Reason comes to know by using predicated universals. These universals are said of many and are therefore not determined to one individual. This means that the mind understands the sorts of things that can be many, even if- as a simple matter of fact- there is only one individual.
Here arises the paradox of the human mind- even though all our knowledge is grounded on things acting upon us, and the object of knowledge is an act of our intelligence, nevertheless we only understand those objects that are potential to a multitude. Our act of understanding consists in creating a universal that- by definition- is not determined to one.
This paradox is simply a way of considering the paradox of man- man’s distinctive operation is rational sensation, as opposed to the mere sentience of other animals. Our constant temptation is either reduction (which denies the duality of our operation) or dualism (which denies the unity of the operation). One or the other of these models in inevitable so long as we don’t recognize the reality of passive potency. It is only in this way that two real things can become one.
The potency of things, therefore, is not only necessary or the unity of things in nature, but even for our knowing of them. We know ony what can be many. It is essential to remember that when we prove the existence of a pure act, we must understand him by a negation of what we know. Pure act is not a single individual of the sort of thing that is a pure act- he is not “one individual of a class of pure act”. In modern logical terms, one cannot use an existential quantifier of pure act. Our mind will immediately construct some such genus that it puts God in, and then ask “is there one God or many”? But this whole question is unnecessary for someone who knows what he is doing when he speaks of pure actuality. It is stupid to ask whether there can be more than one pure act- for this would be to a say that what is only actuality is other than actuality.
There is neither many pure acts, nor is there only one, if one is understood as a number or a source of number. Unity is only a source of number if it can be multiplied, but what can be multiplied has potency to the multitude. God is neither opposed to multitude or to unity. Natural theology teaches a monotheism that consists only in denying division in the divine nature. One might deny this division once or twice or three times, but he has only denied division, not introduced multiplicity. We understand the divine nature in a judgment that negates the predicated universality by which we know- we understand God by erasing the Venn diagram and judging it God. Our discussion of the Trinity cannot bring the diagram back- as so many are tempted to do.
Just Thomism 