Share this entry

contraposition Line breaks: contra|pos¦ition
Pronunciation: /kɒntrəpəˈzɪʃ(ə)n/

Definition of contraposition in English:


[mass noun] Logic
Conversion of a proposition from all A is B to all not-B is not-A.
Example sentences
  • By contraposition and the definition of the existential quantifier, the latter axiom is equivalent to x = x y (y = x).
  • This means that form and content are not fully unified but retain a structure of abstract contraposition: the content is inscribed in the form while retaining much that cannot be grasped in it.
  • As a contraposition to the conclusions derived from the summation theorem, we have used similar mathematical tools to show that dominance is not an inevitable property of metabolic pathways.


Mid 16th century: from late Latin contrapositio(n-), from the verb contraponere, from contra- 'against' + ponere 'to place'.



Pronunciation: /kɒntrəˈpɒzɪtɪv/
adjective& noun
Example sentences
  • The contrapositive of the inference is logically equivalent - X simulates Y, X does not have P therefore Y does not - where P is understands Chinese.
  • And you know also the contrapositive, that your being at place X entails that you are not then in a tank on Alpha Centauri.
  • Then the contrapositive not-PN entails not-MN is also true.

Definition of contraposition in:

Share this entry


What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day exemplum
Pronunciation: ɪɡˈzɛmpləm
an example or model...