|Law of the Excluded Middle: an assertion is either true or false. "There is no third possibility."See also bivalence, anti-realism, multivalued logic.|
|Geach, Peter T.
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|Excluded Middle||I 76ff
Law of excluded middle / Geach: valid without any exception - even Aristotle 9 Chap. De Interpretatione: tomorrow s sea battle: no refutation - no multi-valued logic: if we get the same truth value, if we ascribe P and its negation, then if P u P and P v P - the same as for simple predication - Geach: only exception: vagueness.
Logic Matters Oxford 1972