OBVERSION

Etymology

Noun

obversion (countable and uncountable, plural obversions)

The act of turning toward or downward.

(logic) An immediate inference that denies the opposite of something previously affirmed.

Source: Wiktionary

Ob*ver"sion, n. Etym: [L. obversio a turning towards.]

1. The act of turning toward or downward.

2. (Logic)

Definition: The act of immediate inference, by which we deny the opposite of anything which has been affirmed; as, all men are mortal; then, by obversion, no men are immortal. This is also described as "immediate inference by privative conception." Bain.

Source: Webster’s Unabridged Dictionary 1913 Edition