A-level philosophy: ontological argument

Anselm’s ontological argument and Descartes ontological argument

an Italian medieval philosopher, theologian, and church official who held the office of Archbishop of Canterbury from 1093 to 1109.

• In Proslogion, a prayer, he aims to demonstrate God exists and then explores God’s qualities to show it is rational to believe in them.

• wanted to prove the existence of God beyond any doubt by showing it is a logical certainty and that it is self-contradictory to deny it.

Statements that are true by definition

They do not need to be proven using evidence or experience.

a priori

•A priori arguments are based on definition but not experience.

•It highlights something that, because of the definition, is necessarily true.

•If the premises (statements of evidence building the case) are true (or sound, i.e.: based on accurate facts),

•then the conclusion must also be true (because it flows logically from the premises; it is valid).

•St. Anselm believed that through the concept of God, he could deductively demonstrate God’s existence using a priori reasoning.

•For St. Anselm, ‘God exists’ is an analytic statement.

1.God is ‘that than which nothing greater can be conceived’.

2.Even a fool (someone who doesn’t believe in God) can understand the idea that God is the greatest conceivable being.

3.The fool is convinced that God, the greatest conceivable being, exists only in his understanding and not in reality.

4. It is greater to exist both in the mind and in reality, than merely in the mind (to be a real, existent being than an imaginary being).

5. The greatest conceivable being, God, if it is genuinely the greatest, must exist both in the mind and in reality.

1. God is that being nothing greater than which can be thought of.

2. A being with necessary existence (which has to be that way and cannot be different; which cannot be thought not to exist) is greater than contingent beings (which depend on other things for their existence; which can be thought not to exist).

3. Therefore, God who is the greatest being must exist necessarily.

This sought to question whether you could logically move from the existence of an idea to the existence of an actual object that corresponds to the idea.

• It is possible for a person to conceive of a lost island “greater-than-which-cannot-be-conceived”.

• This island therefore exists in my mind.

• Existence in reality is greater than existence in the mind.

• Therefore, it would be reasonable to conclude that this island does not simply exist in my mind alone but also in reality.

• This is of course absurd, argues Gaunilo, and so is the ontological argument.

• Anselm replies (in Apologetic) that islands and God are not comparable.

• Islands and everything else is contingent.

• But God is unique; only he has necessary existence and the argument only applies to God.

• God is a being “greater-than-which-cannot-be-conceived”.

• A being which can be thought of as never not existing (necessary) is greater than one, which can be thought of as not existing (contingent).

• If God is the greatest possible being it would be self-contradictory for God not to exist.

• Therefore God necessarily exists.

Plantinga argues that unlike God, islands have no “intrinsic maximum” because you could always add another beach etc –

i.e. you can’t imagine a ‘greatest possible island’ because you could always make it better – so Gaunilo’s island is not comparable with God

• Anselm uses a theologically and philosophically convincing definition of God, carefully designed to avoid the problem of defining something that is beyond our understanding. Anselm presents an analogy.

• we can’t fully know God, but can at least understand that he is the greatest conceivable being.

“If you say that what is not entirely understood is not understood and is not in the understanding” – Anselm

Aquinas - that God’s nature is beyond our understanding and that people have different understandings of God so he can’t exist by definition + not self evident to us as we don’t know God’s essence

“Perhaps not everyone who hears this word “God” understands it to signify something than which nothing greater can be thought” – Aquinas.

• Gaunilo doubts that we can understand this idea of the greatest conceivable being: 

“of God, or a being greater than all others, I could not conceive at all” – Gaunilo.

Anselm would not accept that we either understand God fully or not at all. Our limited understanding of God is enough to justify attributing the name “that than which nothing greater can be conceived” to God.

God has traits but infinitely, i.e., omnipotence, omniscience etc. It is impossible to conceive of anything greater. So, we can understand enough of that idea.

Anselm doesn’t rely on conceiving the being itself. We can grasp the concept of a being greater than which none may be conceived. We can then follow Anselm’s reasoning that since it is greater to exist, that being must exist.

Even if Anselm is right that we cannot conceive of God without existence, that only proves that God is a necessary being, such that if God existed it would be in a special way where God could not cease to exist.

This is not the same as proving that this necessary being actually does exist.

A grammatical term which refers to the part of a sentence which gives information about or describes the subject of the sentence; what it is like or what it is doing.

God must exist because he is perfect:

• God is by definition a supremely perfect being

• Existence is a perfection - a thing is less perfect if it doesn’t exist

• God must, by definition, contain all perfections.

• Therefore, God exists.

• A defining predicate is a description that is necessary to the concept.

• e.g. a triangle must have 3 sides and 3 internal angles which add up to 180 degrees.

• one of the defining predicates of God is existence.

• A God who did not exist would not be God.

• Therefore God, by definition, must exist.

• Kant objects that existence being a predicate of God does not establish God’s existence in reality.

• Kant’s objection is that this only shows that if God exists, then God exists necessarily. It doesn’t show that God-the-necessary-being does exist.

Existence necessarily being part of the definition of God only shows that God is the idea of a necessary being. We can still deny God actually exists

Kant is drawing a distinction between judgement and reality. A priori reasoning showing that existence is necessary to the definition of God in our minds is not the same as showing that necessary being actually exists in reality.

Kant’s critique is self-contradictory:

Kant’s 1st objection seems to accept that the ontological argument shows that God is necessary.

Kant must then accept that God is a being which contains its own reason for existence and is thus defined by the impossibility of non-existence.

It’s incoherent of Kant to grant God’s necessity while maintaining the possibility of God’s non-existence.

at most the ontological argument can make religious belief rational – it cannot prove that God actually does exist, however.

“reformulated versions of St. Anselm’s argument … cannot, perhaps, be said to prove or establish their conclusion. But since it is rational to accept their central premise, they do show that it is rational to accept that conclusion” – Plantinga.

existence is not a predicate:

Kant objects that existence is not a quality or attribute that defines a thing.

Kant’s illustration is 100 thalers - you have 100 thalers in your mind as a mere concept. Then imagine you also have 100 thalers in existence, not only in the mind. You have two cases of 100 thalers, one which exists in reality and the other which only exists in your mind.

if Anselm’s argument - the thalers which exist should be conceptually different to the thalers that do not.

Being only in the mind doesn’t make the concept somehow less of a complete description of what 100 thalers is. So, existence is not part of the definition of a thing.

It is not a predicate or property of the definition of a thing.

something is contingent if it is dependent on something else for its existence and a necessary being doesn’t depend on anything else for its existence, so it contains the reason for its existence within itself.

Since the reason for its existence is contained within itself, necessary existence must be a defining part of a thing in a way that contingent existence is not. So, necessary existence is a predicate.

The ontological argument, which relies on necessary existence, is therefore defended from Kant’s critique.

‘Exists’ means there are some things in the world that this concept refers to.

e.g. to say lions exist = to say there are things in the world to which the concept of ‘lion’ responds

It is not to say that lions have a very special property known as existence.

‘All cows eat grass’ (‘eat grass’ is a predicate because it adds meaning to the concept of a cow.)

‘Some cows exist’ (‘exist’ is NOT a predicate as it doesn’t add a description)

In fact it suggests there are cows, some of which have the property of existence, others which don’t

To say that something exists isn’t to describe it or to ascribe a special kind of property to it, but rather simply to say that there is such a thing in the world.

• existence is not a predicate.