Why does Chinese medicine also talk about "yin-yang and five elements"

When it comes to "Yin-Yang and Five Elements", people usually think of "Yin-Yang Masters" who specialize in geomantic omen in cemeteries in the old society, or "fortune tellers" who tell people fortune in stations and busy streets. Thus, in some people's minds, Yin-Yang and Five Elements seem to be synonymous with feudal superstition; Even Chinese medicine is regarded as mysterious metaphysics. The theory of Yin and Yang is a philosophical thought of China in ancient times, that is, simple materialism and dialectics. The word yin and yang is often used in daily life. Take the weather as an example. There are cloudy days, rainy days in Mao Mao and sunny days in Wan Li. Take the calendar as an example. The lunar calendar is called the lunar calendar and the solar calendar is called the solar calendar. Modern medical bacterial culture can be divided into negative bacteria and positive bacteria. In physics, electrodes can be divided into cathodes and anodes; in chemistry, ions can be divided into anions and cations. Physical examination has negative signs and positive signs. Therefore, Yin and Yang, as relative concepts, are used to distinguish the attributes of things. Because everything has two sides of the unity of opposites. Yin-yang theory is widely used in traditional Chinese medicine, permeating all fields of traditional Chinese medicine. From the perspective of human tissue structure, the upper part is yang and the lower part is yin; External yang, internal yin; The body surface belongs to yang, and the five internal organs belong to yin. From the perspective of human physiology and pathology, normal physiological activities are the result of the coordination of yin and yang; If yin and yang are out of balance, diseases will occur. In the diagnosis of diseases, it is necessary to distinguish between yin syndrome and yang syndrome when diagnosing any diseases. The principle of treating diseases is to adjust yin and yang to restore their relative balance. Chinese medicine is also used in clinic under the guidance of yin and yang. For example, pungent and sweet belong to yang, sour and bitter belong to yin; Salty medicine belongs to yin, while light medicine belongs to yang. The theory of five elements is also a philosophical thought of China in ancient times, which explains the changing laws and internal relations of things from another side. It holds that wood, fire, earth, gold and water are five substances that constitute nature, and anything else can be compared with them and fall into these five categories. For example, heart, liver, spleen, lung, kidney (five internal organs), tendons, veins, meat, fur, bones (five bodies), eyes, tongue, mouth, nose and ears (five orifices), spring and summer, long summer, autumn and winter (five seasons), wind, heat and humidity. These five substances and a variety of things summarized according to their attributes have the relationship of mutual gestation and mutual restriction, and are in constant movement and change. This relationship, which breeds and restricts each other, is expressed by the words "life" and "gram". The specific relationship between life and gram is: wood makes a fire, fire produces soil, soil produces gold, gold produces water, aquatic wood makes a fire, wood makes a fire ... This "life" relationship is endless; Mu, Tuke water, water, Huo, Jin Kemu, Mu ... This "gram" relationship has been going on. In a word, the theory of Yin-Yang and Five Elements is a reasoning tool to explain the diagnosis and treatment of human physiology, pathology and diseases, and it is an important part of the basic theory of traditional Chinese medicine, which has nothing to do with feudal superstition.