The ontological argument attempts to demonstrate that the only coherent notion of God includes the notion of God’s necessary existence, and thereby highlights the self-contradiction inherent in proposing that “God does not exist”. In this way ontological arguments seek to prove that God exists. There are a few ways ontological arguments can be spun. For instance, one can try to demonstrate, as Descartes and Anselm do, that one can legitimately go from the essence of God to the existence of God. However, one could also make the ontological argument an epistemological argument: one can say that since the idea of God is the idea of a thing which necessarily exists, then to deny its existence is not rationally possible. If the idea is clear and distinct for any person, as it was for Descartes and seems to be for a considerable number of mystics and philosophers alike, then one cannot even make sense of the proposition that “God does not exist”. Many of you probably know I am, myself, a non-cognitivist with respect to Atheism in this strong sense.
Suppose, however, that one wasn’t completely convinced of the existence of God prior to being exposed to the ontological argument. Suppose the ontological argument brought that person to see clearly and distinctly that God exists, as it often brings people who search themselves and wander through their thoughts face to face with the living God. If such a person has that experience, then what will they answer to Kant’s critique that existence is not a property? Of course Kant’s critique has been dealt with by most analytic philosophers, and it is, it has always seemed to me, not a very good critique at all. However, putting aside my objections to Kant’s objections – supposing one couldn’t clearly see what was wrong with Kant’s clever objections; what then should one respond to them after having become convinced by a good ontological argument? Well, it seems to me that a Moorean response may be appropriate: that we are more sure of the insight of the ontological argument than we are of Kant’s strange critique. I think this is an epistemologically legitimate response within certain domains, and its application here is plausibly legitimate and at least interesting.