The book that represents Mozi's thoughts and achievements is Mozi. Mozi, written in the middle and late Warring States period, is a summary work written by Mozi and his disciples to record Mozi's words and deeds. The book Mozi faithfully records the prototype of Mozi, with a total of 15 volumes 7 1 article. After the Qin and Han Dynasties, there were 18 lost articles, and there are 53 existing 15 volumes. Its content can be roughly divided into five parts: first, the category of Mohism, including Daqu and Xiaoqu. These two articles reflect the logical thought system established by Mozi, which can be compared with Aristotle in Greece and Inming in India in the history of human logical thought development. The second is the category of "theory", which is divided into two parts: general theory and monograph. The General Theory consists of seven articles: Pro-Scholar, Self-cultivation, Feeling, Easy Development, Seven Bitterness, Ci Guo and Three Debates, which generally discusses Mozi's social and political thoughts. The monographs include Shang Xian, Shang Tong, All Love, Non-attack, Festival and Use, Festival and Burial, Tianzhi, Ming Ghost, Le Fei, Feizi and Feiru, etc., with a total of 1 1. Many wise sayings of Mohism, such as "the strong don't praise the weak, the rich don't bully the poor", "words must be kept, actions must bear fruit" and "frugality leads to prosperity, and lewdness leads to death." , "officer impermanence expensive, people have no final base. Lift it up if you can, or get it off if you can't. None of them fall into this category. The third category is "Quotations", including Geng Xu, Gui Yi, Meng Gong, Lu Wen and Gong Bo Pian, which record Mozi's words and deeds during the debate with the outside world and are the first-hand historical materials about Mozi's life. The fourth category is "combat readiness", which includes eleven articles, such as preparing the city gate, preparing the altitude, preparing the ladder, preparing the running water, preparing the dash, preparing the cave, etc., focusing on various guarding city techniques and art of war ideas. The fifth is Mo Jing, which is one of the important contents of Mozi, including Jing and Jing Shuo. It covers the contents of logic, philosophy, ethics, economics, mathematics and physics, and can be called a miniature ancient encyclopedia. Classics are divided into two parts, the first part and the second part, which list the definition, classification and simple topics of basic concepts of various sciences. Jing Shuo is also the first and second article, explaining Jing Shuo means "why" and highlighting the conditions for its establishment. There are more than 50 natural scientific discoveries involved by Mo Jing. Here are just a few examples: For example, a circle in the classic is the same as a circle in China. "(Circle, center and radius are all equal) Make the definition of circle clear. Some experts believe that this is by far the most accurate, concise and scientific definition of a circle. Mozi is a famous craftsman, and most of his disciples have been engaged in industrial and agricultural production. They will encounter geometric problems at any time when building palaces, military facilities and crafts, and manufacturing machinery and tools. On the basis of studying and summarizing the predecessors, they studied and summarized themselves and sorted out a set of theoretical system of Mohist geometry, involving knowledge such as end (point), ruler (line), area (surface), thickness (body), circle, rectangle, coincidence, intersection and comparison of tangent and line segment. Another example is "strength and appearance are also exciting." "Force is the fundamental reason to change the motion or static state of an object. This theory of Mohism can be regarded as an early expression of Newton's second law, but it is earlier than Newton's second law 17800, which is a miracle. In addition, there are "lever balance principle" and "inclined plane stress principle", and according to these principles, a large number of industrial, agricultural and military equipment have been manufactured, such as "oranges, pulleys, hanging spleen (military equipment for guarding the city) and ladders (military equipment). In terms of optics, it is even more commendable. There are many optical projects in Mo Jing, involving object shadow generation, pinhole imaging, light reflection, plane mirror, concave mirror, convex mirror imaging and many other aspects. The discovery of "pinhole imaging" is amazing. Mo Jing

Mo Jing is a part of the pre-Qin ancient book Mozi. There are seventy-one articles in Han Yi Wen Zhi and fifteen volumes in Sui Shu Jing Ji Zhi. There are 18 articles in Song Dynasty, including 15 volumes and 53 articles. Among the existing 53 articles, there are four, which are classics, classics, classics and classics. These four articles were called "Mo Bian" by Mo Jing in Jin Dynasty. Later, people added adjacent "Daqu" and "Xiaoqu" and called these six articles "Mohist Debate". The Mohist Scripture in the history of science generally refers to four articles, namely, the upper and lower classics and the upper and lower classics. These four articles are also mainly discussed here.

