1. A school of logic that teaches critical examination of the truth of an opinion, esp. by discussion or debate. • The method was applied by ancient philosophers, such as Plato and Socrates, primarily in the context of conversational discussions involving questions and answers, and also by more modern philosophers, such as Immanuel Kant, who viewed it as a theory of fallacies, and G.W.F. Hegel, who applied the term to his philosophy proceeding from thesis, to antithesis, to synthesis.
2. An argument made by critically examining logical consequences.
3. A logical debate.
4. A disputant; a debater. Pl. dialectics.