A Critique of the Ontological Argument



The following is a brief introduction to the origins and logical flaws within St. Anselm’s famous Ontological Argument for the existence of G-d. Throughout the time since Anselm first formulated his argument, logicians and philosopher, including Kant, Gödel, and Aquinas, have struggled to reveal its apparent flaws. Through the study of this complex argument in the philosophy of religion, several advances in modern logic have emerged, including an understanding of the sensitive treatment of how to classify existence, whether it is a property of an object, or a quantifier within a logical system.

Throughout the years since St. Anselm of Canterbury first published the original version of his ontological argument for G-d’s existence in the Proslogium, many have come to criticize and analyze the logic behind his famous argument. What separates this argument from others in providing a formal proof for G-d’s existence, was that it had used entirely a metaphysical, a priori method of establishing the existence of G-d, rather than an empirical method as was used by the cosmological argument. St. Anselm was the medieval Archbishop of Canterbury, who lived roughly during the 11th century C.E. (A.D.) Anselm began his argument, claiming that there were two types of existent beings within this world, those who were necessary, that is beings who were needed to exist and contingent beings who existed, but whose existence was not entirely necessary. (3) He then continued to define G-d as “something that than which nothing greater can be conceived.” (1) Anselm then referred to Psalm xiv. 1 stating, “Or is there no such nature, since the fool has said in his heart, there is no God?” (1) He wished to eliminate the fool’s atheistic doubts, which were represented within the psalm, by proving that G-d existed, at least within the fool’s understanding. If he could establish this assumption, then he could lay out the rest of his argument. According to Anselm, even the fool could wholeheartedly admit that he has the ability to imagine “something that than which nothing greater can be conceived,” and that the fool could admit to having this notion within his understanding, even if he fails to see that G-d exists within reality. (1) He continues to claim that if something exists both in reality and within the imagination, then such an existence is greater than something, which exists solely within one’s mind. (1) By accepting this proposition, a reductio argument (a contradiction) can then be formulated, because by the combination of Anselm’s definition of G-d (that which none greater can be conceived), and the fact that the existence of something within the mind and external to the mind is greater than something merely within our minds, it must be by the definition of G-d, that it be existent outside our minds as well. Thus by the reductio argument, G-d must exist externally according to Anselm. Anselm states, “… assuredly that, than which nothing greater can be conceived, cannot exist in the understanding alone. For, suppose it exists in the understanding alone: then it can be conceived to exist in reality; which is greater…Therefore if that than which a greater cannot be imagined is in the understanding alone, that very thing than which a greater cannot be imagined is something than which a greater can be imagined. But certainly this cannot be.” (1) He draws a contradiction from this statement and thus by reductio ad absurdum, he concludes that there must be “something than which a greater cannot be imagined, both in the understanding and in reality,” which is G-d. (1)

Several criticisms of the argument had followed after Anselm first formulated it. The first such criticism was by a contemporary of Anselm, Gaunilo of Marmoutier, a Catholic Monk who rejected Anselm’s rationalization, attacking the reasoning behind the argument, using his perfect island example. His explanation of the problem with the ontological argument went as follows: all have the ability to distinctly conceive of a greatest, largest, most perfect island, but that such a concept within one’s understanding does not entail that such an island exists within reality. Gaunilo didn’t attack any of the premises of Anselm’s argument, but rather followed the argument’s logical steps to come up with a rather insane conclusion, thus weakening Anselm’s reasoning. If the argument had indeed been taken seriously, one could conceive of a perfect island, even a perfect dog, fish, or turtle, or anything for that matter, that must be true to exist within our mind’s understanding and thus exist in reality, by the very definition of “that which none greater can be conceived.” It appeared that Anselm’s argument had suggested that through the definition of something, one could define anything into existence. (2) There are however some notable problems with Gaunilo’s objection, because it used an example of an island, the sort of object, whose properties and qualities of perfection fail to have intrinsic maximum limits of degree, (ex: length, amount of trees, etc. fail to have an ultimate maximum conceivable degree of perfection), unlike Anselm’s argument which is a proof for the existence of G-d, whose properties are intrinsic maximums (maximum good, maximum truth, etc.). Thus according to philosopher C.D. Broad, Gaunilo’s objection cannot be fully applied to Anselm’s situation. (2)

St. Thomas Aquinas, an Italian, Catholic theologian and philosopher also criticized the ontological argument, claiming that the argument only had the ability to work for those who accepted the proposed definition of G-d given by Anselm, whereby many people felt that the definition of G-d might not necessarily be “that which none greater can be conceived,” but rather many believed G-d to be in the form of a body like the resurrected body of Jesus. (2) He continued to explain that G-d was an infinite being, and that finite beings such as ourselves might never come to fully comprehend such a greater being. Even if we take Anselm’s definition of G-d to be “that which none greater can be conceived,” literally, we as finite beings, could only turn to finite examples to be able to comprehend the definition of G-d, and might not fully be able to understand G-d through comparisons within our finite world and understanding of things. (2)

