 Zhu from childhood displayed a genuine interest in natural phenomena and in raising speculative questions. Later he tended to rein in this interest, for example by relating features of observed natural phenomena to human analogues for didactic purposes and by refraining from pressing his speculations very far, i.e., beyond the scope of verifiable knowledge and applicability. Zhu lived during a tumultuous period in Chinese history when Neo-Confucian scholars tended to draw upon the resources of their own tradition to revitalize the empire, an effort in which Zhu’s ouvre constituted a watershed. He sought to wed the objective and subjective trends of the earlier movement into a practical synthesis in which objective inquiry played a key role in subjective cultivation. Subsequently, however, as his disciples refined his thought into a scholastic doctrine, subjective cultivation began to prevail over objective inquiry, which was increasingly redirected into the narrow limits of reading and interpersonal conduct.