A concept used, i.a. by Hegel and Marx to describe e.g. long-term historical change. Dialectics consist (very roughly) in that "powers" that are fundamentally opposed meet in conflict, which is released in a new "synthesis". In Marx's work, this meeting takes place between heavy, institutional principes (means of production and relations of production; higher and lower classes). The concept is also often used more generally (e.g. by Wagner and Bourdieu) about types of logic or processes that develop stepwise through opposition and synthesis.