tautology

English

Etymology

From Late Latin tautologia, from Ancient Greek ταυτολογία (tautología) from ταὐτός (tautós, “the same”) + λόγος (lógos, “explanation”)

Pronunciation

  • (US) IPA: /tɔˈtɒl.ə.dʒi/

Noun

tautology (countable and uncountable; plural tautologies)

  1. (uncountable) redundant use of words
    It is tautology to say, "Forward Planning".
  2. (countable) An expression that features tautology.
    The expression "raze to the ground" is a tautology, since the word "raze" includes the notion "to the ground".
    • 1946, Bertrand Russell, History of Western Philosophy:
      Pure mathematics consists of tautologies, analogous to ‘men are men’, but usually more complicated.
  3. (countable, logic) A statement that is true for all values of its variables
    Given a Boolean A, "A OR (NOT A)" is a tautology.
    A logical statement which is neither a tautology nor a contradiction is a contingency.
    A tautology can be verified by constructing a truth tree for its negation: if all of the leaf nodes of such truth tree end in X's, then the original (pre-negated) formula is a tautology.

Antonyms

Coordinate terms

Derived terms

terms derived from tautology (noun)

Translations

uncountable: redundant use of words
expression that features tautology
in logic

See also

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Last modified on 20 May 2013, at 01:20