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

#### [propositions must be either true or false]

28 ideas
 1312 If everything is and isn't then everything is true, and a midway between true and false makes everything false [Aristotle on Heraclitus]
 1701 A prayer is a sentence which is neither true nor false [Aristotle]
 12363 Everything is either asserted or denied truly [Aristotle]
 21668 Epicurus rejected excluded middle, because accepting it for events is fatalistic [Epicurus, by Cicero]
 6023 Every proposition is either true or false [Chrysippus, by Cicero]
 2669 Dialectic assumes that all statements are either true or false, but self-referential paradoxes are a big problem [Cicero]
 21595 Excluded middle is the maxim of definite understanding, but just produces contradictions [Hegel]
 18844 You would cripple mathematics if you denied Excluded Middle [Hilbert]
 2947 Questions wouldn't lead anywhere without the law of excluded middle [Russell]
 21539 Excluded middle can be stated psychologically, as denial of p implies assertion of not-p [Russell]
 18944 Russell's theories aim to preserve excluded middle (saying all sentences are T or F) [Sawyer on Russell]
 15941 For intuitionists excluded middle is an outdated historical convention [Brouwer]
 9357 Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI]
 19192 The truth definition proves semantic contradiction and excluded middle laws (not the logic laws) [Tarski]
 9024 Excluded middle has three different definitions [Quine]
 9195 Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett]
 8179 The law of excluded middle is the logical reflection of the principle of bivalence [Dummett]
 7334 Anti-realism needs an intuitionist logic with no law of excluded middle [Dummett, by Miller,A]
 17587 The 'Law' of Excluded Middle needs all propositions to be definitely true or definitely false [Inwagen]
 9775 Excluded Middle, and classical logic, may fail for vague predicates [Fine,K]
 10251 The law of excluded middle might be seen as a principle of omniscience [Shapiro]
 8729 Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro]
 9605 If a proposition is false, then its negation is true [Brown,JR]
 21605 Excluded Middle is 'A or not A' in the object language [Williamson]
 10111 Asserting Excluded Middle is a hallmark of realism about the natural world [George/Velleman]
 15934 Mathematical proof by contradiction needs the law of excluded middle [Lavine]
 8709 The law of excluded middle is syntactic; it just says A or not-A, not whether they are true or false [Friend]
 17924 Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan]