Describe the features of the ontological argument for the existence of God

Examine the features of the ontological argument for the existence of God. To what extent do the strengths of the argument overcome its weaknesses?


The major features:

  • Anselm
  • Proof
  • Definition of God …
  • ‘That which can be conceived not to exist is not God!’ Anselm
  • Existence is a necessary quality of God because to exist in reality (de re) is greater than to exist only in the mind (de dicto). Because existence is more perfect than non-existence therefore God must exist or a being that does not exist in the real world must be less than perfect, hence God exists.
  • Premises ——> conclusion
  • Supported by Descartes’    triangle; God to be God must exist.
  • Tillich – the ‘ultimate reality’
  • Plantinga – multi-verse idea
  • Gaunilo despite his objection to the ontological argument on grounds of circular logic argued reduction ad absurdum that since one cannot prove that God does not exist it follows that he must!




Claims to be a proof

Even if not proof, probability?


Even if agree with premises don’t have to agree with conclusion


If agree with the premises should agree with the conclusion.


But can agree with the definition of God but don’t have to agree that he exists. Propositions about existence are synthetic not analytic.


In that the premises should be agreeable with.

A priori

But as Russell realised there is nothing which just by thinking about it can exist. Hence as he would have said the argument is null and void

A priori

Rational based on logic and not based on evidence outside that thought

God is perfection is not the same as God is!

Existence a predicate

a characteristic of perfection because to exist is better than not to.

Not a necessity

E.g. – Unicorns,     fairies, Gaunilo’s island

Therefore necessary existence of God

Necessary existence only applying to God! Cheat! Unverifiable though also un-falsifiable


Defining God into existenc

Just because he ought by logic to exist, doesn’t mean he does!


Kant and Hume refined by Norman Malcolm the flaw in the onto argument as the assumption that existence was more perfect than non-existence or as he put it ‘what could it mean to say that it would be a better house if it exists than if it does not?’ existence adds nothing to our understanding of the subject.


Douglas Gasking made the point in his ironic proof that God does not exist! Though he was merely trying to say that the existence or not of God was too big a question to be decided by ‘dialectical ratiocination!’




A major weakness is that it claims to be a proof as a result it undermines its own claim.

It is a leap too far from existence in the mind to existence in reality; the analogy is too stretched.

Karl Barth said ‘it can tell what theists believe about God but not whether he exists.’

Although logical the atheist will still balk at accepting the conclusion because ultimately even if one agrees that a definition of God is ‘…’ it still does not mean that one has to accept that He actually exists.


Anti-realists however would argue that they do not demand absolute truth but something which is true within its peculiar context. It is though only going to be true for an already existing believer like Anselm because it is true within the religious system to which he subscribes.

This argument can only ever indicate the probability of the existence of God and therefore the weaknesses must outweigh the strengths.


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