PHIL 309: Twentieth Century Analytic Philosophy

LARKIN: Spring 2003

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DATE: 1-21-03

I. Objectives

A. Interpret and Evaluate Moore’s argument against Idealism

B. Discuss Moore’s Common Sense Realism

II. Discussion:

A. How can anyone have thought Idealism was true?

B. Berkleyean Epistemological Argument

P1: We cannot know that material objects exist through the senses.

P2: We cannot know that material objects exist through deductive reasoning.

P3: We cannot know that material objects exist through abductive reasoning.

C: So there are no grounds for maintaining that material objects exist.

III. Lecture:

A. Some Useful Distinctions

1. Metaphysical Distinction: Necessary vs. Contingent

2. Kinds of Necessity

a. Logical

b. Metaphysical

c. Nomological (Physical)

3. Semantic Distinction: Analytic vs. Synthetic

4. Epistemological Distinction: A Priori vs. A Posteriori

B. Applying these Distinctions to “Esse is Percipi”

1. To be significant, it must be synthetic.

2. It is intended as a logical or metaphysical necessity claim.

3. Idealist as rationalist must take it as knowable a priori.

C. Moore’s Argument for P4:

P4: Claiming that ‘esse is percipi’ is a true synthetic necessity that can be proved by the law of non-contradiction alone requires saying both that the object and subject of an experience are identical and that they are not identical.

4a: To prove the claim by the law of non-contradiction alone, one must assume that the object of a sensation and the sensation itself are identical.

4b: But to maintain that the claim is a synthetic necessity, it must at the same time be maintained that the sensation and the object of sensation are distinct.

IV. Discussion: Moore’s Proof of an External World

V. Next Time

A. Topic: Finish Up Moore; Frege and Modern Logic

B. Reading:

C. Reading Questions: