Date: 09/25/98 at 10:51:45 From: Lauren Ray Subject: Disjunctive Syllogism I am enrolled in a Elementary Logic and Set Theory class, and we have an assignment to find out definitions of the words: Modus Ponens, Modus Tollens, and Disjunctive Syllogism. I have already found the first two, but am stuck on the last one. So my question is, what does it mean? Thank you, Lauren
Date: 09/25/98 at 11:28:48 From: Doctor Mike Subject: Re: Disjunctive Syllogism Hi Lauren, See Stefan Waner and Steven R. Costenoble's "Introduction to Logic" on the Web. It has the definition of Disjunctive Syllogism and other logic terms. http://www.hofstra.edu/~matscw/logic/logic4.html The disjunctive syllogism is (P v Q) and notQ --> P. In words: "If one or the other is true, and one of them is false, the other must be true." Here is an example: - Given: Either Congress meets in Washington D.C. OR pigs can fly. - Given: Scientific evidence shows conclusively that pigs cannot fly. - Conclusion: Congress meets in Washington D.C. I hope this helps. "Thanks for writing." OR "Pigs can fly." - Doctor Mike, The Math Forum http://mathforum.org/dr.math/
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