The Ontological Argument for the Existence of God

[God of Mr. Hanky]

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?

Problems with Point 1 have already been exposed.

Point 2 would probably exploit the multiverse hypothesis for the modern audience, ignorant of the fact that an infinity of universes cannot be determined and cannot be ideated logically anyway. Therefore, even if Point 1 could pass, the ontological argument would fail at Point 2.

Also, Plantinga offered no thought to the implication of realistic possibility on supernatural ideas. If something exists in any real world, dimension, or universe, then it is something which can be explained by anyone if they had access to said place for observation. This would necessarily make the subject n.o.t. supernatural! Therefore, the supernatural cannot possibly be any sort of a reality other than what people's minds make of it. It doesn't make the very unlikely idea that the earth was purposefully designed by someone impossible, but in the unlikely event that this is proven to be true the Xtians would have to admit that he is not without faults (perfection is a human construct and would require something supernatural).