One argument used to rationally support the existence of God is the ontological argument. There are many forms of ontological arguments, one of the main perspective of it comes from Anselm. The context of Anselm’s argument is that by logic, God must be an existing being hence nothing greater can be imagined.
Anselm wrote his popular form of the argument in his ‘Proslogion’. He had 2 forms to the argument. The first form said that humans can define God’s being in their mind “That than which nothing greater can be conceived” which refers to the fact that God is the greatest possible being which can be thought of. He also mentioned that God may exist either in the mind alone (in intellectu) or in the reality as well. This logically meant that something which exists in reality as well as in the mind is greater than something which exists in the mind alone. Therefore, as the greatest possible being, God exists in reality and the mind.
The first argument shows that existence is a predicate of God. Back to Anselm’s fundamental basis of the argument ‘God is that being nothing greater than which can be thought of’, this implies that something that cannot be thought of not to exist is much greater than that which can be thought of not to exist. Therefore it is impossible to think that this being cannot exist, this being is God and therefore God must exist. Anselm also argued that even an atheist would agree with this statement hence God is the most perfect being that can possibly be imagined. In Anselm’s second part of the argument which he constructed, he said that God is the ultimate source of perfection, just like the Sun. God is a necessary being, who is not contingent, he does not depend on others for existence.
The Essay on St Anselms God Necessarily Exists
... St. Anselm's definition of God, or if you do not believe to exist is greater than not to exist you cannot use this argument. The argument only ... reality. Therefore God exists. Now then, anyone who truly believes the definition of God can still say God does not exist in their mind. However, in ...
The Benedictine monk Gaunilo labelled Anselm’s attempt to show God as necessary as ‘unintelligible’, he is not trying to disprove God, but he thinks there is something wrong with Anselm’s theory. Gaunilo argued that the fool can have in mind many things which do not exist in reality. For example, someone hearing about a person through gossip, which is, however, unreliable and the person and event in question were made up to trick you. So, Gaunilo implied that you cannot demonstrate the existence of something by just having an idea about it; you cannot define it into existence. He then came up, and put forward an idea of a most perfect island and he used the same argument as Anselm to prove its existence and he concluded that whilst it can be conceived, it does not mean it exists.
