Definition from Wiktionary, the free dictionary
- The act of turning toward or downward.
- (logic) An immediate inference that denies the opposite of something previously affirmed.
- All men are mortal, so, by obversion, no men are immortal.
- 1870, Alexander Bain, Logic: Induction
- From 'warmth is agreeable' we can affirm, by formal obversion, 'warmth is not disagreeable, and not indifferent.' We cannot affirm, without an examination of the subject matter, 'cold is disagreeable.'