Zhu Danxi believes that everything in the world has two sides: the sun and the earth are yin, the sun is yang and the moon is yin. The sky is bigger than the sky, the sun will never change, but the moon is cloudy and full. From this nature, it is the embodiment of "Yang flourishes and Yin declines". Man is a part of nature, of course.
Zhu Danxi also thinks: "Man is born of the qi of heaven and earth, the yang of heaven is qi, and the yin of earth is blood", so there is always a time when the qi is more than the blood. In the course of human life, only the young and middle-aged period is relatively rich in yin essence, and the young and middle-aged period is very short in life, so people live in a state of excess of yang and deficiency of yin. Why is the yin essence of young adults relatively rich?
Yin Qi is difficult to become, and it only forms when men 16 years old and women 14 years old. Yin Qi is easily lost. "Forty Yin Qi is half", when men are 64 years old and women are 49 years old, menopause will stop. From then on, people's vagina will be less and less. Therefore, it is pointed out in "Yin Qi will supply for 30 years" and "Color and Desire" that "those who are ignorant of others are biased towards sex and color, lest they be inferior". Excessive yang, severe yin injury, and persistent essence and blood are harmful to the body. "What is the geometric relationship between blood and qi? But don't feel sorry for yourself! What I gave birth to became my thief. " This is to understand "yin deficiency" from the comparison of quantity.
Danxi lamented the social atmosphere that "since the Middle Ages, the secular world has been increasingly stolen and the endowment has become increasingly thin", and emphasized that there is such an unbalanced relationship between supply and demand between the "Yang" with boundless lust and the "Yin" with reproductive materials that are difficult to become and easy to lose. The theory that "Yin is insufficient and Yang is often surplus" is also of great significance until now. Yin is the foundation of our life activities, so don't overdraw. People who grew up in the countryside can bear the overdraft for a longer time than those who grew up in the city. This is because people who grew up in rural areas went to bed earlier in childhood and stored more energy in their bodies. Today's children go to bed later than the previous generation, so they have less energy to overdraw and less chance of getting seriously ill.
In addition, people who are now rushing about for life and work can only maintain their daily work or activities because they consume a lot of energy. When a general disease invades, the human body lacks resistance and the disease goes straight ahead. Because there is no resistance, there will be no uncomfortable disease symptoms, but it will leave traces on the skin color, body shape and facial features of the human body, which can be recognized by experienced doctors. Many people feel that they are healthy and have endless physical strength. Busy until midnight every day, physical exhaustion to the extreme will not get sick. This phenomenon is a typical yin deficiency, which means that you overdraw your yin without knowing it, and it's too late to regret it when a serious illness comes. Therefore, in daily life, we should save more energy and protect our yin, and don't spend it casually because we are in good spirits and strong bodies. In fact, many times we are unconsciously overdrawn.