I will close this series with a consideration of how the Warring States development of the Yin-Yang system (later developments went in different directions) answered the challenge of Zhuangzi's perspectival relativism. (At my reading, Ziporyn does not demonstrate that the authors of the "Wings" (commentaries on the Zhouyi (Book of Changes)) actually felt the need to meet Zhuangzi's challenge specifically, though they do seem to be answering the proto-Daoist dismissal of the possibility of "true knowledge" generally.)
Zhuangzi's basic argument might be summed up thusly (without the complications of moral or epistemological considerations): Everyone has their self-other dyad; your self is my other; my self is your other. Is there then any true self or other? Zhuangzi replies that there is for each individual, but that they are equal in their validity. Their equality consists in their being completely reversible — your self-other is the same as my self-other. Thus, Zhuangzi states that every self is also other, and every other is also self. And thus every self-created dao is similarly equal.
Yin and Yang, however, are not reversible. They are never equal. One thing may sometimes be in a Yin or a Yang position in relation to other things, but the hierarchical prioritization of Yang remains throughout. A minister, for instance, is Yang to the people, but Yin to the king. Thus, though he is both Yin and Yang, Yin and Yang can never be said to be the same since they always retain their hierarchical character. In this way, the Yin-Yang dyad is able to admit to the relative character of the roles of individual things, but at the same time guarantee knowledge of the precise 'right' way to behave in each situation. It is an intelligible system; it tells us how to live definitively.
Zhuangzi, on the other hand, sees no definitive Dao yielding knowledge of how best to live, any non-ironic 'true' Dao, and thus recommends alighting like a bird in whatever tree one encounters. Being "free as a bird", we need not cling to any one tree, but can make profitable use of them all.
Zhuangzi's way is thus just one more way — all ways being (in some sense) equal; it is distinctive only in that it acknowledges this fact. This fact arises from "the Illumination of the Obvious", that is, by way of an honest look at our tenuous existential circumstances. In this sense, it might be described as a "philosophy of cope"; it makes the best of things as they appear, and does not artificially fabricate an interpretation of reality based on how one wishes things to be.
This, in any case, is how I describe my own philosophy: a philosophy of cope — making the best of circumstances, both general and personal, that are, let’s face it, less than ideal, and far from how I might wish them to be.
You can check out Scott's writings on Zhuangzi here.