A standard criticism of the Ontological Proof is that ‘existence’ can’t be treated as an ordinary term, it is too complicated and requires too much mathematics, the argument appears nowhere in the Christian Bible, or it fails to satisfy our desire for a God who hears prayers.
Answer by Helier Robinson
That’s actually four criticisms, but only the first is philosophical.
The way St. Anselm put the argument was that he could conceive of a being than which nothing greater could be conceived; if this being did not exist it would be less than the greatest, therefore it has to exist. The standard refutation of this is that existence is not a quality of beings: their perfection is unaltered by their coming into, or going out of, existence. St. Anselm also used the expression ‘necessary existence,’ which in itself is a fascinating concept, and claimed that this quality was one of the qualities of a being than which nothing greater could be conceived.
Let us consider the concept of necessary existence, and to be quite clear about it, define it as intrinsic necessary existence. We are familiar with extrinsic necessary existence; for example, a relation cannot exist unless its terms exist, so the existence of a relation necessitates the existence of its terms and this necessitation is extrinsic to the relation and to its terms. So we can say with reasonable confidence that if extrinsic necessary existence is logically possible than so is intrinsic necessary existence. Because intrinsic necessary existence is logically possible, it must exist in at least one of all logically possible beings, and that being must necessarily exist, by its own nature. Does this refute the criticism?