Anselm’s Ontological Argument

Anselm Head

In chapter 2 of Anselm’s Discourse On The Existence of God, Anselm set forth, what was later tagged, by Immanuel Kant, ontological argument, as follows:

[And] so, Lord, do thou, who dost give understanding to faith, give me, so far as thou knowest it to be profitable, to understand that thou art as we believe; and that thou art that which we believe. And, indeed, we believe that thou art a being than which nothing greater can be conceived. Or is there no such nature, since the fool hath said in his heart, there is no God? (Psalms 14:1). But, at any rate, this very fool, when he hears of this being of which I speak—a being than which nothing greater can be conceived—understands what he hears, and what he understands is in his understanding; although he does not understand it to exist.

For, it is one thing for an object to be in the understanding, and another to understand that the object exists. When a painter first conceives of what he will afterwards perform, he has it in his understanding, but he does not yet understand it to be, because he has not yet performed it. But after he has made the painting, he both has it in his understanding, and he understands that it exists, because he has made it.

Hence, even the fool is convinced that something exists in the understanding, at least, than which nothing greater can be conceived. For, when he hears of this, he understands it. And whatever is understood, exists in the understanding. And 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 nothing greater can be conceived, exists in the understanding alone, the very being, than which nothing greater can be conceived, is one, than which a greater can be conceived. But obviously this is impossible. Hence, there is no doubt that there exists a being, than which nothing greater can be conceived, and it exists both in the understanding and in reality.(Anselm 2009:7-8)

Understanding God as that which none greater can be conceived, Alvin Plantinga outlined Anselm’s case as follows:

1) God exists in the understanding but not in reality.

2) Existence in reality is greater than existence in the understanding alone. (premise)

3) God’s existence in reality is conceivable. (premise)

4) If God did exist in reality, then He would be greater than He is. [From (1) and (2)]

5) It is conceivable that there is a being greater than God is. [(3) and (4)]

6) It is conceivable that there be a being greater than the being than which nothing greater can be conceived. [(5) by the definition of “God”]

But surely (6) is absurd and self-contradictory; how could we conceive of a being greater than the being than which none greater can be conceived? So we may conclude that

7) It is false that God exists in the understanding but not in reality.(Plantinga 1978: 87-8)

Question: How persuasive is Anselm’s case for the existence of God? What could be the possible objections to this version of ontological argument? Let the dialogue begin.


Anselm, S., Archbishop of Canterbury, & Deane, S. N. (2009). Proslogium; Monologium; An appendix, In behalf of the fool, by Gaunilon; and Cur Deus homo. Bellingham, WA: Logos Bible Software.

Plantinga,Alvin(1978) God, Freedom, and Evil. Grand Rapids: William B. Eerdmans Publishing Company

27 thoughts on “Anselm’s Ontological Argument

  1. Here’s something to throw into the mix: how much do you think Anselm’s monastic thinking/ideology informed his logic? I think it was Barth who said that Anselm’s ontological proof wasn’t even meant to be a proof at all, but rather an extended mediation on the existence of God. As Carl Trueman points out in his lecture on Anselm in his Medieval Theology class at Westminster, the whole idea of proving God’s existence in the 11th C would have been something of a misnomer b/c most everyone believed that some God did exist, even if they rejected His authority.

    • Thank you for your question. Anselm was a brilliant thinker who carefully integrated classics with Augustinian theology. I think Barth, if he said that, would have misunderstood Anselm’s reason for presenting this case. Anselm from his desire and prayer to attain not a posterior, but a priori case for existence of God was a wish or prayer came true. This case though was not meant for changing an atheist(fool) to theist, but for a theist who believes to understand.

      • That makes sense. Perhaps Barth was responding to the idea that Anselm was trying to conquer the atheistic mind with a logical proof, but given the 11th C context, as well as your comments here, it seems true that he was merely trying to present a logical understanding of God’s existence to those who already had some concept of a Deity already. Thanks for your interaction. Loving exploring your blog.

  2. I’m going to try my best to understand what you said, so correct me if I’m wrong. I’ll use the artist metaphor that Anselm did. Van Gough conjectured Starry Night in understanding, but not yet in reality. Once he painted it, Starry Night was conceived in reality. Thus, the real Starry Night was better than the mental picture of Starry Night.
    Thus, with God, being understood in understanding, would be ‘better than himself’ once he has entered the ‘real realm.’ This is physically impossible, so God cannot exist.

    See, to me, it makes perfect sense. Our understanding of God is not as good as the real God. Why is there a problem there? Does any human perfectly understand God, even in just understanding? Not even the greatest scholars have a full mental grasp on God. Therefore, the God in reality is always better than the one in understanding.

    Back to Starry Night. Its reality is better than my understand of it because there’s no way in the world I could fully grasp the thing in my head until I see it for real.

    To me, this is an anthem of praise, not an argument against God’s existence. It simply says that we cannot fathom anything greater than God, not that we can’t fathom anything greater than an understanding of God.

    Or did I totally misunderstand something?

