All the mysterious things that lead the theory to mysticism can be reasonably solved in human practice and understanding of this practice. Later, people extracted the proposition that "social life is practical in essence" from this passage of Marx, and combined with other thoughts of Marxist classic writers, established this proposition as an important principle of historical materialism. 1) Some understandings of the proposition that "social life is essentially practical" At present, academic circles have different understandings of the proposition that "social life is essentially practical". Generally speaking, there are three main viewpoints. The first view holds that the proposition that "social life is essentially practical" is equivalent to the proposition that "the essence of society (life) is practice". This is the view advocated by most scholars. We believe that strictly speaking, the proposition that "the essence of society (life) is practice" cannot be deduced from Marx's proposition that "social life is practice in essence". First of all, Marx's above proposition only illustrates the materialistic nature of social life, not the essential problem of social life. From the context of Marx's use of the word "practice", we can see that this word is relative to "theory". What Marx means is that social life should be practice rather than theory in the final analysis. Secondly, the essence is relative to the phenomenon. When we talk about the nature of society, it will inevitably involve social phenomena. If Marx's proposition that "social life is essentially practice" is equated with the proposition that "the essence of society (life) is practice", it will be concluded that Marx only regards "theory" as a social phenomenon. So, is "theory" equal to social phenomenon? Inequality. In Marx's view, not only "theory" belongs to social phenomenon, but also social wealth, because the essence of "social wealth" is "general labor" or practice. It can be seen that Marx's proposition that "social life is practical in essence" cannot be simply equated with the proposition that "the essence of society (life) is practice". Thirdly, according to grammatical analysis, Marx's proposition that "social life is practical in essence" is completely expressed as "social life is practical in essence". From this proposition, we can only analyze that practice is one of the important attributes or essential attributes of social life, but we can't explain that the essence of social life is practice. For example, we can also say that "social life is developing in essence". Is development also the essence of social life? Obviously, you can't say that. The second view holds that it is fundamentally wrong to understand Marx's proposition that "social life is practical in essence" from the perspective that practice is the essence of social life. Some scholars advocate this view. The core argument of this view is that the so-called "social life is practice in essence" only shows that practice is an important feature of social life, not that practice is the foundation and essence of social life. In fact, the mode of production of material materials is the basis and essence of human history, and the mode of production of material materials is a kind of "social material", which is different from practice. The mode of production that reduces human society to material data has come to an end. If we ask further, we will slip into idealism. We don't agree with this view. We believe that if we don't understand the mode of production of material materials from a practical point of view, the mode of production of material materials will be unclear. The third view holds that although the proposition that "social life is practice in essence" and the proposition that "society (life) is practice in essence" cannot be regarded as the same thing, when we talk about the former proposition, we usually refer to the second proposition. This is the view of some scholars in our country, and we agree with this view. It goes without saying that looking at the problem in this way naturally extends the original meaning of Marx's proposition that "social life is practice in essence", however, it makes this proposition have a deeper connotation. Specifically, although the original meaning of this proposition expresses the materialistic essence of social life, it is based on practice relative to theory, that is, it is not based on the perspective of practice and social life phenomena, which limits the amount of information that the category of practice should contain, thus failing to fully show the position of practice in social life. After extending this proposition to "the essence of society (life) is practice", it not only explains the materialistic essence of social life, but also regards practice and social life as a pair of contradictory categories, which greatly broadens our horizons, changes our way of thinking to a certain extent, and further deepens our grasp of the position of practice in historical materialism. 2) Practice is the essence of social life. Before explaining why practice is the essence of social life, we should first distinguish three categories: practice, labor and production. This is the premise, otherwise you will encounter difficulties in future discussions. We believe that Marx and Engels basically regard practice, labor and production as the same sequence and synonymous category. Marx pointed out: "Human practical activities are labor", which means that practical activities are labor. Since practice is practice, practice is labor. Marx also pointed out: "Products are only the sum of activities and production. Therefore, if the products of labor are externalized, then production itself must be dynamic externalization, or the externalization and externalization of activities. " It can be seen that labor and production are also synonyms. Of course, there are some differences between these three categories.