the ontological argument

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Arguments for the existence of God 1. The Ontological Argument

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Deductive Reasoning An argument is ‘deductively valid’ when we accept the premises are true, and the conclusion must follow from the premises. The ontological argument is an a priori analytic argument from deductive reasoning. Proponents claim that because the premises are true, the conclusion (that God exists) must be true. The way to analyse such arguments is to look at whether the premises are really true. If the premises are not true, then the conclusion is not true.

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Knowledge ‘a priori’ and ‘a posteriori’ Premises that are knowable ‘a priori’ The information involved is knowable by definition of the words used. E.g. ‘all bachelors are single’ is an a priori statement because it is part of the meaning of the word bachelor that they do not have a partner. Premises that are knowable ‘a posteriori’. The information contained in the premise can only be known from experience. For example ‘all bachelors live alone’ is only a verifiable statement that is true if you had met all bachelors and found out that they live alone.

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Sort these statements into ‘a priori’ and ‘a posteriori’: Boys are tall Girls are weaker than boys Teenagers are lazy Citizens are voters Ghosts are scary My brother is male Humans are not invertebrates God is great

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Propositions: Subject & predicate Subject = the person / thing / concept you are talking about Predicate = the properties of the person / thing / concept.

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St Anselm: Proslogian 2 An essential property of greatness is existence. “God is that than which nothing greater can be conceived”. Even a ‘fool’ (an atheist) must have a concept of God in order to dismiss the concept and say that God does not exist. To deny God is inherently contradictory because the concept of God implies existence qua greatness.

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God is the greatest conceivable being Something that is the greatest could not be any better than it already is Something that exists only as an idea would not be as good as something that also exists in reality Even an atheist (“fool”) has an idea of what God is If we have an idea that something is the ‘greatest’ (or perfect), then it must also be something that exists otherwise it would not be the greatest. Therefore God must exist in reality. The existence of God; a deductive proof:

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St Anselm: Proslogian 2 St Anselm’s ontological argument is A priori analytic (reason alone tells us it is true by definition) Using deductive logic Its logical structure is sound and the conclusion is valid. So do we have to accept it is true?

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Just because you can imagine the perfect island, does this mean it exists in reality? Gaunillo shows that you can imagine that there is a perfect island, but it doesn’t mean that the Island exists in the world.

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Contingent & Necessary existence Anslem replies in Proslogian 3 that the perfect island is not the same order of thing as God. Islands exist contingently – they depend on other things existing for them to exist. If conditions changed, an island would be affected by such changes. God exists necessarily, meaning that God depends on nothing else for existence. The universe changes all the time, but God remains unaffected.