Arguments for the Existence of God based upon Reason - The Ontological Argument

ontological argument - Anselm, Gaunilo's criticisms, Kant's criticisms Discuss: - whether a posteriori or a priori is the more persuasive style of argument - whether existence can be treated as a predicate - whether the ontological argument justifies belief - whether there are logical fallacies in this argument that cannot be overcome

the ontological argument as an a priori argument

the ontological argument as an a priori argument

an argument for existence of God based purely on use of reason

unlike teleological & cosmological arguments, does not use observations/evidence from natural world as a starting point

the ontological argument as an analytic argument

relies solely upon an analysis of the definition of the word ‘God’ to show that once we fully understand what we mean when use the word ‘God’, God cannot fail to exist

the ontological argument as a deductive argument

if you accept the premises of the argument, you logically have to accept the conclusion

not stating the most probable explanation — the argument is either true or false

‘reductio ad absurdum’

Anselm uses this type of argument because once you understand the definition of God as being TTWNGCBC, it would be absurd to admit God does not exist

it would be a contradiction to say God does not exist

existence as a predicate of the definition of God

predicates give us information about subjects

we could say ‘Jack is tall’.

• subject = Jack

• predicate = tall

the predicate adds to our knowledge of the subject. We could continue to add predicates to Jack, e.g. ‘has blonde hair’ or ‘is happy’.

fundamental to Anselm’s Ontological Argument is that existence is a predicate — the very definition of God contains within it the predicate of existence

Explain Anselm’s ontological argument

• Faith in God’s existence is more important than an intellectual argument that ‘proves’ God’s existence

  • raises questions about whether Anselm was attempting to prove existence of God or show faith in God is not irrational

• Defines God as ‘that than which nothing greater can be conceived’

  • the ‘fool’ is an atheist

• Feels he is justified in this definition — ‘God’ in order to be ‘God’ must be ‘that being than which nothing greater can be thought’

  • if we can think of something greater than God, that conception would be God

  • in order to deny the existence of God, the ‘fool’ must have a conception of God & the only available conception of God is ‘TTWNGCBC’

• Something can exist in 2 ways:

  • in the understanding alone (merely as a concept e.g. a unicorn, the idea of a painting)

  • in the understanding & in reality (with real existence e.g. an elephant, the completed painting)

• It is greater to exist in the ‘understanding & in reality’ than just in ‘the understanding alone’ (the completed painting is greater than the mere idea of the painting beforehand)

• It is contradictory to say ‘I can think of TTWNGCBC but this does not exist’ because it is greater for something to exist both as a concept & in reality. Therefore, TTWNGCBC would not be TTWNGCBC

  • It is absurd to say TTWNGCBC does not exist

• Because we have reduced the ‘fool’s’ argument that God doesn’t exist to absurdity, we cannot be in any doubt that TTWNGCBC must exist in the understanding & in fact

Anselm’s argument in Proslogion 3 — What type of existence does God have?

Anselm describes 2 types of existence:

Contingent existence — that which ‘can be thought not to exist’

• comes into & goes out of existence so requires a cause of its existence (e.g. living things). Can be thought not to exist without any logical contradiction

Necessary existence — that which ‘cannot be thought not to exist’

• does not need a cause for its existence so must always exist (cannot not exist)

• must exist at all times since it does not come into/go out of existence

It is greater for something to have necessary existence than it is to have contingent existence

• If we think of God as a contingent being, God cannot be ‘TTWNGCBC’ as we can think of something greater than it — contradictory

• Therefore, God must have necessary existence (exist eternally & cannot not exist)

Who criticised Anselm’s argument using the analogy of ‘perfect islands’?

Gaunilo

Gaunilo’s criticisms of Anselm’s ontological argument ()

Gaunilo’s argument

P1 I can have an understanding of an island that than which nothing greater can be conceived (a perfect island)

P2 Existence in reality is greater than existence merely in the understanding

P3 If the perfect island existed only in my understanding, it would not be the perfect island

P4 The perfect island, in order to be the perfect island, must exist in reality

C The greatest possible island exists (obviously absurd because we cannot observe this perfect island — it does not exist)

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• Shows Anselm’s argument is absurd — it is absurd to think just because we can conceive of a greatest island (or any other object) it must exist

• We cannot argue/define things into existence

• Existence cannot form part of the definition of something, but must come from our observations

• Just as it is absurd to argue for the existence of the perfect island, Anselm’s original ontological argument is absurd

• Existence is a separate type of knowledge which comes from observation so we cannot say something exists merely based upon its definition

• Knowledge of God’s existence cannot be analytic but must come from revelation & observation of God’s creation (e.g. cosmological & teleological arguments)

Anselm’s response to Gaunilo