The existence of God

5  Arguments based on reason

The ontological argument

Essential terminology

Analytic

A priori

Contingent

Incoherent

Necessary

Predicate

Synthetic

Key scholars

Boethius (480–524)

Anselm (1033–1109)

Gaunilo of Marmoutier (eleventh century)

Pierre Gassendi (1592–1655)

René Descartes (1596–1650)

Immanuel Kant (1724–1804)

The issues

  1. 1 If someone has an idea of what God is, can his existence be proved?
  2. 2 Is it part of the definition of God that God has to exist in reality, not just in people’s minds?
  3. 3 Whether a posteriori or a priori is a more persuasive style of argument
  4. 4 Whether existence can be treated as a predicate
  5. 5 Whether the ontological argument justifies belief
  6. 6 Whether there are logical fallacies in the argument that cannot be overcome.

What you will learn about in this chapter

The ontological argument with details of this argument with reference to:

The OCR checklist       

Arguments based on reason

The ontological argument – details of this argument, including reference to:

Learners should have the opportunity to discuss issues related to arguments for the existence of God based on reason, including:

Thought point

Look at the following statements. How would you prove the truth of each of these statements?

  1. 1 Father Christmas has a white beard.
  2. 2 Unicorns are silver.
  3. 3 All war is evil.
  4. 4 God exists.
  5. 5 Rape is wrong.
  6. 6 Three plus three equals six.
  7. 7 All dwarves are small.

Introduction

This chapter examines the ontological argument, which claims to demonstrate that the statement ‘God exists’ is analytically true – meaning that it would be make no sense to doubt God’s existence. The ontological argument claims that once someone has understood what the word ‘God’ means he must recognise that God exists. This argument is a priori and tries to show that it is possible to argue for God’s existence without making any reference to sense experience, as the definition of God means that he exists necessarily.

Thought point

Analytic and synthetic statements

Anselm wanted to show that the statement ‘God exists’ cannot be doubted. This is an analytic statement.

Look at the following statements and consider which of these statements are true and which need to be proved with evidence.

  1. 1 A triangle has three sides and the internal angles add up to 180 degrees.
  2. 2 Mount Everest is the highest mountain in the world.
  3. 3 Unicorns are silver and have a horn on their head.

Analytic statements

An analytic statement is a statement which it is ridiculous and impossible to think is false. For example a triangle having three internal angles adding up to 180 degrees is an analytic statement, because it is ridiculous and impossible to think of a triangle in any other way. Richard Swinburne gives the following example: ‘An analytic or logically necessary proposition is one which it would be incoherent to suppose to be false; “all squares have four sides” and “red is a colour” are logically necessary, because it would be incoherent, make no sense to suppose that red could be anything except a colour, or that a square could have only three sides’ (Swinburne, The Existence of God).

Synthetic statements

A synthetic statement is a statement in which the statement’s truth or falsity depends on evidence which has to be collected. An example of a synthetic statement is statement 2 above. The truth or falsity of this statement depends on evidence one collects.

Anselm’s ontological argument

For medieval theologians, the existence of God was a ‘given’ – they did not need to debate it. However, as Aristotle’s philosophy and his Muslim commentators were introduced into the universities, they were seen as threatening traditional Christian belief. A debate raged between the supporters of the new philosophy and the ‘orthodox’ traditionalists. Anselm wanted to reconcile the two approaches.

Anselm wrote The Monologion as a meditation on the Divine Being, saying that he wanted to find a single argument which would show that God exists. His argument came to him after a long period of contemplative prayer – it is said that he was at vespers when the idea hit him.

He explained his argument in The Proslogion. He based his argument on a quotation from Psalm 14:1, which says, ‘Fools say in their hearts, “There is no God.” ’ Anselm argued that it is possible for anyone to conceive of ‘that than which nothing greater can be thought’.

Anselm’s thoughts on this passage have become known as the ontological argument for God’s existence. The name for this argument comes from two Greek words – ontos (being) and logos (reason or word: the ontological argument is concerned with the being or nature of God).

