The Ontological Proof

I’ve always felt that the ontological proof of the existence of God was one of the more compelling and interesting arguments about God. The proof, which was originally composed by Saint Anselm, amounts to a simple syllogism:

1) God is, by definition, the most perfect entity.
2) Something which exists is more perfect than something which does not exist.
3) Therefore, God exists.

It’s a natural first response to dismiss this argument as mere logical legerdemain, confusing words with their meanings. But I think that sort of thinking misses the real power of an omnipotent entity. For God, being omnipotent and encompassing the whole universe, thoughts are indistinguishable from actions. The universe as a whole is simply than the thoughts of God. If God thinks “what if Ian went to bed instead of writing in his blog” there would in effect be two different universes, albeit perhaps only temporarily. I don’t think we can casually dismiss the ontological argument without understanding that for God, words and meanings are the same thing. Or, to put it another way, the syntax is itself semantics.

I think the weak point in the argument is the notion that existence is more perfect than non-existence. I think existence implies change. If something truly never changes, then in what sense does it exist? The only way to not change is to not be subject to time. But how can we speak of something existing without speaking of some time in which it exists? (The observant reader will note that I am resorting to rhetorical questions, a sure sign of a shaky argument. These are definitional issues, but the definitions are the key to the ontological proof.)

The next step is to observe that if God changes, then it follows that God is not always the single perfect entity. If there are multiple possible perfect entities, then it follows that there are multiple Gods, which is not satisfactory. So there must be only one perfect entity. And it must never change.

So, since perfection implies not changing, and existence implies changing, it follows that non-existence is more perfect than existence. And thus we see that the ontological proof actually proves that God does not exist. At least not if we define God as the most perfect entity.

On a related topic, here is a brief consideration of the old schoolyard riddle: “Could God create a rock so heavy that He (or She) could not lift it?” As mentioned above, since God is omnipotent, any thought is reality. As Dante put it, “this has been willed where that which is willed must be.” So another way to put the question is “could God choose to never think a particular thought (namely, to lift that rock)?” Or, to put it yet another way, “could God lose the quality of being omnipotent?” I think the answer to that question has to be no: I don’t believe that an omnipotent being can cease being omnipotent. God might never, as a matter of fact, lift the rock. But it is not possible for God to be unable to lift the rock.


  1. tromey said,

    December 25, 2005 @ 3:27 pm

    I was thinking about this today, and there is an even more
    fundamental objection to step 2. Namely, nothing in our experience
    indicates that something that exists is more perfect than something that
    does not exist. Quite the opposite in fact — for instance we talk of Platonic
    ideals, which are the superior form; with reality being shadows projected
    on a wall. Also the imperfection of reality is a common, and generally
    well-founded, argument against Marxism, anarchism, libertarianism, and
    other idealist doctrines.

    I think this is actually a proof that God is an idea, or more likely that the concept
    of “perfection” is somehow incoherent.

  2. fche said,

    December 31, 2005 @ 6:19 am

    > I don’t believe that an omnipotent being can cease being omnipotent.

    Maybe, but I’ll bet she can make you believe otherwise.

  3. Ian Lance Taylor said,

    December 31, 2005 @ 1:06 pm

    > > I don’t believe that an omnipotent being can cease being omnipotent.

    > Maybe, but I’ll bet she can make you believe otherwise.

    I know it’s just a joke, but I want to point out that it may be incorrect. Clearly God could simply present arguments to convince me that I am wrong–an approach which is available to any thinking person. But I don’t think it’s coherent to argue that God could reach down and simply change my beliefs, because that would turn me into a different person. That is, there would be a new person, similar to me, with different beliefs, but it would not be me.

  4. fche said,

    January 3, 2006 @ 9:02 am

    … or rather, she can make you think that you are the same person, despite the interference.

    That’s one problem with the notions such as omnipotence. They seem to be either too fluffy (“can do anything!”) or paradoxical (“can lift the unliftable?”) or redefined as convenient (“can do anything, except those things that cause problems for my argument” :-).

  5. Ian Lance Taylor said,

    January 3, 2006 @ 10:34 am

    The Scholastic philosophers, including Saint Anselm and, most famously, Thomas Aquinas, thought about what it means to say that God is omnipotent. They took it to mean that God can do anything which is not a logical contradiction. For example, God can not make an object which is a single color which is both green and non-green, because that would be a contradiction. On the other hand, God could certainly make the object appear green to some people and non-green to other people.

    You’re right of course that God could change my mind and make me think that I am still me. When I say that I would be a different person, I’m basically making a definitional statement.

    More generally, I was trying to get at the idea that people’s beliefs are not like light switches. You can’t flip them independently. They are interconnected at many levels. Changing one belief means changing the whole system. God can presumably bypass that in some supernatural way. But if we assume that God will want me to continue to be a normal human with no supernatural adjunct, then it is not possible to change one belief in isolation. But in any case I agree that God could certainly arrange for me to believe that I am still me.

  6. fche said,

    January 3, 2006 @ 12:19 pm

    It may be interesting to read how exactly Aquinas etc. reason “logical contradictions” as an ungodly behaviors, but miracles as godly ones. It’s as if a contradiction in the platonic abstract world is verboten, but a contradiction in the natural world is okay.

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