Ontological Argument for GodIntroduction to PhilosophyJason M. Chang

Lecture Outline

1. Background

2. Major ideas

3. The argument

4. ObjectionsA. Gaunilo’s objectionB. Perfect objectionC. Kant’s objection

Background

Background

o Definition of “ontology”

o A priori vs. a posteriori

o St. Anselm of Canterbury

St. Anselm 1033-1109 AD

Major ideas

Major ideas in the ontological argument

• Necessary vs. contingent attributes

o Definition

• Attributes of a Perfect Being (the greatest possible being)

Major ideas

Major ideas in the ontological argument

• Existence in reality vs. existence only in the understanding

• Anselm on existence

o The claim

o Reasoning

The argument

(P1) God is the greatest possible being.

(P2) Existence in reality is greater than existing only in the understanding.

Therefore,

(C) God must exist (given that He is the greatest possible being)

 

Note: This is a simplified version of Anselm’s argument. In the original version, Anselm shows that believing that the greatest possible being exists only in the understanding leads to a contradiction. (reductio)

Common objections

Gaunilo’s objection

Gaunilo’s objection

• Strategy

o Refute (P2)

• Perfect island

Gaunilo of Marmoutiers

Gaunilo’s objection

“Suppose that a person tried to prove to me by this reasoning that this island actually exists […] [If I believed him], I would not know which I ought to regard as the greater fool: perhaps myself for supposing that I should allow this proof, perhaps him for supposing that he had established with any certainty the existence of this island”

Perfect murder objection

Greatest demon objection

• Strategy

o Denies that “existence” makes a thing greater

• Q Is something really greater if it exists in the world than if it exists only in the mind?

Perfect murder objection

Things in which “existence” adds to their

goodness

Things in which “existence” detracts from their goodness

Kant’s objection

Kant’s objection

• Strategy

o Deny that “existence” is an attribute

Immanuel Kant (1724-1804)

Kant’s objection

Attributes are characteristics or properties ascribed to something

-Intelligent-Witty-Thin-Fit

Many of these attributes can add to the value of something

Kant EXISTENCE is not an attribute