Mozi (about 480- 400 BC) was a thinker, scholar and founder of Mohism in the late Spring and Autumn Period and the early Warring States Period. His real name is Zhai, a native of Lu, and some people say that he is a native of Song.

Mozi was born a commoner and was a coolie. He is proficient in handicrafts and can be compared with Luban, a skilled craftsman at that time. He calls himself "my man" and is called "man in cloth" and "bitch". Wang Chong of the Han Dynasty even said that the ancestors of Confucius and Mozi were common people. Mozi used to be a doctor in the Song Dynasty, boasting that "there is nothing better than a monarch in the world, and there is no difficulty in farming in the world". He is a scholar who sympathizes with the "workers and peasants". Mozi once studied Confucianism, learned the skills of Confucius, praised Yao and Shun Dayu, and learned Confucian classics such as poetry, calligraphy and the Spring and Autumn Period. But later, I grew tired of the complicated rites and music of Confucianism, and finally gave up Confucianism and formed my own Mohist school.

In order to publicize his ideas, Mozi accepted disciples widely, with hundreds of disciples in general, forming a huge Mohist school. Mozi traveled widely, starting from Qi in the east, reaching Zheng and Wei in the west and Chu and Yue in the south. He also argued with the public transport class and successfully stopped Chu's war of aggression against Song.

Mozi is knowledgeable and good at craft and production. He once made a wooden kite. It is said that he flew in the sky for three days and nights without falling. He is also good at guarding the city, and his disciples summed up his experience in guarding the city into 21 articles.

2. The main ideas of Mohism

Mohist's political proposition is mainly Mohist's "love without attacking", which directly determines Mohist's principle of "only defending without attacking" in the military. It is precisely because Mohist did not use its sophisticated machinery made of advanced scientific principles to attack and defend that the rulers did not attach importance to Mohist (and could not attach importance to it), which directly led to Mohist's subsequent decline.

Civilian thought and the background of the times

The clan land ownership finally replaced the clan hereditary, and the clan and land ownership could not be bought and sold. Agriculture and handicrafts are relatively developed, and the use of iron is also very common; Large-scale industry and commerce flourished, and Confucius' disciple Zi Gong was both an official and a businessman, and he was rich in the world. In addition, there are many "people in agriculture and industry", that is, small producers, who are oppressed and have a hard life. In this context, Mozi's opposition to the "weekly system" and propaganda of "promoting benefits and eliminating pests" are all important and reflect the thoughts of ordinary people. A period is an era of historical upheaval at the turn of the Spring and Autumn Period and the Warring States Period. The political system of the Zhou Dynasty completely collapsed: politically, Jin was divided by Han, Zhao and Wei, Tian replaced Qi, and the administrative and bureaucratic systems of various countries (the "state" here is different from modern countries) replaced the power system, thus creating a "scholar" class; Economically, the feudal Lord economy has become a feudal landlord economy, and the family land ownership that individuals can buy and sell has finally replaced the hereditary clan and land ownership era. Agriculture and handicrafts are relatively developed, and the use of iron is also very common; Large-scale industry and commerce flourished, and Confucius' disciple Zi Gong was both an official and a businessman, and he was rich in the world. In addition, there are many "people in agriculture and industry", that is, small producers, who are oppressed and have a hard life. In this context, Mozi's opposition to the weekly system and propaganda of "promoting benefits and eliminating pests" are all important and reflect the thoughts of ordinary people.

Second, the achievements of Mohist scientific research

1. optics

Pinhole imaging-the first scientific explanation of light straight line propagation

"Classic": The scene has arrived, and there is an end and a long scene in the afternoon, which is said to be at the end.

Classics say Xia: Classics: If the light shines, the low enters the high, and the high enters the low.

The foot blocks the light, so it becomes a scene. There is light in the distance, so it is also in the scene library.

Ancient people realized from a large number of observation facts that light travels in a straight line. During the Warring States Period about 24,500 years ago, Mo Zhai and his disciples proved the essence of light through experiments, and made a scientific explanation for the straight-line propagation of light for the first time in China and the world.

