The ontological argument

An ontological argument is an attempt to prove the existence of God using logic alone. It is one of those things that I had come across a few times in the past but  never took the time to understand.  So, when a blog post by Nathan Schneider on this topic appeared last week in the New York Times, I finally tried to follow the argument.  There have been many attempts at an ontological proof throughout history.  Schneider wrote about an early one from the eleventh century by an English Catholic Bishop named St. Anslem of Canterbury.  I couldn’t really understand Schneider’s somewhat poetic version of the proof but after reading several other versions on the web I think I finally get it.  It is actually quite clever although it obviously must make some assumptions that are not self-evident.

Here’s the proof:  The first assumption is that God is the greatest possible being that can be conceived.  The second assumption is that existing and being conceived is greater than not existing and being conceived.  Hence, God must exist, since a God that exists is greater than a God that doesn’t exist.  Another way of saying this is that the fact that I can think of a God implies that she must exist.  In some sense, this is a precursor to modal realism.

There have been many historical criticisms of this proof.  Kant’s critique is that existence is not a predicate.  By this he means that existence is not a property of an object.  For example, a unicorn has properties such as having a horn, looks like a horse and so forth.  But a unicorn could exist or not exist and that doesn’t change what a unicorn is. So existence is something that must be inferred empirically and can never be deduced a priori.  I think Kant effectively kills Anslem’s proof. However, another weakness in the argument is that Anslem assumes that the set of all conceived beings has an upper bound.  This may not be true as well.  There could be an infinite hierarchy of Gods, a possibility that has interesting philosophical consequences as well.

3 thoughts on “The ontological argument

  1. Anslem’s proof seems to say that the existence of God is related to conception and more specifically, the greatness of the concept. Just for fun, run this idea out a bit. The essential nature of the conceiver seems to imly some interesting things about God.

    God gets greater as we get better at conceiving her. Conceivers are all in the hierarchy of gods because we, in fact, overthrow a god every time we upgrade our conceptions. That is, we are next to God, ahead of all other previous gods. Monotheism is is assured in this system. There can be only one “greatest conceived” at a time. And by extension only one “greatest conceiver”, one adherent to the true God at a time. Everyone is a heretic most of the time. And so on…

    I agree that Kant’s attack on this proof is convincing. But it also seems Anslem had a very different metaphysical model of subject-object-perception. He doesn’t seem to be encumbered by a concept requiring a conceiver. Anslem seems to get on fine with disembodied concepts. I guess this Concept would be what is in the Platonic Mind?


  2. There could also be a Bayesian interpretation where you can gain more information and conceive more of God, rather than overthrowing God. I also agree that you could form the proof by simply saying that God is the greatest possible being and existence is a greater property than nonexistence. However, conception would give an a priori reason for why existence is better.


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