Descartes Version of the Ontological Argument

Rene Descartes (1596—1650)

Descartes pic

What was Descartes version of the Ontological Argument?

Descartes Ontological Argument uses the example of triangle to try to prove God’s existence. His argument is that existence is necessary to God as 3 sides are necessary to a triangle.  In this argument, existence is a predicate. Descartes writes this argument in his Meditations on First Philosophy.

What are the problems with Descartes Ontological Argument?

Kant argues against Descartes, saying that existence cannot be a predicate, because it does not add value to something. For example, when I describe my Jack Russell Terrier, I say that he is a small dog with white fur and a black spot on his back. I don’t then say ‘and he exists!’

The Ontological Argument for the Existence of God

The Ontological argument for God’s existence is often the most difficult to understand.  I would like to simplify the argument and break it down into easy understandable steps! The Ontological argument is a popular exam or essay question in AS, A-Level and degree level philosophy.

The Ontological argument was first asserted by St. Anselm. It is the only A Priori argument for God’s existence. That means that it derives from logic and reasoning rather than from experience.

The Ontological argument according to Anselm in 4 easy steps…

1. Anselm defined God as ‘a being than which nothing greater can be conceived’.

2. If we conceive of a God that has existence, and a God that does not have existence, which would be greater

3. If God with ‘existence’ is greater than God without existence, it follows that God must have existence in order to be ‘a being than which nothing greater can be conceived’.

4. Therefore, God must exist.

Get it?  No? Ok, imagine a Mars bar in your mind. If you look in the cupboard and find a Mars bar that actually exists, you can eat the one that has existence, but not the one in the mind. Therefore the Mars bar in reality is greater than the one in the mind.

Criticisms of Anselm’s Ontological Argument

In Anselm’s argument, God appears to have necessary (rather than contingent) existence. Whether or not necessary existence is possible is another matter. Also, it could follow that using Anselm’s logic, you could conceive of anything at all coming into existence! If you are interested in looking at the criticisms of the Ontological argument in more detail, have a look at Gaunilo. He criticised Anselm by saying that using this logic, he could think about the most perfect conceivable Island, and that the one in reality would be more perfect than the one in the mind, therefore it must exist!

Further Reading on the Ontological Argument for God’s Existence

An excellent book on the arguments for God’s existence is John Hick. For more further reading, click here.