Learning From the Ontological Argument

Philosophers generally agree that no version of the ontological argument is compelling. Although it may contain premises that are true and the argument is recognized to be valid by everyone, no atheist believes all of the premises. So as an argument, it can do very little. What the ontological argument can do is demonstrate the status of God's existence. It also shows that there are interesting implications for existence proofs related to Anselmian theism.

Plantinga has a modal ontological argument that is like this one: It is possible that God exists. It is part of God's nature that he exist necessarily. Therefore, God exists. This argument may sound like cheating, but it is a valid argument. Atheists must deny the first premise, since the second premise follows from the definition of God in Anselmian theism. So either God exists necessarily, or it is impossible for God to exist at all. This is agreed by everyone.

This has interesting consequences for proofs for or against the existence of God. Any time that an atheist is attempting to prove that God does not exist, he must assume that there is something about our world that conflicts with the very nature of God. Now he must point to something that is actual. It will not work to move from what he thinks is possible to a proof against God's existence. The reason for this comes from implications about necessary beings.

If God is a necessarily existent being and his nature is incompatible with the existence of something, then that something cannot exist. So if we find that something, then we know that God does not exist. But we cannot suppose that the something is possible merely because it is conceivable. For if God does exist, then it is not possible. Let's use an example. Suppose that a world in which an evil demon tortures babies forever is an evil that a good God could not allow to exist in any circumstances. Such a world is clearly conceivable, but it is not possible if God exists.

Nor can we suggest that the mere fact that we can conceive of such worlds should count against the existence of God. There are good reasons that the theist can give as to why such worlds are conceivable. She could suggest that the human mind is capable of thinking of contradictions and errors, so why is it not also capable of thinking of non-possible things? Such a response is surely plausible. In any case, the facts about what sort of thing we can conceive are facts about the actual world, and not facts about possible worlds. So even if that was a good argument, it would still be within the range of acceptable arguments.