Ontological argument

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An ontological argument for the existence of God is an argument that God's existence can be proved a priori, that is, by intuition and reason alone. In the context of the Abrahamic religions, it was first proposed by the medieval philosopher Anselm of Canterbury in his Proslogion, and important variations have been developed by philosophers such as René Descartes, Gottfried Leibniz, Norman Malcolm, Charles Hartshorne, and Alvin Plantinga. A modal logic version of the argument was devised by mathematician Kurt Gödel. The ontological argument has been controversial in philosophy and many philosophers have famously criticized or opposed it, including Anselm's contemporary Gaunilo of Marmoutiers, as well as David Hume, Immanuel Kant, and Gottlob Frege.

The argument works by examining the concept of God, and arguing that it implies the actual existence of God; that is, if we can conceive of God, then God exists — it is thus self-contradictory to state that God does not exist. This is obviously a controversial position, and the ontological argument has a long history of detractors and defenders.

The argument's different versions arise mainly from using different concepts of God as the starting point. For example, Anselm starts with the notion of God as a being than which no greater can be conceived, while Descartes starts with the notion of God as being maximally perfect (as having all perfections).

Contents 1 Anselm's argument 2 A modern description of the argument 3 Criticisms and Objections 3.1 Gaunilo's island 3.2 Necessary nonexistence 3.3 Existence as a property 3.4 Hume 4 Revisionists 5 Descartes' ontological arguments 6 Plantinga's modal form and contemporary discussion 7 Notes 8 Bibliography 9 See also 10 External links

[edit] Anselm's argument

The ontological argument was first proposed by Anselm of Canterbury (1033–1109) in Chapter 2 of the Proslogion. While Anselm did not propose an ontological system, he was very much concerned with the nature of being. He argued that there are necessary beings – things that cannot not exist – and contingent beings – things that may exist but whose existence is not necessary.

Anselm presents the ontological argument as part of a prayer directed to God. He starts with a definition of God, or a necessary assumption about the nature of God, or perhaps both.

"Now we believe that [the Lord] is something that which nothing greater can be imagined."

Then Anselm asks: does God exist?

"Then is there no such nature, since the fool has said in his heart: God is not?"

To answer this, first he tries to show that God exists 'in the understanding':

"But certainly this same fool, when he hears this very thing that I am saying – something than which nothing greater can be imagined – understands what he hears; and what he understands is in his understanding, even if he does not understand that it is. For it is one thing for a thing to be in the understanding and another to understand that a thing is."

Anselm goes on to justify his assumption, using the analogy of a painter:

"For when a painter imagines beforehand what he is going to make, he has in his understanding what he has not yet made but he does not yet understand that it is. But when he has already painted it, he both has in his understanding what he has already painted and understands that it is.

"Therefore even the fool is bound to agree that there is at least in the understanding something than which nothing greater can be imagined, because when he hears this he understands it, and whatever is understood is in the understanding."

Now Anselm introduces another assumption:

"And certainly that than which a greater cannot be imagined cannot be in the understanding alone. For if it is at least in the understanding alone, it can be imagined to be in reality too, which is greater."

(For example, most people would prefer a real £100 rather than an imaginary £100.)

"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."

Anselm has thus found a contradiction, and from that contradiction, he draws his conclusion:

"There exists, therefore, beyond doubt something than which a greater cannot be imagined, both in the understanding and in reality."

[edit] A modern description of the argument

Here's a short, and very general description of the ontological argument:

1. God is the greatest possible being and thus possesses all perfections.
2. Existence is a perfection.
3. God exists.

This is a shorter modern version of the argument. Anselm framed the argument as a reductio ad absurdum wherein he tried to show that the assumption that God does not exist leads to a logical contradiction. The following steps more closely follow Anselm's line of reasoning:

1. God is the entity than which no greater entity can be conceived.
2. The concept of God exists in human understanding.
3. God does not exist in reality (assumed in order to refute).
4. The concept of God existing in reality exists in human understanding.
5. If an entity exists in reality and in human understanding, this entity is greater than it would have been if it existed only in human understanding (a statement of existence as a perfection).
6. from 1, 2, 3, 4, and 5 An entity can be conceived which is greater than God, the entity than which no greater entity can be conceived (logical self-contradiction).
7. Assumption 3 is wrong, therefore God exists in reality (assuming 1, 2, 4, and 5 are accepted as true).

Anselm in his Proslogon 3 made another a priori argument for God this time based on the idea of necessary existence. He claimed that if God is that than which nothing greater can be conceived, it is better to be necessary than contingent. Therefore God must be necessary, to sum it up:

1. God is that than which nothing greater can be conceived.
2. It is greater to be necessary than not.
3. God must be necessary.
4. God exists

[edit] Criticisms and Objections

[edit] Gaunilo's island

One of the earliest recorded objections to Anselm's argument was raised by one of Anselm's contemporaries, Gaunilo. Gaunilon invited his readers to think of the greatest, or most perfect, conceivable island. As a matter of fact, it is likely that no such island actually exists. However, his argument would then say that we aren't thinking of the greatest conceivable island, because the greatest conceivable island would exist, as well as having all those other desirable properties. Note that this is merely a direct application of Anselm's own premise that existence is a perfection (point 5 in the previous section). Since we can conceive of this greatest or most perfect conceivable island, then it must exist. While this argument seems absurd, Gaunilon claims that it is no more so than Anselm's.

Such objections are known as "Overload Objections"; they don't claim to show where or how the ontological argument goes wrong, they simply argue that if it is sound, then so are many other arguments of the same logical form which we don't want to accept, arguments which would overload the world with an indefinitely large number of things like perfect islands, perfect pizzas, perfect pencils, etc.

However, the island is qualitatively different than that than which nothing greater can be conceived, because even if the island existed, it would do so only contingently on and in time. If at some point before or after now the island will not exist, it follows that the island does not necessarily have to exist at any point. However, that than which nothing greater can be conceived would be outside of time, without beginning or end, thus, if it exists, its existence would not be contingent on time.

[edit] Necessary nonexistence

Another rationale is attributed to Melbourne philosopher Douglas Gasking ^[1] (1911–1994), one component of his proof of the nonexistence of God:

1. The creation of the world is the most marvelous achievement imaginable.
2. The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
3. The greater the disability (or handicap) of the creator, the more impressive the achievement.
4. The most formidable handicap for a creator would be non-existence.
5. Therefore if we suppose that the universe is the product of an existent creator we can conceive a greater being — namely, one who created everything while not existing.
6. Therefore God does not exist.

Gasking was apparently thinking of the "world" or "universe" as the same as "everything." The proof is strengthened if "everything" is substituted. However, defenders of Anselm would reject the thesis that disability and handicap are things that make a creator greater.

[edit] Existence as a property

Another traditional criticism of the argument (first found in Gassendi's Objections to Descartes' Meditations, and later modified by Kant) is that existence is not a perfection, because existence is not a property as such, and that referring to it as a property confuses the distinction between a concept of something and the thing itself. The argument is that anything which has the property of being non-existent could not possibly have any other properties, being non-existent, and thus not having color, location, or any other property. One cannot, the argument says, speak meaningfully of the non-existent apple that one is holding, saying that it is red, crisp, weighs a certain amount, is in one's right hand, and does not exist. ^{[citation needed]}

[edit] Hume

David Hume claimed that nothing could ever be proven to exist through an a priori, rational argument by arguing as follows: ^{[citation needed]}

1. The only way to prove anything a priori is through an opposite contradiction. For example, I am a married bachelor.
2. The resulting contradiction makes something inconceivable. Obviously it is impossible to have a married bachelor.
3. It is possible to comprehend anything not existing. Thus it is not inconceivable to imagine anything not existing.
4. Nothing can be proven to exist a priori, including God.

