Sociologists love structures but have avoided motivation. In recent decades, some sociologists have realized the importance of motivation, but most theories lack middle-range mechanisms. Self-concept can appropriately solve the problem and theorize actors' motivations. The three components, i.e. self-esteem, self-efficacy, and authenticity, develop out of social interactions, which makes the self-concept a social product and social force while avoiding biological or psychological determinism. Based on a survey of current sociological research on the formation of intellectual ideas, this article discusses the structural bias as a result of the lack of self-concept, the possibility of a synthesis between self-concept and concepts such as fields and habitus, and the potential of a set of explanatory mechanisms.