[p. 223] As social practice continues, things that give rise to man’s sense perceptions and impressions in the course of his practice are repeated many times; then a sudden change[3-302]
takes place in the brain in the process of cognition, and concepts are formed. Concepts are no longer the phenomena, the separate aspects and the external relations of things; they grasp the essence, the totality and the internal relations of things. Between concepts and sense perceptions there is not only a quantitative but also a qualitative difference. Proceeding further, by means of judgement and inference one is able to draw theoretical conclusions.[3-303] The expression in