The experiment is: open a small hole in the Chaoyang wall of a dark hut, and people stand outside the house facing the hole. Under the sunlight, an inverted figure appeared on the wall opposite the room. In this regard, Mo Jing explained: "The light shines on people. The people below are also tall, and the people above are also tall. " It means that light travels in a straight line through a small hole, just like archery. People's heads block light from above, forming the shadow below, and people's feet block light from below, forming the shadow of handstand. This passage scientifically explains the linear propagation principle of light and expounds the pinhole imaging phenomenon. This experiment made by Mohism is the first experiment in China and the world in which small holes become inverted images. The Greek Pareto School, which was almost contemporary with Mo Zhai, acknowledged the straight-line propagation and reflection of light, but their optical theory was later than Mohist Classics, and its level did not exceed Mohist Classics.

The relationship between objects and shadows

Mohism first used the principle of straight-line propagation of light to explain the relationship between objects and shadows. The Mohist classic said: "The scene (shadow) does not move, but it is changed to" light comes, and the scene dies; If so, then do your best. " It means that at a certain moment, the shadow of a moving object is static, and the shadow of a moving object looks moving, which is the result of the old shadow disappearing and the new shadow constantly producing. For example: a flying bird, its shadow seems to be flying, but it is not. Mohism pointed out that birds blocked the direct light and formed shadows. After a while, the bird moved its position. Now, where the light can't shine, the old shadow disappears, and in a new place, a new shadow appears. That is to say, when a bird is flying, its shadow does not move with it, but the old and new projections are constantly updated.

After studying the phenomenon that two light sources irradiate an object at the same time and form a shadow, Mohism pointed out that an object has two kinds of projections because it is irradiated by two light sources; If only one light source illuminates an object, only one projection will be produced. These discussions are very consistent with the description of "umbra" and "penumbra" in modern optics.

More than 2000 years ago, it was not easy to study the nature of light and explain the relationship between moving shadow and immobile shadow.

C. mirror image theory

Bronze mirrors appeared in China more than 3000 years ago. By the Warring States period, rich experience had been accumulated in the manufacture and use of bronze mirrors. Mozi and his disciples deeply studied the principle of mirror imaging, and put forward the imaging theory of plane mirror, concave mirror and convex mirror.

When analyzing mirror images, Mohism regards an object as composed of countless objects, and the resulting image is composed of countless "embarrassing" (sound: Qiu). The original meaning of the word "embarrassed" is fried rice noodles. Here, we take its tiny meaning to describe the image points of objects.

Mohism knows that light will be focused in front of a lens or concave mirror. The Mohist classic said: "There is light in the distance, so it is also within the scene." The scene is a shadow, which refers to the image of the object; Being inside is satisfaction, that is, gathering at one point. Focus is often called "positive" or "internal" in Mohist books, so we know that Mohist has studied the principle of focusing.

Mozi also knows the principle that convex mirrors produce virtual images. "The Book of Mohism" records: "Scenery stinks countless times, and it must be too positive, so it is naturally the same." The shadow of an object is determined by the distance between the object and the mirror. It can be formed anywhere, so there are countless shadows, but these shadows must pass through the focus, that is, through the "positive". Of all the objects we know that can be imaged, the sun is the farthest, so it images at the focal point. The closer the object is to the mirror, the farther the imaging position is; If the object is as far away as the sun and the image is in focus, then, "in the same place, its shape is natural."

Mohism has long known that concave mirror became a real image. The Mohist book says, "Stand in front of the mirror and watch the scenery." It means that the object is reflected by concave mirror, the image is inverted, and "to" means inverted. The book explains this phenomenon: "The feet are open to light, so the scenery is on them;" The first time it shines, it becomes a landscape. "

It can be seen from the records in Mo Jing that Mohism is quite familiar with the essence of light and the imaging phenomenon of concave-convex mirror. It is not difficult to speculate that concave mirror and convex mirror have appeared in the Mohist era in China. Moreover, Mozi and his disciples must have done a lot of experiments and carefully observed and thought about these experiments before reaching these conclusions.

