Is the Ontological Argument Valid?

The ontological argument has fascinated philosophers for centuries in attempting to prove God’s existence from the concept of God. The argument does not appeal to any facts of experience, but solely on the implications of conceiving of God a priori. This differs from other a posteriori arguments for God’s existence such as the cosmological (creation), teleology (design), or axiological (moral) which depend on at least one empirical premise. The first philosopher to apply the word “ontological” to the argument was Immanuel Kant (1724-1804) who believed it made an invalid transition from thought to being (ontos). St. Anselm (1033-1109), the archbishop of Canterbury is considered the architect of the argument and interestingly enough formulates the argument in writings meant to worship God. This explains why the argument is also called the “proof from prayer”. Anselm himself is not a skeptic, but writes as a believer seeking rational persuasion for God’s existence. He prefaces the argument in his Proslogion with his famous pronouncement, “For I do not seek to understand that I may believe, but I believe in order to understand. For this also I believe, – that unless I believed, I should not understand.”[i]

The goal of this series of blogs is to evaluate the argument in its various forms from Anselm to modern philosophers. I will be unable to discuss every philosopher who addressed this argument, but tour through the highlights of the development of the argument to the present. This historical approach will address the charges against the argument and help the reader determine if the original argument (or any subsequent argument) is valid.

Anselm’s argument proceeds from chapter two of Proslogion which he describes as follows:

[Even a fool], when he hears of … a being than which nothing greater can be conceived…understands what he hears, and what he understands is in his 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.[ii]

The argument in this difficult passage can be summarized as follows:

1. It is a conceptual truth that God is a being than which none greater can be imagined.
2. God exists as a concept in the mind.
3. A being that exists as a concept and in reality (other things being equal) is greater than a being that exists only as a concept.
4. If God can only exist as a concept in the mind, then we can imagine something that is greater than God.
5. But we cannot imagine something that is greater than God (i.e. it is a contradiction to suppose that we can imagine a being greater than the greatest being possible that can be imagined.)
6. Therefore, God exists.

Premise three asserts that existence is a perfection of a great-making property. To further understand the argument and subsequent criticisms, it can be restructured around great-making properties.

1. The greatest possible being possesses all possible great-making properties.
2. God is the greatest possible being.
3. Therefore, God possesses all possible great-making properties.
4. Existence is a great-making property.
5. Therefore, God possesses the property of existence (i.e. God exists).[iii]

The first criticism to this argument arrived from Gaunilo, a monk and contemporary of Anselm’s, who was concerned that this illegitimate move (from thought to being) would allow one to simply define things into existence. Most (upon first contact with the ontological argument) have the same sort of reaction as Gaunilo who stated the following:

Now if some one should tell me there is … an island [than which none greater can be conceived], I should easily understand his words, in which there is no difficulty. But suppose that he went on to say, as if by a logical inference: “You can no longer doubt that this island which is more excellent than all lands exists somewhere, since you have no doubt that it is in your understanding. And since it is more excellent not to be in the understanding alone, but to exist both in the understanding and in reality, for this reason it must exist. For if it does not exist, any land which really exists will be more excellent than it; and so the island understood by you to be more excellent will not be more excellent.”

Gaunilo, although a fellow believer in the existence of God, used Anselm’s strategy to deduce the existence of a perfect island and then demonstrated the argument as a counterexample to Anselm’s argument. Gaunilo’s argument can be outlined as follows:

1. It is a conceptual truth that darrenland is an island than which none greater can be imagined.
2. Darrenland is a concept in the mind.
3. An island that exists as a concept and in reality (other things being equal) is greater than an island that exists only as a concept.
4. If darrenland can only exist as a concept in the mind, then we can imagine an island that is greater than darrenland.
5. But we cannot imagine something that is greater than darrenland.
6. Therefore, darrenland exists.

One could do a similar exercise with many different concepts such as Pegasus, Santa Claus, or the Tooth Fairy. Although these beings can exist in our mind and are possible in a contingent world, this does not prove they exist in our actual world. Gaunilo objected that Anselm’s argument is based upon the false premise that whatever exists in the mind must also exist in reality outside the mind. Anselm responded to this criticism by noting an important distinction between a perfect island and a perfect being: it is possible for a perfect island not to exist, whereas if it possible for a Necessary Being to exist, then it is necessary for him to exist. Anselm charged that Gaunilo misunderstood his argument in that God is “the greatest possible Being”, not the “greatest of all beings.” Another problem with Gaunilo’s argument is the incoherence of premise one. The very concept of a maximally great island is unintelligible because for any great-making property one chooses, one could conceive of an island greater. For instance, if one considers fruit-abundance a great-making property, no matter how great darrenland may be, one could imagine a greater island because there is no intrinsic maximum for fruit-abundance. On the other hand, God escapes this criticism because of the coherence of a being of maximal greatness.[iv]

(I will continue with Aquinas’ evaluation of the argument next month)

[i] St. Anselm, Proslogion. All quotes from St. Anselm are from St. Anselm’s Basic Writings, translated by S.W. Deane, 2^nd edition (La Salle, Ill: Open Court Publishing Co., 1962)

[ii] St. Anselm, Proslogion Chapter II.

[iii] Outline of argument taken from lecture notes from Garry DeWeese for theistic arguments in summer 2005, Biola University.

[iv] See Alvin Plantinga’s definition of maximal greatness in ‘The Ontological Argument’ in Philosophy of Religion ed. William Lane Craig (New Brunswick, New Jersey: Rutgers University Press, 2002), 180-188. Although some have charged that omniscience, omnipotence and moral perfection are logically impossible in the same being (or even the incoherence of these terms), this has been addressed by -Alvin Plantinga, Alfred Freddoso and other philosophers and is beyond the scope of this paper.