Broadly speaking, a dialectic is an exchange of propositions and counter-propositions resulting in a synthesis of the opposing assertions or at least a qualitative transformation of the direction of the dialogue.

Table of contents
1 In Philosophy
2 Marxist Dialectic

In Philosophy

When using the word "dialectic" philosophers usually refer to either the Socratic dialectical method of cross-examination, or to Hegel's dialectical model of history.

Socratic Dialectic

In Plato's dialogues, Socrates typically "argues" by means of cross-examining someone else's assertions in order to draw out the inherent contradictions within the other's position. For example, in the Euthyphro, Socrates asks Euthyphro to provide a definition of piety. Euthyphro replies that the pious is that which is loved by the gods. But, Socrates points out, the gods are quarrelsome and their quarrels, like human quarrels, concern objects of love or hatred. Euthyphro consents that this is the case. Therefore, Socrates reasons, at least one thing exists which certain gods love but other gods hate. Again, Euthyphro consents. Socrates concludes that if Euthyphro's definition of piety is true, then there must exist at least one thing which is both pious and impious (as it is both loved and hated by the gods) -- which, Euthyphro admits, is absurd.

Hegelian Dialectic

Although Hegel never used such a classification himself, Hegel's dialectic is often described as consisting of three stages: a thesis, an antithesis which contradicts or negates the thesis, and a synthesis embodying what is essential to each. In the Logic, for instance, Hegel describes a dialectic of existence: first, existence must be posited as pure Being (thesis); but pure Being, upon examination, is found to be indistinguishable from Nothing (antithesis); yet both Being and Nothing are united as Becoming (synthesis), when it is realized that what is coming into being is, at the same time, also returning to nothing (consider life: old organisms die as new organisms are created or born). Like Socratic dialectic, Hegel's dialectic proceeds by making implicit contradictions explicit: each stage of the process is the product of contradictions inherent or implicit in the preceding stage. For Hegel, the whole of western history is one tremendous dialectic, the largest moments of which chart a progression from self-alienation as slavery to self-unification and realization as the rational, constitutional state of free and equal citizens.

Marxist Dialectic

Karl Marx and Friedrich Engels saw Hegel as "standing on his head", and put him back on his feet, ridding Hegel's logic of its idealist orientation, and conceiving what is now known as materialist or Marxist dialectics. The dialectical approach to the study of history then gave rise to historical materialism, the school of thought exemplified by the works of Marx, Engels, Lenin, and Trotsky. Under Stalinism, Marxist dialectics developed into what was called "diamat" (short for dialectical materialism), a system of thought which became increasingly dogmatic and thus intellectually bankrupt due to the overpowering influence of its attendant political ideology. Some Soviet academics, most notably Evald Ilyenkov, did continue with philosophical studies of the marxist dialectic free from ideological bias, as did a number of thinkers in the West.

See also: Dialectician, Universal Dialectic