Yin and Yang is the ancient Chinese philosophical understanding that everything in the natural world will have an opposite, and that nothing in the natural world can exist without its opposite.
In ancient Chinese culture, people were interested in the relationships and patterns that occurred throughout the natural world. The School of Yin-Yang, believed to have been founded by Zou Yan (305 BC – 240 BC), gave rise to the concept of Yin and Yang. Zou Yan believed that the universe could be explained in terms of the basic forces of nature.
Yin represents the black side of the circle: negative, dark, moon, passive, cold, female. Yang represents the white side of the circle: positive, light, sun, active, hot, male.
Yang is associated with the functional aspect of an object and has more energetic qualities: moving, progressing, expanding, heat, bright, ascending, active and hyper-functioning states. Yin, on the other hand, is associated with the physical form of an object and has less energetic qualities such as stillness, degenerating, contracting, cold, dark, descending, latent and under-functioning states.
Yin and Yang explains that although everything has an opposite, the two opposites exist in harmony and only exist because of the other. Everything in the natural world exists in harmony: dark follows light and vice-versa, passivity is followed by activity and vice-versa. Yin and Yang also explains that one thing cannot exist without its opposite. Positive can not exist without negative, male cannot exist without female.
Yin and Yang complement each other, they do not oppose each other. They interact to form a whole, greater than either separate part.