The idea behind the symbol of the yin and the yang was based on:

royal ancestral worship and filial piety

the understanding that the nature of man is evil

the Daoist belief that every living thing had a life force

the Confucian thought that there is harmony within nature

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.