Anselm's Ontological Arguments

(Originally written March 6, 2007 in Book 13)

Ontological Arguments

The ontological argument is supposed to leave the realm of experience and enter the realm of pure reason.

Some proponents of the ontological argument have stated that the existence of God is more necessary than the conclusions of mathematics.

Anselm of Canterbury (1033-1109) authored the argument as a "proof from prayer". Kant labeled it the ontological argument.

Anselm's First Ontological Proof

1. God is by definition that than which nothing greater can be conceived.
2. It is one thing to exist in the understanding only and another thing to exist both in the understanding and outside the understanding.
3. It is greater to exist both in the understanding and outside the understanding than in the understanding only.
4. Therefore, God must exist both in the understanding and outside the understanding. If he did not, then we could conceive of One who did, which would be greater. But God by definition is the greatest Being conceivable. Hence, God must exist.

Another way of stating it:

1. Whatever can be predicated of the most perfect Being possible must be affirmed of it.
2. It is possible to affirm a real existence of the most perfect Being possible.
3. Hence, a real existence of the most perfect Being must be affirmed.

Negative Form:

1. Nothing possible can be denied of the most perfect Being possible.
2. Real (extramental) existence is possible for the most perfect Being possible.
3. Therefore, real existence cannot be denied of the most perfect Being possible.

Anselm's second form of the Ontological Proof

1. It is logically necessary to affirm of a necessary existent what is logically necessary to the concept of such a Being.
2. Real existence is logically necessary to the concept of a necessary Existent.
3. Hence, it is logically necessary to affirm that a necessary Existent really exists.

Negative form:

1. It is logically impossible to deny what is necessary to the concept of a necessary Existent.
2. Real existence is logically necessary to the concept of a necessary Existent.
3. Therefore, it is logically impossible to deny real existence of a necessary Existent.

The first form is based on predictability of existence to an absolute perfect Being. The second form is based on the inconceivability of the non-existence of a Necessary Being.