I think that man and the universe (referred to as "heaven") have profound unity and are an inseparable whole. Therefore, people's morality, medical care and all other social life should be connected with the sky accordingly. "Biography of Classical Chinese" said: "My husband is in harmony with heaven and earth, with the sun and the moon, with the four seasons, and with ghosts and gods." The "ghosts and gods" mentioned here are synonymous with the ghosts and gods in the "essence for things, wandering souls for change, and knowing the realm of ghosts and gods", which refers to the transformation of qi exchange. The Book of Changes holds that a person's morality, will and practice must give full play to his subjective initiative on the basis of obeying the way of heaven and earth and conforming to God's will, in order to succeed and reach an ideal state. The so-called "Heaven and Earth have a position, and saints can become useful" ("Cohesion Biography") requires people to know and seek for heaven and earth, so as to achieve the role of heaven and earth in educating all things, which is what Taoism later said: "Where heaven and earth are combined, they seize the opportunity of Yin and Yang." As long as people master the laws of nature, they can change what nature gives them and create miracles.

The so-called health preservation in China culture is by no means a pure concept of physiology, medicine or natural science, nor is it just for health and longevity. At the same time, keeping in good health includes morality and even managing the world. From the Yi-ology and China's philosophy, keeping in good health, Xiu De and governing the world are mutually restricted and promoted, which is a process. Therefore, the unity of man and nature is not only the theory of Yi-ology philosophy, but also an extremely important theory of health preservation.