Anselm of Canterbury (1033–1109), scholastic philosopher and saint

St Anselm of Canterbury

Pictorial Press Ltd/Alamy

Anselm was born in Aosta (Piedmont), Italy. As a young man he became a monk at the famous monastery of Bec, in Normandy, France. Eventually he became abbot of the monastery and in 1093 he was chosen as archbishop of Canterbury. During his life he wrote a large number of works examining both the nature of God and the relationship between the Church and the state in medieval Europe. Anselm’s writings were influenced by the philosophy of Plato and he was an important early figure in the scholastic movement.

For example once you have understood what is meant by ‘a square’ you understand that by a square you mean something with four sides and four internal right angles, which add up to 360 degrees.

Anselm’s first ontological argument

The Proslogion is written as a prayer:

Therefore, Lord, you who give knowledge of the faith, give me as much knowledge as you know to be fitting for me, because you are as we believe and that which we believe. And indeed we believe you are something greater than which cannot be thought. Or is there no such kind of thing, for ‘the fool said in his heart, “there is no God” ’ (Ps. 13:1, 52:1)? But certainly that same fool, having heard what I just said, ‘something greater than which cannot be thought,’ understands what he heard, and what he understands is in his thought, even if he does not think it exists. For it is one thing for something to exist in a person’s thought and quite another for the person to think that thing exists. For when a painter thinks ahead to what he will paint, he has that picture in his thought, but he does not yet think it exists, because he has not done it yet. Once he has painted it he has it in his thought and thinks it exists because he has done it.

Thus even the fool is compelled to grant that something greater than which cannot be thought exists in thought, because he understands what he hears, and whatever is understood exists in thought. And certainly that greater than which cannot be understood cannot exist only in thought, for if it exists only in thought it could also be thought of as existing in reality as well, which is greater. If, therefore, that than which greater cannot be thought exists in thought alone, then that than which greater cannot be thought turns out to be that than which something greater actually can be thought, but that is obviously impossible.

Therefore something than which greater cannot be thought undoubtedly exists both in thought and in reality.

(www.fordham/edu/halsall/source/anselm.html)

What does this mean?

  1. 1 This ‘something greater than which cannot be thought’ must exist, at least in the mind.
  2. 2 However, if it exists only in the mind then it is inferior to anything that exists both in the mind and in reality.
  3. 3 It must therefore be that the thing than which nothing greater can be thought exists both in the mind and in reality.
  4. 4 The most perfect conceivable being must exist in reality as well as in the mind.

Anselm’s argument is based on the following points:

Anselm based his argument on his reply to the fool who said there is no God, as in order for the fool to say ‘there is no God’ the fool has to have had some idea in his mind of what God ‘is’. Anselm put forward a definition that he thought the fool would accept: that God is the ‘greatest possible being’. According to Anselm God is the greatest possible being that can be ‘conceived’ – meaning ‘thought of’.

Anselm then pointed out that it is greater to exist in reality than in the mind alone. For example people have an idea of what a fairy is and can give a description of it. However, while we can happily talk about the idea of a fairy and its nature or qualities (e.g. a small imaginary being of human form with wings that has magical powers), that does not make it exist. Fairies may be brought to life using computer animations in films or in books, such as Tinker Bell in Peter Pan, but they do not exist in reality. What was important for Anselm was that what exists in reality as well as in the mind is greater than something that is only an idea in the mind.

Anselm’s argument hinges on the assumption that something that really exists is greater than something which is only imaginary. An idea that exists in reality and in the mind has the extra quality of existence that something which exists only in imagination can never have.

Analytic

A proposition or statement that it is incoherent to doubt (e.g. triangles have three sides).

Synthetic

Usually refers to a proposition or statement the truth or falsity of which has to be verified. Predicates of synthetic propositions are not intrinsic to the subject of the proposition (e.g. the car is green – this may or may not be true; check to be sure of your answer).

Thought point

Watch the film The Matrix (1993) and ask yourself whether it supports Anselm’s claim that existence in reality is better than existence in the mind alone.

Existence is a predicate

The word ‘predicate’ is used in philosophy to mean intrinsic property or quality of something. For example a predicate of a particular breed of dog might be its form or its colour. In other words, predicates tell us something about the nature of a thing.

Anselm says that it is part of God’s nature that God exists, so in philosophical terms: a predicate of God is God’s existence.

Philosophers say that the predicates of something are included in the subject itself so a bachelor refers to an unmarried man. The predicate of being a bachelor is that ‘you are unmarried.’ This is part of the nature of being a bachelor. It is unnecessary to say: Mr Brown is a bachelor who is unmarried.

