[An old and beloved professor of mine put up five objections to proving God’s existence at Strange Notions. I formulated some objections on the comment thread but then started fiddling with them and expanding them here. My intuition about the last three objections is that they are pointing to how metaphysics has a different mode of proof than physics or math. The first objection, I think, is a way of seeing that our proofs for the existence of God require our conceptualizations of creatures to be theophanic from the start, i.e. as Augustine would put it, when we see a good thing, God is just the good, and nothing more.]
Thesis: we prove the existence of God from creatures:
1.) If one proves the existence of God from creatures, he has to negate something from his conception of the creature. This negation is either total or partial. But it cannot be total, for then he would have no concept at all and so be thinking of nothing; and it cannot be partial because then something that is by definition of a creature is being transposed to a non-creature. (cf. Edouard LeRoy, Dogme et critique or a summary by Rousselot in Théorie de concepts par l’unité fonctionnelle…etc tr. in “Essays on Love and Knowledege” p. 87-91).
2.) When we prove God’s existence from nature, God’s existence must be taken as a theoretical entity explaining facts in nature (N.B. this would be true even if we take the theory as being somehow logically necessary to accept) But the theoretical as such does not provide information about its real existence but requires additional information, which is called verification in science and which is unknown in mathematics (see ¶ 2 in #3 below).
3.) If one proves the existence of God from creatures, he appeals to the same data (e.g. moved movers, natural regularities) when proving that God exists as when proving he has certain properties. But some of the properties proved by these data are deeply paradoxical and even inconceivable (sc. a definition/ essence which, if known, would provide us information that such a thing existed; or a being that is not a being; or an intelligence that is not distinguished from or perfected by what it knows, etc.) Given that both are proved by the same data, we don’t know whether to take the existence proof as showing us that the paradoxes are to be accepted, or to take the paradoxes as as showing us that the existence is to be denied. But proving existence requires us to know that we should do the former rather than the latter. Therefore, proving the existence of God from creatures is impossible.
Compare our situation in proving the existence of God to our situation in proving the existence of other things with paradoxical qualities (black holes, non-computable numbers, fractal infinities) since in these cases the proof that such things exist is either taken from sensation (the things astronomers point to as evidence of black holes are different from the paradoxical elements which arise from theory) or else, like mathematicals, when we get a proof for existence of something we do not get information about whether it exists in reality (cf, the Pythagorean theorem does not decide the question between Platonic realism and Abstractionism).
4.) The only criterion in natural theology that something is not true of God is that it admits of a formal contradiction, and so for natural theologians, if something is not true of God, then it admits of logical contradiction. Contrapositively anything within the subject of natural theology that is free from logical contradiction is true of God. But logical possibility differs from real possibility in that the latter requires reference to the real order to be known. Therefore, we do not need reference to the real order to know what is true about God, and so a fortiori we do not need to have reference to creatures.