The author has been thinking about such a question for many years: why should there be a scientific community? Can't you insist on being a scientific self-employed? How did the scientific community come into being? What is the size of a suitable scientific community? In fact, we seem to know some of these problems, but once we ask them in depth, we feel at a loss. In this sense, the topic of the scientific community has not been effectively cleared up, and it is still in a dark state.

Today, most of our understanding of the scientific community comes from two approaches: the sociological approach of science and the philosophical approach of science. The former analyzes the social characteristics and structure of the members of the scientific community. A typical example here is the invisible college written by crane, which has a good analysis. Merton also has a preliminary involvement in his famous work science, technology and society in Britain in the 17th century. The latter approach focuses on emphasizing the essential characteristics and internal provisions of the scientific community. In other words, no one can call himself a scientific community together. There are many classification methods for the community, and the more common is to divide it by industry. The scientific community, as its name implies, is an ideological group that takes science as its industry. Its essential feature and internal regulation require this group of people to share a common paradigm. The representative figure holding this view is the American scientific philosopher Kuhn, which is mainly reflected in the structure of the scientific revolution. Moreover, Kuhn especially emphasized the so-called "paradigm" in the postscript of the reprint in 1969 More equivalent to the scientific community. Due to the ambiguity of the concept of paradigm, our understanding of the scientific community is not very clear, but the basic elements of the paradigm are indeed a good demarcation standard for the division of the scientific community and the non scientific community. Even if it is not clear-cut, it is also very practical. The problem now is that the analysis of the concept of scientific community from both the sociological approach of science and the philosophical approach of science is an analysis in the college away from daily life. In this sense, it is an urgent task to return the scientific community to the life world, because if the public can not accurately understand the connotation and legitimacy of the scientific community, then, The public can vote with their feet in the market and refuse to support and fund the community, so that the scientific community is in danger of being deconstructed in the era of big science. Based on this consideration, the author tries to reinterpret this problem from the perspective of economics and try to solve the following two questions: first, why is there a scientific community? Secondly, where are the boundary constraints of the scientific community? That is, how large is the scale of a community more suitable for the reality of scientific development?

As we all know, the scientific community is not always there, but the product of the development of science to a certain stage. According to the research of scholars, the scientific community in the modern sense appeared in Europe in the 16th century, and initially existed in the form of various scientific colleges and loose associations. It has experienced a long process from informal institutional arrangements to formal institutional arrangements, such as various institutionalized research institutions and societies. So why is there a scientific community? In order to solve this problem, we need to return to the starting point of science. Why is there no scientific community in the embryonic stage of science, but only "scientific self-employed"? At that time, the scale of science was very small and the cost of manufacturing and production was relatively low. This condition determined that individuals could still bear the cost of engaging in science. Even once new discoveries were made and demonstrated, they could obtain some unexpected benefits and grants, so that the science of individual workshop can be maintained. However, when the scale of science gradually increases, it is difficult or impossible for one person to undertake all the human and material resources required for the operation of science alone. At this time, some people with the same interests need to engage in scientific research together, and the existence of this small group has the advantage that they can share the tasks of science together, At the same time, this group also undertakes the identification and evaluation of each other's achievements, and indirectly realizes the confirmation and recognition of scientific research results. Through the spread of this group, science can quickly enter social life, which greatly promotes the development of science. So, is it okay without this group? Obviously not, because science has developed to a certain extent, it involves many and complex problems. No matter in terms of human or material resources, one person can't undertake and be competent independently. At the same time, with the development of society, the demand for science is huge. In other words, there is strong demand and insufficient supply, and science is scarce, Therefore, it is also expensive in the market, and engaging in science can also become a career to make a living. This situation directly contributed to the emergence of the scientific community, so as to alleviate the balance between supply and demand of scientific achievements. Based on the requirements of this era, scientific development itself needs more people to engage in relevant scientific research, which is the external condition for the formation of the community. Within the community, with the emergence and expansion of the community, this group virtually provides a mechanism for mutual competition and cooperation. Due to the complementary characteristics of knowledge among members, the phenomenon of increasing marginal income occurs in a small range, which improves the productivity of scientific achievements and indirectly solves the contradiction of insufficient scientific supply, So as to gradually realize the balance between supply and demand of social science. From a micro perspective, this small circle can not only stimulate and motivate each other, but also complete the larger problems raised by science through cooperation. This process is the result of spontaneous order. With the development of practice, this informal institutional form is gradually fixed by the formal institutional arrangement because it conforms to the economic principle. The number of people in this initial research circle is not very large, but most of them are like-minded people. They provide mutual support and share tasks, and realize the identification and promotion of research results. This has accelerated the development of science. Therefore, the philosopher Whitehead once wrote a Book Science and the modern world (1925). He generally defined the rise of science as from the 16th century, which is the era of the rapid rise of European capitalism. In this sense, its demand for science is huge, It was the 16th century that gave birth to the emergence of the scientific community in the modern sense.

