1. in general, any investigation of the truth of ideas through juxtaposition of opposing or contradictory opinions.

2. the conversational mode of argument attributed to Socrates, in which knowledge is sought through a process of question and answer.

3. in the work of German philosopher Georg Wilhelm Friedrich Hegel (1770–1831), the pattern of statement, contradiction, and reconciliation (thesis, antithesis, and synthesis) that he held to govern thought processes and the progress of human history. See also dialectical materialism. —dialectical adj.