Chapter 3 Well-formed

# Chapter 3 - Validity An argument is valid if and only if it is impossible for the premises of the :necessarily,if thepremises

This preview shows pages 1–2. Sign up to view the full content.

Validity:  An argument is valid if and only if it is impossible for the premises of the  argument all to be true and the conclusion of the argument to be false. An argument is valid if and only if the following condition holds: necessarily ,if  the premises of the argument are all true, then the conclusion is true as well. sentential logic ( ) propositional logic( Sentential connectives: Conjunction: P and Q Disjunction: P or Q  Negation:  ~P Conditional: If P then Q Biconditional: P if and only if Q (if P then Q, and if Q then P)  Some valid patterns of argument in sentential logic: A. Argument by elimination: 1. Either P or Q. 2. ~P. ---------------------------- 3. Q. B. Simplification  1. P and Q. -------------------- 2. P. C. Affirming the antecedent(modus ponens) 1. If P then Q. 2.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 06/27/2010 for the course PHIL philoXX1 taught by Professor Harbon during the Fall '08 term at Simon Fraser.

### Page1 / 4

Chapter 3 - Validity An argument is valid if and only if it is impossible for the premises of the :necessarily,if thepremises

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online