ontological argument

  • Created by: Lucy
  • Created on: 11-09-14 11:19

Form of the ontological argument

Ontological- meaning 'concerned with being'.

A priori- the argument does not rely onthe evidence of the senses (empirical evidence) for its premises or conclusion; rather it move from stages of logical argument to a conclusion which is self-evidently true or logically necessary.

Deductive- the premises if the argument contain the conclusion that it reaches, and is structured so that the conclusion of the argument is the only possible one that can be deduced from it's premises.

Analytic- the argument is true by definition alone; the argument reaches conclusions about the existence of God that are based on the definition of God used in the premises.               


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Origin of the argument

The ontological argument was developed in 1078 by Anselm, the Archbishop of Canterbury of the time. Anselm prayed for a concise argument that was singular in nature which could prove almost everything about God, including both his nature and his existence.

As a result, the ontological argument came to him one night when he was in the process of praying; 'the grace of God illuminated his heart, the whole matter became clear to his mind, and a great joy and exultation filled his inmost being'. (the Proslogion)


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Anslem's first form of the argument

P1: God is 'that than which nothing greater can be conceived'.

P2: That than which nothing greater can be conceived has to contain all perfections, including the perfection of existence.

P3: If God exists only as a contingent being, then a greater being could be conceived that has necessary existence.

C: Thus, God must exist.

Hence, it is a contradiction to be able to conceive of something than which nothing greater can be thought of, and yet deny this something to exist.

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Anselm's second form of the argument

P1: God is the greatest possible being.

P2: It is greater to be a necessary being than a contingent being.

P3: If God exists only as a contingent being, then a greater being could be imagined that has necessary existence.

P4: this being would then be greater than God.

P5: God is therefore a necessary being.

C: God must necessarily exist.

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Anselm and the fool

Anselm cites Psalm 53; 'the fool has said in his heart there is no God'.

The Psalmist's fool is the atheist who the impossible- that God does not exist. Regardless, the Atheist still says this, and Anselm explains that the atheist only says this because they have failed to understand the full implications of the concept of God. The atheist must grasp the real meaning of God as that than which nothing greater can be conceived before he can accept God's necessary existence.

Even to deny the existence of God, the atheist must then have had at least some understanding of God conceptually, thus regardless if the atheist chooses to believe in God or not, this in no way undermines God's actual existence. Because the atheist has an understanding of a being than which none greater can be thought, even if they deny God's existence themselves, God must still be necessarily in existence.


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Logical necessity and reductio ad absurdum

The ontological proves God's existence to be true by logical necessity, because it relies only on the analysis an meaning of terms within the argument and avoids deduction concerning God's nature drawn from observing the natural world.

The Proslogion offers a form of deductive metaphysics, by setting out from self-evident premises to try and answer the central question of metaphysics itself; why should anything be in existence at all? This notion of to be or not to be focuses the argument on the problems of what it means to be in existence or that something has existence or is in being.

Effectively, this process of proving the need for God's existence caused Anselm use reductio ad absurdum as a means to ensure God's necessary existence can be proved. This aims to show the truth of something by reducing the opposite of what you're aiming to prove an absurdity.

In the case of the ontological argument, the opposite is that 'God does not exist', which Anselm proved to be absurd by demonstrating thsat the existence of God is logically necessary- he cannot not exist.

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Descartes and the Perfect being

  • Rene Descartes reformulated the ontological proof five hundred years after anselm. He argued that when proving God's existence, he would proceed only by unaided human reason, without the evidence of the senses. Being a rationalist philosopher, he found it appealing to try and prove the existence of God through reason alone, as well as rejecting untrustworthy information that comes from the senses alone. Through doubting his own knowledge, he realised that this ability to doubt proved his own existence, which he explained as Cogitio, ergo sum (I think, therefore I am).


  • 1. I exist
  • 2. In my mind, I have the concept of a perfect being.
  • 3. As an imperfect being, I could not have conjured up the concept of a perfect being
  • 4. The concept of a perfect being must therefore have come from the perfect being itself.
  • 5. A perfect being must exist in order to be perfect.
  • 6. therefore, a perfect being must exist.



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Gaunilo and the perfect island

Gaunilo showed that if the logic of the ontological argument were applied to things other than God, it led to invalid conculsions. He replaced the word God with 'the greatest island' which led to an argument that has true premises yet leads to a false conclusion:

  • 1. I can conceive of an island that than which no greater island can be thought.
  • 2. Such an island must possess all perfections.
  • 3. Existence is a perfection.
  • 4. Therefore, the island exists.

However, Anslem rejected this on the basis that his proof was intended to apply strictly to necessary beings, not contingent ones or items, such as the island which may or may not exist. Also, there is not logical point on which to arrive at perfection in regards to any contingent thing, because it can always be more perfect and our concept of perfection in contingent things is subjective, yet a necessary being does not have this problem.

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Kant- existence is not a predicate

It is assumed in the ontological argument that existence is a predicate- a quality that something can have or similarly lack. Kant, however, observed that existence is not associated with a definition of something, because it adds nothing to our understanding of that thing. We have to first establish the existence of something before we can comment on what it is actually like, not the other way.

