The Ontological Argument - valid or debunked?

[Esquilax]

The argument can be summed up as: If you think that it is broadly logically possible that God (the maximally great being most think of when you say God) exists then he does exist.

Which, again, merely presumes without justification that existence is a component of maximal greatness, which is an entirely subjective criteria asserted out of convenience. I would, for example, suggest that a being capable of doing all of the things a god is purported to do, while simultaneously not existing, is far greater than a being hamstrung by this requirement that he must exist to do things: the latter has a limitation that the former does not.

But then, I too would be making an argument based on my own subjective opinions of what greatness entails, which is good for the hypothetical but doesn't escape my main point, which is that the ontological argument relies exclusively on unsupported opinions of the criteria it seeks to explain, which doesn't exactly count for a lot.

As Irrational said, it is important to understand the S5 modal logic that if something is even possibly necessary, it is actually necessary. (which would answer Kevin's question about the jump from 2 to 3.)

Then I would point out that "necessity," where it isn't supported in any way, is not different than a petulant foot stomp and a yelled "because I said so!"

@Esquilax, one of your objections to maximally great being is that something "slightly more great" can be imagined makes no sense. What could be greater than an omnipotent, omniscient, morally perfect, and necessary being?

An omnipotent, omniscient, morally perfect, necessary being that can eat the one you're proposing. What's greater than that? Same deal, but it can eat the one preceding it. And so on. And so forth. Greatness has no upper bound.

More importantly, did you just not notice that this argument of yours is just one big argument from incredulity and ignorance? Your inability to fathom something greater is not an argument against my position.

If you could logically conceive of anything greater, then that would be God.

But once your god is a real being, with defined characteristics, then I can always conceive of a greater being. If you've got a god who is omnipotent and maximally great, then it's simplicity itself to logically consider a being that is identical, but has within its omnipotent power set the ability to be greater than your god, and also to bar your god from using his own power set to become greater than that.

This is the problem when your argument, like so many theistic arguments, rely on hazy, ill-defined yet strongly worded terms that are easy to manipulate.

Your parody about the greatest conceivable girlfriend illustrates nothing. 1) the qualities of such a person would be subjective and 2) there is nothing about such a person that would make her necessary.

1: and the qualities of a maximally great god aren't subjective? What makes you say that?

2: If she's maximally great then, by your own argument, she would have to be necessary. You seem to have appended necessity into your subjective definition of maximal greatness, so it's interesting to see you drop that part the moment it's convenient to do so.

To defeat the argument, you are left with showing why premise 1 is not true. This would require you to show that the concept of a maximally great being (God) is illogical.

"Greatness," both has no upper bound, and is a subjective criteria without an objectively set definition or list of minimal characteristics. Therefore, no entity or object of maximal greatness can exist, as there can be- especially within Craig's sphere of argumentation- no actual infinites, and if it did exist, it would only be maximally great insofar as it aligns with your personal idea of greatness, and not some global definition that would logically allow that being to be some dimension hopping ubermensch.

In short, you can't talk a god into existence with your own personal opinions.