Immanuel Kant, the famous Prussian philosopher, had several objections to the ontological argument, found within the Critique on Pure Reason. Kant argued against Anselm’s premise that things which exist both in reality and in the mind, are greater than those things which solely exist within the mind. He proposed that adding such a premise to the ontological argument, forces existence to be viewed as a property of a concept, and that existence cannot be thought of as a property (later on it would come to be defined as a type of logical quantifier). (2) Because modern logic hadn’t been available to Kant during the late 18th century, he had creatively used the relationships between subject and predicates of sentences to indicate why existence should not be categorized as a property, where a predicate represents the properties of the subject of the sentence or concept. Philosopher Alvin Plantinga had simplified Kant’s ambiguous argument, which used a confusing subject predicate relationship, into a more modern perspective using logic. Plantinga explained that one should consider the example, that of the concept of a bachelor, which is defined as an unmarried man. By the definition of a bachelor, B the bachelor had certain properties (P1, P2, P3,…, Pn). (5) Using Anselm’s logic, a bachelor would be a contingent concept, “that is to say, it is not necessarily true that there are things to which this concept applies…the proposition there are bachelors, while true, is obviously not necessarily true.” (5) One could then claim that there had indeed been a super bachelor SB, with the property of existence E so that SB has all of the properties of being a bachelor and the new property of existence, SB(P1, P2, …., Pn, E). (5) It would appear that we had just defined a SB into existence by the new property E we assigned to it. Even after we have defined the concept of a SB with the property E, this does not entail that there are in actuality any SB, “all that follows is that…All the superbachelors there are exist.” (5) It also follows that because SB holds all of the properties that a B holds, every SB is a B. If a SB exists, then a B must also exist, but remember a B is contingent and so SB must also be contingent and so, it then becomes apparent that every B must also be a SB. It appears, as mentioned previously, that using such logic, one could define any concept they wished into existence, providing existence or being was used as a property in the sense Anselm had used in his argument. (5)

The most fascinating aspect of Anselm’s argument had not been the proof itself, but rather the criticisms, which arose by philosophers across the centuries, as a response to the logical formulation of the proof. The argument had sparked an increased curiosity into the study of the metaphysics of existence through the search for the inherent flaws within the constructs of Anselm’s argument. It is interesting to note, that even within the root of the word ontological, there lies the root, ont which is Greek for being and existence. Once more, for almost one thousand years, the argument seemed not only to inspire others, including Descartes, Leibniz, Goedel, and Plantinga, to improve upon Anselm’s proof and create their own formulations of ontological arguments, but also to analyze the argument and gain insight into the nature of logic through the study of metaphysics. Such inspiration ultimately led to several major advancements in our understanding of logic and the nature of existence and how it is to be handled in logical systems. The ontological argument sparked much debate, and as Bertrand Russell proposed, it is much harder to put one’s finger on exactly why the argument was flawed, rather than to be able to say that it was indeed flawed. (4)

Works Cited

1. “Anselm (1033-1109): Proslogium.” Medieval Sourcebook. 1998. Fordham University. <http://www.fordham.edu/halsall/basis/anselm-proslogium.html>.

2. Himma, Kenneth E. “The Ontological Argument.” The Internet Encyclopedia of Philosophy. 2006. Seattle Pacific University. <http://www.iep.utm.edu/o/ont-arg.htm>.

3. “Ontological Argument.” Wikipedia. 13 Mar. 2008. Wikimedia Foundation, Inc. <http://en.wikipedia.org/wiki/Ontological_argument#Anselm.27s_argument>.

4. Oppy, Graham. “Ontological Arguments.” Stanford Encyclopedia of Philosophy. 2007. Metaphysics Research Lab, CSLI, Stanford University. <http://www.science.uva.nl/~seop/entries/ontological-arguments/#GodOntArg>.

5. Plantinga, Alvin. “A Modal Version of the Ontological Argument, From God, Freedom and Evil.” Philosophy of Religion. Comp. William L. Rowe and William J. Wainwright. Ed. Robert Ferm. New York: Oxford UP, 1998. 109-125.

Matthew Rowe (’10) is a Philospohy and Physics double major at Carnegie Mellon University

One thought on “A Critique of the Ontological Argument

  1. Mr. Rowe,

    Thank you for writing about this subject. I enjoy reading about philosophy and especially arguments for and against God’s existence. The ontological arguments have been particularily difficult for me to grasp. However, your critique has helped me understand the subject far better than I ever have! Thanks for writing clearly and persuasively. Best of luck in all you do.


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