The Ontological Argument (Tutorial Group Write-up) [For a comprehensive account of my lecture notes and a discussion of Gaunilo's Island Objection see below.]


1. a)
God is the greatest conceivable being.
God exists in the mind.
Existance is a great-making quality.
.:It is an absurdity to conclude that God does not exist in reality, as
that would mean the greatest conceivable being could, conceivably, be
greater if it existed, making that which is only in the mind the second
greatest conceivable being.

b)
The most obvious flaw in Anselm's argument is his presumption that
existance is a greatmaking quality. If you can fully conceive of
something in your mind, its mere existance in reality is not going to
impress you any more. This is only the case if you have in fact not
fully conceived it.
To use a typical example: there is no cure for AIDS. Some say that if a
person could form an exact mental image of what the cure would be (how
it would look, how it would work, what it was made from, etc) the
resulting cure would be inferior to an identical counterpart that
existed in reality.
I would argue that if a concept is a fully identical and accurate conception of its object, then the object's existence in reality cannot make the concept any greater than it already is [see Kant's Thalers example below for another account of this.]. If I see a diamond ring in an ad, and then
receive the same ring for Christmas, it is not the ring that has
changed and become greater, but my reactions to it. Likewise, a cure
for Aids would not be greater if it existed in reality; the lives of
the people affected by Aids, and consequently cured, would be altered.
If this premise of Anselm's argument is false, the whole argument
collapses. The absurd conclusion that is necessary to reach his real
intended conclusion is no longer an issue. If existance is not a
great-making quality, then it is perfectly acceptable that the greatest
conceivable being might only exist in ones mind.