The Ontological Argument

1
The Ontological Argument

• Weber State University
• Spring 2007
• PHIL 1000

2
What is the foundation of the arguments for Gods
existence?

• A priori arguments based on reason alone.
• A posteriori arguments that depend on premises
  that can only be known on the basis of experience.

3
The Ontological Argument

• Brief History of the Argument
• St. Anselm of Canterbury
• Rene Descartes
• Gottfried Leibniz
• Kurt Godel

4
How do we begin an a priori argument for Gods
existence?

• A definition of God A being than which nothing
  greater can be conceived.
• No one, no matter how clever or smart, can
  conceive of anything greater than the being than
  which nothing greater can be conceived

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Anselms Ontological Argument

• Reductio ad absurdum (reduce to absurdity)
• Begins with a supposition (call it S) that is
  contradictory to what one desires to prove.
• One goes on to show that S together with other
  certain or self-evident assumptions yields a
  contradiction.
• This demonstrates that the contradictory of S
  must be true.

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Who is S for Anselm?

• Anselms S is the fool, an atheist, who has
  said that there is no God.

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Anselms Argument

• God is the being than which nothing greater can
  be conceived. (premise)
• A being that exists in reality is greater than a
  being that exists on in the understanding.
  (premise)
• The fool understands the concept of God as the
  being than which nothing greater can be
  conceived. (premise)
• Therefore, God exists in the fools
  understanding. (3)
• Suppose that God exists only in the understanding
  and not also in reality. (premise fools
  assumption)
• Then, we can conceive of a greater being, namely
  one that also exists in reality. (2,5)
• We can conceive of a greater being than God. (6)
• But that means (5) leads to a contradiction.
  (1,7)
• Therefore, God exists in reality and not just in
  the understanding. (8)

8
Existing in the Understanding

• We can replace talk of existing in the
  understanding with talk of concepts.
• Is the concept of a being that lacks existence as
  great as the concept of a being that also
  actually exists?

9
The problem with the understanding

• If we assume that a being than which nothing
  greater can be conceived exists in the
  understanding but not in reality, then
• A being than which nothing greater can be
  conceived (if it exists in the understanding
  alone) is not a being than which nothing greater
  can be conceived namely, the being than which
  nothing greater can be conceived in reality.

10
The Fools, i.e., Gaunilos, Objection

• Anselms argument if correct, would prove the
  existence of an island than which nothing greater
  can be conceived.
• The Perfect Lost Island exists!

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I pity the Fool

• Anselms response to Gaunilo
• Anselm believes the idea that a being than which
  nothing greater can be conceived makes sense.
• What we need to say here is that no matter what
  worldly kind of thing we pick, it wont make
  sense to talk about one than which nothing
  greater can be conceived.
• Worldly things are inherently limted! God is not!

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Kants Problem with the Ontological Argument

• Existence is not a predicate (quality or
  property).
• If so, then existence is not a perfection, and so
  it does not make God greater.

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Kants Argument

• If Anselms argument succeeds, then existence
  must be a perfection. (premise)
• For existence to be a perfection, it must be a
  predicate. (premise)
• So, if Anselms argument succeeds, existence must
  be a predicate. (1,2)
• Existence is not a predicate. (premise)
• Therefore, Anselms argument does not succeed.
  (3,4)

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The Anselm/Malcolm Argument

• God is a necessary being.
• A being than which none greater can be conceived
  would have to be so great that its nonexistence
  in inconceivable.

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The Argument

• The concept of God is the concept of a being so
  great than none greater can be conceived.
  (premise)
• A being whose existence is conceivable is not as
  great as a being whose nonexistence is
  inconceivable. (premise)
• So, the concept of God is the concept of a being
  whose nonexistence is inconceivable. (1,2)
• If a beings nonexistence is inconceivable, then
  the being exists. (premise)
• Therefore, God exists. (3,4)