u/193yellow

Is substance and essence the same thing? If not, what is the difference between substance and essence?

Generally when I hear explanations of the First Way, the way they reason to the conclusion is by saying that if we take an essentially ordered series, since this type of series cannot regress infinitely, it needs to end in a being that has inherent causal power and can actualise the beings in the causal chain without it itself being actualised.

So far, so good. The issue is that then, the person making the argument claims that this being is not only the prime mover of that one chain, but is the prime mover of all beings in all chains.

Why would this be the case? Why should we assume that all these chains end with the same being, as opposed to each chain having their own being with inherent causal power?

Generally the answer I hear is that such a being would be Pure Act, and there can only be one Pure Act being, and so every chain must be actualised by the same being. The issue with this though, is that the reasoning for the being in question being a Pure Act being doesn't really follow unless you already grant that this being is the source of *all* actuality in existence. But this is the claim that needs to be proven.

Please correct me if I'm making a basic mistake or missing something.

"Again, a thing is intelligent because it is without matter. A sign of this is the fact that forms are made understood in act by abstraction from matter. And hence the intellect deals with universals and not singulars, for matter is the principle of individuation. But forms that are understood in act become one with the intellect that understands them in act. Therefore, if forms are understood in act because they are without matter, a thing must be intelligent because it is without matter. But we have shown that God is absolutely immaterial. God is, therefore, intelligent."

What reason is there to believe that something being immaterial means that is intelligent?

e.g. the Principle of Proportionate Causality; how can we known that this applies to all beings? How can we know it's not just a principle that only applies to beings within our universe?

Let's say (A) is currently actualising the existence of all beings, including (Z). And, (Z) is actualising a potency of (A) that is unrelated to the causal power of (A) (or is able to actualise it, it doesn't actually need to actualise it). Is this possible?