Contraposition

ʿaks al-naqīḍ

عَكْسُ النَّقِيض

Contraposition (ʿaks al-naqīḍ), in the account of the earlier logicians, makes the contradictory of the predicate the subject and the contradictory of the subject the predicate, keeping quality and truth.

Second readingFrom the commentariesDraft · awaiting review

Explanation

“Every human is an animal” becomes “every non-animal is non-human”.

Later logicians gave a second account that changes the quality; the commentaries compare the two.

Also written as: aks al-naqid, contraposition.

Related terms

Simple conversion
Contradiction

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