There are always different opinions about the author of Mozi and the date of its completion. Mo Jing is a part of Mozi, and its arrangement style and content are obviously different from other articles in Mozi, so there are more statements about the age of Mo Jing's works. Some people think that Mo Jing was written by Mozi. Some people think that the classics were written by Mozi, and the classics are about Mozi's oral theory, which is supplemented by later research. More people think that Mo Jing is a post-school work of Mohist school, which was compiled by Mohist school in the process of arguing with other schools in the later period, in order to sum up the debating experience. Based on these statements, if Mo Jing was indeed written by Mo Zi, then its book should be written in the second half of the 5th century BC. If it was written by Mohism, it would not be later than the end of the Warring States period, because Mohism declined after the Warring States period. As a school, Mohism no longer exists. In this way, we can be sure that Mo Jing is a work of China in the pre-Qin period between the second half of the 5th century BC and the middle of the 3rd century BC.

Mo Jing is a wonderful book in the academic history of China, not only because of its layout, but also because of its theoretical content.

Formally, Mo Jing is composed of many articles. Classic and Shuo are two independent articles, but they correspond to each other in content. Shuo Wen Jie Zi explains the classics one by one. Because each classic book is compiled in different chapters with its corresponding classic book, in order to facilitate retrieval and reading, the beginning of the classic book is marked with one to four words at the beginning or key point of the corresponding classic book, which Liang Qichao called "the title of the classic book". The topic has nothing to do with classics. This "title of genealogy" is unique in ancient books. Moreover, when the ancients copied Mo Jing, because some entries were very short, in order to save space, the silk book Mo Jing was divided into two columns, one for each column, first copied from right to left in the upper column to the end, and then returned to the beginning to continue copying from right to left in the lower column. In order to prevent reading confusion, the words "reading the side line of this book" are marked at the end of the classic column (these five words are mistakenly entered into the text in this edition of Mo Jing). After the publication of Mo Jing, there were few annotations. It was not until the Western Jin Dynasty that Lu Sheng made annotations for it for the first time. In the process of annotation, Lu Sheng suspected that the original classic was separated from Shuo Wen Jie Zi, which was inconvenient to read, so he quoted Mohist classics, each with its own rules, and the skeptics lacked it. However, Lu Sheng's adjustment aroused the dissatisfaction of later generations, thinking that it upset the old view that the Mohist Classics was divided into four parts, and should be restored. In the process of recovery, the copywriter didn't know the book examples and didn't follow the "side by side" writing method in the upper and lower columns. Instead, he copied the upper column and then directly copied the next column opposite. In this way, the content of the book was completely disrupted and Lu Sheng's notes were lost. The book of Mohism has become a heavenly book, "it has lasted for thousands of years and cannot be read sentence by sentence." It was not until the Qing Dynasty that Bi Yuan realized the unique writing style of this book from "reading this book", and the content of Mo Jing was gradually understood by people. Later, Liang Qichao pointed out the law of "book title", and Mohist books were slowly understood by people. Since then, pen reporters have sprung up like mushrooms after rain, and the study of Mo Jing has become a craze. However, due to the conciseness and long-term confusion of the words used in Mo Jing, the academic circles have not yet unified the explanations of the specific words used in Mo Jing. However, we have a general understanding of the basic contents of the Mohist Classic.

In terms of content, Lu Sheng once pointed out: "Mozi wrote a book to debate the classics in order to make a name for himself." (Biography of Lu Sheng in the Book of Jin) This means that the Mohist Scripture is mainly a book of argument. This comment is correct. The compilation of "Mo Jing" is mainly to summarize Mohist debate practice, sublimate their debate experience, and provide them with weapons and guidelines for debate. In the existing Mo Jing, logic and epistemology account for the largest proportion, which fully embodies this guiding ideology. If Mohism wants to improve the art of argumentation, it must work hard on terms, concepts and logic, which naturally promotes the progress of science. This is also evident in Mo Jing. In addition, Mo Jing extended the metaphor made in the debate to the definition of natural and social things. In order to win the argument, it is necessary to study the natural phenomena involved, even observation and experiment. In this way, Mo Jing not only contains the research results of Mohism on epistemology and logic, but also contains a lot of natural science knowledge, which is outstanding in the works of pre-Qin philosophers.

