I have written previously about Guo Xiang's (252-312) discussion of "traces" in his philosophy as derived from the Zhuangzi. "Traces" is usually translated "footprints", and this is generally the intended reference. We are told not to follow the footprints of others, but to make our own paths. Guo takes this metaphorical usage and applies it to absolutely everything we think we know about reality. Everything we 'know' is mere cognitive representation, a formulation in words entirely divorced from things-in-themselves. Nothing 'understood' escapes this simple fact. We truly 'know' nothing. This includes ourselves.
We are told to know ourselves, and this is essential to establishing the objective transcendence necessary to transformation. Understanding what motivates us, we are able to consider other alternatives. But though necessary, this might be compared with knowing the mechanics of how a tree lives and grows; we would not want to confuse this with the wonderful mystery of the living tree. All things, including ourselves, are essentially mystery. We do not and cannot truly know them. Everything we believe ourselves to know is a trace, a cognitive representation.
For some, the mention of mystery might seem a step toward the hocus-pocus of a new age, self-indulgent and self-imposed ambiguity. But if this is metaphysics, it is the metaphysics of the obvious. It adds nothing. Explains nothing. It is simple honesty about the facts of the case.
Guo's response to this reality was to advocate "vanishing into things". If reality cannot be known, it can still be experienced, and the way to experience mystery is mystically. By "vanishing into things" Guo meant, I believe, a psychological release into the unity of all things consequent to the release of one's sense of fixed-identity. We do not release into Oneness because there is Oneness; there is Oneness because we make it so. Let go fixity, and all things are unfixed. Let go the sense of a separate self, and all things are One. But like Zhuangzi's Oneness, it is a simple experiential consequence of a way of being in the world, not a declaration of the nature of Reality.
In an ancient post entitled "Traces" I suggested that Guo might have also profitably said "vanish into yourself". Zhuangzi suggests both 'directions', 'internal' and 'eternal', as a means to vanishing, but I believe he also saw internal vanishing as facilitating external vanishing. We are able to "follow along with things" (and this refers to ‘events’ as well as ‘things’) because we have released into the mystery of ourselves. We have released into the "empty room", the nameless foundationlessness at the core of our apparent existence, where "'myself' has not yet begun to exist". (Zhuangzi, 4:10; Ziporyn) We let life live us instead of trying to live life.
I believe it was Fung Yu-lan who summarized Zhuangzi’s philosophy as a path to “pure experience”. By this is meant unmediated experience, beyond the cognitive traces.
You can check out Scott's writings on Zhuangzi here.