mid-14c., logike, "branch of philosophy that treats of forms of thinking; the science of distinction of true from false reasoning," from Old French logique (13c.), from Latin (ars) logica "logic," from Greek (he) logike (techne) "(the) reasoning (art)," from fem. of logikos "pertaining to speaking or reasoning" (also "of or pertaining to speech"), from logos "reason, idea, word" (see Logos). Formerly also logick. Sometimes formerly plural, as in ethics, but this is not usual. Meaning "logical argumentation" is from c. 1600. Contemptuous logic-chopper "sophist, person who uses subtle distinctions in argument" is from 1846.

"pertaining to logic as illustrated by physics," 1704, from physicologic "logic illustrated by physics," from physico- + logic. Related: Physicologic; physicologically.

1580s, earlier dialatik (late 14c.), "critical examination of the truth of an opinion, formal reason and logic applied to rhetoric and refutation," from Old French dialectique (12c.) and directly from Latin dialectica, from Greek dialektike (techne) "(art of) philosophical discussion or discourse," fem. of dialektikos "of conversation, discourse," from dialektos "discourse, conversation" (see dialect).

Originally synonymous with logic; in modern philosophy refined by Kant ("the theory of false argumentation leading to contradictions and fallacies), then by Hegel, who made it mean "process of resolving or merging contradictions in character to attain higher truths." Used generally in 20c. Marxism for "evolution by means of contradictions." Related: Dialectics.

"beyond the sphere of logic, transcending logic," by 1865; see meta- in the third sense of "transcending, overarching, dealing with the most fundamental matters of" + logical. Related: Metalogic (n.), by 1842; metalogical.