This chapter focuses on Zhu Xi’s theory of knowing in order to show how Zhu consciously appropriated Buddhist ideas to develop his own thought. Zhu repurposed the Buddhist term zhijue (perceptual awareness) to become a general term for the mind’s various kinds of knowing activity. Zhu’s epistemology was a conscious rejection of radical approach associated with the Song dynasty Chan master Dahui Zonggao (1089–1163). Two parallel lines of argument are presented. First, the main reason that key aspects of Zhu’s thought resemble Buddhist ideas and modes of thought is due to the deep-rooted cultural embeddedness of those Buddhist ideas and modes of thought. Second, despite the fact that Zhu’s epistemic theorizing is replete with terms and phrases that are strongly associated with, and in some cases originate from, Buddhist writing, the similarities in terminology or structure actually mask deep differences.