The Ontological Argument:
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THE ONTOLOGICAL ARGUMENT
 Attributed to St Anselm, Archbishop of Canterbury in
the 11th century.
 Attempts to prove that God is a necessary being with
every positive attribute: infinitely powerful, wise and
good.
 There is still much interest in it in modern times.
THE ESSENCE OF THE ARGUMENT
 Anselm defines God as a being greater than which
nothing can be thought.
 By 'greater' he meant 'more perfect'.
 However, if the object of this idea only existed in our
mind, we could frame an idea of something superior to
it.
 This being would be a being with all the perfections of
the idea we had framed, but with the improvement of
actually existing in reality.
 It therefore follows according to this argument that
God must exist in reality: the concept of a most
perfect being that we have must include real
existence.
 Any conceptualisation of a being greater than which
nothing can be thought must include real existence as
one of its qualities: existence belongs to the nature of
the most perfect being.
GAUNILON'S OBJECTION
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 Gaunilon was a monk at Marmoutiers in France, and a
contemporary of Anselm's.
 He was the first important critic of the ontological
argument.
 In his introduction of the ontological argument, Anselm
referred to the psalmist's 'fool' who says in his heart,
'There is no God.'
 Anselm believed that even a fool would have the idea
of the greatest possible conceivable being.
 Gaunilon therefore entitled his objection On Behalf of
the Fool.
 He claims that Anselm's reasoning would lead to
absurdities if applied in other areas.
 Gaunilon develops a parallel ontological argument for
the existence of the most perfect island.
 The argument can be made that, unless it also exists in
reality, the island cannot be the most perfect
conceivable.
 We could therefore use the ontological argument to
prove the real existence of the perfect island.
ANSELM'S REPLY TO GAUNILON
 Anselm said that the ontological argument could only
be applied to God.
 The important concept for the argument to work is
necessary existence.
 Anselm stated that we could easily imagine an island
not existing because it is just a material object and
forms part of the contingent world.
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 Contrasted with this, God as an infinitely perfect being
would not be limited by space or time.
 He therefore could not be conceived of as coming into
existence at a particular point in time, or ceasing to
exist at a particular point in time.
 According to Anselm, this renders his non-existence
impossible.
 As He is perfect, God would not only have to exist, but
also have to exist necessarily.
NORMAN MALCOLM AND NECESSARY EXISTENCE
 Norman Malcolm thought that existence is not a
predicate.
 However, he thought that necessary existence is a
predicate.
 An object that exists necessarily depends for its
existence on nothing outside itself. Malcolm argues
that if we say God exists necessarily, we vastly add to
his powers.
DESCARTES' REFORMULATION
 The French philosopher Descartes (1596-1650)
reformulated the ontological argument.
 He treats existence as a predicate: Descartes believed
that saying about something that it 'exists' describes
a characteristic.
 He thought that existence must be a necessary
characteristic of a perfect being: a defining property
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of God. It is an essential attribute, without which God
would not be perfect.
 So Descartes thought that the idea of existence
belongs analytically to the concept of God.
KANT'S OBJECTION
 Kant thought that saying about something that it
'exists' does not add anything in thought to the
concept.
 All that is added by saying that a concept 'exists' is
that it is instantiated: that there is something in the
world that corresponds to it.
 Kant accepted that real existence belonged analytically
to the concept of God, the most perfect being.
 However, he asserted that it did not necessarily follow
from this that God existed.
 The most we could say is that, if there is a supremely
perfect being, then that being must really exist in
order to be supremely perfect.
IS EXISTENCE A PREDICATE?
 Kant expressed this objection formally by saying
'existence is not a true predicate'.
 In saying about something that it exists, are we
actually adding anything at all to the concept of the
thing?
 Or are we instead saying that there is at least one
instance in reality of the thing in question?
 Consider the following argument:
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1) Elephants exist.
2) Dumbo is an elephant.
3) Therefore Dumbo exists.
 However, when we say 'elephants exist', do we not
mean that some elephants exist?
 This would allow us to say that Dumbo does not happen
to exist.
DISTINCTION BETWEEN BEING AND EXISTENCE
 Are we forced to make this distinction?
 We would then have to say that there are things that
do not exist.
IS 'EXISTENCE' A PROPERTY, (A PREDICATE)?
 If God is the greatest being, and existence is a
property, then God must exist - otherwise He would
not be the greatest being.
 He would be less good, omnipotent and omniscient if He
did not exist, than the perfect being we can imagine.
PLANTINGA AND POSSIBLE WORLDS
 Plantinga presents a version of the ontological
argument by using the concept of possible worlds.
 'Maximal excellence' = omniscience, omnipotence and
moral perfection.
 It is possible that a maximally excellent being exists.
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 There is therefore a possible world in which a
maximally excellent being exists.
 'Unsurpassable greatness' = 'Maximal excellence in
every possible world'.
 An 'unsurpassably great' being exists either in every
possible world or in none.
 Therefore if any world contains an unsurpassably great
being, then every world contains him.
 However, there is a possible world in which an
unsurpassably great being exists.
 Therefore an unsurpassably great being exists
necessarily in all possible worlds.
OBJECTIONS TO PLANTINGA
 This argument assumes that what is necessary or
impossible does not vary from world to world.
 A crucial premise is that maximal greatness, and
therefore unsurpassable greatness, are instantiated in
a possible world.
 Leibniz maintained that the ontological argument does
not prove God's existence: it just proves that God's
existence is either necessary or impossible.
THE DEVIL AND THE ONTOLOGICAL ARGUMENT
 Perhaps Plantinga's methodology could be adapted to
prove the non-existence, or the existence, of the
Devil.
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 The Devil could be defined as a being of 'minimal
greatness'.
 The Devil would possess the ultimate of all negative
attributes.
 If 'non-existence' is regarded as a negative attribute,
then this could be attributed to him as well.
 We would then have to regard 'non-existence' as a
predicate, which seems conceptually difficult.
 We might counter that evil is in fact increased, and not
decreased, by the actual existence of the evil being.
 Perhaps the ontological argument can therefore be
used to prove the necessary existence of the Devil, an
unsurpassably evil being, rather than his non-existence.