Similarly Kant agreed, he stated that a person can define something but whether it fits into reality is a different question, saying something exists does not tell us anything about it.
Descartes, a rationalist philosopher, was a strong supporter of the ontological argument; he said that existence can’t be separated from God just as the idea of a mountain can’t be separated from the idea of a valley. The point he was trying to get across was that God would not be God if he didn’t exist; existence is a predicate of a perfect being. Benevolence is listed as one of the established characteristics of God, thus, as existence is part of the essence of God, He must exist. Descartes dismissed Gaunilo’s argument against Anselm as he believed the ontological argument could only apply to a completely necessary and perfect being thus, he argued, it can’t be applied to the example of the ‘perfect island’.
St. Thomas Aquinas completely disagreed with the ontological argument; he accepted that it would be impossible to have a mountain without a valley and a triangle with more than three angles, as the predicates follow from the subject. However, this does not really tell us much at all, it does not prove the existence of a triangle or a mountain instead it only tells us about the idea of one, not the actual thing. I can claim to have a belief in fairies and then go on to say that all Fairies have wings and that this is a necessary property of being a fairy, but I don’t actually prove the existence of Fairies.
Immanuel Kant, the philosopher who gave the ontological argument its name because of what he perceived to be an absurd leap from ideas to actual reality put forward many objections to the argument, including the claim that a predicate of a perfect being, such as God, is not existence. The reasoning for objections like this come from Kant’s view that you need evidence from experience to evaluate whether God exists, he could not accept perfection as a way of proving God’s existence or the idea that existence is part of the essence of God. Kant basically explained how it is logical to accept that the existence of God is necessary if you accept that there is a God but he argued that you do not have to accept there is a God. To Kant the statement “God exists” is synthetic because it can only be proved through experience.
Anselm’s Prosologion can not be viewed as a piece of actual philosophy because Anselm, who was a believer, addressed God in it and as a consequence the Prosologion is more like a prayer. The reason why this is so important is because Anselm is writing from a particular point of view, he already believes in God and sees no reason in which this existence can be denied, it can therefore be argued that his argument has a heavy underlying bias as he is trying to understand what he already believes not evaluate it in any serious way. God exists to Anselm because he is a theist.
None of the arguments for the existence of God contain anything that can be considered conclusive proof of some form of deity. Despite this some academics argue that this does not actually matter because, to them, a religious belief does not need to be backed up by arguments, you can have a belief in something without needing any proof other than the faith that guides you.
Anselm’s explanation for the proof of God as necessary is quite clearly absurd, just by claiming that a being which “noting greater can be conceived” must therefore exist is illogical, as Gaunilo points out, you can’t simply think something into existence. It would appear that the ontological argument can be perceived as an argument that manipulates language in order to gain substance and meaning, but when you take this view you must also accept that it is not a very convincing argument. I can assert that “Father Christmas is an old man with a beard” yet this does not mean that Father Christmas actually exists! To accept the ontological argument there must be more than a definition of what God might be if he existed. Consequently, it could be argued, the statement “God exists” is synthetic and not analytic because it has to be proved to be believed.