Anselm claimed that existence is a predicate of God (i.e. a property or quality of God’s nature). Therefore, God, being the greatest possible being, must exist, since an imaginary idea is not as great as an idea that exists in reality. To be the greatest possible being, God must, necessarily, have his property of existence.

Anselm concluded that because God is the greatest being that can be thought of, part of being a ‘being’ or ‘thing’ of any sort is that you exist. So God must exist. For Anselm, God’s existence is therefore analytic.

Anselm’s second version of the argument (Proslogion 3, 1078)

In the third chapter Anselm argues that for God existence is necessary.

In fact, it so undoubtedly exists that it cannot be thought of as not existing. For one can think there exists something that cannot be thought of as not existing, and that would be greater than something which can be thought of as not existing. For if that greater than which cannot be thought can be thought of as not existing, then that greater than which cannot be thought is not that greater than which cannot be thought, which does not make sense. Thus that than which nothing can be thought so undoubtedly exists that it cannot even be thought of as not existing.

And you, Lord God, are this being. You exist so undoubtedly, my Lord God, that you cannot even be thought of as not existing. And deservedly, for if some mind could think of something greater than you, that creature would rise above the creator and could pass judgment on the creator, which is absurd. And indeed whatever exists except you alone can be thought of as not existing. You alone of all things most truly exists and thus enjoy existence to the fullest degree of all things, because nothing else exists so undoubtedly, and thus everything else enjoys being in a lesser degree. Why therefore did the fool say in his heart ‘there is no God,’ since it is so evident to any rational mind that you above all things exist?

Why indeed, except precisely because he is stupid and foolish?

(www.fordham/edu/halsall/source/anselm.html)

Anselm aims to define God in such a way as to make it impossible to conceive of him as not existing.

What we cannot conceive of as not existing must be greater than what we can conceive of as not existing.

It would make no sense to propose that the greatest thing that can be thought of did not exist, because there would be something greater in reality than the thought first proposed.

Assuming Anselm’s definition of God as ‘the greatest thing that can be thought’ can be accepted. If we can hold the concept of God in our minds, God must exist in reality, since that which exists in reality is always greater than that which exists only in the mind. Therefore, it is impossible to think that God cannot exist. God, then, has necessary existence – he has to exist, unlike dogs, which are contingent, as they might exist or they might not: it just depends if the mating was successful or not!

It is impossible for God not to exist, so if a person claims that God does not exist, this, according to Anselm, is a contradiction as it is part of God’s nature to exist. Additionally, if God existed only contingently, like the dogs, he would depend on something else for his existence and so could not be a great a being as one which had to exist and could not fail to exist: one whose existence is necessary.

Necessary

In philosophy ‘necessary’ is used to refer to something which has to be that way and cannot be different, whatever the circumstances.

Contingent

Something which is not necessary, which depends on something else for its existence.

Criticisms of Anselm’s argument

Gaunilo’s criticism of Anselm’s argument

There have been many criticisms of Anselm’s argument, the most famous one being that of a Benedictine monk called Gaunilo. His argument was entitled On Behalf of the Fool and it is a defence of the fool against Anselm’s ideas.

Gaunilo argued that Anselm’s conclusion, that God cannot fail to exist, is ‘unintelligible’ – it cannot show that God necessarily exists. Gaunilo suggests that the fool mentioned in Psalm 14 might reply to Anselm by saying that if what Anselm said was true, then the same could be said to prove the existence of an imaginary island.

  1. 1 Gossip

    First, the fool could imagine sorts of things that do not exist in reality. Gaunilo gave the example of someone hearing about a person from gossip. However, gossip is notoriously unreliable, and the person and event in question need not be true at all.

  2. 2 Defining things into existence

    Additionally, Gaunilo argued that you cannot prove the existence of something by just having an idea about it; you cannot define the idea into existence. Philosophers in the Middle Ages would say you cannot prove that just because something is said (de dicto) it exists in reality (de re).

  3. 3 Gaunilo’s island

    Gaunilo’s most famous argument against Anselm’s ontological argument was that of a perfect island. He suggested that anyone can imagine a most perfect island and argued that while the most perfect island can be conceived of, this does not mean that it exists.

