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9605 | If a proposition is false, then its negation is true [Brown,JR] |
Full Idea: The law of excluded middle says if a proposition is false, then its negation is true | |
From: James Robert Brown (Philosophy of Mathematics [1999], Ch. 1) | |
A reaction: Surely that is the best statement of the law? How do you write that down? ¬(P)→¬P? No, because it is a semantic claim, not a syntactic claim, so a truth table captures it. Semantic claims are bigger than syntactic claims. |