(Greek for "setting opposite", from ἀντί against + θÎσις position) is a counter-proposition and denotes a direct contrast to the original proposition. In setting the opposite, an individual brings out of a contrast in the meaning (eg., the definition, interpretation, or semantics) by an obvious contrast in the expression.
Description
A simplistic description of dialectics is thesis, antithesis, synthesis. Hell is the antithesis of Heaven; disorder is the antithesis of order. It is the juxtaposition of contrasting ideas, usually in a balanced way. In rhetoric, it is a figure of speech involving the bringing out of a contrast in the ideas by an obvious contrast in the words, clauses, or sentence, within a parallel grammatical structure, as in the following:
"When there is need of silence, you speak, and when there is need of speech, you are dumb; when present, you wish to be absent, and when absent, you desire to be present; in peace you are for war, and
Source:
http://en.wikipedia.org/wiki/Antithesis