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Single Idea 18944

[filed under theme 5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle ]

Full Idea

Russell's account of names and definite descriptions was concerned to preserve the law of excluded middle, according to which every sentence is either true or false (but it is not obvious that the law ought to be preserved).

Gist of Idea

Russell's theories aim to preserve excluded middle (saying all sentences are T or F)

Source

comment on Bertrand Russell (On Denoting [1905]) by Sarah Sawyer - Empty Names 3

Book Ref

'Routledge Companion to Phil of Language', ed/tr. Russell/Graff Faria [Routledge 2015], p.156


A Reaction

That is the strongest form of excluded middle, but things work better if every sentence is either 'true' or 'not true', leaving it open whether 'not true' actually means 'false'.


The 28 ideas with the same theme [propositions must be either true or false]:

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For intuitionists excluded middle is an outdated historical convention [Brouwer]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