The Ontological Argument - valid or debunked?

[Esquilax]

I need to clarify. The difference is between epistemic possibility and metaphysical possibility. Epistemic possibility is simply "for all we know something is possible". On the other hand, to illustrate metaphysical possibility take a math equation 24673244/8=3005567. While we might say "for all we know" this might be true, but if it is true, than it is necessarily true if it is false than it is necessarily false. If a maximally great being exists, it exists necessarily in a metaphysical sense. Therefore, God’s existence is either possible or impossible.

That's... not exactly a big conclusion.

Then you have simply changed the definition of omnipotent. Equivocating. An omnipotent God could prevent getting eaten. 

My point is that there exists, if we so wish to discuss it, an infinite number of ever increasingly maximally great beings, each one identical to the last, only with the ability to limit the one preceding it. You propose an omnipotent god, and this is your maximally great being, in response I propose a being with an identical power set, plus one more ability which allows it to weaken your god, thus making it the maximally great being, and so on, ad infinitum. Yes, I suppose in some sense I'm simply broadening the definition of omnipotence, but we're not talking about omnipotence, we're talking about maximally great beings within the premises of the ontological argument, and the fact that I can erect an infinite regress around that at all demonstrates my point: the concept of a maximally great being is logically incoherent in that any maximally great being that actually exists serves as little more than a platform from which other, more powerful beings can be posited. The moment you show a demonstrably real maximally great being is the moment that being can be surpassed simply by proposing additional beings capable of negatively influencing the extant one. And you can say that a really omnipotent god could prevent that, but that's the point: that god would no longer be omnipotent because I've built into the power set of my being the ability to take that power away from yours, and it's hardly like we're discussing real things anyway, we're just talking in hypotheticals. You've no reason to dismiss my concept out of hand.

Greatness has no defined criteria, nor an upper bound, and this is the problem here. The first premise of the ontological argument is roughly akin to saying "the greatest possible number exists," and then you, as a numberist, telling me what number you think that is. 64, you say, for the benefit of my analogy. Then I rightly point out that 65 is a higher number than 64: you just telling me that 64 is the highest possible number necessarily, therefore it can prevent 65 from being higher... well, that just doesn't make any sense, does it?

First, at most that would undercut theistic belief, not that theism is false. Second, a limited grasp of God's properties does not entail that our conception of God is false. Third, we can believe in God without being able to grasp all there is to know about God (because that would be impossible).

First, "I know it's an argument from ignorance, but I'm going to believe in the conclusion anyway," is one of the most intellectually dishonest things I've ever heard. Second, I'm not talking about your belief in god generally, here I'm talking about the ontological argument and why it fails. Third, regardless of your beliefs, surely you can see the problems with defending them using clear logical fallacies?