The Ontological Argument for the Existence of God

[Natachan]

I have never seen this argument before, so I'm interested in some discussion of it. A philosopher by the name of Alvin Plantinga states it this way:

The Ontological Argument

1. It is possible that a maximally great being exists.
   
2. If it is possible that a maximally great being exists, then a maximally great being exists is some possible world.
   
3. If a maximally great being exists in some possible world, then it exists in every possible world.
   
4. If a maximally great being exists in every possible world, then it exists in the actual world.
   
5. If a maximally great being exists in the actual world, then a maximally great being exists.
   
6. Therefore, a maximally great being exists.
   

Thoughts?

1. What is a "maximally great being"? Without a clear definition of this we can't even accept the first premise.

2. This is fine.

3. No. No no no. That's like saying "if I have the ace of spades in the deck, then I have all the cards in the deck." That's not how it works. This world is a subset in the set of possible worlds. If this maximally great being is in some possible world, then it is in another subset. It's presence in one subset of the set does not necessitate the presence in all the other elements of the set.

Let's put it another way. I am creating a set a call "letter sets."
SubSet 1: [A, C, T, R, Q]
SubSet 2: [B, D, R, E, C]
SubSet 3: [K, L, M, C, Z]

Now, just because K is a member of subset3 of "letter sets" does not mean it shows up in all three subsets. But this is the argument that point three is trying to make. It would be more accurate to say that since C is a member of all subsets of the set "letter sets" it exists in subset 3.

4. This is right, but since the argument failed spectacularly already the point is moot.

5 &6. Still don't know what a maximally great being is.

This argument attempts to define god into existence. But it doesn't work that way. You can make as many definitions as you wish, but no amount of defining can pop anything into existence. I define a plippityploop as a flying toaster that dispenses bagels that dispenses bagels to hungry people and exists necessarily. Where is my bagel?