Medieval Philosophy

by Peter S. Adamson

Now Anselm sets out to show the Fool that his atheistic position makes no sense. It is contradictory to suppose that God doesn’t exist in reality, but only in the mind, if we understand God as that than which nothing greater can be conceived. This is because, if God existed only in the mind, it would be easy to conceive of things better than Him. Notably, we could conceive of Him as existing in reality and not just in the mind. As Anselm puts the point, “if that than which a greater cannot be thought exists in the mind alone, this same that than which a greater cannot be thought is that than which a greater can be thought; but this is obviously impossible” (§2). This is the same sort of reasoning used later in the Proslogion to prove that God is, for instance, eternal. It belongs to the very nature of that than