Talons Philosophy

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Ontological argument

St. Anselm was the archbishop of Cantebury from 1033 to 1109. He is the originator of the ontological argument, which he describes in his book Proslogium;

God is that, than which nothing greater can be conceived.… And [God] assuredly exists so truly, that it cannot be conceived not to exist. For, it is possible to conceive of a being which cannot be conceived not to exist; and this is greater than one which can be conceived not to exist. Hence, if that, than which nothing greater can be conceived, can be conceived not to exist, it is not that, than which nothing greater can be conceived. But this is an irreconcilable contradiction. There is, then, so truly a being than which nothing greater can be conceived to exist, that it cannot even be conceived not to exist; and this being thou art, O Lord, our God.


The argument in this passage can be simplied to standard form:

  1. It is a conceptual truth (true by definition) that God is a being than which none greater can be imagined (the greatest possible being that can be imagined)
  2. A being that necessarily exists in reality is greater than a being that does not necessarily exist.
  3. So,by definition, if god exists as an idea in the mind but does not necessarily exists in reality, then we can imagine something greater than god.
  4. But we cannot imagine something greater than god.
  5. So, if god exists as an idea, then it must necessarily exist in reality.
  6. God exists in the mind as an idea.
  7. Therefore, god necessarily exists in reality.

This passage relies on two important premises. God, by definition, is a being that which a greater cannot be conceived. And the second premises claims that a being whose non-existence is logically impossible is greater than a being whose non-existence is logically possible. Considering these premises are factual correct by definition, premises 3-5 follow the logic of the first 2 premises, which validates premise 6 and the conclusion follows the last premises. If the definition of god is factual correct and the conclusion follow the premises, then Anselm’s argument is valid and factually correct which makes it sound.

I chose Anselm’s argument as my logical argument example because this religious clerk tries to explain the existence of an higher being (god) with a logical argument. Which is fascinating to me because this argument makes me look at monotheism from a different perspective. A lot of people ( believers of a certain faith or critiques of a monotheistic faith) try to discuss the nature of an higher being but most does not put their ideas in a logical idea. Furthermore, the concept of an idea that could be imagined in the human mind is logically a possibility in reality brings up more questions in my mind. To be able to discuss to existence of an higher being, wouldn’t we have to discuss the mere idea of existing and what that would mean to be a higher being that none greater that could be conceived?



One Response to Ontological argument

  1. Chris says:


    Great job! I think you have clearly outlined the ontological argument for God’s existence in its original form. I appreciate what you wrote in your last paragraph. It is important that this attempted proof at God’s existence made you view monotheism in a different light. While it is certainly true that many people seem to base their religious faith, or irreligious faith, on feelings, rather than logical demonstrations, or other various kinds of evidence, it is important to note that great thinkers, philosophers and scientists, have tried to argue for the truth of theism (and atheism) using logical arguments. This guards us from assuming that people who ascribe to a theistic worldview, when we ourselves do not, are of necessity unable to provide logical arguments or other kinds of demonstration for the rationality of their belief system. For another interesting article on this, see the post on ‘A contentious argument for God’s Existence?’

    That being said, the ontological argument is not without its significant difficulties. In fact, when it was first written one philosopher, also a theist, wrote a critique that poked fun at Anselm’s argument. He discussed the greatest possible Island; an Island greater than any other that can be conceived. Obviously an Island like this that exists in reality, is greater than an Island which only exists in our imagination. For example, if it exists in reality more people than you can visit it and enjoy its splendours. Therefore, this Island must exist. Probably somewhere around the Bermuda Triangle. It would have been interesting to hear you interact with a potential objection like this in your post.

    Now, I actually think this critique fails (as stated) because it is difficult to see how ‘a greatest possible Island’ can even be a coherent concept, and I don’t think the same can be said of a maximally great being like God (for reasons I can’t go into here). However, the above critique does suggest a significant problem, one that most people intuitively feel, even if they can’t put it into words.

    That being, we can’t just assume that because we can conceive an idea of something, that this somehow necessitates that it exists in reality. We don’t get to simply define things into existence. Reality is not that cooperative. This is why reality doesn’t often appeal to children.

    Moreover, the Ontological argument, as Anselm’s states it, assumes that existence itself is a perfection that a greatest conceivable being must possess. I believe it was Immanuel Kant, another theist, who pointed out that existence cannot be included amongst God’s attributes that make ‘him’ maximally great. Rather, existence is the ‘ontological’ requirement that precedes God having any maximally great attributes to speak of in the first place. In other words, nice try, Anselm, but it is not going to work.

    What is so fascinating about philosophy of religion is that, an argument like Anselm’s has been widely abandoned by theists (though it is great fun as a logical exercise and an excursion in the history of western thought), until some daring philosopher reinstates it in a revised form that avoids some of the philosophical critiques that have been levied against it. If you are curious you may try googling Alvin Plantinga’s Ontological Argument for the existence of God, for a different version than Anselms.

    Great stuff



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