[From Greek dialektikos: relating to dialogue or discussion, and Latin materia: physical stuff.]
(politics) A form of historical determinism espoused by Marxism. The dialectical aspect derives from Hegelianism, which holds that history proceeds in something like the stages of a conversation, with each stage overcoming the previous stages and therefore coming closer to finally attained unity or truth. The materialist aspect replaced Hegel's emphasis on spiritual improvement and the collective unconscious with a focus on economic classes and the economic-technological basis for social relations. Thus dialectical materialism posits that history progresses in stages that are based solely on ownership of the means of production: i.e., feudalism replaced aristocracy, capitalism replaced feudalism, and true socialism or communism will replace capitalism - all according to inexorable, immutable laws.