Originally meant the art of argument, a method of logical inquiry that proceeded by question and answer. The idea of dialectic was developed by the nineteenth century German idealist philosopher Hegel into a way of understanding all natural and historical processes: everything conformed to a dialectical process of thesis, antithesis and synthesis. One thing produces from within itself its own opposite or negation, and from the conflict between the two emerges a synthesis. Hegel's idea of dialectic was adapted by Karl Marx to form dialectical materialism, the foundation of Marxist doctrine.