Among China's voluminous works on classics and history, Mo Jing is the only one that systematically discusses the development of geometric optics in ancient China.

2. Mechanics

Definition of force

Shang Jing said, "Power is the reason why shapes are exciting."

"Jing Shuo Shang" explains: "Force: the important thing is also called it. Weightlifting is also very exciting. "

On matter and force

What is a shape? Mozi believes that everything in the world begins with existence, and existence is action. The extension of this concept ranges from heaven and earth to particles, and all tangible things are things. It can be seen that "shape" is an objective substance, which always captures everything.

What is excitement? It means "moving" and "vibrating". It is believed that the essential attribute of things in the morning is universality, and there are three kinds of universality, one is separability, the other is initiative, and the third is formation. According to the classics, the separation and distribution of matter become various objects. From this point of view, there is no matter in the universe that does not move.

Why do objects move? Mozi believes that the movement of matter is caused by force, which is the cause and movement is the result. "Force, shape is also exciting", that is to say, it is force that keeps matter moving. If we give this category a new meaning, it is equivalent to "energy" and form is equivalent to "quality".

The definition of force in Mohist classics is derived from the concept of human physical strength. The book defines that "force is the exciting reason for punishment." The "punishment" here is "shape", which refers to the human body. The original meaning of "Fen" is that birds fly out of the field with open wings. The meaning of this sentence is that force is the reason that causes people's movement to shift and change.

mechanical movement

Mechanics is an important branch of modern physics and a science to study mechanical motion. Mo Jing recorded a wealth of mechanical knowledge. The Mohist classics put forward the correct definition of mechanical movement: "movement, domain shift" It means that the essence of mechanical motion is the movement of object position. This fully conforms to the definition of modern mechanical movement. Several different forms of mechanical movements, such as translation, rotation and rolling, are further elaborated in Mojing. The definition of these sports forms in Mojing is very scientific. For example, translation is defined as "all stops and moves" in the book, which means that all parts of an object are still when they want to be still, and move when they want to be moved.

Buoyancy principle

"Mojing" wrote: "The punishment (shape) is large, but shallow, which is called balance." In other words, a large object sinks shallowly in the water because the weight of the object is balanced by the buoyancy of the water. These understandings show that Mohism not only qualitatively recognizes the balance relationship between buoyancy and gravity, but also has a quantitative concept. From one side, we can see that our people have recognized the principle of buoyancy as early as the Spring and Autumn Period and the Warring States Period, and began to apply it in production.

Lever balance principle

Lever balance is discussed in Mo Jing. In Mohist books, the instrument is called "the instrument" and the hanging instrument is called "the instrument". One side of the fulcrum is called "Mark" (arm of force) and the other side is called "Ben" (heavy arm). If both sides are balanced, the lever must be horizontal. In a balanced state, if one side has weight, it will definitely make this side sag. At this time, in order to restore the balance between the two sides, it is necessary to move the fulcrum, shorten the "base" and lengthen the "target". However, in the case of short "Ben" and long "Biao", if equal weight is added to both sides, the end of "Biao" will definitely sag.

Mo Jing not only clearly described the results of various lever experiments, but also gave correct explanations to these experiments. For example, it explains the experimental phenomenon of "standard" drooping at one end, and thinks that the joint action of arm and weight is greater than that of heavy arm and weight. This explanation not only considers the magnitude of force or weight, but also considers the relationship between distance and balance. Although there is no clear quantitative relationship, the concept of "moment" in mechanics is actually put forward. So it can be said that Mohism discovered the principle of lever balance.

3. Geometry

In mathematics, Mo Jing put forward some definitions of geometry, which indicated that the seeds of theoretical geometry had appeared in China during the Warring States Period. For example:

"Ping, the same height." Say the definition of flat, pointing out that the same height is flat.

"Straight, and also. The reference here is three. The three-point line is straight, which is the definition of a straight line.

