a. and sb. [f. L. contrāposit-, ppl. stem of contrāpōnĕre (see prec.) + -IVE.]
A. adj. Of, belonging to, or produced by contraposition.
1870. Jevons, Elem. Logic (1886), 84. We may also prove the truth of the contrapositive proposition in this way. Ibid., 85. Contrapositive conversion cannot be applied to the particular propositions I and O at all.
B. sb. Anything characterized by contraposition. In Logic, a contrapositive proposition.
1870. Jevons, Elem. Logic (1880), 302. Convert and show that the result is the contrapositive of the original. Ibid. (1884), Stud. Deduct. Logic, 43. The contrapositive of the proposition ‘all birds are bipeds’ will be ‘all that are not bipeds are not birds.’
1876. Kennedy, trans. Reuleaux’ Kinem. Machinery, 181. The hydraulic press forms the contra-positive of … the pulley-tackle, the pressure-organ water in the one being replaced by the tension-organ rope in the other.
