Ever since Joseph Needham in the 1950s made the comment that in many ways the daoxue of Zhu Xi (1130-1200) resembled the process philosophy of Alfred North Whitehead there has been a debate on whether or not this is an accurate assessment of the Master Zhu's massive philosophical synthesis. This paper argues that there are substantive grounds to suggest that both Master Zhu and Whitehead are process philosophers. Based on Whitehead’s observation that some philosophers emphasize the role or function or process as a key element of their philosophical vision and hence can be deemed 'process' philosophers, it is clear that Zhu certainly affirmed a central place for notions of process, change, transformation and creativity within his daoxue or Teaching of the Way. In many ways there is little argument about the general nature of this comment: the problem is, just how central to Zhu's daoxue is the notion of process? Is process more apparent than real? There has been a constant debate for the last eight hundred years as to whether or not Zhu Xi's commitment to process as a central theme or motif of daoxue is as strong as it appears at first glance. Zhu was famous for saying that the nature of the cosmos is, for instance, constant generation or shengsheng buxi 生生不息. Nonetheless, many competent scholars have argued that Zhu's crucial notion of li 理 or principle, rationale, pattern, or order might actually be a static concept: hardly the kind of key theme to build a process philosophy around if indeed it is the case that principle is a static or merely a formal principle of order or pattern. One of the best ways of putting the question was, how can a dead rider (a static li) ride a live horse (qi 氣or vital force)? This is a serious question, and in fact later Korean scholars debated the issue with great subtlety in the great Four-Seven Debate. This paper will defend the notion that li can indeed be interpreted as a living principle or rationale. If this is the case, then Zhu's daoxue can be rightly deemed a process philosophy in the strongest sense of the term as defined by scholars such as Whitehead and Nicholas Rescher. Although Zhu Xi offered a number of different interpretations of li, it is entirely plausible that principle or the rationale for the things and events of the world can be construed as processive, even creative in terms of its role in the complex daoxue architectonic. For instance, the influential Beixi ziyi [or Neo-Confucian Terms Explained as translated by Wing-tsit Chan] of Chen Chun (1159-1223) proves that one of Master Zhu's most philosophically astute disciples understood li to be proccessive. Therefore, based on one important stream of exegesis of Zhu's daoxue, we can agree with and support Joseph Needham's insight that daoxue is a form of process philosophy.