Question: "What is the meaning of the yin and the yang?"
Answer: The concept of yin yang (often called “the yin and the yang”) is a Chinese philosophical idea used to explain how opposite forces are interconnected and interdependent upon each other. In other words, black could not exist without white, dark without light, cold without heat, etc. The yin yang concept is the basis of many branches of classical Chinese science and philosophy, traditional Chinese medicine, and different forms of Chinese martial arts and exercise, including tai chi.
As with much of Chinese philosophy and culture, the concept of yin yang is mysterious and complex, and a full treatment of it is not possible here. The connection between yin yang and Taoism, however, is undeniable. Tao deals with the flow of the universe, or the force behind natural order that keeps all things balanced and in order. It is considered to be a source of existence and "non-existence." Most adherents of Taoism believe anything from polytheism (belief in many gods) to ancestor worship. Taoists tend to worship mostly on holidays in their calendar when food is set out as a sacrifice to the gods or the spirits of departed ancestors. Other forms of sacrifice include burning paper money so it will rematerialize in the spirit world for a departed ancestor to use. A number of martial arts disciplines such as T'ai Chi Ch'uan and Bagua Zang have their roots in Taoism.
Taoism and the yin yang concept are directly contradictory to biblical Christianity. While it is true that evil would not exist without goodness, the converse is not true. Goodness can and does exist without evil. Evil is not required to understand good or to have good. A doctor does not have to have asthma, in order to know how to treat asthma. Rape does not have to exist in order to understand the joy and intention that God has for sex. DaVinci’s mural The Last Supper is an example of terrific workmanship, yet today it is faded, chipped, and marred by decay. Must the decay exist in order to appreciate the beauty of the art? Not at all.
The holiness of God is eternal, complete, and undivided. God’s righteousness admits no admixture of sin; there is no “balance” or “integration” or “interdependence” between the holiness of God and the evil that exists in the world.