In Chinese philosophy yin (shadow) and yang (brightness)—the male and female, positive and negative principles in the world—must ideally be balanced in all aspects of life, including nature and the human body. Traditional Chinese medicine, for instance, attempts to balance the two principles. In Taoism, yin and yang are the opposite boundaries of the absolute supreme reality (T’ai). The meditative exercises known as t’ai chi represent, in part, the balancing of the two principles in unity with the supreme being.

In a creation-based myth of the second century B.C.E., it is said that in the beginning there was only chaos, containing light and dark. Light, which was the yang principle, became the sky and dark, the yin principle, became the earth. The sky—yang—gave, and the earth—yin—received. This is like Indo-European concepts of the original union of sky and earth. In the Chinese myth, when yin and yang became one—that is, tiandi—the elements came into being and humans were created.