Outline the Ontological argument for the existence of God and consider the view that, while it may strengthen a believer's faith, it has no value for the non-believer.
The word "ontology" is a Greek word relating to the concept of being. The ontological argument itself therefore an a priori argument that argues the existence of God by saying that He must necessarily exist. This argument is very important for religious believers, but has come under criticism from those who do not believe who say that it is flawed.
St Anselm introduced the first form of the argument in his book Proslogion and claimed that God was "aliquid quo nihil maius cogitari possit" which means nothing greater can be conceived.
In the next stage of Anselm's argument, he wanted to demonstrate that it is impossible to conceive of God not existing. God is eternal and, therefore, must be. Anselm felt that he had demonstrated not only the existence of God but also that his existence is "necessary" (must be).
Descartes developed Anselm's argument. His definition of God as a "supremely perfect being" is the basis of his argument. From this, Descartes believes we can conclude that God exists because existence is a predicate of a perfect being; Therefore, God must exist to avoid being self-contradictory. Descartes says that to imagine God without existence is like imagining a triangle without three sides.
Philosophers have also considered this argument in more recent times such as Norman Malcolm (necessary existence) and Alvin Plantinga (possible worlds). Iris Murdoch also pointed out that the ontological argument is not simply a piece of logic, but something that points to a spiritual reality that transcends any limited idea of God. However, this argument has also had its fair share of criticisms.
Gaunilo opposed Anselm, putting forward his own argument of the most perfect island. He said that if you were to believe this island must exist because of its perfection then you are a fool.