(1) Labor creates people and promotes the emergence and development of human society.

② ? The history of labor development is the key to understand all social and historical mysteries.

(3) Human history is a history composed of human social practice. To study the laws of human history is to study the laws of movement of human social practice.

2. All social life is essentially practical-understanding social life as practice.

① Material production practice constitutes the economic field of social life.

② The practice of adjusting and reforming social relations constitutes the political field of social life.

③ The practice of creating scientific culture constitutes the spiritual and cultural field of social life.