The ontological argument
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tnformation Sheet
Anselm and the Proslogion
The ontological argument is based on Anselm’s stated definition of
God as that than which nothing greater can be conceived’, expressing
all the perfections of God and assuming that since that which is
perfect must exist, then God must exist. The argument works
analytically, establishing a proof for the existence of God based on an
analysis of the word 'God' If God’ means existence’, as Anselm
claims, in the same way that triangle’ means three angles and three
sides’, then he must necessarily exist — he cannot not exist.
This argument is based on definition and language, and seeks to
establish that God necessarily exists because he can do no other by
virtue of being the greatest conceivable being. In the Proslogion,
Anselm argues that:
• God is that than which nothing greater can be conceived
since he is such a being God’s non-existence is inconceivable
That than which nothing greater can be conceived
As that than which nothing greater can be conceived’ God is the sum of all
perfections, and no more perfect being can be described. He is not simply
the most perfect being that exists, but the most perfect being conceivable.
Anselm distinguished between a being existing only in the mind (in
intellectu) and in reality (in re). If it exists only in the mind, then there may
exist a being greater in reality also. Therefore ‘that than which nothing
greater can be conceived’ must exist in reality also, if it truly fulfils that
definition.
Now we believe that thou art a being than which none greater con be
thought. . . clearly that than which a greater cannot be thought cannot
exist in the understanding alone. For if it is actually in the
understanding alone, it con be thought of as existing in reality, and
this is greater. Therefore, if that than which a greater cannot be
thought is in the understanding alone, it can be thought of as existing
also in reality, and this is greater.... Without doubt therefore, there
exists, both in the understanding and in reality, something than which
a greater cannot be thought.
StAnselm of Canterbury, Proslogion
Inconceivable non-existence
If God is ‘that than which nothing greater can be conceived’ he must
therefore necessarily exist, since by definition it is impossible to
conceive of him not existing. At the heart of Gods existence is his
aseity — he is independent of all other beings, not limited by time or
space — and so it is impossible to speak of him as having come to
exist or ceasing to exist. His non-existence is therefore impossible.
Anselm’s argument depends on maintaining that it is more perfect to
exist necessarily than to exist contingently, and so an unsurpassably
perfect being must exist necessarily. Even ‘the fool’ (the atheist of
Psalm 53) who denied the existence of God had comprehended what
constituted God’s essence, and as such was saying the unsayable
when he denied his existence.
Con it be that there is no such being since, the fool hath said in his heart
There is no God ''' But when this same fool hears what I am saying — “A
being than which none greater can be thought” he understands what he
hears.. , . even if he does not understand that it exists,, . . Even the fool,
then, must be convinced that a being than which none greater can be
thought exists at least in his understanding.
For something con be thought of as existing which cannot be thought of as
not existing, and this is greater than that which can be thought of as not
existing.. So, then, there truly is a being than which a greater cannot be
thought
so truly that it cannot even be thought of as not existing.. . He therefore
who understands that God thus exists cannot think of him as non-existent
StAnse!rn of Canterbury, Proslogion
Remember that:
- a necessary being cannot not exist
• a contingent being comes into and goes out of existence
Descartes and the ontological argument
René Descartes (1598—1650) argued that existence belonged analytically
to God as three angles
were analytically predicated of a triangle, (A predicate is a defining
characteristic of a thing or
being — something that can be possessed or lacked.) For God to lack
existence would be for him
to lack perfection, and hence not to be God. Descartes’s argument runs
thus:
I The idea of God is the idea of a supremely perfect being.
2 A supremely perfect being has all perfections.
3 Existence is a perfection.
4 A supremely perfect being has the perfection of existence.
5 It is impossible to think of God as not existing.
6 God exists,
Why does this fail?
If ‘existence’ is not a predicate, then Descartes’s approach fails. Some
characteristics can be possessed or lacked and are part of the description
of a thing or being: green, large round, generous. Immanuel Kant (1724—
1804) argued that ‘exists’ does not work in the same way as these
adjectives — it cannot be listed when saying what God is like: ‘Whatever,
therefore, and however much our concept of an object may contain, we
must go outside it if we are to ascribe existence to the object? In other
words, we have to establish that something exists first before we can say
what it is like, not the other way round. All that Kant was prepared to say is
that if there is an infinitely perfect being, then he must exist, just as if there
is a triangle it must have three sides,
Bertrand Russell (1872—1970) also denied that existence could operate as
a predicate, claiming only that it has a propositional function: it asserts that
there are beings in the world that answer to a particular description, but it
adds no further information about them. It conveys nothing of their essence
or nature, To say cows are brown and exist’ says nothing more than ‘cows
are brown~
Gaunilo’s island
A contemporary of Anselm, Gaunilo of Marmoutiers, claimed that the
argument leads to absurd conclusions if applied to different examples. He
demonstrated a reductio aa absurdum by suggesting that he could
conceive of an island than which no greater could be conceived, and
according to Anselm’s logic that the most perfect conceivable contains
existence within its very definition — it must exist.
Anselm responded, however that his reasoning was intended to apply only
to God, because things that are part of the contingent universe can be
thought of as non-existing, whereas God cannot, since he alone possesses
necessary existence:
So, then, it is peculiar to God to be unable to be thought of as non-existent.
Support for the argument
Alvin Plantinga suggested that whatever the world in which we live is like,
God must exist, even if it is considerably different from the world as we
know it. Hence God can exist in all possible worlds; there are many
possible worlds in which to exist, including our own, and since God can
exist in all possible worlds he is, Plantinga maintained, maximally great. If
he possesses all the attributes of God in all possible worlds he must be
maximally excellent.
In a similar vein Norman Malcolm proposed:
If God, a being a greater than which cannot be conceived, does not exist
then he cannot come into existence. For if he did he would either hove
been caused to come into existence or have happened to come into
existence, and in either case he would be a limited being, which by our
conception of him he is not,.. Thus God’s self existence is either impossible
or necessary. It can be the former only if the concept of such a being is
self-contradictory or in some way logically absurd, Assuming that this is not
so, it follows that he necessarily exists.
Cited n John Hick (ed), The Existence of God (Mocmilloo, 1964), pp. 48ft
The ontological argument
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Wor*sheet
I The ontological argument is a deductive, analytic, a priori argument. Discuss the benefits of such an
argument. How successful is this method of reasoning in establishing a decisive proof for the existence of
God? What particular flaws are inherent in it? You may want to consider the value of an argument that rests
on a definition of God.
2 Now consider in what ways an a posteriori argument may prove more successful. What are the particular
strengths of this method of reasoning when compared to a priori reasoning?
3 If the ontological argument fails as an argument for the existence of God does it have any other value?
Consider the fact that Anseim was not attempting to prove the existence of God, what may he have
succeeded in doing nevertheless?
Homework tasks
Consider the following questions~
I Do we have any grounds on which to say that existence belongs to God by the very nature of his being?
Do we need to know God first before we can say this?
2 Is there any absurdity in saying that there exists a being who cannot not exist? Or that a being who cannot
not exist nevertheless does not exist?
3 Could the ontological argument ever serve to convince an atheist of God’s existence?
4 Does it tell theists anything they do not already know?