[edit] Revisionists

Obviously Anselm thought this argument was valid and persuasive, and it still has occasional defenders, but many, perhaps most, contemporary philosophers believe that the ontological argument, at least as Anselm articulated it, does not stand up to strict logical scrutiny^{[citation needed]}. Others, like Gottfried Leibniz, Norman Malcolm, Charles Hartshorne, Kurt Gödel and Alvin Plantinga have reformulated the argument in an attempt to revive it.

[edit] Descartes' ontological arguments

René Descartes (1596-1650) composed a number of ontological arguments which differed from Anselm's formulation in important ways. Generally speaking, it is less a formal argument than a natural intuition.

Descartes wrote in the Fifth Meditation: ^[2]

But if the mere fact that I can produce from my thought the idea of something entails that everything which I clearly and distinctly perceive to belong to that thing really does belong to it, is not this a possible basis for another argument to prove the existence of God? Certainly, the idea of God, or a supremely perfect being, is one that I find within me just as surely as the idea of any shape or number. And my understanding that it belongs to his nature that he always exists is no less clear and distinct than is the case when I prove of any shape or number that some property belongs to its nature (AT 7:65; CSM 2:45).

The intuition above can be formally described as follows:

1. Whatever I clearly and distinctly perceive to be contained in the idea of something is true of that thing.
2. I clearly and distinctly perceive that necessary existence is contained in the idea of God.
3. Therefore, God exists.

Another formulation of his argument is as follows:

1. I exist
2. I have an idea of a supremely perfect being, i.e. a being having all perfections.
3. As an imperfect being I would be unable to create such a concept.
4. The concept must have come from God.
5. To be a perfect being God must exist.
6. God exists.

In another, less formal statement of his argument, he draws an analogy between belief in the existence of God and the geometric demonstration:

Whatever method of proof I use, I am always brought back to the fact that it is only what I clearly and distinctly perceive that completely convinces me. Some of the things I clearly and distinctly perceive are obvious to everyone, while others are discovered only by those who look more closely and investigate more carefully; but once they have been discovered, the latter are judged to be just as certain as the former. In the case of a right-angled triangle, for example, the fact that the square on the hypotenuse is equal to the square on the other two sides is not so readily apparent as the fact that the hypotenuse subtends the largest angle; but once one has seen it, one believes it just as strongly. But as regards God, if I were not overwhelmed by philosophical prejudices, and if the images of things perceived by the senses did not besiege my thought on every side, I would certainly acknowledge him sooner and more easily than anything else. For what is more manifest than the fact that the supreme being exists, or that God, to whose essence alone existence belongs, exists? (AT 7:68-69; CSM 2:47)

[edit] Plantinga's modal form and contemporary discussion

Alvin Plantinga has given us another version of the argument, one where the conclusion follows from the premises, assuming axiom S5 of modal logic. A version of his argument is as follows:

1. By definition a maximally great being is one that exists necessarily and necessarily is omniscient, omnipotent and perfectly good. (Premise)
2. Possibly a maximally great being exists. (Premise)
3. Therefore, possibly it is necessarily true that an omniscient, omnipotent and perfectly good being exists (By 1 and 2)
4. Therefore, it is necessarily true that an omniscient, omnipotent and perfectly good being exists. (By 3 and S5)
5. Therefore, an omniscient, omnipotent and perfectly good being exists. (By 4 and since necessarily true propositions are true.)

The axiom S5 says that if a proposition is possibly necessarily true, then it is necessarily true.

Plantinga's ontological argument has two controversial premises: The axiom S5 and the "possibility premise" that a maximally great being is possible. The more controversial of these two is the "possibility premise" since S5 is widely (though not universally) accepted. Some critics (e.g., Richard M. Gale for more info look below) have even argued that the "possibility premise" begs the question, because one only has the epistemic right to accept it if one understands the nested modal operators, and if one understands them then one understands that "possibly necessarily" is basically the same as "necessarily".

