PHIL 110 Lecture Notes - Lecture 8: Ten Feet Tall, Disjunctive Syllogism, Modus Ponens

• School: Simon Fraser University
• Department: Philosophy
• Course: PHIL 110
• Professor: Jill Mc Intosh

Document Summary

Each line of a proof must either be a premise or follow validly from something that came before it: ~r, s r, ~s. / ~s: dr. mc is ten feet tall or dr. mc is a fire-breathing dragon. Disjunctive syllogism (ds: p v q, ~p / q, ~q / p, p v q, dr. mc is not ten feet tall. Also: q r / p r (cid:1005). p q / p (cid:1005). p q / q, q / p q, p / p v q, p. It indicates why it"s okay that the line is there. No. (cid:1005). (cid:894)h k(cid:895) l (cid:1006). ~r k: k (h v r, k, ~r, h v r, h, h k, l. / r v s: p v q, p r, q s, c, a b, c d, d e, c e, c v a, e v b.