What are the specific meanings of Yin-Yang and Five Elements?

The theory of Yin-Yang and Five Elements is China's simple materialism and spontaneous dialectics in ancient times. It believes that the world is material, and the material world is nurtured, developed and changed under the impetus of yin and yang. People think that the five most basic substances, wood, fire, earth, gold and water, are indispensable elements in the world. These five substances depend on each other and are in constant movement and change. This theory had a far-reaching impact on the later ancient materialist philosophy, such as ancient astronomy, meteorology, chemistry, mathematics, music, medicine, etc., all developed with the help of the theory of Yin-Yang and Five Elements.

Yin and Yang are a pair of categories in China's ancient philosophy. The original meaning of yin and yang is very simple, indicating that the sun faces the back, the sun faces the sun, and the back faces the sun. Later, it was extended to the warmth and coldness of the climate, the up and down or so, the internal and external directions, and the restlessness and tranquility of the movement state. The ancient philosophers in China further realized that all phenomena in nature are antagonistic and interactive, so they used the concept of Yin and Yang to explain two kinds of antagonistic and interactive material forces in nature, and thought that the opposition and fluctuation of Yin and Yang were inherent in things themselves, and further thought that the opposition and fluctuation of Yin and Yang were the basic laws of the universe.

The five elements refer to the movement of wood, fire, earth, gold and water. The ancient Chinese people realized that wood, fire, earth, gold and water were the most indispensable basic substances in their long-term life and production practice, which extended that everything in the world was produced by the movement of five basic substances: wood, fire, earth, gold and water. These five substances are mutually enriched and restricted, and maintain a dynamic balance in the constant movement of mutual development and mutual resistance, which is the five elements.