There are many constraints affecting the structure and boundary of the community, such as culture, transportation, communication and spatial geographical location among members, which all affect the scale and structure of the community. Why did the earliest scientific community in human history appear in Western Europe? The reason is that its economic development level is relatively uniform, its cultural background converges, the gradient of scientific development level is not very large, and its geographical location is relatively close. It is these conditions that determine the spatial boundary conditions for the existence of a scientific community. However, there is another problem here. From the perspective of economics, scientific exchanges need costs, This cost is the transaction cost. The emergence and existence of scientific community has greatly reduced the transaction cost of scientific exchange, which directly promotes the development of science. These conditions of the Western European scientific community are reduced to economic factors: they are relatively close, convenient for communication, and can fully save transportation costs; Cultural background convergence can reduce the cost of identification and understanding in communication. These factors were very realistic and important in ancient times. The existence of transaction cost limited the spatial boundary of the community. Even today, the existence of expensive transaction costs is also a very key factor that hinders us from expanding the community. For example, we cannot quickly and effectively form a real community with foreign counterparts. The key obstacle lies in the existence of these large transaction costs. With the advent of the information age, such transaction costs are gradually decreasing. For example, e-mail is a very cheap tool for communication. Even so, the scale of the community is limited, and it will not expand indefinitely, because with the expansion of the scale, the cost of maintaining the community will rise sharply, The existence of a huge scientific and technological community is an extremely uneconomical phenomenon. So what factors determine the boundary constraints of the scale structure of the scientific community?

The author believes that the key constraint affecting the scale structure of the community is that the marginal income of the community must be greater than or equal to the marginal cost. In other words, the existence of a community is in line with the economic principle only when the marginal income is greater than or equal to the marginal cost, which determines the boundary conditions of the community scale structure. What needs to be explained is, what is the marginal income of the community? Suppose that the income function of the community is r = f (x), when the members of the community change from X to X as an independent variable+ Δ When x, the dependent variable changes from R to R+ Δ R， Δ R/ Δ X is the marginal income (MR). In short, it is the incremental income brought to the community by adding a member. Similarly, every time a new member is added to the community, the corresponding cost also increases, which is the marginal cost (MC). Only when the marginal income is greater than or equal to the marginal cost, the scale structure of the community can play the greatest role in promoting scientific development. It is this condition that determines the boundary constraints of the scale structure of the scientific community. Three interesting phenomena can be inferred from this constraint: first, nominal community and actual community. The nominal community does not need individuals to consider marginal benefits and marginal costs. Its scale can be very large. For example, various national societies are communities of this nature (in fact, the nominal community is also restricted by this constraint, but the state pays no attention to individuals). The promotion of science by the nominal community is indirect. The scale of the actual community is strictly restricted by this constraint. For example, how many people does a laboratory need? What kind of people are required to comply with this constraint, so the scale of the actual community is very small, and its role in promoting science is direct. Second, in the information age, the scale of the actual community tends to expand, but this expansion strictly follows this constraint on the path. In the era of small science, the membership size of a community is maintained between 20 and 30 (Kuhn also holds this view). In the era of large science, due to the disappearance of various constraints restricting the scale of the traditional scientific community and the reduction of relevant costs, coupled with the significant increase of social investment in science, the scale of the scientific community has been directly promoted. The most obvious example here is the "space-time compression" effect in the information age, which directly contributes to the reduction of communication and communication costs. For example, in the 1920s and 1930s, Chinese scholars went to the United States to communicate and study with their peers. It took more than a month to take a boat. The cost is amazing and few people can afford it. Now they can take a plane and send e-mail in a very short time. This change is revolutionary. It provides the potential possibility of expanding the community boundary. So, how large should the modern scientific community be? This is a difficult question to speculate in vain. The author takes the liberty to believe that the upper limit of the scientific community is basically limited to the scope of a secondary discipline (tertiary discipline is preferable). Therefore, here we can see the third inference: the condition for the convergence of the community scale, that is, the sunk cost of becoming a member of the community is gradually increasing. In other words, the threshold of entering the core scientific community of a discipline is gradually rising, which restricts the potential expansion trend of the community scale, which also confirms that the boundary of the community is limited. The scientific community is a very stratified society, and the resistance to upward flow gradually increases, restraining the impulse of expansion. Just imagine that it is very difficult for a doctoral graduate to immediately enter a core scientific community. You should know that usually, a doctoral will pay 22 years of time cost and opportunity cost from primary school to doctoral graduation under China's education system. The road to the spire is long and even tortuous. The door of the scientific community is always open to everyone, but there is still a long way to go to really enter.