Here's some more about the 'existence' issue Chuck brought up. This link should get you to a forum that discusses some of the points
http://memoriapress.com/forum/showthread.php?t=27&highlight=existence

But this paragraph make the main point:

"The reason for this would involve a more complicated discussion of set theory’s acceptance of the possibility of an empty set, but the fundamental reason goes back to the fact that, in traditional logic, predicates refer to concepts (where the nature or essence of a thing is known), whereas in modern logic predicates are sets that are defined by their members. All of which is just another way of saying that traditional logic assumes that words have meaning apart from the actual existence of their objects and modern logic does not."

This ties into several other issues. The modern idea that "words don't really have meaning" is where the idea comes from that the constitution, or the Bible for that matter, doesn't have any meaning apart from the meaning the reader wants to put into it. So things can mean whatever you want them to mean. But more to the point is that the traditional approach assumes that essence precedes existence, whereas the modern approach assumes that existence precedes essence.



This all incredibly brief, but it seems to me the "existence" contention assumes a modern instead of a Judeo-Christian perspective. We know the Bible assumes that our essence precedes our essence. God had us in His mind, and what we were supposed to be, before we were born. God had right and wrong, and meaning and purpose, all figured out before people came along to decide those things.



That seems a long way from the Ontological Argument, but it's all part of the discussion of whether 'existence' is really an attribute.



There have been other rebuttals of the Ontological Argument. One is that the argument is really a tautology. That is to say it is just a redundant statement with the conclusion just restating the premise. But that doesn't refute anything, because tautologies are valid. If the premises are true a tautology is sound. And some people argue that all deductive arguments are tautologies because the conclusion is really contained in the premises. But that is a little convoluted, because it is like complaining that a conclusion really does follow from the premises. The thing about tautologies is that sometimes they are useful to unpack or restate something in a way that shed's more light on the subject, and I think the Ontological Argument clearly does.