Evaluate and analyse this claim.
The ontological argument claims to be a proof of the existence of God rather than indicating the probability of His existence, unlike the cosmological or teleological arguments, because being an a priori argument and an inductive one it is based on logic. This argument relies on the agreement on the definition of terms, specifically of the definition of the word God. If all can agree on what God is or what is meant by the term God then all should agree that God exists.
Anselm defined God as the ‘Greatest being imaginable.’ If we agree that this is what God is then we should logically agree that God must exist since many much less great beings do exist.
The problem with arguments like this is that though we might agree if we were talking about something prosaic, when it comes to God we can’t!
Anselm’s case was this….
He was supported by Descartes who used the analogy of …. and argued…
But his opponents contested their conclusions, asserting like Gaunilo did that God could not be defined into existence…
Immanuel Kant too didn’t regard existence as a necessary quality, a predicate. Just because we might agree on what we mean by God doesn’t mean he has to exist, rather like the tooth fairy, unicorns or aliens! And further that, though it was logical to agree that things which exist in reality must be greater than those which exist only in the mind (after we’d all rather win the lottery rather than just dream about it!), it doesn’t mean that the reality has to happen. As Norman Malcolm pointed out the situations are not parallel, merely analogous and we are playing language games.
Though this seems to be a strong argument it will nevertheless not convince a non-believer who will happily follow the logic that the definition of God might well be ‘the greatest being imaginable’ but that doesn’t mean that God actually exists and that it was a leap too far, from existence in the mind to existence in reality.
In fact what this argument does more successfully is to define the characteristics of God, as Karl Barth said, ‘it can tell what theists believe about God but not whether he exists.’
Ultimately it has the force of logic but an atheist will not be convinced even if he agrees with the logic. This argument does not look at evidence or experience merely words and ends up being a weak argument which can indeed only indicate the probability of the existence of God and perhaps not even as successfully as the teleological argument does.