In other words, one cannot go around adding existence as a property to God (or anything else for that matter) in order to define God (or anything else) into existence.

Descartes had argued that God had existence in the same way as a triangle has three sides. Kant would agree, if you had a triangle then you did indeed have an object with three sides. But if you do not have the triangle, you have neither its three angles or its three sides. If you accept that there is a God, it is logical to accept also that His existence is necessary. But you don’t have to accept that there is a God in the first place.

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Support for Kant: G.E Moore

Moore demonstrates further that existence could not be grammatically used as a predicate because the word does not function as other predicates. He demonstrated this using the following statements:

  • A: some tame tigers growl.
  • B: some tame tigers do not exist.

Statement A makes perfect sense, as it implies there are such beings that fit the description of a 'tame tiger', and that a characteristic they possess is that they do not growl. Statement B, on the other hand, uses 'does not exist' in the same way as 'do not growl', yet it doesn't make sense in the same way.

You learn nothing about the tame tigers, except that they do not exist, which logically means there is nothing to learn about them anyway.

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Support for Kant- Bertrand Russell

Russell proposed that 'existence' is not a predicate, but rather an indication of of something's instance in the spatio-temporal world. Existence tells us nothing about the nature of certain things or beings, only that it indicates if there is a proven instance of something in the world.

For example, the statements 'cows are brown' and 'cows are brown and exist' tell us only one thing; that cows are brown. 'And exists' only shows that they exist in the world, is simply tautology, because in saying that cows are brown we presume it is referring only to existent cows as opposed to imaginary ones.

However, we must distinguish grammatically between claims which appear to function in the same way; for example, 'all cows have tails' and 'all unicorns have horns' are identical grammatically, so it is therefore reasonable to assume that cows and unicorns both exist.

So, the logical structure of a statement is not enough to show the implicit information about the existence of what it is talking about. We must also have more information about this thing/being before we can claim it's existence.

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Douglas Gasking

Gasking also offered reductio to show the fallacy of the ontological proof.

  • 1. The creation of the world is the most supreme achievement that can be conceived
  • 2. The value of the achievement is measured by its intrinsic quality and the ability of the creator.
  • 3. The greater the limitation of the creator, the more impressive the creation.
  • 4. The greatest limitation the creator could possess is non-existence
  • 5. Therefore, a world created by a non-existent creator would be greater than one created by an existing creator.
  • 6. An existing God is therefore not the greatest conceivable being, as an even greater being would be one which does not exist

Thus, God does not exist. ;

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Support for the argument- Leibniz

Since it is impossible to think of God lacking any perfection, then he must exist, since to possess all perfections but not to exist would be pointless.

The definition of perfection Leibniz uses is as follows; 'a simple quality which is positive and absolute, and expresses without limitation whatever it does'.

Recently, the formulations of the argument have maintained that God's necessary existence is existence which is not brought about or threatened by anything else.

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Support for the argument- Norman Malcom

Malcom proposed another form of the argument to support the idea of necessary existence, based on the presumption that if God could exist, he does, because he cannot not exist.

  • 1. God is that than which nothing greater can be thought.
  • 2. Necessary existence is a perfection.
  • 3. If God possesses all perfections, he must possess necessary existence as well.
  • 4. A necessary being cannot not exist.
  • 5. If God could exist then he would exist necessarily.
  • 6.It is contradictory to say that a necessary neing does not exist.
  • 7. Therefore, God must exist.

God's existence is necessary or impossible, and he can't have contingent existence, so logically God must have necessary existence.

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Support for the argument- Alvin Plantinga

Since we can think of limitless alternative worlds in which things may be different, there must be any number of possible worlds, including our own. So, if God's existence is necessary, he must exist in them all and have all the characteristics of God in all of them.

This is because God is maximally great and maximally excellent. He proposed that:

  • A: There exists a world in which there is a being of maximal greatness
  • B: A being of maximal excellence is omnipotent, omniscient and omnibenevolent in all worlds.


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Richard Dawkins

Dawkins rejects the ontological argument on the basis that it is 'infantile', as he believes it is child like in nature and it's reasoning. He says that that the fact that God exists through the ontolgical argument is offensive intellectually; 'could follow from such logo-machist trickery offends me aesthetically'.

Dawkins argues that our automatic reaction to the argument should be suspicion, because any line of reasoning the lacks a 'single piece of data from the real world' should not lead to such a significant conclusion.  

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Arguably, the ontological argument is successful if we accept that the statements are not made to be objectively true, but subjectively. Peter Vardy says that these subjective claims are successful if they 'cohere with other true statements made within a particular form of life'. Thus, supporters of the argument are committed to these claims, especially the notion that God is that than which nothing greater can be conceived and all the other classical features of God. Anselm argues that God is self-evident and necessary, so if committed to these claims, the argument cannot fail.

On the other hand, the anti-realist approach doesn't need absolute truths, only that something is true in a particular context. For Anselm and his supporters, the claim that God is necessarily existent is true only in their particular 'form of life', which is true for other claims made within the religious system that believers subscribe to.

But to anti-realist, the claim is meaningless, and cannot be verified, because it doesn't correspond to the state of affairs and reality to which it describes.

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