In Marx's Economic Manuscripts from 1857 to 1858, he applies the method of "ascending from the abstract to the concrete" to the study of "value," the basic category of political economy.First, he criticized the Proudhonist understanding of the metaphysics of value, and then transitioned to his own theory of value.Value is a scientific abstraction of use-value, and at the same time an abstract category containing a unity of contradictions.
Chen et al. (Sun,) studied this question.