The Ontological Argument - valid or debunked?

[Esquilax]

You are correct that the argument hangs on the concept of necessary. The opposite of necessary is contingent. Since being contingent on something is a defect it would not be considered maximally great to be contingent. A maximally great being would be a necessary being because it could not be contingent on another (then that would be a greater being). 

You can dream up all the parodies you like but you have to answer the question of why whatever example is necessary rather than contingent.

Okay, I refuse to believe that you're really this obtuse. Are you just making fun of us, here?

Why is a maximally great being necessary rather than contingent? If you're just building necessity into the definition of maximally great, then first of all congratulations, you've got subjective opinion number 9,800,654 on what constitutes maximally great, and unfortunately for you your personal opinions are no more binding or objective than anyone elses'. Second of all, you've got the mother of all circular, question begging, garbage fire arguments here, because you're building the thing you're trying to prove (the existence of god) into the definition of the thing itself. You might as well just say "god exists because existing is a thing that god does." Whoop-de-freaking-do.

And it's so clearly circular that I have a hard time accepting you don't see it: why does god exist? Because god is a maximally great being. So what? "Maximally great" includes necessity in its criteria, so god exists necessarily. Therefore, god exists. So basically, god exists because you've defined a label for him that includes existence as part of that? Yes, maximal greatness means he exists.

Don't bullshit us, Steve. If I'd made a logical argument for why god couldn't exist that began with me bestowing upon god a title, and ended with me telling you that title includes non-existence as a part of it, you would dismiss that argument, quite rightly, so fast. Don't use arguments you wouldn't accept if they didn't line up with what you already believe, it's breathtakingly lazy.