There are, nonetheless, yet other approaches to the possibility premise. Leibniz thought that the possibility premise followed from the claim that "positive qualities" could not logically conflict with one another, and hence the notion of a being that had all the positive qualities had to be coherent. Gödel's ontological proof uses similar ideas.

A very different approach has recently been attempted by Pruss ^[3] who starts with the 8th-9th century AD Indian philosopher Samkara's dictum that if something is impossible, then we cannot have a perception (even a non-veridical one) that it is the case. Contraposing, it follows that if we have a perception that p, then even though it might not be the case that p, it is at least the case that possibly p. If mystics in fact perceive the existence of a maximally great being, it follows that the existence of a maximally great being is at least possible. And that is all that is needed to get the modal ontological argument off the ground. One difficulty in this argument is that one might misinterpret the content of one's experience, and hence the mystic might be incorrect even in a cautious description of an experience as an experience "as of a maximally great being."

Interestingly, Plantinga himself does not think the modal ontological argument is always a good proof of the existence of God. It depends on what his interlocutor thinks of the possibility premise. Nonetheless, Plantinga has suggested that because we do not have any evidence against the possibility premise, it might be reasonable to suppose it has probability 1/2. It follows from this that the existence of God can at the outset be held to have probability 1/2, though further evidence may increase or decrease this. Though, the possibility God does not exist is just as likely by this reasoning.

[edit] Notes

1. ^ W.Grey, "Gasking's Proof", Analysis 60:4 (2000), pp 368–70.
2. ^ René Descartes. Meditations on First Philosophy: 5th Meditation.
3. ^ A.R.Pruss, "Samkara’s Principle and Two Ontomystical Arguments", International Journal for Philosophy of Religion 49 (2001), 111–120

[edit] Bibliography

• Hartshore, Charles, The Logic of Perfection (LaSalle, IL: Open Court, 1962)
• Jori, Alberto, 'Die Paradoxien des menschlichen Selbstbewusstseins und die notwendige Existenz Gottes - Zu 'Cogitatio' und 'Intellectus' im Streit zwischen Anselm und Gaunilo', in: C. Viola and J. Kormos (ed.), Rationality from Saint Augustine to Saint Anselm. Proceedings of the International Anselm Conference - Piliscsaba (Hungary) 20-23 June 2002 (Piliscsaba 2005), pp. 197-210.
• Malcolm, Norman, "Anselm's Ontological Arguments" Philosophical Review, vol. 69, no. 1 (1960), 41-62
• Plantinga, Alvin, The Ontological Argument from St. Anselm to Contemporary Philosophers (Garden City, NY: Doubleday, 1965)
• Plantinga, Alvin. God, Freedom and Evil. (Grand Rapids, Michigan: Eerdmans, 1977) pp.85-112

[edit] See also

• Overviews: Arguments for the existence of God, Arguments against the existence of God
• Other major attempted proofs: Cosmological argument, Teleological argument, Argument from morality
• Gödel's ontological proof for the existence of God
• Pascal's Wager

[edit] External links

• Ontological Arguments — from the Stanford Encyclopedia of Philosophy
• Kenneth Einar Himma, The Ontological Argument — from the Internet Encyclopedia of Philosophy
• Medieval Sourcebook: Gaunilo: In Behalf of the Fool, and Anselm's Reply
• Medieval Sourcebook: Philosophers' Criticisms of Anselm's Ontological Argument for the Being of God
• Paul E. Oppenheimer & Edward N. Zalta, "On the Logic of the Ontological Argument" from James Tomberlin ed., Philosophical Perspectives 5: The Philosophy of Religion (Atascadero: Ridgeview, 1991) pp. 509–529
• Peter Millican, "The one fatal flaw in Anselm's argument" from Mind Vol.113, pp451ff (2004)
• Gregory S. Neal: "Anselm's Ontological Argument For the Existence of God" from Grace Incarnate (1990)