To Thomists: Is potentiality an incoherent concept?

Our resident philosopher hammiesink has been doing a series on the foundational metaphysics underlying Thomas Aquinas' arguments for a god (I say "a god" instead of "God" because Aquinas' arguments inevitably attempt to connect the dots between the so-called "first mover" and the deity of a specific religion).

One of the concepts Thomist philosophy relies on is potentiality: The potential for X to become Y. For example, water is potentially ice. For a potential to become "actual," something has to actualize it. Water needs to be put in the freezer, and then its potential to become ice is actualized. Aristotle used the concept as a sort of intermediate between being and not-being.

In hammie's second explanatory post about Thomism, joeflux asked this in the context of a discussion about how water can be split into oxygen and hydrogen, and then set aflame:

So, does water have the potential to become fire or not? Do you say that it does not, because it has to become oxygen + hydrogen first? Or do you say yes, because potentiality is transitive? (If A has the potential to become B, and B has the potential to become C, then A has the potential to become C ? )

In one tiny little question, joeflux appears to have killed potentiality -- and therefore Thomism -- dead.

Here's the problem: If the concept of potentiality is coherent, it must either be transitive or not transitive. But both have devastating repercussions for its coherence.

The problem with non-transitive potentiality

If potentiality is not transitive, then water is not potentially flammable until it is split into hydrogen and oxygen. But how does water become hydrogen and oxygen? Through electrolysis. So then water isn't potentially hydrogen and oxygen until it is electrified. But how does water become electrified? Well, first it has to be placed between positive and negative electrodes. So then water isn't potentially electrified until it is water between electrodes.

And so on, and so on, and so on. It is infinitely divisible. You never get to hydrogen and oxygen. It's akin to Zeno's paradox.

This appears to be a successful reductio ad absurdum. Non-transitive potentiality doesn't work, and must be discarded.

The problem with transitive potentiality

The solution, at first blush, is to make potentiality transitive. Water is potentially flammable, so long as it passes through the intermediate stages necessary for it to become a flammable substance. Zeno's paradox avoided! Yay! And it's not like transitive potentiality could go very far... could it?

Uh-oh. The human body is around 70% water. A lot of what you drink becomes part of you, and sticks around for a little while. So I guess water is potentially part of the cells in your liver. Or any other body part. Of any animal. In the whole world. Oh, and look at that... Most of the Earth's outer crust is made of silicates of oxygen, so water is potentially... part of rocks? All it needs is to pass through some intermediate potentialities along the way.

But it gets worse. Much worse.

The advent of modern particle accelerators -- something poor Aristotle couldn't possibly have predicted, or even understood -- tells us that particles are potentially other particles. All they need is the right particle accelerator, in the right configuration, and suddenly you're turning one element into another and filling out the old empty slots on the periodic table.

Particles accelerators are modern alchemy that actually works. Prohibitively expensive and resource-intensive alchemy, but it is now theoretically possible to turn any arbitrary particle of an element into another element. What does that tell us about potentiality?

Well, it tells us that if we accept transitive potentiality, we must accept everything being potentially everything else, just given the right series of circumstances.

What we have here is another successful reductio ad absurdum.

Can potentiality be salvaged?

There are whole libraries devoted to expounding on potentiality. How presumptuous of me to just pop onto an internet forum and declare it incoherent! Surely someone, somewhere has looked at the repercussions of both views of potentiality, and found a third way. A way that sidesteps Zeno, and skips around shape-shifting elements.

But if such cleverness exists, I haven't found it. So much of the philosophy built on Aristotle is very old, predating particle acceleration and much of the modern understanding of energy.

So I ask you, Thomists of r/DebateReligion, is this the end of potentiality, and thus a nail in the coffin of Thomism itself? Or is there some way of rescuing it?