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5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle

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.