Mo Jing is full of scientific spirit, which is the unanimous view of modern scholars. Liang Qichao said in the preface to the collation and interpretation of Mohist Classics: "In our ancient books, Mohist Classics is the only one in the world that should be linked to the so-called scientific spirit!" Qian also said: "Looking at the works, it is the text of definition, ... it is the text of proposition, ... it contains hundreds of definitions and laws of natural phenomena and thoughts in a book, which is unique in the works of pre-Qin philosophers." Among the ancient books seeking world coexistence, only a few works of ancient Greece are enough to make the other side sigh. (Qian's Mohist Essays on Optical Mechanics, source 1943, reprinted in History of Science, China University of Science and Technology Press, 1987 edition).

Mo Jing's scientific knowledge mainly focuses on mathematics, mechanics and optics.

The mathematical knowledge in Mo Jing fully shows Mohism's highly abstract thinking ability. The following are the definitions of some basic mathematical concepts, such as the definition of "zhong", which is said in the classic: "zhong, the same length." Jing Shuo explained: "China is naturally similar." This definition applies to all kinds of geometric shapes and is very accurate. Another example is, "the same length, the same positive phase." This is the definition that two line segments are equal, which is very appropriate. Another example is the definition of a circle, which is defined in the classics: "A circle is the same length as one." A circle has only one center, and the length from the center to any point on the circumference is equal. This definition is impeccable even today. Mo Jing's mathematics mainly focuses on geometry, involving geometric concepts such as point, line, surface, square and circle, and the relationship between geometric bodies. In addition, it also involves other branches of mathematics. For example, the classic mentioned that "one is less than two and greater than five, and it is said to be under construction." This is an emphasis on decimal numerical system, which plays an important role in the history of mathematics.

In mechanics, there are more related projects in Mo Jing, and the contents are more extensive. Mo Jing discussed the definition of force, the classification of motion, the relationship between motion and time and space, material structure, stress and strain, etc. The motion of the ball and its neutral balance, the forces on the axis and inclined plane are briefly discussed. Buoyancy is described in the book, and the relationship between the submerged part of the floating body and buoyancy is roughly correct. The book also discusses the working principles of some simple machines, reflecting the mechanical knowledge developed by the ancients in the process of using simple machines such as levers, pulleys, axles, oranges and pulleys in long-term practice. It is rare for a book to discuss so much pure mechanical knowledge.

What deserves special mention is Mo Jing's knowledge of optics. There are eight * * * in Mohist Scripture related to optics. For these eight articles, money has an incisive exposition. He said: "Although these eight optical characters are a small part of more than 80 classics, they are all arranged in a very scientific order by the author after careful consideration. This is no accident. The first of these eight articles is the definition and generation of narrative. The second article explains the relationship between light and shadow. The third is that light is linear, and an experiment of pinhole camera box is described to illustrate it. Article 4 says that light has the characteristic of reflection. The fifth chapter discusses the relationship between light and light source and the size of gaze. These five articles discuss the relationship between light and objects and shadows. From the definition of the first shadow to the complex relationship among light, object and shadow in the fifth, the optical theory of shadow in physics is complete. From then on, the next step is the relationship between things and images. The sixth article describes the relationship between objects and images in a flat mirror. The seventh article continues to describe the relationship between objects and images in concave spherical mirrors. The eighth chapter describes the relationship between object and image in convex spherical mirror. In this way, the image theory in optics is completed. The shadow theory and image theory are established, which lays the foundation of geometric optics and establishes the beginning and end. Such a clear and complete record, although there are only eight words before and after, is indeed a great optical work in the world more than 2,000 years ago. " (Qian's On the Knowledge of Morphology, Mechanics and Optics in Mojing, Science Bulletin, Vol.2, No.8 195 1)

In addition, Mo Jing also includes some other scientific contents, which reflects the scientific level reached by China in the pre-Qin period, and is a valuable legacy for studying ancient science, especially physics in China.