Anslem starts his argument b saying God ‘that than which noting greater can be conceived.’
According to this definition God, is the greatest, most perfect being possible. Then Anslem goes on further to argue that God must exist or it would not be ‘that then which noting greater can be conceived.
Anslem’s has two arguments written in his book Proslogion. In his first argument he says that god exist, both in understanding and in reality. According to Anslem, everyone has some idea of God in their understanding. He says that God has to exist in both reality and in the idea in the mind. For example like a unicorn, we have a picture in our mind but they don’t really exist, and if God is ‘that then which nothing greater can be conceived’ unime the unicorn, it has to exist in reality or there would be a disagreement.
In the second argument Anslem says that God cannot be conceived not to exits. He believes this because God that cannot be thought not to exist is greater than anything that can be thought not to exist. For5 somebody to say that God can not exist would be a contradiction because God is ‘that than which noting greater can be conceive,’ therefore god has to have an existence.
In his second argument Anselm concludes that God cannot be conceived not to exist. This is because he believed that something (in this case God), which cannot be thought not to exist, is greater than anything which can be thought not to exist. To say “God does not exist” would be a contradiction as God is, “that than which nothing greater can be conceived” and so God has to have existence.
When one of the Anslem’s arguments is criticised by Gaunilo with his argument, On Behalf of the Fool, Anslem’s replies and say that anyone can think of a perfect island but this does not mean it has to exist, whereas God is unique. Also Anslem argues that only Gid has all perfections and so the argument an only relate to God. Anslem also believed that God is a necessary being (one which cannot not be) not a contingent being. He concludes by saying that God has a necessary existence and is unreasonable to think that he is not.