Proof of God's Existence from Definitions 1.) I possess an idea of a perfect being. 2.) By definition, this is the idea of God. 3.) A perfect being, by definition, possesses all perfections. 4.) Existence is a perfection. 5.) So the very idea of God entails the idea of His existence. 6.) So God exists. This argument is very similar to Anselm's famous ontological argument. Ganilo's objection to Anselm: Proof proves too much (i.e., existence of perfect islands) Hamlet's worry: Is existence necessarily a perfection? Isn't it sometimes better not to be, than to be?