The theory of Yin and Yang developed around the fourth century BC and is often called the theory of systematic correspondences. It is because of its unique contribution to the idea that the universe and the body consist of dynamic and functional interrelations. It attempts to explain the universe as forces or principles instead of the whims of gods, ancestors, or demons.
The Yi Jing (The Book of Changes, 易经) is about the constant flux and permanence of this process in the universe. The character “Jing” means ” “great book,” and the character “Yi” is derived from an abstract pictorial representation of the sun and the moon in combination, which signifies Yang and Yin, respectively.
Yin and Yang Theory
Originally, Yang and Yin represented the sunny and shady sides of a mountain. Chinese science later developed this principle to stand for opposites of interrelated phenomena. Yang represents the functional energetic qualities of the universe, while Yin represents the structural and substantive qualities of the universe. It has been explained in the following way: “In modern terms, Yang corresponds to all that is active, expansive, centrifugal, aggressive, demanding, polar negative and Yin implies all that is structural, substantive, contractive, centripetal, responsive, conservative, polar positive.”
These interrelated phenomena are expressed in terms of correspondences between qualities of any identifiable object. One cannot exist without the other. For example, the concept of “up” cannot exist without the idea of “down”, nor the concept of “fast” without the corresponding idea of “slow.”
Change, or “Yi,” in the universe is a dynamic interaction between Yin and Yang, in which the constant interplay of these fundamental forces creates and is created by the universe of which we are all apart.
The universe is in movement or transform from birth very moment. Life itself is a process of never-ending change from birth to death. The Yi Jing is an attempt to find reliable rules for nature and human life in relation to changes in the universe.
The Yi Jing forms the basis for all Chinese science and is a fundamental part of Chinese cultural expression. In medicine, the theory of Yin and Yang is the organizing principle in the correlation of all medical information.
For example, the differentiation of syndromes and pulse qualities combines with other critical theories like the Five Transformative Phase and Meridians theories. So, in essence, Yin and Yang doctrine is simple, but its influence has been pervasive. No aspect of Chinese civilization: metaphysics, medicine, government, or art – has escaped its imprint.