Man has often seen himself, uncertain and searching, between two opposing forces, for example, darkness and light or good and evil. As these pairs of forces are described in various commentaries and scriptures, it is clear that they have much in common beyond polarity. There are attractions—whether in the form of virtue, love, safety, or temptation—on either side of each pair; and a certain amount of knowledge, faith, searching, judgement, or wisdom is required to avoid the "bad" side, or departure from the "golden mean" or from Tao (the "way"). So persistent is this theme of opposites that it has, from all quarters of the earth, pervaded religions and philosophies.
Relatively late in man's history, the concept of opposites appeared in mathematics, physics, and chemistry; but in these sciences the opposites have no ethical or judgemental connotations. The "negative pole" may have a pejorative ring in daily conversation, but not