PHILOS 2CT3 Lecture Notes - Lecture 11: Iced Tea, Loaded Question, Modus Ponens

• School: McMaster University
• Department: Philosophy
• Course: PHILOS 2CT3
• Professor: James Sikkemma

Document Summary

Formal fallacy = a error in the formal structure of an argument that makes it invalid. If i know that 2+2=4, then i know something to be true . I know something to be true, therefore i know that 2+2=4: e. g. If there is order in nature, then god must exist. But god certainly exists, therefore there is order in nature: e. g. If i can ride a bicycle, then i can skate. I can skate, therefore i can definitely ride a bicycle. Since the valid form of modus tollens is: if p then q. not q therefore not p: the negation / denial of the consequent necessarily derives the negation / denial of the antecedent. Formal fallacy of denying the antecedent: if p then q. Not p therefore not q: the denial of the antecedent does not necessarily derive the denial of the consequent, e. g. If i can walk, then i can talk.