The Ontological argument


See here for content about the status as a proof and value for religious faith of arguments for the existence of God. It is also needed for some philosophy dialogues questions about the relevance of reason and philosophical argument for religious faith.

St Anselm’s Ontological argument

Anselm refers to Psalm 14:1 ‘the fool says in his heart, ‘there is no god’.” Since the fool can conceive of God as the greatest being, it would be contradictory to then think that God doesn’t exist since then God wouldn’t be the greatest being. As existence in reality is an intrinsic quality of greatness (by definition). To say there’s no God is simply to misunderstand what the word ‘God’ means.

P1 – God is the greatest conceivable being
P2 – It is greater to exist in reality than the mind alone
P3 – God exists in the mind
C1 – Therefore, God exists in reality

Gaunilo’s criticism makes the point that if we apply Anselm’s logic to something other than God, like an Island, we get an ‘absurd’ outcome (reductio ad absurdum) that it must exist. We can conceive of a perfect Island but that doesn’t mean it exists, so why should that be the case for God?

Anselm’s 2nd version of the ontological argument. Anselm strengthened his argument into a 2nd form.

Something is greater if it doesn’t depend on anything for its existence. An Island by definition is land enclosed by water – thus part of the concept of an Island involves a dependence on things such as an ocean to exist. So, the greatest possible Island will still be contingent, which means that it is not the case that it must exist. There is nothing in the concept of the greatest being that involves dependence however, unlike the Island. So, Anselm can now argue that this is why the argument works for God but not an Island.

Descartes Ontological Argument:

P1 – God is a supremely perfect being
P2 – A supremely perfect being contains all perfections
P3 – Existence is a perfection
C1 – God exists

Descartes said that the relationship between God and existence was like that of a triangle with the property of ‘having three sides’ or a mountain and a valley. It is part of the definition of those things that they are together.

Immanuel Kant’s critique of the Ontological argument

Kant argued that existence was not a predicate, meaning not an attribute or quality that is part of the definition of a thing.

Anselm’s argument depends on existence being part of the definition of God. His argument is that God is the greatest possible being and that since it’s greater to exist, God must exist. If God didn’t exist, he wouldn’t be the greatest possible being, but he is the greatest possible being so he must exist. This amounts to claiming that if God didn’t exist, that would no longer be God. This means that for Anselm, existence is an attribute of the concept of God, along with all-powerful, all-knowing, etc. Thus, for Anselm, God’s existence is part of what God is. The question of God’s existence is a question of what God is.

Kant rejected the idea that existence could be an attribute. What something is, is defined by the attributes it has. For Kant, what something is, is different from whether it exists.

Imagine you did not believe in mermaids but argued with someone who did, about whether they exist. You would be agreeing on the definition of the concept of what it meant to be a mermaid (half fish, half human etc) but disagreeing on whether that concept is instantiated (exists) in reality. If you can agree on the concept but disagree about existence, then it seems that the question of whether something exists is different from the question of what it is.

Kant illustrated this with 100 thalers, which are coins. Imagine you have 100 coins in your mind as a mere concept. Then imagine you also have 100 coins in existence, not in the mind alone. The coins in existence have existence, the concept of coins in your mind does not.

Kant argues that the concept of what it means to be 100 coins is no different whether it is a mere concept in your mind or whether that concept actually exists in reality as an existing thing. 100 coins is just 100 coins; it has the attributes of shininess and roundness, whether in your mind or in reality. If there is no conceptual difference in between the coins in the mind or the coins which exist in reality, then existence cannot be an attribute of a concept. This means that existence cannot be part of the concept of a thing; it is not a predicate.

Malcolm criticised Kant, arguing that Kant’s argument only worked for contingent existence but not necessary existence, so Anselm’s second version of the argument was right. Something is contingent if it is dependent on something else for its existence. The reason for its existence is external to it. However, a necessary being doesn’t depend on anything else and so contains the reason for its existence within itself. This reason is the logical impossibility of non-existence. Since that is contained within itself in a way that contingent existence is not, Necessary existence can therefore be a part of a thing in a way that contingent existence can’t.

Existence is not a perfection/greatness

Malcolm’s objection that Anselm was wrong to claim that existence is ‘greater’ or ‘more perfect’ than non-existence. Why is it ‘greater’ to exist in reality than in the mind? Isn’t ‘greatness’ subjective? Isn’t that merely the subjective preference of humans to exist?

