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Introduction to Philosophy

Anselm's "Ontological Argument"

Abstract: Anselms's Ontological Argument is stated, and a few standard objections to his argument are listed.

  1. St. Anselm of Canterbury (1033-1109) was a Neoplatonic Realist and was often called "the second Augustine."
    1. The doctrine of realism implies that the extent to which anything is real is dependent upon its degree of universality; hence, God is the most real. Other existent things in the world are emanations from archetypes.
    2. The general idea of the ontological argument is based on the notion that the concept of God as the greatest being implies that God exists—if not, there could be something greater, namely an existent greatest being—but this being would be God.
    3. The structure of the Ontological Argument can be outlined as follows (The argument is based on Anselm's Proslogion 2):
      1. We conceive of God as a being than which no greater can be conceived.
      2. This being than which no greater can be conceived either exists in the mind alone or both in the mind and in reality.
      3. Assume that this being than which no greater can be conceived exists in the mind alone.
        1. Existing both in the mind and in reality is greater than existing solely in the mind.
        2. This being, existing in the mind alone, can also be conceived to exist in reality.
        3. This being existing in the mind alone is not therefore the being than which no greater can be conceived. (See statement 1 above.)
      4. Therefore, this being than which no greater can be conceived exists in reality as well as exists in the mind.
  2. Some standard objections to the Ontological Argument are listed below. (References to the formal logical background given below can be safely omitted by the introductory student.)
    1. The Perfect Island Objection: Gaunilo argues that the concept of a perfect island does not thereby prove the existence of an island. Perfection in this case does not imply "existence." Gaunilo argues by analogy that if we insert the phrase "perfect island" for "God" pari passu in Anselm's Ontological Argument, no one would reasonably conclude that the existence of a perfect island has been proved. (Cf, the strategy of analogical refutations in syllogistic logic at Refutation by Means of Devising a Logical Analogy. The important logical point is that true premises and a false conclusion can never occur in a valid argument. If we can construct a similar argument to a given argument with the same form as the original with true premisses and a false conclusion, then the given argument is also shown to be invalid.)
      1. Anselm's Reply: There is no contradiction in denying the existence of a perfect island, but there is in denying God's existence. (Note: does Anselm relate an intuitive recognition of the distinction between à priori and à posteriori truth?)
      2. Anselm notes the only way God can be conceived of not to exist is to conceive of the word "God" not existing since this kind of perfection implies existence. (Note: it's difficult to phrase Anslem's objection without circularity—cf, the informal fallacy of petitio principii.
    2. The "Fool's Objection": Anselm's definition of God as " the being than which no greater can be conceived" is impossible to understand—there is no clear and distinct idea of a "being than which no greater can be conceived." (Note: how this idea of a being than which no greater can be conceived is aproximated in such a way that it is similar to the notion of infinitesimals or the notion limit later developed in the calculus by Newton and Leibniz.)
      1. Anselm's Reply: If one does not understand the definition, then one is a fool. You cannot argue with a fool. (Anselm here can be charged with committing the fallacy of ad hominem).
      2. Anselm believes that one must suppose a minimum of intelligence in anyone considering the argument—but, of course, the burden of proof in this regard is on Anselm. Cf, the related ideas of the prinicple of charity and the argumentum ad ignorantiam
    3. Objection of "Existence is not a Predicate":In the consideration of any idea one cannot get outside of the conception to reality; Anselm's argument compares the conception of existing in the mind with the conception of existing in reality. Yet, an argument can only deal with concepts, not existent things in the external world. As Immanuel Kant argues, one cannot compare the value of the idea of 100 thalers (i.e., coins) with 100 real thalers.

      We assume existence in our conversation and arguments—we do not prove existence. Consider this case: One doesn't laud someone you are to marry to your folks, and the add, "Oh by the way, that person really exists."

      One cannot argue towards existence.  One cannot prove existence.  (Q.v., As Søren Kierkegaard points out, you cannot prove existence of Napoleon by his deeds, because to mention his deeds is to assume the existence of someone who did them. So any such argument presupposes the existence of the subject it talks about.)

      See also the related logical problem of existential import of statements in Aristotelian logic. If the existence of something is implied by a statement, then the statement is said to have "existential import." For Aristotle, statements of the form, "All S's are P's" imply that there is at least one existent S that is a P, whereas in modern logic (quantification theory), no such existential commitment of universal statements is implied.

      (Note that Anselm's argument is similar in form to Socrates' defense in the Apology against the charge that he is an atheist: he argues he is not an atheist because his accusers recognize he believes in divine things.)
      1. Anselm's Reply:  No, not at all—Anselm believes he is not just comparing ideas. The comparison is between existing in the mind alone and existing in the mind and in reality. Both of these are thought of as they are, not thought of as in the mind. (Note: Yet how can this objection be phrased without the notion of "the thought or idea" of existence…)
      2. If Anselm is wrong here, it would seem to follow that deductive arguments (i.e., à priori arguments) are of no use to proving things about the nature of the world of existent entities. Instead, this kind of rationality only shows the relations of ideas to other ideas.
Further Reading:
  • Anselm of Canterbury. Wikipedia's reprint from the scholarly 1911 Encyclopedia Britannica on Anselm's life and works.
  • Anselm, "The Ontological Argument" A short selection of Anselm's argument from Proslogium 2 in the online Reading for Philosophical Inquiry on this site.
  • Ontological Arguments. A good discussion with extensive links to the history, classification, and classic objections to various versions of the ontological argument by Graham Oppy in the Stanford Encyclopedia of Philosophy.
  • The Ontological Argument. Anselm's argument together with Gaunilo's, Aquinas' and Kant's objections are conveniently summarized by Kenneth Einar Himma in the Internet Encyclopedia of Philosophy. This entry is a good place to start for clarification of the above notes to the argument.
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“For I do not seek to understand in order to believe; I believe in order to understand. For I also believe that ‘Unless I believe, I shall not understand.’” St Anselm, Proslogion I, trans. Thomas Williams (Indianapolis, Indiana: Hackett Publishing, 2001) 6.

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