I thought I'd observe the feast of St. Anselm today by pointing readers to a truly remarkable little essay by Brandon Watson on Anselm's argument for God's existence in Chapter 2 of the Proslogion. Though written three years ago, and garnering zero comment, it's well worth discussing. I'd like to initiate discussion of it here.
To that end, I'll just post the heart of it; but I caution those interested to read it all before commenting.
....the Fool either understands what he says does not exist, in which case he contradicts himself, or he does not contradict himself because he does not understand what he is saying does not exist. As Anselm says, "Even though he may say those words in his heart he will give them some other meaning or no meaning at all." So what is to be made of this?
I myself take Klima's view that the argument is sound. However, most of what I will say here does not require agreeing with me on this point. All it requires is that we ask, "Even supposing it is sound, what then?"
A sound argument is one that is logically valid and has true premises. But not all sound arguments are particularly helpful for coming to a conclusion. For instance, it is fairly easy to create arguments that are sound but that beg the question -- that is, arguments that are logically valid and have true premises, but whose premises can only be known to be true if we already accept the conclusion. When our interest is persuasion, the discovery of the truth, or anything else that relies on going from the unknown to the known or from the not-believed to the believed, we need something more than soundness. Klima argues, and I think that he's right, that the problem Anselm's argument faces is precisely at this level. Despite the fact that it is a sound argument, and shows that the atheist (the one who denies there is a God because that than which no greater can be thought does not exist) would be contradicting himself if he were seriously to reflect on that than which no greater can be thought, nonetheless it's possible to rationally reject the argument. As Anselm himself recognizes, understanding the words "that than which no greater can be thought" is not the same as having that than which no greater can be thought as an object of the understanding.