The Ontological argument is Anselm of Canterbury’s main argument, which concerns the inference of God’s existence based on premises that are supposed to come from some source other than observation of the universe, such as reason alone. Anselm defines God as “that than which nothing greater can be conceived” (Cahn), arguing that the being resides in everyone’s mind, even those who do not believe in Him. This led him to the conclusion that if the best possible exists in the mind, it must exist in reality as well. Denying the presence of God, the greatest possible being, according to Anselm, is self-contradictory. Anselm holds that it is self-contradictory to deny the existence of God, the greatest possible being. This view has however attracted criticism from other philosophers on various basis.
One of the earliest critic of Anselms ontological argument monk Gaunilo of Marmontier who ironically did not identify any specific fault but argued that something must be wrong with it. According to him, there exist no logic that can be used to prove things that people have no reason to be true. In proving this point of view, Gaunilo constructed an argument with the same form but used perfect island instead of greatest possible being (Cahn). According to him, if we assume Anselms argument holds, it would be possible to conceive the existence of perfect Island, which then must exist, an argument he termed as being absurd (Davies). Since such an assertion would not hold in the real life then the Ontological argument constructed by Anselm does not hold. Gaunilos own assertion has also been criticized on several bases. For instance, the concept of Perfect Island has been found to be incoherent and difficult to be defined, and therefore its existence is in question. This is contrary to the concept of perfect God expressed in Anselms argument, where the concept of God is coherent with power, knowledge as well as the quality upper limits hard to be passed. Despite this criticism, Guanilo expresses a strong criticism of Anselms ontological argument, which cannot be ignored.
Another major critic of Anselms ontological argument is Immanuel Kant who argues that it rests on a confusion. Kant argues that existence is not a predicate, a property that a thing may either possess or otherwise. This implies that if we say that God exists, we are simply saying that there is God who is in possession of property of existence. The other argument would be if we believe God do not exist this would simply saying God is there but lacks the property of existence (Cahn). For instance, if we imagine and object and give it complete description including size, weight and color and assume that it does exist, this would not add anything to its concept. The object will remain the same as imagined whether it exists or not. Asserting the existence of the object is saying something about the world, which is possess something matching that concept, does not in any way translate to saying another regarding the object itself
Kants assertions, therefore, imply, it would be impossible to make a comparison of God that exists and one that does not. Both Gods would have the same qualities, that is the God does exist would be omnipresent, Omnipotent, Omniscient and other qualities the same way the God that does not exist would be. In another word, both Gods would be the same and none greater than the other thus the Anselms Ontological would not hold.
Anselms ontological argument is also disputed by Aquinas who despite believing of the existence of God, he does not agree with the view that this can be deuced through the concept of God. According to him, the ontological argument is based on the premise that everyone who hears the word God understands it well to signify a greater being than that can be thought. This is however not the case as different people have a different perception of God, thus ruling out the ontological argument which can only work with people defining the notion of God in a similar way. However, this criticism is disputed on the premise that the ontological argument can be restated even without defining the word God. Aquinas, however, advances a second argument that discrediting Anselms ontological argument. According to him, even if we make an assumption that everyone has the same concept of God, as a being greater than imagination, “it does not, therefore, follow that he understands what the word signifies exists actually, but only that it exists mentally” (Himma).
Anselm ontological arguments fail in many premises. Imagining the existence of a superior being does not prove its existence just as one cannot imagine the existence of a feature somewhere and assume this is true. The Ontological argument also fails due to the fact that something which is imagined will have the same quality whether it exist or not. Therefore having qualities such as omnipresent, omniscient, and others can be imagined of God whether he does or does not exist the qualities will remain. Moreover, the ontological assumption of everyone views God in the same light is not accurate, as different people view God differently.
Cahn, Steven M. “Exploring Philosophy: An Introductory Anthology.” (2009). Web.
Davies, Brian. “Philosophy of religion: A guide and anthology.” (2000). Web.
Himma, Kenneth Einar. “Ontological Arguments for God’s Existence.” (2015). Web.