contrapositive

[ kon-truh-poz-i-tiv ]

adjective

1. of or relating to contraposition.

noun

1. a contrapositive statement of a proposition.

contrapositive

/ ˌkɒntrəˈpɒzɪtɪv /

adjective

1. placed opposite or against

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

Word History and Origins

Origin of contrapositive¹

First recorded in 1855–60; contraposit(ion) + -ive

Example Sentences

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg

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

From Project Gutenberg