King Hui's cook explains how it is that he can turn the prosaic and somewhat gruesome activity of butchering an ox into a joyful dance. He used to study oxen, he tells us, so that all that he saw was an ox. But now, he "encounter(s) it with the spirit". This is made possible when, "[His] understanding consciousness, beholden to its specific purposes, comes to a halt, and thus the promptings of the spirit begin to flow." (Zhuangzi, 3:4; Ziporyn)
One would think that studying an ox so as to know how best to cut it up would be the most effective way to go about doing so. But though such a procedure might be a necessary place to begin, it does not lead to an activity that "advances beyond mere skill". This requires something altogether different; and this entails a certain receptiveness where previously there was only assertiveness. The "understanding consciousness" imposes itself on things; it artificially divides them according to its own "purposes". Encountering them with the spirit, on the other hand, allows things to present themselves as they actually are, rather than how we imagine them.
"I go by Heaven's unwrought perforations. . . . I go by how they already are . . ." The secret to his success in allowing butchery to become a spiritual experience lies in following along with, adapting to, encountered reality, rather than trying to impose himself upon it. An "ordinary cook . . . hacks"; he attacks the job and gets it done, but misses the joy.
"Heaven's unwrought perforations" is tianli. This, according to Ziporyn, is the only use of li in the Inner Chapters and the first known use of the binome tianli in Chinese literature. Here, it is used to speak of the natural divisions within the body of the ox. In the rest of the Zhuangzi li begins to be used to speak of "principles" which one might discover in nature. Still later, tianli became a technical term in Neo-Confucianism where it describes "Heavenly Principles" which, once known, can be followed and applied to life. Thus, we see what was originally an openness to the concrete and unique become a tool of the "understanding consciousness" by which to once again impose itself on life and reality. This pattern repeats itself endlessly; an original insight which runs counter to the 'normal' human inclinations, is subsequently re-integrated into those inclinations. Is this not the essence of religion?
In allowing a spiritual receptiveness to guide his work, the cook effectively gets out of the way so as to allow things to happen. This is seen by analogy in the effectiveness of a knife whose edge "has no thickness": "When that which is thickless enters into an empty space, it is vast and open, with more than enough room for the play of the blade." The narrowest space is "vast and open" when that which enters it is thickless. And this, of course, speaks to Zhuangzi's summary of sagacity in the closing remarks of the Inner Chapters: "It is just being empty, nothing more." (7:13) Here, to be empty is to be thickless.
You can check out Scott's writings on Zhuangzi here.