PHL 3305 Lecture 21

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Begin Exam 2 content

No class Wednesday or Friday, but still do the readings

Chapter 15: Introduction to the Logic of the Third Act

reasoning

the movement of th emind from some known truth(s) to another unknown truth through a discursive process

argument

a number of propositions which, taken together as given, yield another proposition

antecedent

consequent

what follows from the antecedent

inference

the movement of the mind that occurs when proceeding from the antecedent to the consequent

In order for argument to yield a valid inference, the argument must exibit the proper relation of universality among the propositions

Syllogism is best served by universal statements

Statement vs. Propositition: A proposition often refers only to a statement that is used within a syllogism.

Major (A), Minor (C), and Middle (B) Terms:

All B is A
All C is B
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All C is A

Chapter 16: Principles and Rules of the Syllogism

Rules of Syllogism

1. A syllogism must have 3 (and only 3) terms
2. The middle term must be distributed in at least one of the premises
3. If a term is distributed in the conclusion, it must also be distributed in the premise in which it occurs
4. No conclusion follows from two negative premises
5. The conclusion always follows the weaker part. (affirmative/universal is stronger than negative/particular)