Just think about it
Jonathan Barnes records an after-dinner conversation about St Anselms exquisite ontological argument for the existence of God

They had dined well and were warming their Armagnac. From the inclination of the ebony cigarette-holder, Charles Morse could deduce that his host was in didactic mode, and it was with little hope of success that he attempted a diversion: Well, as you know, Jean-Franois, we English dont like to discuss religion for us, its a private matter, like politics and personal hygiene, not something you argue about in public. Mon cher ami, cried Charpentier who in moments of emotion would lapse into his native tongue mon cher ami, how I adore your little English ironies. But you do not need to remind me that the most subtle the most exquisite of all religious arguments was discovered in England. For if I recall aright, the ontological argument for the existence of God was discovered in Canterbury, in the year 1078, on a Sunday in April, at two in the morning.

Morse knew when he was beaten you do not easily divert the holder of the chair in metaphysical theology at the Sorbonne, and in any event Charpentier had given him a remarkably good dinner. He tamped his pipe, and settled back. Yes, of course you are right, though St Anselm was hardly a typical Englishman, and ontological is not an English word.

Perhaps not it is one of those ponderous German epithets which some ponderous German attached to the argument. But let us agree to call it Anselms Argument: what matters is not its name but its substance.

Its substance ...would you mind frightfully jogging my memory a little about its substance? It was a generous long-hop, which Charpentier had no compunction in accepting. Nothing could be easier, he began; for it is really the simplest of arguments: a couple of premises which even my dear students could understand, and a conclusion which follows as the night the day, in the words of your goose of Avon. First, then, we lay it down as an axiom that God is something than which nothing better can be conceived.

You mean that He is unimaginably good, I suppose?

Not at all, mon cher, said Charpentier, rather nettled by such an early interruption. It is only Protestant theologians who say that God passes our feeble human understandings. What I mean is precisely what I said: God is so good that nothing could conceivably be better. This Armagnac is very good, really extraordinarily good, but we can both conceive of something better, even if we are very unlikely ever to find anything better. Your gracious Queen (like most Frenchmen, Charpentier was a royalist to his bootstraps) is extremely good, quite exceptionally good for an English lady (like most Frenchmen, Charpentier had limited ideas on the subject of English women), but we can both imagine something even better. God is not like that: He is not only supremely good, infinitely good nothing at all could conceivably be better.

You ask me how I know that? Morse wondered if he did. No the question was rhetorical. There is nothing deep or mysterious about it: it is a simple a priori truth, a truth which expresses one aspect of our concept of what God is, which depends on nothing but the very meaning of the word God. How do I know that a triangle has three sides? I know it insofar as I understand what a triangle is or what the word triangle means. How do I know that you cant divide a prime number by any numbers other than itself and one? Well, I know what it is to be a prime number. If someone wonders whether he might not at least conceive of something greater than God, then he doesnt know what God is he hasnt grasped the concept. He might as well wonder whether or not Clos des Mouches is a wine....

There was a brief pause, which Morse did not think to break. Secondly, Charpentier continued, we observe that something which really exists is better than something which, however similar in other respects, is merely imaginary.

Im not so sure about that, said Morse, rashly. After all, Id rather have an imaginary hangover than a real one.

Charpentier chuckled. I really think, my dear Charles, that your head is not made for philosophy. I meant, of course, that if something is a good thing and you will allow that if anything is a good thing, then God is that if something is a good thing, then a real sample of it is greater than an imaginary sample. It is true that the German Kant once claimed that a thousand imaginary euros were just as valuable as a thousand real euros; but I believe that he recanted before his next months salary was due. For existence, as my compatriot Descartes pithily put it, is evidently a perfection: a good dinner well digested is more perfect than a good dinner well imagined. And that, Charles, is that. We see that something which really exists is greater than something similar which does not exist. So if God didnt really exist, then we could conceive of something greater namely, something which was just like Him but which really did exist. But we know that we cannot conceive of anything greater than God. So, necessarily, God exists. QED.

Morse sat up with a start: he hadnt imagined that anything philosophical could be over so quickly. Very clever, for a saint, he said; very, very clever. But, you know, I cant say that Im quite convinced.

Convinced! exclaimed Charpentier. What has conviction got to do with it? Do you think that your Anselm was convinced by his argument? Of course not he believed the conclusion long before that moment of insight. He didnt need an argument to convince him, and I daresay he didnt think that his argument would or should convince anyone else. What he wanted to do was not to convince a sceptic but to prove a fact. If you tell Euclid that his proof of Pythagoras theorem doesnt convince you, will he care? Not a jot. Hes not in the business of persuasion that is something for preachers and politicians. His is a higher calling: he offers not persuasions but proofs.

So Anselm found a proof that God exists?

Well, he certainly gave us philosophers something to think about. It is true that youll find few enough of us who hold that the argument is a genuine proof; but although most philosophers agree that the argument goes wrong at one point or another, no two of them agree on the where and the why. Thats what makes it such an exquisite argument.

It was late, and Morse was tired. But he was feeling benevolent. Let us not worry about your bickering colleagues; tell me what you think about the argument yourself. Generosity is sometimes rewarded, even in Paris. It is not for me, said Charpentier, to assess the excogitations of an English saint. But I think that we might each assess another drop of this excellent French cordial.