A nice step by step explanation of Kurt Goedel's proof of the necessary existence of a Being that possesses the Godlike property of possessing all properties that are good.
When I asked my friend, whether he thought the proof succeeded, he replied that it did, and perhaps too well, because it left open the possibility of many such Beings. He himself provided me with a tweaking that would prove the unicity of such a Being.
I have lately gotten into a discussion with someone speaking perhaps carelessly, who said that God "probably did not exist." It appears to me, though, that that is one thing you surely cannot say of God.
Probability governs only those things dependent upon contingencies, and to measure probability, you have to posit some "universe" of events or objects that instantiate or do not instantiate the contingent conditions you need for the thing in question to happen or to exist.
But God, by definition, cannot "happen" or "happen to be." God either exists necessarily, or it is necessarily the case that He does not exist. If, however, it is POSSIBLE that Necessary Being exists, then it is necessary that Necessary Being exists.
I know, I know I am channeling Anselm here, as Goedel was, but I do not see how we evade the conclusion. Nothing in this universe, as those who posit alternate universes concede whether or not they are aware of all the implications, exists necessarily; name any thing, and it is possible that it should not exist, as it is, with the characteristics it possesses, and this is so even if we concede for the sake of argument that the universe had no beginning in time.
(Aquinas did not believe that you could prove by reason alone that the universe must have had a beginning in time; so his proofs for the existence of the Creator God did NOT depend upon that terminus a quo. A universe perpetually existent backward and forward in time still requires a Creator.)
But no matter how many contingent objects you may point to, three or three zillion, they cannot all depend upon one another in some great circle of logic and onto-logic; a thing cannot be dependent from beforehand upon its own effect.
A bag of contingencies is just a bag of contingencies, no matter how big the bag is. A multiplicity of such bags is just another bag, and we move not one step closer to resolving the problem, unless we conclude that there must exist some X whose existence is necessary and not contingent.