Definition of contraposition in English:



  • Conversion of a proposition from all A is B to all not-B is not-A.

    • ‘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.’
    • ‘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.’


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