Ontological arguments

essay introduction

• OAs aim to deduce existence of God from the definition of God using a priori reasoning

• a priori = not requiring experience of the world, proven using logical reasoning alone e.g. 1+1=2

• OAs of St Anselm and Malcolm fail due to objections of Gaunilo and Kant, and unclear meaning of necessary existence used by Malcolm

St Anselm - ontological argument

• God is a perfect being, or that than which nothing greater can be conceived

• God might exist only in the mind, or in the mind and reality

• a being that exists both in reality and the mind is greater than a being that exists only in the mind

• therefore God must exist in reality, or we have not thought of the greatest conceivable being

• thus Anselm claims to be able to analytically prove God’s existence (in virtue of the meanings of the words)

Descartes - ontological argument

• we can know that God exists through intuition (determining which ideas are clear and distinct)

• we intuitively know that a triangle has three sides, because it is impossible to conceive of a triangle separated from having three sides

• similarly we cannot conceive of a supremely perfect being separated from existence - thus intuition shows us that God exists

P1 I have an idea of God (a supremely perfect being)

P2 A supremely perfect being must have all perfections

P3 Existence is a perfection

C Therefore God exists

• having three sides is a predicate of the subject of a triangle

• existence is a predicate that is part of the definition of God - so stating “God exists” is a tautology, and stating the opposite is a contradiction

Malcolm - ontological argument

• accepts Kant’s criticism that existence is not a predicate

• agrees with Anselm that God is the greatest conceivable being possessing all perfections

P1 God cannot come into existence (as nothing can cause God to exist)

P2 So if God does not exist, then God’s existence is impossible

P3 God cannot cease to exist (as nothing can cause God to cease to exist)

P4 So if God does exist, then God’s existence is necessary

C1 Therefore God’s existence is either impossible or necessary

P5 Something’s existence is impossible if it is self-contradictory

P6 God’s existence is not self-contradictory

P7 Therefore God’s existence is not impossible

C2 Therefore God’s existence is necessary and God necessarily exists

• unlike general existence, necessary existence is a predicate, as it provides new information about the subject (a God that exists necessarily is different to a God that is contingent)

response to Malcolm - fallacy of equivocation

• ambiguous use of a phrase with multiple possible meanings

• in setting out his premises he uses “necessary existence” to mean a property that something can have

• in his conclusion he suggests that God’s existence is a necessary truth

• however this conclusion does not follow from his premises - he only demonstrates that God must have the property of necessary existence IF HE EXISTS - he does not prove that God does actually exist in reality

Gaunilo response - perfect island

• using St Anselm’s reasoning we might form the following argument:

P1 We can imagine an island that is the greatest possible island, with the greatest possible characteristics

P2 Something that exists in reality and in the mind is greater than something that exists only in the mind

C Therefore the island exists in reality

• however this conclusion is clearly absurd as we cannot define something into existence

• whether I can conceive of something has no bearing on whether that thing actually exists in reality

• this concept can be applied to any subject e.g. the perfect car etc. - so St Anselm fails to prove the existence of God

Hume response

• Hume’s fork - matters of fact vs relations of ideas

• the existence of anything is a matter of fact - these cannot be proven unless its opposite would be a contradiction

P1 Nothing that can be distinctly conceived of entails a contradiction

P2 For any being that we can conceive of as existing, we can also conceive of it as not existing

C Therefore there is not any being whose non-existence entails a contradiction

Ayer response

• verification principle - for a proposition to be meaningful it must be either true by definition or empirically verifiable

• arguments based on a priori statements cannot draw conclusions that tell us anything new about the world (i.e. whether God exists)

P1 A priori propositions are certain because they are tautologies

P2 We can only use tautologies to deduce further tautologies

P3 The existence of anything, including God, is not a tautology

C Therefore we cannot validly deduce the existence of God from a priori propositions, and the OA fails

Kant response - existence is not a predicate

• St Anselm claims that “existence” is a predicate of God - an intrinsic property or quality of God (in the same way that “having one horn” is a predicate of being a unicorn)

• however existence is not a predicate that a subject can have, because it adds nothing new to the subject

• e.g. if I imagine a “a pile of coins” and then imagine “a pile of coins that exists”, I am thinking of the same thing in both cases

• therefore St Anselm’s argument is unsound as it is based on the flawed assumption that existence is a predicate