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contrapositive

[kon-truh-poz-i-tiv]Logic.
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adjective
  1. of or relating to contraposition.
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noun
  1. a contrapositive statement of a proposition.
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Origin of contrapositive

First recorded in 1855–60; contraposit(ion) + -ive
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words

antipodeantithesiscontraryconversecounterinversereverse

Examples from the Web for contrapositive

Historical Examples

  • Every positive in thought has a contrapositive, and the positive and contrapositive are of the same kind.

    Logic, Inductive and Deductive

    William Minto

  • For a Disjunctive in I., of course, there is no Contrapositive.

    Logic

    Carveth Read

  • In the case of the I proposition the contrapositive is impossible, as infringing the main rule of conversion.

  • There is an apparent exception to this when the real Middle in an argument is a contrapositive term, not-M.


British Dictionary definitions for contrapositive

contrapositive

adjective
  1. placed opposite or against
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noun
  1. logic
    1. a conditional statement derived from another by negating and interchanging antecedent and consequent
    2. a categorial proposition obtained from another, esp validly, by any of a number of operations including negation, transferring the terms, changing their quality, and also possibly weakening from universal to particular
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for contrapositive

adj.

1858 (implied in contrapositively), from Latin contraposit-, past participle stem of contraponere (see contraposition) + -ive.

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Online Etymology Dictionary, © 2010 Douglas Harper