Abstract: Fang Yizhi inherited and further developed the “Entrusting the Orphan” (tuogu) theory, employing Zhuangzi as a mediating framework to reconcile the theories of human nature advanced by Mencius and Xunzi. He affirmed the remedial value of Xunzi’s thought as a corrective to Mencius, construing “good” and “evil” in terms of the “substance-function” (ti-yong) relationship, and, through the paradigm of “the principal and the residual” (zheng-yu), argued for the ontological reality of “evil” and its necessity for the actualization of “good”. Drawing on the logic of his own school of Yijing studies, he further proposed that “the supreme good governs both good and evil”, thereby integrating the innate and the acquired dimensions of human nature so as to achieve a synthesis between the doctrines of the goodness and the evilness of human nature. His underlying aim was to rectify, through an attitude of non-attachment, the cognitive defects arising from treating substance and function as bifurcated. Fang Yizhi’s reconciliation of Mencian and Xunzian theories of human nature reflects his broader effort to remedy dualistic modes of thinking against the backdrop of the convergence of the Three Teachings—Confucianism, Buddhism, and Daoism—during the late Ming and early Qing transition.