Concept of Yin and Yang
The concept of yin and yang is probably the single most important and distinctive theory of Chinese medicine. It could be said that all Chinese medical physiology, pathology and treatment can eventually be reduced to yin yang. The concept of yin yang is extremely simple and yet very profound. One can understand it on a rational level, and yet continually find a new expression of it in clinical practice and, indeed, in life.
The concept of yin yang, together with that of qi, has permeated Chinese philosophy over the centuries and is radically different from any Western philosophical idea. In general, Western logic is based upon the opposition of contraries, which is the fundamental premise of Aristotelian logic. According to this logic, a pair of contraries such as’ The table is square’ and ‘The table is not square’) cannot both be true. This approach has dominated Western thought for over 2000 years. The Chinese concept of yin and yang is radically different from this system of thought. Yin and Yang represent the opposite but complementary qualities. Each thing or phenomenon could be both itself and it is contrary. Moreover, yin contains the seed of yang, so that yin can transform into yang and vice versa.
A passage from a commentary on Zhuang Zi highlights this thinking about the complementary
of opposites: ‘ there are no two things under Heaven which do not have the mutual relationship of the ‘self’ and the ‘other’ equally desire to act for themselves, thus opposing each other as strongly as East and West. on the other hand, the “self; and the “other” have at the same time the mutual relations of lips and teeth… therefore the action of the “other” on its own behalf at the same time helps “self”. Thus, though mutually opposed, they are incapable of mutual negation.