    Gaunilo’s island analogy implies that it makes no sense to say that just because you have an idea of something it must exist. Following Gaunilo’s argument you can also have, for example, a clear idea of what a perfect car is; it does not mean that the car exists. This led Gaunilo to claim either that the argument about the perfect island is a joke or that the man making the argument is a fool, or that the person believing the argument is a fool.

    According to Gaunilo, Anselm was unable to prove that the idea of God as the greatest possible being means that God exists in reality.

Gaunilo’s own words

On gossip!

The being is said to be in my understanding already, only because I understand what is said… . For, suppose that I should hear something said of a man absolutely unknown to me, of whose existence I was unaware. Through that special knowledge by which I know what man is, or what men are, I could conceive of him also, according to the reality itself … And yet it would be possible if the person who told me of him deceived me, that the man himself, of whom I conceived, did not exist.

(Deane, trans., St Anselm: Basic Writings)

The island analogy

For example: it is said that somewhere in the ocean is an island… [and] that this island has an inestimable wealth of all manner of riches and delicacies that is told of the island of the Blest … it is more excellent than all other countries … Now if someone should tell me that there is such an island, I should easily understand his words, in which there is no difficulty. But suppose that he went on to say, as if by a logical inference: ‘You can no longer doubt that this island which is more excellent than all lands exists somewhere, since you have no doubt it is in your understanding. And since it is more excellent not to be in the understanding alone, but to exist both in understanding and in reality, for this reason it must exist.’

(Deane, trans., St Anselm: Basic Writings)

If a man should try to prove to me by such reasoning that this island truly exists, and that its existence should no longer be doubted, either I should believe that he was jesting, or I know not which I ought to regard as the greater fool: myself … or him, if he should suppose that he has established with any certainty the existence of the island.

(Deane, trans., St Anselm: Basic Writings)

Thought point

A newspaper story reports that ‘Princess Diana was seen in London yesterday.’ What problem with Anselm’s argument might this highlight?

Anselm’s reply to Gaunilo

Anselm himself provided a reply, pointing out that an island is a finite, limited thing. When somebody imagines a perfect island, there will always be other perfect islands. The ‘that than which nothing greater can be thought’ is unique. Anselm believed that Gaunilo’s argument was defeated by his own proposition of ‘necessary existence’.

Anselm pointed out that whereas the greatest possible island is contingent – it does not have to exist – God’s existence is necessary. Gaunilo’s argument, he claimed, is totally different from his own. Anselm rejected Guanilo’s argument that it is possible to prove a perfect island exists simply because it is possible to imagine it.

Alvin Plantinga added to this by saying that Anselm could also say that however marvellous an island is there could always be a better one as Gaunilo’s island has no ‘intrinsic maximum’ or limit to its marvels. Plantinga concluded that any idea of a greatest possible island is, therefore, an incoherent idea (Plantinga, God, Freedom and Evil).

Plantinga considered that God is maximally great according to Anselm – nothing greater can be possible so it is impossible to compare the greatest possible being with the greatest possible island.

Why Thomas Aquinas rejected Anselm’s argument

Aquinas did not consider that the existence of God is self-evident to humans, as humans are unable to understand God’s nature. So even saying that God exists is beyond human understanding.

‘God exists,’ of itself is self-evident, for the predicate is the same as the subject, because God is His own existence as will be hereafter shown … Now because we do not know the essence of God, the proposition is not self-evident to us; but needs to be demonstrated by things that are more known to us.

(Summa Theologia 1a q2 a1)

Incoherent

A philosophical argument which fails because it is illogical.

Aquinas concluded that it is possible to understand God only indirectly through the world and his actions in it. Aquinas’ cosmological or design arguments are synthetic arguments that look for evidence to prove God’s existence.

Some final thoughts about Anselm’s argument

Anselm’s argument is not meant as proof of God’s existence like Aquinas’ cosmological argument, as Anselm does not question God’s existence. Instead Anselm is simply showing what he believes to be true.

Boethius and Anselm

It has been said by some philosophers that the development of Anselm’s ontological argument was influenced by Boethius’ book the Consolation of Philosophy.

