For years, many arguments have been proposed by philosophers, theologians, scientists, and others to prove that God does exist. St. Anselm‟s Ontological Argument is certainly one of the most famous arguments in the history of philosophy. Anselm argues for the existence of God based on deductive reasoning and inferences of existence. He gives an a priori proof of God's existence with premises that logically entail to the conclusion that God exists. In this paper, I will briefly present the Ontological Argument and will demonstrate prominent objections made by Gaunilo, Malcolm, and Craig and Moreland to evaluate the validity and soundness of the Anselm‟s Argument. Ultimately, I will try to conclude that Anselm‟s argument is not valid since he bases his notion of the existence of God on existence-in-understanding, not existence-in-reality, there is no concrete, factual proof that God exists in reality, and therefore he cannot exist.
2. Anselm‟s Argument.
Anselm presents his argument based upon reductio ad absurdum by using reason and logic in order to draw a conclusion that it would be absurd to reject God's existence. He formulates the argument in two parts; "What is God?" and, "Is existence necessary for being that than which none greater can be conceived?"According to Anselm, the being that than which none greater can be conceived exists in the understanding. Since what can be conceived to exist in reality is greater than what is conceived to exist only in the mind, that than which none greater can be conceived cannot exist only in the understanding. Therefore that than which none greater can be conceived must exist both.
in the mind and in reality. So, this argument is not based on any observations of the external world, nor any kind of experience or knowledge. It attempts to prove the God‟s existence from the attributed meaning of the word God by using logic.
3. Objections.
Gaunilo was the first philosopher who argues against the Anselm‟s argument with his commonly known the "Dream Island" objection.