Before moving on to Ziporyn's treatment of the Qiwulun (2nd) chapter of the Zhuangzi, I'd like to take one last look at how the more difficult philosophical arguments of that chapter are more simply reflected in the myth of Peng.
In an apparently irrelevant aside in his description of Peng's ascent to ninety thousand miles above the earth, Zhuangzi asks: "And the blue on blue of the sky — is that the sky's true color?" (1:4; Ziporyn) As is so frequently the case, he leaves the question unanswered. But then the word translated as "true" [zheng] reappears in his summation of the mind set free of psychological dependence: "But suppose you were to chariot upon what is true both to Heaven and earth, riding atop the six atmospheric breaths, so that your wandering could nowhere be brought to a halt. You would then be depending on — what?" (1:8) Ziporyn makes note of this apparent reference back to the question of the sky's "true" color.
So, what is "true", that we might know to chariot upon it? If we had to know, wouldn't this be to depend on something? The point, then, is that whatever is true of things is irrelevant to our wandering. It is enough that we chariot upon whatever seems to be true, without needing to know what is in fact "true".
Coming back to earth, we can see how this applies to our more mundane social experience. Let's suppose that we feel imposed upon, that our 'rights', our needs, are not properly taken into account. We might be inclined to speculate upon what faults in those who slight us possess; they are selfish, full of resentments (which, of course, is precisely what we are ourselves nourishing in our speculation). Yet, since we find it so incredibly difficult to discover our own motivations, how can we presume to be able to know the "true" motivations of others? Dwelling on what is "true" of others, moreover, disallows our riding atop their behaviors so as to freely wander.
In the end, all that really matters is our own response to what we encounter; we don't need to know what is “true” of it. Only when we allow things to be whatever they are without our knowing what they are will our "wandering nowhere be brought to a halt".
You can check out Scott's writings on Zhuangzi here.