Claim
Law of excluded middle
Overview
logical principle stating that for every proposition, either it or its negation is true
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
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They are as follows: (1) _The law of identity_: 'Whatever is, is.' (2) _The law of contradiction_: 'Nothing can both be and not be.' (3) _The law of excluded middle_: 'Everything must either be or not be.' These three laws are samples of self-evident logical principles, but are not really more fundamental or more self-evident than various other similar principles: for instance, the one we considered just now, which…
Bertrand Russell, The Problems of Philosophy
The author is tied to Law of excluded middle in the knowledge graph.
In like manner as the Principle of Contradiction (that one of two contradictories must be false) means that an assertion can not be _both_ true and false, so the Principle of Excluded Middle, or that one of two contradictories must be true, means that an assertion must be _either_ true or false: either the affirmative is true, or otherwise the negative is true, which means that the affirmative is false. I can not…
John Stuart Mill, A System of Logic, Ratiocinative and Inductive
Close in meaning to Law of excluded middle; the term itself is not named.
In every proposition and in every inference there is, besides the particular subject-matter concerned, a certain _form_, a way in which the constituents of the proposition or inference are put together. If I say, "Socrates is mortal," "Jones is angry," "The sun is hot," there is something in common in these three cases, something indicated by the word "is." What is in common is the _form_ of the proposition, not an…
Bertrand Russell, Our Knowledge of the External World as a Field for Scientific Method in Philosophy
The author is tied to Law of excluded middle in the knowledge graph.
Philosophers who discussed Law of excluded middle
Related ideas
- Exclusive or
- Buddhist logico-epistemology
- Pyrrhonism
- Springer Science+Business Media
- Zermelo–Fraenkel set theory
- Negation
- Truth value
- Kurt Gödel
- Intuitionistic logic
- Posterior Analytics
- Foundations of mathematics
- L. E. J. Brouwer
- Latin
- Logic programming
- Liar paradox
- Propositional logic
- Stoicism
- Intuitionism
- Mathematical logic
- Indian logic
- Sir William Hamilton, 9th Baronet
- Plato
- Principle of bivalence
- Principia Mathematica
Place in the tradition
Part of Anti-realism.