The fool says in his heart, "There is no God." (Ps.14:1)
This must be greater than something whose non-existence can be conceived. So, if this thing (than which no greater can be conceived) can be conceived as not existing, then, that very thing than which a greater thing cannot be conceived is not that than which a greater thing cannot be thought. This is a contradiction. So it is true that there exists something than which nothing greater can be conceived, that it cannot be conceived as not existing.
- If one can think of the fool's god, then one can think of Anselm's God. [Both the fool's god and Anselm's God can be said to exist in the intellect].
- If one can think of Anselm's God then the fool's god is no God because it doesn't satisfy the definition of God [Any God worthy of the name cannot be conceived as not existing. Therefore the god of the fool never was].
- Only Anselm's God can satisfy the definition of God.
- Only God can exist in reality and in the intellect [i.e., God belongs to a class of one, of things which if he is in the intellect he must also be in reality] .
- Therefore God, being what he is must exist not only in the intellect but outside it as well.
- Therefore God is.