Within Hegelianism, dialectic acquires a specialised meaning of a contradiction of ideas that serves as the determining factor in their interaction; comprising three stages of development: a thesis, giving rise to its reaction; an antithesis, which contradicts or negates the thesis; and the tension between the two being resolved by means of a synthesis.
Dialectic tends to imply a process of evolution, and so does not naturally fit within formal logic; see logic and dialectic. This is particularly marked in Hegelian and even more Marxist dialectic which may rely on the time-evolution of ideas in the real world; Dialectical logic attempts to address this.
In classical philosophy, dialectic (διαλεκτική) is a form of reasoning based upon dialogue of arguments and counter-arguments, advocating propositions (theses) and counter-propositions (antitheses). The outcome of such a dialectic might be the refutation of a relevant proposition, or of a synthesis, or a combination of the opposing assertions, or a qualitative improvement of the dialogue.
Moreover, the term "dialectic" owes much of its prestige to its role in the philosophies of Socrates and Plato, in the Greek Classical period (5th to 4th centuries BCE). Aristotle said that it was the pre-Socratic philosopher Zeno of Elea who invented dialectic, of which the dialogues of Plato are the examples of the Socratic dialectical method.