. Hence to assert that the powers of hydrogen and oxygen remain in water even though hydrogen and oxygen themselves do not, is metaphysically impossible.
…[P]rime matter always exists in the real world as limited by its form, and hence having limited potency instead of infinite potency (as is the case with prime matter). Thus, when you die, you undergo substantial change, but there is a limited amount of things that you can transform into, because the matter of your body doesn’t have infinite potency. Thus, your corpse retains some similar properties to the current you but different in other properties. In A-T philosophy, form, not prime matter, “controls” above anything else about what changes can or cannot happen.
The fact that there’s only a limited amount of things that I can transform into does not in any way imply that any properties will persist or carry over, if one substantial form is replaced by another. All it tells us is that certain bizarre properties will not be exhibited under the new form.
And again, Thomism offers no explanation as to why certain properties of my body carry over into my corpse (e.g. mass, size, shape), while others (e.g. color, hardness, smell) are radically different.
Robert Koons seems to think (at least tentatively) that they [photons] are only accidents of whatever body emitted them, but this is by no means representative of the “orthodox” Thomist view. There is no orthodox view in Thomism regarding what photons are, because Aristotle’s science is now agreed to be outdated and not talking about photons as we conceive them today.
This is precisely the kind of woolly thinking that makes me want to scream. Photons are an important part of the world around us. We couldn’t see without them. If Thomists can’t even decide whether they’re substances or accidents, then I have to say that their metaphysical theory is impossibly vague: you can’t pin it down on anything.
Still, is there anything fundamentally objectionable with the idea that there is constant substantial change going on around us in the case of small objects like raindrops and puddles?
Nothing at all, except Occam’s razor. Why would you want to posit a substantial change to explain the separation of an aggregate (such as a body of water) into two smaller parts? You might just as well say that when two children playing with a pile of sand in the park agree to divide it in two, a substantial change has taken place. Pile of sand, pile of water: what’s the difference?
Most atoms (for example the ones that make up the table your computer is on) only exist within a larger body which has its own structure and rules.
But on your proposed account, since a table and a chair are two different kinds of macro-level objects, each with their own structure and rules, then we have no a priori reason to expect the atoms of carbon in a table to have the same mass and other physical properties as the atoms in a chair. And yet they do.
The conclusion I draw is that Aristotelian Thomism is an inadequate account of change, as it stands. Certainly it beats Heracliteanism and Parmenidean philosophy, but those are absurd extremes, and there are many other rival accounts of nature which successfully avoid both extremes. Cheers.