The Ontological Argument - valid or debunked?

[SteveII]

Now let's break it down and expose the slights of hand:

"A possible world is just a way the world might have been. It's a complete description of reality. So a possible world is not a planet or a universe or any kind of concrete object, it's just a world description. The actual world is just the description that it true. Slight of hand: the actual world is not the description that is true - Craig is blurring the distinction between the actual world and the description of it. 

"Other possible worlds are descriptions that might have been true, but are not in fact true." Yes - but this means that the word 'possible' in 'possible world' does not actually make it possible in the sense that 'it can be the case in some reality', it is simply hypothetical. This is the key point: possibility is a positive claim, and it has to be demonstrated. It does not stand simply because the contrary claim that it is impossible has not been demonstrated either, because it has to uphold its own burden of proof. This is where the meaning of 'possible' and 'hypothetical' are confused.  

To say that something exists in some possible world is to say that there is some description of reality which includes that entity. To say that something exists in every possible world is to say that no matter which description is true, the entity will be included in that description. So, for example, Unicorns do not in fact exist. But, there is some possible world in which Unicorns exist. On the other hand, many mathematicians think that numbers exist in every possible world, they exist necessarily." It's true but look at what he's saying. He isn't saying that there IS a world where Unicorns exist, he's saying that there can be a description of a world in which Unicorns exist. The devil is in the detail here. 

You seem to think that Craig developed this framework to trick you. It existed long before Craig.  You still do not understand it. Did you bother reading the link I first posted: https://en.wikipedia.org/wiki/Possible_world. Philosophers writing philosophical arguments assume you understand this.

Craig then goes on to use 'possible' in different sense in his syllogism:

"It's possible that a maximally great being exists." - and that's simply not true! Not yet anyway because he hasn't demonstrated that it is. He is using 'possible' in this premise before he even gets to 'possible worlds' but he hasn't demonstrated that it is in fact possible that a 'maximally great being' exists. He's just asserted it. It's also an incredibly ill-defined idea. "God is by definition the greatest being conceivable" - this is meaningless - think about it, 'greatness' is not some objective quality, it's a subjective description. It's going to be different for everyone, and is limited by people's imaginations. The only reason this sticks for Christians is that they are already indoctrinated with these ideas about God, they already believe God has these qualities, so they accept everything he says about God even though he doesn't substantiate any of it.  This is all smoke and mirrors!!

The first premise is talking about broadly logically possible. This simply means there are no contradictions in the idea that a maximally great being exists. There is nothing to prove. To defeat that premise you simply have to show why the idea of God is not broadly logically possible. The rest of your post is meaningless because you do not understand the argument you presented in the OP.