What is the basic principle of physical exchange between the two parties?

Between the normal subjects of freedom and equality, the exchange follows the principle of reciprocity and synchronization.

Exchange is an indispensable link in the process of social reproduction and a bridge between production and distribution and consumption determined by production. In the process of social reproduction, the nature, depth, breadth and mode of exchange are determined by the nature, development level and structure of production.

For example, production based on private ownership of means of production determines that exchange must also be commodity exchange between private individuals; The development level of production is relatively low, which determines that the exchange mode is relatively simple. However, exchange also has a negative effect on production, which will promote or hinder the development of production.