Logic Laws of thought

Ponendo 推理 [MPP] A-> B，A |-B Tollendo 推理 [mtt 比色法] A-> B ~ B |-~ A Ponendo 推理 [MPT] ~(A & B) & |-~ B ~(A & B) & B |-~ A Tollendo 推理 [MTP] V B，a ~ A |-B V B，a ~ B |-A ================================================= 'Modus ponendo tollens' (MPT) says P, ¬(P ∧ Q) |- ¬Q [Lemmon] Full Idea: 'Modus ponendo tollens' (MPT) says that if the negation of a conjunction holds and also one of its conjuncts, then the negation of the other conjunct holds. Thus P, ¬(P ∧ Q) |- ¬Q may be introduced as a theorem. From: E.J. Lemmon (Beginning Logic [1965], 2.2) A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule. 'Modus tollendo ponens' (MTP) says ¬P, P ∨ Q |- Q [Lemmon] Full Idea: 'Modus tollendo ponens' (MTP) says that if a disjunction holds and also the negation of one of its disjuncts, then the other disjunct holds. Thus ¬P, P ∨ Q |- Q may be introduced as a theorem. From: E.J. Lemmon (Beginning Logic [1965], 2.2) A reaction: Unlike Modus Ponens and Modus Tollens, this is a derived rule ====================================================== crisis:危機,決定,審判.