Between Ought and Ought-Not Reconfiguring the Cheng-Zhu and Dai Zhen Debate on Li and Yu

The li-yu debate in Chinese philosophy has long been framed as an opposition between principle (li理) and desire (yu欲). However, I argue that the debate is essentially a struggle over the domain of the ought and the ought-not—a question of how people ought to live. This article constructs a boundary model to analyze the differences between Cheng-Zhu程朱 and Dai Zhen戴震 in terms of the ought and traces this model back to the Pre-Qin period to show the dynamic development of the debate. For Cheng-Zhu, the boundary lies in conformity to principle, and only basic survival desires are included within the domain of the ought. For Dai Zhen, the boundary lies harm to others—only harmful desires are with in the domain of the ought-not. This classification reveals a long-neglected intermediate zone of desire, which is neither basic nor harmful. I term this intermediate desire, which, I argue, stands at the center of Dai Zhen’s philosophical concern. The article contributes by approaching the li-yu debate from an ought-based perspective, which helps clarify conceptual confusion caused by different definitions of principle and desire, and by revealing the important domain of intermediate desire, thereby offering some insight into contemporary moral life. Meanwhile, the boundary model can also be applied to other philosophical issues concerning normative domains.