In particular, Boethius suggested that

The universally accepted notion of men proves that God, the fountainhead of all things, is good. For nothing can be thought of better than God, and surely He, than whom there is nothing better, must without doubt be good. Now reason shows us that God is so good, that we are convinced that in Him lies also the perfect good. For if it is not so, He cannot be the fountain-head; for there must then be something more excellent, possessing that perfect good, which appears to be of older origin than God: for it has been proved that all perfections are of earlier origin than the imperfect specimens of the same: wherefore, unless we are to prolong the series to infinity, we must allow that the highest Deity must be full of the highest, the perfect good.

(Boethius 1902, Consolation of Philosophy)

According to Boethius God is perfect and nothing can be better than God. This shares some similarities with Anselm’s ontological argument. However, there are differences as Anselm’s ontological argument stresses that God is the greatest conceivable being, whereas Boethius seems to suggest that God is the most perfectly good being that exists.

Descartes the man (1596–1650)

René Descartes

GL Archive/Alamy

René Descartes was born in La-Haye, France. He joined a Jesuit school in Anjou and later studied at the University of Poitiers. He joined the army of the Prince of Orange in 1618, but did not actually fight in any battles. From 1628 to 1649 he lived in Holland. In 1649 he became the tutor of Queen Christina of Sweden. He died of pneumonia in 1650.

Descartes wrote widely on philosophy, and he is significant because many philosophers see him as the founder of modern philosophy; he developed new approaches to philosophy which differed from the traditional philosophies of Europe that came from the great Greek philosophers of the ancient world. He wrote many books, but the most famous is his Meditations on Philosophy (1641), which examines the nature of reality and God. It is this book which contains his version of the ontological argument.

Descartes’ ontological argument

Descartes’ version of the ontological argument is not required for the examination, but it is important as Kant’s criticisms of Descartes’ argument can also be applied to Anselm’s version.

Descartes wrote about the existence of God in Meditations 3 and 5 of his Meditations on Philosophy. Meditation 5 is a version of the ontological argument.

The background to Descartes’ ontological argument

Before he even presented his form of the ontological argument Descartes wrote that God had already placed in everyone the idea of God. He also stated that God’s existence cannot be doubted – just as mathematics is a truth that cannot be doubted as it has been demonstrated clearly. Thus he suggested that showing that God exists is not intended to prove that God exists but it is simply showing that there is no reason to doubt that fact. This is what his version of the ontological argument is intended to demonstrate.

Descartes’ ontological argument

Descartes considered that God was perfect, as an imperfect being could not be God. One property of perfection is existence so it was part of God’s nature to exist – in other words existence is a predicate of God and thus tells us something about God. He used the example of a triangle and said that the nature of a triangle is to have three sides and three interior angles which add up to 180 degrees, and it could not be different in any way. Descartes used the word ‘immutable’ to describe the nature of the triangle – it was incapable of change.

According to Descartes, God, like the triangle, has an ‘immutable’ nature and part of this nature is that God exists; thus existence is a predicate of God.

Descartes’ argument

  1. 1 God is a supremely perfect being.
  2. 2 A property of perfection is existence.
  3. 3 Therefore, God exists.

Thought point

Think of the characteristics of your dream car. Could your dream car be described as the ‘perfect’ car? What would Descartes say?

Kant’s objection to the ontological argument

Kant objected to Descartes’ version of the ontological argument, but his objections also apply to Anselm’s ontological argument.

Kant argued that the statement ‘God does not exist’ is not self-contradictory, in the same way that to say that fairies do not exist is not a contradiction. Some statements do contradict themselves, such as ‘a dwarf is a tall being,’ but denying something is not a contradiction. Therefore, the denial of God’s existence isn’t self-contradictory. And because the ontological argument rests on God’s non-existence being self-contradictory, it is not sound.

Furthermore, Kant argued that existence is not a ‘predicate’. For example one can have an idea of what a fairy is. However, that does not mean it exists in reality, even though we can think about fairies as living creatures. It is possible to consider that a predicate of a fairy is that it is a small being of human form with wings, but that does not mean that it is necessary to believe that fairies exist.

Therefore, for Kant existence is not a real predicate as it does not tell us what something is like. Kant felt that ‘exist’ merely meant that a concept had actuality and it did not add anything to the concept.

