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A comment on A Simple Logical Puzzle That Shows How Illogical People Are. Parent comment

Re:A Simple Logical Puzzle That Shows How Illogical People Are by dragonwriter on Friday May 22, 2015 @04:59PM (#9590892)
> Then there's the issue of negation. "if P then Q" negated is "if not Q then not P".

No, "if P then Q" negated is "P and not-Q"

"If not-P then not-Q" is the inverse of "if P then Q".

"If not-Q then not-P" is the contrapositive of "if P then Q".

  S is true -> the negation of S is false
            -> the contrapositive of S is true
            -> (nothing at all about the inverse of S)
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