Anselm’s Ontological Argument
Anselm's ontological argument purports to be an a priori proof of God's existence. Anselm starts with premises that do not depend on experience for their justification and then proceeds by purely logical means to the conclusion that God exists. His aim is to refute the fool who says in his heart that there is no God (Psalms 14:1). This fool has two important features.
- He understands the claim that God exists.
- He does not believe that God exists.
Anselm's goal is to show that this combination is unstable. Anyone who understands what it means to say that God exists can be led to see that God does exist. On this view, the atheist is not just mistaken: his position is internally inconsistent.
What follows is an attempt to clarify the argument as it is presented in Chapter II of the Proslogium. The argument in Chapter III (3) is rather different, and in some ways more interesting. After you have worked through this page, you might try to produce a similar gloss on the second argument. This will not be easy: the argument is notoriously complicated. But you might find it a useful exercise nonetheless.
In the area marked A we have things that exist in the understanding alone; in the area marked B we have things that exist both in the understanding and in reality; and in the area marked C we have things that exist in reality but not in the understanding. (For obvious reasons, we cannot give any concrete examples of the last category.)
At this stage the fool has conceded that God exists in the understanding: so God belongs either in A or in B. Anselm now argues that God cannot exist in the understanding alone. The argument seems to proceed as follows.
(1) Suppose (with the fool) that God exists in the understanding alone.
(2) Given our definition, this means that a being than which none greater can be conceived exists in the understanding alone.
(3) But this being can be conceived to exist in reality. That is, we can conceive of a circumstance in which theism is true, even if we do not believe that it actually obtains.
(4) But it is greater for a thing to exist in reality than for it to exist in the understanding alone.
(5) Hence we seem forced to conclude that a being than which none greater can be conceived can be conceived to be greater than it is.
(6) But that is absurd.
(7) So (1) must be false. God must exist in reality as well as in the understanding.
This reading of the argument is amply confirmed by the final paragraph: