Evaluate Anselm's Ontological Argument

Anselm's ontological argument is a priori proof of God's existence. Anselm begins his argument with ideas that do not depend on experience and progress to a throughly logical explanation that God necessarily exists. Anselm's goal is to prove to the "fool" that God has to exist. He says that anyone who has an understanding of the existence of God can and logically has to believe that God really does exist. Anselm starts off with a statement that is slightly simple and straight forward; God is that thing which nothing greater can be conceived. Even to an atheist this idea is clear. Anyone, even if they do not believe this statement, has it in their understanding that if their was a God, it would be that thing which nothing greater
Anselm says that it exists only in the understanding or it exists there and in reality. That means that since everyone can conceive of the idea of a thing which nothing greater can be conceived, than the only other group, is of people who believe it to be true. Suppose then, that it exists just in the understanding, then one can really conceive of it actually existing. As Anselm asserts, " And surely than that which a greater cannot be conceived cannot exist just in the understanding. If it were to exist just in the understanding, we could conceive it to exist in reality too, in which case it would be greater"(Anselm, 78). Meaning that if, that which nothing greater can be conceived exists only in the understanding, than something greater than that can be conceived, one that exists in reality is clearly greater, better, more perfect. That idea cannot work. So that which nothing greater can be conceived cannot only exist in the understanding, God must exist in reality as well as in the understanding. "No one who understands what God is can possibly conceive that He doesn't exist"(Anselm, 79).So