    • I believe what Anselm is after is not x is better, but greater if it exists in the mind and reality than it would have if it was in the mind alone. I find Anselm ‘s painter example rather poor though what he contended very strong.

      Immanuel Kant’s critique of Descartes versions of ontological argument actually brought to light a better example when he wrongly thought, as I judged, that the concept of say a dollar is same as a real dollar. What would be greater if I have concept of 1000 USD for my finances, say I am broke, or if I have both the concept of 1000 USD in mind and in reality? For my finances the latter is greater than the former.

      Anselm’s example does not really explain his case as I understand his case. Would you love me to expound it in modal logic?

        • Something to do with possibilities and necessity where we think of states of affair could be. I can make it easy for you by explaining the basics and offering examples for you to understand.

          • Think of a series n[where n ≥ 1] of how things could be, in modal logical terms possible states of affairs or possible worlds(Wn), let say W1, W2, W3 …Wn. Suppose that a being A and B are omnipresent, omnipotent, omniscient and perfectly good.

            Say A exists in every even number possible states of affairs, thus A is in all W2n. If any of the even number possible state of affair was actualized, then A would exist.

            Let say B exists in all possible states, namely all Wn, thus if any possible state of affair was actual B, unlike A, would necessarily exist. In this sense B is said to be greater than A.

            So God existing only in mind would be like A, but if God is greatest conceivable being, then God would have to be like B, thus Anselm’s idea that existing both in mind and reality is greater than existing in mind alone. Are you with me?

        • His aim was to show that God, a being that none greater can be conceived, necessarily exist. Not that this being is a Triune God.

          After accepting that God exists then Christians could argue that this God is truly revealed by Jesus of Nazareth and thus a triune God.

          • Prayson, right. I understand the argument. But, I don’t see how it is helpful as it would only serve to illustrate a general conception of God, a Necessary Being as such. This Necessary Being doesn’t, so far as I understand, need to be Personal, however. So, I don’t find the argument particularly helpful, especially if we need to supplement the argument with others to make the point we wish to make.

          • I think being personal is greater than being non-personal(example I am greater than my iPad, or John’s dog). If this is true the Anselm’s case does show, unlike what Spinoza thought, a personal being.

            The strength of this case, if sound, is that it gives a perfect being theological concept of God, namely a being who is greater than any being and without equal.

            If we are looking for this case to show God of particular Abrahamic religions, then I believe, like all other classical arguments for God, it is useless.

    • Most philosophical arguments for the existence of God are non-trinitarian.
      Cosmological, Contingency, Moral, Teleological, Ontological. None point explicitly to a trinitarian God, but to the general revelation of God’s existence. It’s far more reasonable to argue for trinitarian theism, in particular, once a person accepts the existence of God, generally.

      • Peter B.

        Thank you for your reply. I realize that most philosophical arguments are broad in their range. Though, why are arguments for the God of Christianity far more reasonable than say that of the God of Islam or Judaism?

  3. For me as we’ll regarding the OA argument. I am not a philosopher by academic terms but have some serious study in philosophy and apologetics over a good many years. I have been called to ministry (liberal arts Christian think tank) to help both our non-theistic friends and our church friends understand the importance of thinking and discussion.
    I give you that background to say that these arguments, both old and reworked, are foundational to even today’s cultural and social thinking. I have been faced lately with this argument – “imagination precedes all thought and rationality; the enlightenments reason, anthropologically speaking, is not how humans really are constructed or how reality functions towards life.”
    Anselm’s and Plantinga’s work on “understanding and reality” in the above, help in humbly debunking such arguments where imagination is valued over reason as a more trustworthy source of reality.
    Thanks for your work Prayson.

    • You are welcome Mark. I also once answered the objection that Christian God is imaginary God using this case. I contended if Christian’s God exists only in imagination then He is not the being which nothing greater can be conceived, and thus not a being worthy of worship and adoration. But Christian God, at least according to Christians, is a being which nothing greater can be conceived, a being worthy of worship and adoration, therefore Christian God cannot exist only in imagination.

  4. The ontological argument is probably my favorite of the commonly used arguments. I just got done writing a research paper that argues the ontological argument is the best of all arguments to be used as a foundation for philosophical apologetics. The OA makes all other arguments more powerful, and it becomes more relevant when used with all other arguments.

    I must admit I am more of a Plantinga`s modal OA, but each variation throughout history has extreme value in the defense of logical theism.

    • It is my number one favorite case for existence of God. I have defended both Anselm’s and Plantinga’s versions in my debates. Sadly few apologists and atheists understands how powerful it is.

      • The major problem is that most people don’t understand the notion of maximal perfection, out possible worlds, or necessary existence… Instead, they dismiss the ontological argument by simply saying it is wordplay and logic-chopping. It really sad.

        If the IS is of interest to me, let me know, I can send you a copy of my paper; I always love having extra critiques.

    • Totally understandable. The love of knowledge(philosophy) through a pursuit of wisdom by logical reasoning and critical analysis of fundamental beliefs is not a cup of tea for all.

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