"Same length, positive phase" means that when two objects are compared, their lengths are exactly the same.

"China, the same length." What is said is the definition of the load-bearing center of the car body.

"Round, one is the same length." This is Mo Jing's definition of a circle. This is completely in line with the definition of a circle in modern mathematics, "a locus with a point equidistant from the center."

In addition, Mo Jing put forward the concepts of "end", "ruler", "area" and "hole", which are roughly equivalent to points, lines, surfaces and bodies in modern geometry. The book wrote: "The end is not thick and the former is also." "The end is seamless." The original meaning of the word "Duan" is a newly unearthed bud tip of a plant, from which the whole plant grows. It is used here to describe a geometric "point" without thickness, gap and interruption. Although this idea is not completely accurate at present, it is very remarkable in civilized times.

Mojing contains some mathematical thoughts of Mohist school, mainly some formal logic principles and ideas of defining mathematical concepts. Mohism pays attention to "correcting the name" and attaches importance to concepts, and gives a clear definition of some mathematical concepts, as shown in the right table:

Mohist school's basic mathematical concept definition and logical thought once shone brilliantly in the pre-Qin period. However, due to the limitation of historical conditions, these thoughts were not really combined with China's ancient mathematics. It was not until the Qing Dynasty that they were re-studied. Nevertheless, the emergence of mathematical ideas in the Mohist Classic shows that China had made a more detailed study of geometry 2,500 years ago, which was 1000 years earlier than Euclid's Elements of Geometry.

4. Cosmology and space-time theory

The cause of everything in the universe

The classic says, "So, what you get is what you get."

"Jing Shuo Shang" explained: "Therefore, it is inevitable that there is a small reason, and it is inevitable that there is no. Body also, if there is an end. If there is a big reason, it is inevitable, if not, it is not. If you see prejudice. "

In the classics, "reason" has a kind of power, which is enough to make another phenomenon appear. It can be seen that "reason" is the cause of a thing, so it is the cause of objective things. Explain why leads to the result, and the result explains why. Therefore, the category of "reason" embodies the inevitable connection between things and reasons.

In Jing Shuo Shang, it is pointed out that there must be one thing or several things as its premise for the emergence of one thing in the world. "Xiao Li" is a necessary condition for the formation of things and a part of "Dali". Great reason is a necessary and sufficient condition for the formation of things.

(2) About the universe as a whole

The classic says: "The body is divided into two parts."

"Jing Shuo Shang" explains: "Body: If it is half, the end of the ruler is also."

The word "concurrently" in the classics means whole, whole and whole. Aspect means individual, individual and part. Therefore, "the separation of the individual from the whole" shows that the universe is a unified whole, and everything is a part of it and separated from the whole.

The "ruler" in Jing Shuo Shang refers to the line, and the end is the guidance. Examples show that everything in the world shows the existence of the relationship between "concurrently" and "body".

"Classic" said: "If it is long, it will be different."

Lun Jing explains: "Dragon: combining ancient, present, Dan and dusk."

Shang Jing said, "Yu is different."

Jing Shuo Shang explains: "Yu: Mengdong, West, South and North."

The word "long" in the classics is eternal and long-lasting. "Rice" is a combination, it is everywhere, it is omnipresent. "Yu" is a moral. "suo" is the place and place.

The word universe means time and space. But Mohism has a special philosophical term-nine realms.

Mozi expounded his view of time and space with the theory of contradictory unity, made a dialectical view of whether the universe is finite or infinite, and clarified that the movement of objects must exist in time and space. Mozi believes that the universe is made up of matter, which is the broadest concept, including all the matter in the universe, and its connotation refers to what actually exists. Some places in the universe are full of matter, while others are not. The universe is the unity of existence and non-existence. Time and space are the fundamental characteristics and forms of all matter. Mozi studied time and space through the movement of (things), and gave an accurate definition, thus clarifying that the universal image of Mozi, who is "poor" in time and space, is that space, time, matter and movement are infinite, and the infinite universe is full of infinite matter, which keeps moving.

