As we were saying, Anselm’s argument in the “Proslogion” is called the “ontological argument” because it moves from the thought of God to Its existence (ontology = being). He said that if you can conceive of a being as perfect as God in your mind then you are not capable of saying that It does not exist.
This logic turns out to be remarkably easy to parody (which doesn’t make it wrong, of course). Right away, a Benedictine contemporary of Anselm’s named Gaunilo of Marmou-tiers invented the famous “Lost Island” ha-ha that seemed to put a stake in the heart of the proof.
Gaunilo called his brilliant, 8-part riposte to Anselm “On Behalf of the Fool” (i.e., the atheist mention in Psalm 14:1). Imagine an island, he says:
“… which, because of the difficulty (or rather the impossibility) of finding that which does not exist, some have called the ‘Lost Island.’ … It is superior in every respect … to all those other lands that are inhabited by people.”
This is the real Fantasy island. No greater island can be conceived. Using Anselm’s logic, Gaunilo said, for this island to exist would be even greater than for it not to exist. Ergo, it exists. But it doesn’t. So it’s the argument itself that’s absurd, not the island:
“I say that if anyone wanted to persuade me in this way that this island really exists beyond all doubt, I should either think that they were joking, or I should find it hard to decide which of us I ought to think of as the bigger fool.”
As a monk, Gaunilo presumably was a believer – just not in Anselm’s logic.
Our friend responded to Gaunilo in a way that has disappointed fans for 900 years. He said the monk misunderstood him, but didn’t really say why. What we have here is a failure of communication.
Anselm’s argument is a slippery one. It feels like there’s something wrong with it but it’s not clear exactly what. Obviously, there’s a difference between God and Fantasy Island, but what?
The problem seems to lie here: Anselm’s parodists all rely on the assumption that Anselm claimed “to exist is greater than not to exist.” But that’s not what he says; he says that IF you are capable of conceiving the greatest possible thing ever, THEN you will be unable to conceive of it not existing.
He’s preaching to the choir – his motto was “Faith seeking understanding,” which starts with Faith. Although he did claim in the intro to his proof that an open-minded atheist “could at least convince himself of most of these things by reason alone … if he is even moderately intelligent.”