ANSELM'S ARGUMENTS FOR THE EXISTENCE OF GOD
William A. Wisdom

Not long ago I gave to a monthly meeting of the Freethought Society of Greater Philadelphia a talk on the rational justification of my major views on religion.

Tucked away in that talk were these remarks: "If God is to be an adequate object of characteristically religious devotion, of absolutely unqualified commitment, (a) He has got to be something that exists of necessity--not merely contingently, the way people and rocks and chairs and galaxies exist--and (b) the reasons for believing that He exists must guarantee His existence, and not merely make it likely that He exists....No appeal to observable facts can guarantee the existence of a necessary being. Only some sort of Ontological Argument for the existence of God--deducing His existence, of logical necessity, from some unavoidable concept of deity--could do the job. I don't think that an Ontological Argument can be as easily refuted as most commentators do. I think that there is a deductively valid inference to the conclusion 'God exists' from unassailable premisses."

I offer here the argument I had in mind, to challenge non-believers to an exercise in critical thinking. I first present this argument as a commentary on the arguments of St. Anselm of Canterbury (1033-1109). Can you say, clearly and without question-begging, what if anything is wrong with this proof that there is a God?

I'm going to try to get to the heart of Anselm's arguments for the existence of God. I'll find that he presents two importantly different arguments--one in Chapter 2 and the other in the first half of Chapter 3 of his Proslogion. I'll try to show that these two arguments have exactly the same structure. And, further, I'll argue that they are both valid.

In both arguments, Anselm holds that the word God means that than which a greater cannot be thought (= ttwagcnbt). This captures what we mean by supreme being or most perfect being; his version of the concept is greatest conceivable being.

In Chapter 2, he distinguishes between "existence in the understanding" and "existence in reality". When he says that something exists in someone's understanding he simply means that that person has the concept of the thing. When he says that something exists in the understanding alone, he means that it doesn’t really exist, even though we have the concept of that thing. Because I know what the Loch Ness Monster is supposed to be, but don't think that it exists, I claim that the Loch Ness Monster exists in the understanding alone. Anselm holds that existence in the understanding and in reality is greater or more perfect than existence in the understanding alone. Roughly, this means that what actually exists is greater or more perfect than what does not actually exist: existence is a "good-making property", a property that improves its possessor, a property that it's better to have than not to have. An existent ship is "greater" than a non-existent one, an existent friend better than a non-existent one.

With these preliminaries, the argument proper proceeds thus: We do have the concept of God as ttwagcnbt. Suppose that ttwagcnbt does not actually exist (i.e., exists in the understanding alone). Then, because you could imagine that thing as actually existing, that than which a greater cannot be thought would be that than which a greater can be thought. But that’s impossible--that ttwagcnbt is not ttwagcnbt. So God must actually exist!

The logic of this is simple and valid. A contradiction is a statement that can't possibly be true. If some proposition P logically implies a contradiction, then P is necessarily false. That is, if the truth of P would guarantee that a contradiction was true, then P can't be true. The assumption that God doesn't exist implies that ttwagcnbt is not ttwagcnbt. So the assumption must be false, and God must exist.

Notice that this argument, if successful, would establish only that God shares with me the property of existence. That's O.K., of course; but someone might well feel that God's is a different kind of existence than mine--that it's not good enough, for religious purposes, for God to exist in the same sense that I do. The argument of the first paragraph of Chapter 3 is meant to prove not that God exists (that's already been done), but that His is a unique kind of existence. Here Anselm says not that what exists is greater than what does not, but that a thing whose non-existence is inconceivable is greater or more perfect than a thing whose non-existence is conceivable. Here the good-making property is inconceivable non-existence, this being the property a thing has if it cannot be conceived not to exist. (You can, if you want, think of it as the property of necessary existence.) The core of the argument comes in sentences 3-5 of Chapter 3: if God’s non-existence is conceivable, then ttwagcnbt is not ttwagcnbt. This is impossible. So God's non-existence is inconceivable--His existence is necessary. In this respect, of course, God’s existence differs from that of any natural thing, whose non-existence is always conceivable. Lots of things have existence; but only God has inconceivable non-existence--necessary existence.

So each of the arguments has this structure: If God lacks property X, then ttwagcnbt is not ttwagcnbt. This is impossible. So God has property X. In Chapter 2, property X is existence. In Chapter 3, property X is inconceivable non-existence, or necessary existence. This sort of argument is obviously valid. Further, it seems legitimate enough to conceive of God as a thing than which a greater cannot be conceived--i.e., as the most perfect being possible. This seems the hard core of the conception of God in the major western (i.e., near-eastern) religions: Judaism, Christianity, and Islam.

So if there's something wrong with Anselm's arguments, it would take more analysis to show it. Can you do it--calmly, clearly, and rationally?

I can abbreviate the argument somewhat. Grant, for the sake of argument, that there could be a God--that God's existence is not impossible: this just means that you're open-minded on the issue. Now by virtue of what you might call the "anti-idolatry clause" of the major western religions, God's existential status (His non-existence or existence, as the case may be) is not contingent: whichever way it is, it has to be that way. By virtue of a minimally adequate conception of God, His existential status can't be like that of the Loch Ness monster if God doesn't exist (for the non-existence of the Loch Ness monster is contingent) or like that of the Blarney Stone if He does exist (for the existence of the Blarney Stone is contingent). So it's either impossible or necessary that God exists. Therefore it's necessary that God exists. (I hope you've been following closely enough to see why.)

Copyright © 2004, William A. Wisdom