Why it is greater to be necessary than contingent? Anselm clearly thinks it is greater to be unable to fail to exist. A contingent being can fail to exist, therefore it’s lesser, for Anselm. However, that assumes that existence or inability to fail to exist is greater than an ability to fail to exist, which still operates on the same assumption that existence is greater than non-existence. Why?

Malcolm claims to get around this objection by removing the claim that existence is a greater or more perfect than non-existence, which he claims is a ‘remarkably queer’ idea. Malcolm’s Ontological argument the runs as follows:

1 God either exists or does not exist
2 God cannot come into existence nor go out of existence as that would be a limitation
3 So If God exists, God cannot cease to exist
4 Therefore if God exists, God cannot fail to exist = necessary
5 But if Goes doesn’t exist, he can’t come into existence (as that would make him dependent on whatever caused that which would make him contingent therefore limited)
6 Therefore If God does not exist, God’s existence is impossible
7 God’s existence is either necessary or impossible
8 The concept of God is not self-contradictory (like a four-sided triangle), therefore God’s existence is not impossible
9 Therefore God exists necessarily

Malcolm commits the fallacy of equivocation as in premise 6 he uses the term impossible to mean ‘can’t come into existence’ due to the metaphysical status of reality (God not existing), i.e. metaphysical impossibility. In premise 8 Malcolm uses the term impossible to mean conceptually incoherent, i.e. logical impossibility.

Arguably God is impossible because it is an incoherent concept, e.g. the logical problem of evil, omnipotence paradox or the conflict between omniscience, free will and omnibenevolence.

Hume’s fork and the impossibility of a necessary being

“there is an evident absurdity in pretending to demonstrate a matter of fact, or to prove it by any arguments a priori” – Hume.

A necessary being must exist – it cannot be the case that it does not exist. This means we shouldn’t even be able to conceive (imagine) it not existing, without contradiction. However, Hume claims that whatever we conceive of as existing, we can conceive of as not existing. Hume concludes:

“The words, therefore, necessary existence, have no meaning.”

This argument references “Hume’s fork”:

A priori reasoning can only tell us about the relations between ideas, i.e. analytic knowledge (true by definition). E.g. “a bachelor is an unmarried man”.

A posteriori reasoning can only tell us about matters of fact, i.e. synthetic knowledge (true by the way the world is). E.g. “The sun will rise tomorrow”

Matters of fact, such as whether a being exists, cannot be established a priori, according to this argument. Hume’s basis for the fork is that if a particular truth is a matter of logic/definition, then it will be true or false no matter the factual state of the universe. E.g., one plus one will always equal two, regardless of what happens to be factually true of the universe. This suggests there is a disconnect between logical truth and factual truth. The term “necessary existence” seems to ignore this disconnect. It’s invalid to claim that a being’s existence is logically necessary, since a being’s existence cannot be established through logic. Since Hume’s fork has shown that logical truth is disconnected from factual truth, the idea that something could necessarily exist is incoherent.

The ontological argument therefore fails because it attempts to establish a matter of fact (God’s existence) through a priori reasoning. Also attacked is any argument which involves the incoherent idea of a necessary being (some cosmological arguments e.g. Aquinas’ 3rd way).

Masked man fallacy. Hume’s argument depends on conceivability entailing possibility. It is therefore succeptible to the masked man fallacy, which shows that we can concieve of the impossible. Imagine someone heard of a masked man robbing a bank. They can concieve that it is not their father. Yet, if it was their father, then it is impossible that it is not their father. Yet, that was what they concieved of. So, we can concieve of the impossible. Hume is therefore wrong to think that our being able to concieve of God not existing means that it is possible for God to not exist.

Hume conflates logical necessity and metaphysical necessity. Hume rejects the idea that ’God exists’ could be a necessarily true proposition, since we can conceive of God not existing, which shows that “God exists” cannot be necessarily true. However, what if the actual claim is that “If God exists, God exists necessarily”. This claim is not attributing logical necessity to the truth of a proposition; it is attributing metaphysical necessity to a being. This being, if it exists, exists necessarily because it does not depend on anything else for its existence. It’s not necessarily true that such a being exists, but if it does, its existence is necessarily.

Hume’s fork: even if we take arguments for God involving necessity to be attributing necessity to a being, not to a proposition, it’s existence still cannot be established by a priori reasoning. Matters of fact can only be inferred by a posteriori reasoning.

It could be inferred by a posteriori reasoning, however, such as is found in the cosmological argument.