To say that something exists does not add to our understanding of that thing. Kant puts it in terms of a sum of money:

If, now, we take the subject (God) with all its predicates (among which is omnipotence), and say ‘God is’, or ‘There is a God’, we attach no new predicate to the concept of God, but only posit the subject in itself with all its predicates, and indeed posit it as being an object that stands in relation to my concept. The content of both must be one and the same; nothing can have been added to the concept, which expresses merely what is possible, by my thinking its object (through the expression ‘it is’) as given absolutely. Otherwise stated, the real contains no more than the merely possible. A hundred real thalers* do not contain the least coin more than a hundred possible thalers.

* A thaler was a German silver coin.

Kant said that an idea of a pile of 100 coins that exist in my mind and the pile of 100 coins that exist in reality will have the same worth. Thus adding existence to the idea will not make it any better but will only affirm what is. Thus existence is not a predicate, or existence in reality is not a special attribute of God, because it virtually adds nothing to the idea of God. For example in the statement ‘the plant is green’ the word ‘green’ is a predicate. The concept of something existing does not change our concept of the thing itself, just the world in which it now exists.

Therefore, according to Kant, existence is not a predicate. And if it’s not a predicate, it can’t be a perfection. Thus, God can be defined as perfect regardless of whether he exists.

Replies to Kant

Is Kant correct in saying that existence is not a predicate? For example one can have an idea of what the fairy is and list the particular properties of the fairy, such as size, human-like, with wings and magical powers and so forth. However, if I have actual evidence that fairies exist, that adds something to the idea. It can, therefore, be argued that asserting that an object exists can change the way that we conceive of it. For example if someone read about Socrates in the works of Plato, and then discovered that he was a real historical figure – that is that he existed – then this extra information will change the way that the person thinks about him. In the same way it could be suggested that to say that God is not a mere figment of believers’ imaginations, but actually exists, does add something to the concept of God. Perhaps, then, Anselm’s comparison between a God that exists and a God that does not is possible, and the ontological argument survives Kant’s criticism.

Norman Malcolm (Malcolm, ‘Anselm’s Ontological Argument’) suggested that necessary existence could be a predicate of God. He argued that the existence of God is either impossible or necessary. Following Anselm’s second formulation of the ontological argument, Malcolm claimed that God cannot contingently exist; otherwise God would not be the greatest possible being. According to Malcolm God’s existence is impossible only if God’s existence is both self-contradictory and illogical.

However, the problem with Malcolm’s claim that God necessarily exists is that you cannot prove God exists by stating what is not the case. Even if God’s existence is not impossible or contradictory, this shows only that God’s existence is possible, not that God necessarily exists.

Summary

1 Anselm’s ontological argument
Anselm started with a response: ‘Fools say in their hearts, “there is no god” ’ (Psalm 14: 1).

2 Anselm’s first ontological argument

3 Anselm’s second version of the argument

4 Gaunilo’s criticism of Anselm’s argument

5 Anselm’s possible reply to Gaunilo

6 Descartes’ ontological argument

7 Kant’s objections to the ontological argument

Review questions

Look back over the chapter and check that you can answer the following questions:

  1. 1 Briefly explain Gaunilo’s criticism of the ontological argument.
  2. 2 What are the two most serious weaknesses of the ontological argument in your opinion? Justify your choice.
  3. 3 Summarise Anselm’s and Descartes’ version of the ontological argument.
  4. 4 What is the difference between an analytic and a synthetic statement? Explain with reference to an example.
  5. 5 Explain what Kant means when he says existence is not a predicate.
  6. 6 Descartes says that existence is a perfection of God. What does this mean?

Examination questions practice

In order to achieve a high mark when answering questions about the ontological argument, you must make sure you understand the different forms of the argument. It is all too easy to achieve a low mark if you confuse the different writers, ideas and terminology of this topic.

Sample exam-style question

  1. To what extent can logic prove the existence of God?

AO1 (15 marks)

AO2 (15 marks)

Further possible questions

Further reading

‘The Ontological Argument’ (J. Frye, in Dialogue 20, April 2003) provides an excellent overview of the mistakes students often make when answering questions about the ontological argument. It is written for advanced students and is well worth reading.

Mackie, J.L. 1982. The Miracle of Theism: Arguments for and Against the Existence of God. Oxford: OUP.

Swinburne, R. 2004. The Existence of God. Oxford: OUP.