Gaunilo’s Perfect Island
The ontological argument is the argument that it follows from the concept of God that God actually exists. There is no need, according to this argument, to go looking for empirical evidence in order to prove God’s existence; we can come to know that God exists just by thinking about it.
God is, as Anselm’s ontological argument puts it, that than which no greater can be conceived. A God that does not exist, though, cannot be that than which no greater can be conceived, for he could be conceived to exist which would be greater. Anyone who thinks that God does not exist, then, is confused; the concept of God entails God’s existence.
Parodies of the Ontological Argument
One problem with this argument is that it invites parody. Parallel arguments purporting to prove the existence of any perfect thing at all can be constructed.
This objection was first raised by one of Anselm’s contemporaries, the monk Gaunilo of Marmoutiers, who constructed an ontological argument for the existence of the perfect island in his On Behalf of the Fool.
The perfect island, this argument goes, is the island than which no greater can be conceived. Any island that does not exist, though, cannot be the island than which no greater can be conceived, for it could be conceived to exist which would be greater. Anyone who thinks that the perfect does not exist, then, is confused; the concept of the perfect island entails that there is such a thing.
Similar arguments for the existence of the perfect baseball pitcher, or the perfect husbandâ€”for the existence of any perfect thing at allâ€”can be constructed. If any of these arguments is sound, it seems, then they must all be sound.
Clearly, though, these arguments are not all sound; the perfect baseball pitcher does not exist, and neither does the perfect husband. There is something wrong with the logic of these arguments. Each of these ontological arguments, though, uses the same logic. They must therefore all be unsound.
The fact that there is no perfect island, and no perfect baseball pitcher, then, shows that the logic of the ontological argument for God’s existence is flawed.