## 80-110: The Nature of Mathematical Reasoning

**Richard Scheines**

### Spring Semester 1998

**Lecture Notes**

**January
15 **(Pythagoras and the Cult of Whole Numbers)
**January
20 **(Proof and Truth)
**January
22 **(Axioms, Definitions, and Theorems)
**January
27 **(Definitions I: GDP, even and odd)
**January
29 **(Definitions II: Causation and Infinite Sets)
**Feb. 3
**(Subjective vs. Objective)
**Feb. 10
**(Lets Make a Deal: Fallacies)
**Feb. 12
**(Lets Make a Deal: Rigorously)
**Feb. 17
**(Characterizing Deductive Arguments)
**Feb. 19
**(The Language of First Order Logic)
**Feb. 24
**(Review for Test I: Sample Questions)
**Feb. 26
**(Test I)
**March 5th.
**(Possible Worlds)
**March 10th.
**(The Semantics of Sentential Logic)
**March 12th.
**(Knights, Knaves, and Portia)
**March 17th.
**(Formal Proofs)
**March 19th.
**(Examples of Proofs)
March 30: Test Review
April 2: Test 2
April 7: Go Over Test 2
**April 9th,
**( Quantifiers )
**April 16th,
**( Set Theory: Part I)
**April 21st,
**( Set Theory: Part II)
**April 23rd,
**( Set Theory: Part III)
**April 28th,
**( Set Theory: Part IV)

*Maintained by: Richard
Scheines*

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