This paper investigates Mencius’s notion of sympathy from the perspective of evolutionary biology. First, I point out that Mencius and evolutionary biologists concur that humans are endowed with a unique ability to sympathize with others beyond kin and friends. Subsequently, I offer an analytic account from an evolutionary perspective on how this ability emerged and developed as an innate human quality—especially referencing recent theories that state that cooperation is a crucial factor that helped foster such a quality. Further, this paper (...) addresses in-group/out-group distinction in terms of the scope of sympathy. In particular, I respond to Donald Munro’s thesis that this distinction serves as a critical boundary for the workings of sympathy. Finally, I show that Mencius’s (and other Confucian thinkers’) thoughts on sympathy are not only compatible with modern evolutionary discourses but also contribute to the psychological mechanisms that may have enabled humans to regard others with sympathetic concern. Thus, this essay sheds light on the mechanisms of sympathy that Mencius and other Confucian thinkers illustrated as identifying oneself or one’s kin with others. I then surmise that such mechanisms most likely emerged as a fundamental psychological principle for humans initially reaching out to others. (shrink)