This article aims to critique the recent claim raised in Korea that Toegye's theory on lifa 理發 “negates the activity of li.” In my view, although the idea of lifa is not clearly presented by Zhu Xi and even contradicts his conception of “non-action of li,” it recovers fundamental Confucian principle and reaffirms valuable attributes of humanity. Toegye's notion of lifa establishes the ground for distinguishing humans from animals by emphasizing the subjective spontaneity and activity of moral rationality. To expound (...) on this, I shall first review the concepts of li, qi, heart/mind, nature, feeling, and their relationships in Toegye's philosophy. Then, I shall examine the significance of lifa and criticize that the claims which deny the activity of li are ungrounded. (shrink)