The Ontological Argument for the Existence of God

[The Grand Nudger]

Well, okay...I'll try. But let me clear: I don't know whether this argument holds water or not. Like I said in the OP, I just heard about it. And I'm just repeating what I've read because you asked me to...not because I'm an expert on this. So, you'll have to do more than simply dice me up; my inability to articulate or defend something I'm barely familiar with is not proof that the argument itself fails. Failure in this situation may be due entirely to shortcomings of the one making the argument!

Granted...but hopefully, by doing our best we can become more knowledgeable.  

Let's start with the first premise. It seems intuitive that a maximally great being might possibly exist. In order for its existence to be impossible, it must be logically incoherent...like the idea of a married bachelor. But proponents claim that there is nothing logically incoherent about the idea of a maximally great being. Are they right? If not, I don't see why they're wrong.

What you're discussing is what's referred to as "the innocence of the premise".  The premise  "A maximally great being might not exist" is equally possible.  The trouble, with this premise and modal logic..is that if you agree, -not- demonstrate, mind you, but simply agree that the form is or could be informative, you must also agree that a precisely opposite claim is also equally informative.  An equally innocent premise.  The premise, though..isn't actually innocent at all, as existence...the conclusion..is already included as an attribute, as has already been mentioned.

As a side note, it just occurred to me that we might argue that there is no such thing as a cat that glows in the dark. However, scientists are experimenting with genetic manipulation that will introduce the "glowing" ability of other species (fish?) into the DNA of cats. So, the possibility of glowing cats is real, even though until recently we would have said that we'd never seen one or that there is no experiential evidence that one exists. Bottom line? What is possible and what actually exists are two different things. Similarly, we not have seen a maximally great being (yet), but that is not the same as saying that it is impossible for one to exist.

-and yet the premise is equally innocent (or not).  

Moving on, it seems to follow that a being which is not merely "great" but is "maximally great" must be one which has certain characteristics, and these would be the "omni's" that are commonly referenced by theists when speaking of God: omnipresent, omniscient, etc.

That's a personal value judgement of attributes relative value or worth.  It seems to you that the maximally great being must posess omnipresence or omniscience..but a maximally great being to me might need to possess the "attribute" of non-existence.  After all..the only thing greater than a god that exists and creates a world, for example..is one that can create a world without even needing to exist. Or, less quixotically, that a being which is not omipotent or omnipresent or omniscient who still manages to do all the "god" stuff is much greater than a being who does the same things with those omni's as a crutch.

To repeat, even though we don't know of an actual maximally great being, it does not follow from may simply be our ignorance that one does not exist...or at least there is no reason for us to conclude that one cannot possibly exist. IOW, in the absence of logical incoherence, we must say that it is at least possible that a maximally great being exists. Which is all that premise (1) says.

Your thoughts so far?

That you didn't even attempt to demonstrate the veracity of the propositions..instead launching off on a sidebar about what attributes a maximally great being would have - according to you.  That you've abandoned your argument...and are now presenting another...even as you agreed to at least try. That you're aping WLC's "and this we all consider to be god" routine. I doubt that an omnipotent, omnipresent, omniscient toaster would be a satisfying god to those inclined to belief, or inclined to swallow such "arguments".