A Deep Study of Xunzi's 'Jie Pi' Chapter: On the Cognitive Foundations of the Mind—Emptiness, Unity, and Tranquility
This paper provides an in-depth analysis of the core proposition in Xunzi's 'Jie Pi' concerning the nature of cognition: 'How does man know$41 By the mind. How does the mind know$42 By being empty, unified, and tranquil.' It systematically interprets the dialectical relationship and philosophical implications of 'emptiness' (xu), 'unity' (yi), and 'tranquility' (jing) in cognition, tracing their ancient intellectual origins to reveal the systematicity and sophistication of Pre-Qin cognitive theory.
Section 6: The Deeper Significance of the Water Tray Analogy
Master Xunzi offers the famous "Water Tray Analogy" in this section:
"Thus the Human Mind is like water in a shallow tray. If placed correctly and not stirred, the muddy sediment settles below, and the clear brightness remains above; it is then sufficient to see the eyebrows and hair and discern principles. If a slight breeze passes over it, the sediment below stirs, and the clear brightness above becomes chaotic, so that one cannot capture the true form. The Mind is just like this."
The subtlety of this metaphor lies in several points:
First, water itself contains both "sediment/turbidity" (zhan zhuo 湛浊) and "clear brightness" (qing ming 清明)—just as the Mind contains components of the "perilous human mind" and the "subtle Dao mind." Water is neither purely clear nor purely turbid, and the Mind is not purely good or purely evil.
Second, the key is "placed correctly and not stirred" (zheng cuo er wu dong 正错而勿动)—if the conditions are right (still and level), the turbid naturally sinks, and the clear naturally rises. Similarly, if the Mind is in a state of "Emptiness, Singularity, and Stillness," the "perilous" components naturally quiet down, and the "subtle" aspects naturally manifest.
Third, "if a slight breeze passes over it"—even the smallest interference can disturb the clarity. The Mind is extremely sensitive; any minor external object, desire, or emotion can disrupt its tranquility, causing it to lose its capacity for clear judgment. This is why the cultivation of "Emptiness, Singularity, and Stillness" requires such refinement—because the sources of "obscuration" are ubiquitous and constant.
Fourth, "so that one cannot capture the true form"—once disturbed, it loses not only the grasp of detail but even the basic outline. This illustrates what happens when "drawn away by small things, its rectitude is externally compromised; if its inner core leans, it is insufficient to resolve even crude principles."
Historically, the decline of many states occurred because rulers were drawn away by "small things"—indulging in sensual pleasures, trusting sycophants, chasing short-term minor gains while ignoring long-term great plans—ultimately leading to a complete loss of judgment and the state's ruin.