Obverted

Part of speech: adjective

Definitions

1. Transformed a categorical proposition into its obverse form by negating the predicate and replacing the quality while keeping the subject unchanged
2. Changed a statement in logic by substituting its predicate with the opposite and reversing affirmative or negative quality, preserving the subject term
3. Converted a logical statement into its obverted equivalent by denying the predicate and switching the quality, without altering the subject part

Etymology: "Obverted" is the past participle and adjectival form of "obvert," a verb from Latin "obvertere," meaning "to turn toward" or "to turn against," built from "ob-" ("toward") and "vertere" ("to turn"). The English verb is the older of the two uses in logic, where it describes the operation of turning a proposition into its obverse by changing its quality and replacing the predicate with its complement. A statement such as "All birds are animals" becomes "No birds are non-animals" under this operation. The term "obvert" in its logical sense belongs to the traditional Aristotelian logic taught in medieval and early modern schools, where such operations were classified as immediate inferences. The sense of "turning" in the Latin root explains the choice: the proposition is turned over to show its other face, while the subject term stays where it was.