The Ontological Argument for the Existence of God

What is the Ontological Argument?

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.

Ontological argument for the existence of God

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.

4 thoughts on “The Ontological Argument for the Existence of God”

  1. It would be helpful if you also presented St. Anselm’s reply to Gaunilo.

    A key difference that St. Anselm points out is that ‘that which nothing greater can be conceived’ is not the same as saying ‘the greatest being’.


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