What do you think of this argument for God?

[Jesster]

That is the main problem with it, why assume this "greatest possible being" is necessary? If we do, then it is pushing the concept into existence, which can be done with nearly anything.

However, it does not ride on the idea that anything is possible, but bases itself on whatever is possible.

Then if you don't hold to the idea that "anything is possible" you will have to accept that the actual possibilities of reality may not include the "God" that this argument is trying to define away.

[SuperSentient]

@TheAtheologian,

What does "Manifestation of every logical possibility" mean? Logical deduction needs Axioms as a starting point, so this concept of greatest depends on your assumptions then?. Also, to use poor abused Goedel, "Logical possibilities" tend to include mutually contradictory statements. Does a perfect God believe in the Axiom of Choice or not or both?

It assumes logic exists independent of Humans and their rationality. A contradiction would be impossible to exist, and so does not exist in any possible world. 
All logical possibilities would be manifested in God and all logical impossibilities wouldn't.

[Alex K]

@TheAtheologian,

What does "Manifestation of every logical possibility" mean? Logical deduction needs Axioms as a starting point, so this concept of greatest depends on your assumptions then?. Also, to use poor abused Goedel, "Logical possibilities" tend to include mutually contradictory statements. Does a perfect God believe in the Axiom of Choice or not or both?

It assumes logic exists independent of Humans and their rationality. A contradiction would be impossible to exist, and so does not exist in any possible world. 
All logical possibilities would be manifested in God and all logical impossibilities wouldn't.

Logic may well exist independent of humans, but logic is just a way to go from assumptions to conclusions.

[SuperSentient]

That is the main problem with it, why assume this "greatest possible being" is necessary? If we do, then it is pushing the concept into existence, which can be done with nearly anything.

However, it does not ride on the idea that anything is possible, but bases itself on whatever is possible.

Then if you don't hold to the idea that "anything is possible" you will have to accept that the actual possibilities of reality may not include the "God" that this argument is trying to define away.

Haha, you got me there, after I typed this:
Accepting that the actual possibilities would not include God would be a contradiction since God in this case by definition is whatever the greatest possible being (remember premise 1) is. Like what I said before, the "greatest possible being" would be the manifestation of all logical possibilities, so it would be nonsense to say that the actual possibilities of reality may not include the manifestation of all logical possibilities. 
The last sentence of the two proves your point, so I have two main options:
1. Retract my claim that the "greatest possible being" is the "manifestation of all logical possibilities"
2. Retract that Premise 5 follows from Premise 4 and then this argument essentially falls apart.

---

It assumes logic exists independent of Humans and their rationality. A contradiction would be impossible to exist, and so does not exist in any possible world. 
All logical possibilities would be manifested in God and all logical impossibilities wouldn't.

Logic may well exist independent of humans, but logic is just a way to go from assumptions to conclusions.

I guess another assumption made would be that all objective logic is absolute.

[Jesster]

And that's exactly why I was mostly aiming the argument about possibilities at the rest of the premises. To bring all that back to the first premise, what if the greatest possible being turns out to be nothing more than human? Would you call that being "God" by your definition? If so, then I don't see the point here.

[BrianSoddingBoru4]

My two main issues with the argument are 1) That which is possible in not required and 2) It isn't at all clear that existence is a necessary component of greatness.

Boru

[SteveII]

You are just arguing a slight variation of Ontological Argument developed by Anselm almost a 1000 years ago. You can get the full idea here.

[Pat Mustard]

I heard an argument like this:

1. God is the greatest possible being.

2. God is a necessary being, which means that God exists in every possible world (If God exists). 

3. If God exists in one possible world, God must logically exist in every possible world. 

4. Since God is the greatest possible being, it follows that every aspect of God (being possible) exists in some possible world.

5. Therefore, God exists (in all possible worlds, including ours).

I actually just structured the premises this way myself but is the same idea as an argument I heard before. 

What do you think of it?

It is ancient first of all. Aquinas stole it from Kalam who in turn stole it from Aristotle.

With regards to this specific "way" of Aquinas, the fourth, it is sufficient to realise that it is a completely subjective argument to disprove it. First of all, who is defining "greatest" (usually formulated as most perfect), and how are they measuring it against extant objects?

Secondly just because you can imagine a "perfect" thing it does not follow that that thing must therefore exist, a subjective want for something to exist does not give existence to the thing. I can imagine the most invisible, most pink, most corned unicorn ever, yet that animal has no existence outside my imagination.

[Mister Agenda]

I heard an argument like this:

1. God is the greatest possible being.

2. God is a necessary being, which means that God exists in every possible world (If God exists). 

3. If God exists in one possible world, God must logically exist in every possible world. 

4. Since God is the greatest possible being, it follows that every aspect of God (being possible) exists in some possible world.

5. Therefore, God exists (in all possible worlds, including ours).

I actually just structured the premises this way myself but is the same idea as an argument I heard before. 

What do you think of it?

1. That's an odd definition. The common definition is along the lines of 'the creator and ruler of the universe'. This definition just calls whatever the greatest possible being is, 'God'. Maybe the 'greatest possible being' is a supercomputer made out of a network of neutron stars connected by wormholes. According to this definition, that supercomputer is God. I don't think that many people who believe in God would agree that the supercomputer is God.
2. It's entirely possible that there is a necessary thing, that 'can't not exist'. There's no reason to think that thing, if it exists, is a being. Quantum foam is a candidate for the position.
3. If God does not exist in one possible world, God must logically not exist in any possible world. There seems to be a missing step here where demonstrating that there is a possible world where God exists would be helpful.
4. How so?
5. There doesn't seem to be an actual argument preceding this conclusion.

[brewer]

You/anyone does not get to argue a god into existence. That is an argument for belief/faith, not existence. I don't accept premise 1 and 2, therefore the argument is over.