Kant and the Ontological Argument

a) Explain how Kant challenged the ontological argument

The ontological argument is unlike most other arguments for the existence of God because it claims to be a priori; that is to say it is a demonstration that something must be true, as opposed to just deducting the probability of something being true using our senses and experience. The idea was first put forward by an Archbishop of Canterbury who lived between 1033 and 1109, Anselm. He attempted to prove the existence of God by way of reductio ad absurdum of atheism. There are two stages of Anselm’s ontological argument; the first demonstrates that God must exist, and the second shows that God has a necessary existence.

The first part of Anselm’s argument is taken from Chapter two of his book Proslogion. Anselm started by creating a definition of God as ‘a being greater than which nothing can be conceived’. This being must possess all perfections to be described as such and cannot be lacking in anything. Anselm therefore believed that such a being must exist in reality and not just only in one’s mind for if it was only a concept then it would be lacking in existence and therefore would not possess all perfections. For something to exist in reality is greater than for something to exist only as a concept therefore the greatest possible being must exist in reality. According to Anselm for an atheist to state that God does not exist is contradictory and he therefore is a fool. If an atheist understand the concept of a God that greater than which nothing can be conceived then he could not say that it does not exist, for if it existed in only the mind than it would be possible to conceive a greater being that is the same but existing in reality as well as the mind. For an atheist to reject the idea of God they must have some sort of concept of a God in their mind and, according to Anselm, the logic of their own concept proves God’s existence.

To put this in a clearer way we know that God must exist or not exist...