Social scientists tried to answer the origin and existence of society for years now. There are different ways to look towards it. Social Solidarity is one such view which refers to the reason for the people being together. It is the glue which binds people together. French social scientist Émile Durkheim (1858–1917) introduced the concepts, namely Mechanical and Organic Solidarity to explain the cohesiveness in the society.
Mechanical solidarity talks about the social formation based on a simple division of labor in the smaller groups, un-industrialized or pre-industrialization societies. The division of labor characterizes it, but there is a traceable chain of dependencies and its easier to control. There are shared values, believes and norms which drive society. People are helping each other to complete the social expectations. Varna system in Hindu scriptures talks about the similar division of work.
Organic Solidarity is explained by the division of labor in the industrialized or post-industrialized world. People are divided based on the responsibilities they take and their social roles. It causes people to depend on each other, leading to the formation of society. Metros or cosmopolitan urban spaces are classic examples of organic solidarity.
Division of labor is one of the reasons for social cohesion. It is becoming complicated day by day. We are living in a world of specializations and super-specializations. People will have to depend on each other and will lead to cohesive social structures. It has also helped in getting over the caste system at least in the urban industrial spaces. There are criticisms of this theory, as this is not the only variable in social cohesion.