This idiom is a household name, and it is an important proposition of China's ancient epistemology, which has had an ideological impact on the development of ancient science. This word was first seen in the pre-Qin classic book The Book of Rites University, which is the first two of the eight stages of Confucianism proposed in the book: "The ancients wanted to be superior to the world, and ruled their country first; If you want to govern your country, you should first get your family together; If you want to reunite with your family, you should first repair your body; If you want to cultivate yourself, you should be upright first; If you want to be correct, be sincere first; If you want to be sincere, let him know first. Knowledge exists in things. Know things and then know, know and then be sincere, be sincere and then correct, be correct and then repair, repair and then stay at home, stay at home and then rule the country, and rule the country and then level the world. " This passage is a staged behavior goal put forward by Confucianism to realize its political thought of self-cultivation, family harmony, governing the country and leveling the world. The starting point of this program behavior program is to know what to do. It can be seen that the understanding of things really plays an extremely important role in Confucianism. "Ge" and "Wu" were widely used in ancient times, which is probably not difficult to understand in Confucius' time. Confucius himself did not explain, nor did his disciples explain the meaning of Wu Ge, which led to many ambiguities in later generations' understanding of Wu Ge's meaning. Everyone wants to explain it according to their own philosophical tendency, which makes this issue really blossom. Therefore, to understand the original intention of knowing things, we should put it in the era when The Book of Rites University came into being and make a comprehensive study with reference to other Confucian classics, especially Confucius' epistemological thought. According to later research, The Book of Rites University mainly expresses the meaning of Confucius and his disciple Ceng Zi. At that time, Confucius was famous for his natural history and knew many things that others didn't know, which was naturally related to his knowledge. In another Confucian classic, The Doctrine of the Mean, Confucius' grandson Zisi pointed out the way of acquiring knowledge advocated by Confucianism, which is called "erudition, interrogation, deliberation, discernment and hard work". Confucius is learned because his way of doing research cannot be different from this. Therefore, the emphasis in The Doctrine of the Mean can be regarded as an annotation to the theory of "knowing people by things". That is, through extensive study, careful study of something and practical experience, you can gain true knowledge. Therefore, it can be considered as its original meaning to emphasize the correct understanding through investigation, investigation or poor study of things. In fact, because the theory of "knowing knowledge by considering things" has the meaning of studying objective things to acquire knowledge, some people of insight who attach importance to natural research also use this slogan to give it new connotation to explain their thoughts. For example, Wang Fuzhi once said, "Mi Weng (Fang Yizhi) and his son are qualitative scholars, and their sincere study and thinking have contributed greatly. Those who cover things are poor, and quality is the only thing. If Shao Kangjie and Cai Xishan, they will stand up for poverty and non-standard things. " . Wang Fuzhi's "research on qualitative measurement" is a pioneering work of Fang Yizhi, and its central content is to study natural phenomena by empirical methods. Wang Fuzhi believes that only qualitative measurement is the real understanding of things, which gives the epistemology of things a new meaning and marks that this term has entered the category of natural science. With the introduction of science and technology in the late Ming and early Qing Dynasties, the enthusiasm of China people to study natural phenomena also rose. At this time, when people talk about knowing things, they often refer to studying nature to acquire knowledge. The ancient theory of "knowing people by things" has been reborn and has become the theoretical basis for people to engage in scientific research. Some western scientific and technological books translated in the late Qing Dynasty were named "Gezhi". The word Gezhi has become a general term for natural science departments such as acousto-optic, electrification and so on. Mr. Lu Xun wrote in the preface to Scream: "Only in this school did I know that there are so-called disciplines, mathematics, geography, history, painting and gymnastics in this world." He is talking about natural science. In the process of the confluence of China's traditional science and western science and technology, the "material-oriented" epistemology participated in and accelerated this process in a unique way, thus gaining a permanent foothold in the history of science and technology.