Yin-Yang

Duality is found in many belief systems, but Yin and Yang are parts of a Oneness that is also equated with the Tao. A term has been coined dualistic-monism or dialectical monism. Yin and yang can be thought of as complementary (rather than opposing) forces that interact to form a dynamic system in which the whole is greater than the assembled parts. Everything has both yin and yang aspects, (for instance shadow cannot exist without light). Either of the two major aspects may manifest more strongly in a particular object, depending on the criterion of the observation. The yin yang (i.e. taijitu symbol) shows a balance between two opposites with a portion of the opposite element in each section.

In Taoist metaphysics, distinctions between good and bad, along with other dichotomous moral judgments, are perceptual, not real; so, the duality of yin and yang is an indivisible whole. In the ethics of Confucianism on the other hand, most notably in the philosophy of Dong Zhongshu (c. 2nd century BC), a moral dimension is attached to the idea of yin and yang.