3. Postscript-the decline of Mohism

Mohism existed for a short time in history (when Mozi was alive)

The disappearance of Mohism is not that Mohism helped Qin unify the world. Mohism was divided during the Warring States Period. In addition to Xiangguang, Xiangfu and Dunling, there are Song Yan, Yin Wen, a famous scholar based on Mohist logic, and Xu Xing's Nongjiale. At the end of the Warring States period, the Mohist center was transferred to Qin, but it did not advocate that Qin destroyed the six countries. The same is true of the art of guarding the city recorded in the< Mozi >> book. Mozi was afraid that Sun Tzu's art of war would be used by invaders, so Mozi only wrote the art of defense, not the art of attack. Mohism dissipated because & gt as the saying goes, "Confucianism flouts the law, and chivalrous men violate the ban by force." Qin used Mohist theory to make the country simple, save resources for the military, and use Mohist disciples to defend the city. After reunification, most of the rangers at that time came from Mohism, which was a military group guarding the city for the invaded country, and the rulers could not tolerate Mohism at all. Therefore, after the unification of Qin Dynasty, Mohist school was forced to decline rapidly because of Mohist anti-war thought, and the unification of Qin Dynasty was fundamental. & lt Han Feizi >> Qiang Bing, a rich country of China Thought, Han Fei was framed by Li Si and wrote << Han Feizi >> In the end, Li Si forced Han Fei to commit suicide by taking poison. Qin Huang finally regretted it, but he accelerated the annexation war with the hegemonic thought of Han Dynasty, and implemented the policy of ignorance after reunification. At the beginning of the Han Dynasty, the rulers of the Han Dynasty did not make Mohism flourish. & lt> There are no biographies of Mohist disciples, friends Lu Ban who were influenced by Mohist school because of "stopping Chu from attacking Song Dynasty", farmers Song Yan and Yin Wen who studied Mohist school, hermit Chen Zhong who was influenced by Mohist school but opposed to aristocratic exploitation. Only Yan should be passed on, and Mozi is just "Doctor Song, or at the same time as Confucius."

In fact, Mohism has not completely dissipated, but has lost its position as an official theory. But hidden among the people, there are three branches of Mohism. One is the traditional Mohist scholars, who jointly criticized the dark rule in the mid-Western Han Dynasty at a debate meeting. Among them, Confucianism is the majority. One is the ranger, mostly from Mohism, because the ruler forced Mohism to separate into a free form in organizational form, that is, the ranger made a biography of the ranger in Sima Qian, which essentially hinted at the whereabouts of Moxia, and the other was a disciple of Mohism who later merged with the ecliptic. Liu An, the king of Huainan, once recruited wise men, many of whom came from Mohism.> According to some records, Liu An later wrote & gt based on yellow thoughts and combined them with various thoughts, and>, but> today, there are only fragments, but many of them are related to the science and technology recorded in>'s book. The rebellion of King Huainan failed, and many disciples were implicated and killed. But since then, one of the Mohist disciples has merged with Huang, Fang and folk Confucianism, forming the Yellow turban insurrectionary peace road. Classic & gt It continues to regard heaven as the supreme master, and many ideas stem from & gt The slogan of the Yellow Scarf Uprising is "Heaven will die, and Yellow Heaven will stand". Its essence is to challenge the official Confucian thought of "life and death are life, wealth is in heaven" with the ambition of Mohism. When Mr. Ge Hong was in Kim. Baopuzi >> Only

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Mohist science and technology and the profundity of its thoughts cannot but marvel at its greatness now. In such a distant era, such extraordinary thoughts and achievements suddenly interrupted its science and technology and thoughts, which made me feel extremely sorry and confused. It is necessary for us to learn from the thoughts of the ancients, not to get the answer to the problem, but to get the solution to the problem.

Reference: Mo Jing.

Physics in Mohist Classics

Shang Jing, On and On.

Mo Yan's taboo

Mohism and Science and Technology Education

history

Life of Mozi [He Xun Blog]