Theology — Arguments from Reason for God (Ontological Argument)

Anselm’s definition of God

That than which nothing greater can be conceived

Anselm’s argument for God

P1: God is a being greater than which cannot be conceived

P2: I can conceive of such a being, ie the concept is coherent

C1: God exists in the mind

P3: It is greater to exist in reality than to exist only in the mind

C2: Therefore, God exists in reality

Anselm’s argument in Layman’s terms

P1: God exists in the mind

P2: God exists in reality

P3: God’s existence in reality is necessary

Gaunilo’s Parody (Lost Island) Argument

P1: The Lost island is that than which no greater island can be conceived

P2: The Lost Island exists in the mind, but not in reality

P3: Existence in reality is greater in existence in the understanding alone

P4: It is conceivable that the Lost Island exists in reality

P5: It is conceivable that there is an island greater than the Lost Island

P6: It is conceivable that there is an island greater than the island than which no greater island can be conceived.

C1: Therefore, the lost island exists in reality

Gaunilo’s other objection

• The Ontological Argument thinks about how great this being would be if it existed

• But that doesn’t show that it does exist

Anselm’s reply to Gaunilo

• The concept of a perfect island is incoherent

• To be perfect is to be self-sufficient and self-sustaining

• An island is not sustaining; it is fundamentally dependent on external factors such as the water around it

• A decent response to a weak counter argument attacking a very weak argument

Aquinas’ objection to Anselm’s Ontological Argument

God is beyond our understanding; if we could conceive of God, then we’d have to be God

Descartes’ Ontological Argument

P1: I have an innate idea of God

P2: The idea of God is the idea of a supremely perfect being

P3: A supremely perfect being does not lack any perfection

P4: Existence is a perfection

P5: Therefore, God exists

Descartes’ Trademark Argument

P1: The idea of God is the idea of an infinite and perfect being

P2: I have the idea of God

P3: I am a finite being who has only experienced finite and imperfect things

P4: Therefore, my idea of God cannot have come from experience

P5: A cause must contain at least as much reality as its effect (Causal Adequacy Principle)

P6: The cause of an idea of infinity or perfection must itself possess at least as much reality as the idea

P7: The cause of the ideas of infinity and perfection cannot be derived from experience of finite or imperfect things, as these have less reality than the ideas of infinity and perfection

P8: The only possible cause for an idea of an infinite and perfect being is an infinite and perfect being itself

P9: A perfect and infinite being is God

C1: Therefore, God exists

Objections to Descartes’ Trademark Argument

• The Causal Adequacy Principle (a cause must contain at least as much reality as it’s effect) could be false

• The idea of God could be derived through abstraction; obtaining general concepts from real things

Kant’s objection to Anselm and Descartes

• Existence is not a predicate

• Anselm and Descartes talk of existence as a property that makes something ‘greater’ or ‘perfect’

• However, existence is not a property

• ‘God exists’ cannot be an analytic truth; analytic truths unpack concepts, which ‘x exists’ doesn’t

Kant’s argument against the Ontological Argument

P1: If ‘God doesn’t not exist’ is a contradiction, then ‘God exists’ is an analytic truth

P2: If ‘God exists’ is an analytic truth, then ‘existence’ is part of the concept of God

P3: Existence is not a predicate, something that can be added on to another concept

P4: Therefore, ‘God exists’ is not an analytic truth

P5: Therefore, ‘God does not exist’ is not a contradiction

P6: Therefore, we cannot deduce the existence of God from the concept of God

C1: Therefore, ontological arguments cannot prove that God exists

Norman Malcolm’s argument for necessary existence as a predicate

P1: If God is that than which nothing greater can be thought, and He does not exist, then He cannot come into existence

P2: God, therefore, has either always existed, or will never exist

P3: If He does not exist, His existence is impossible

P4: If God does exist, His existence is necessary

P5: God’s existence is therefore either impossible, or necessary

P6: His existence cannot be impossible since the concept is not self-contradictory

C1: God exists necessarily

Objection’s to Malcolm’s argument

• Malcolm switches between two meanings of necessary existence; metaphysically and logically

• He reaches a conclusion about logical existence based on premises about metaphysical existence

• Therefore, Malcolm commits the fallacy of equivocation