Hitchens’s argument was first made by a contemporary of Anselm, a monk named Gaunilo, and Gaunilo’s version is much more effectively argued than Hitchens’s. Gaunilo accused Anselm of making an illicit transition from the conceptual to the existential. Gaunilo’s point was that just because we can imagine unreal things like unicorns, mermaids, and yellow flying dogs does not mean that any of these creatures exist. Anselm answered Gaunilo by pointing out his ontological argument does not say that everything we can imagine in our heads necessarily exists. The argument merely insists that “that than which no greater can be thought” exists and exists by necessity. In other words, Anselm is only making his claim in one particular case. It is precisely the character of “that than which no greater can be thought” to exist necessarily: there is nothing in the definition of unicorns and yellow flying dogs that confers existence on them, much less necessary existence.”
There have been other objections to Anselm, and I don’t propose to discuss them here. My point is that theology gives evidence of a high order of reason at work, and one cannot, as many atheists do, dismiss these arguments as unreasonable even if you don’t agree with them. Consider many of the famous arguments in philosophy, say, Locke’s argument aboutprivate property or Wittgenstein’s argument about the possibility of a private language. Whether or not we think these arguments successful, it can hardly be said that they are irrational. Rather, they represent powerful rational claims about the nature of reality.
So it is with Aquinas and Anselm. In proving God’s existence they at no point appeal to supernatural revelation. Theirs are arguments based on reason alone. They were, of course, devised in a very different historical and philosophical context than the one we now inhabit, so they need to be updated to be persuasive. And when they are reformulated in modern terms, they are persuasive. I intend, as you will see, to make an argument very similar to Aquinas’s in a later chapter on the origin of the universe. My point is that the kind of reasoning about God that we see in Augustine, Aquinas, and Anselm is typical of Christianity. There is very little of this in any other religion. And out of such reasoning, remarkably enough, modern science was born.
