The classic ontological argument

[Modern Atheism]

There is a thread about the modal ontological argument, but not about the classical one. Here is the original ontological argument as formulated by Sain Anselm: 

1. By definition, God is the greatest being that can be conceived of.
   
   
2. But if God did not exist in reality, we could imagine a being that had all the other properties of God but that also existed in reality, and this being would be greater than God.
   
   
3. Since God is the greatest being that can be conceived of, this is impossible.
   
   
4. Therefore, God must exist in reality.
   

When you first read this, something about it immediatly feels wrong to me. Instead of an argument, it feels more like some kind of semantic trick like the Missing dollar riddle. However, it can be deceptively difficult to tell exactly what is wrong about it.

A line of response is to parody the argument and refute it by reductio ab absurdum. You can claim, for example, that the maximally greatest pizza must exist, because otherwise we would be able to imagine an even greater pizza: one which existed in reality in addition to being maximally great. Some apologist try to claim that the concept of a maximally great pizza is incoherent, but they use very dumb reasons to do so. For example, they say that a maximally great pizza would have an infinite size, but at this point it cannot be eaten so it does not count as food, and so on.

I would also say that you just cant just define something into existence. If the mere definition of something implies that it exists, then you really can't use this definition in an argument to prove its existence. That would be circular logic.

[Ivan Denisovich]

There's a single problem with this "argument" - it's just bullshit with no substance behind it. Perhaps it sounded clever to some yokels back when even wisest of people knew less than today preschoolers but today it's just pile of shit.

[Mister Agenda]

The most you can get from this is that God exists necessarily or necessarily doesn't exist. Sounds a lot like square one to me.

[The Grand Nudger]

Anselm was in modal error and the successful version of this argument is a modal correction.

Anselm tells us that he suffers from a failure of imagination, positing a definition from personal incredulity. Anselm then tells us that a being that existed would be greater than a being which does not. Anselm realizes that this would be bad for his argument, and so concludes that such a thing is impossible.

However, it's clear that we can imagine sweeter apples than any existent apple, and that this ability of ours does not produce those sweetest imaginary apples in mere reality.