The original Chinese (I need confimation from a native speaker!):
曰：是不是，然不然。是若果是也，則是之異乎不是也亦無辯；然若果然也，則然之異乎不然也亦無辯。忘年忘義，振於無竟，故寓諸無竟。The translation by Lin Yutang (I have italicized my favorite line):
The right may not be really right. What appears so may not be really so. Even if what is right is really right, wherein it differs from wrong cannot be made plain by argument. Even if what appears so is really so, wherein it differs from what is not so also cannot be made plain by argument. Take no heed of time nor of right and wrong. Passing into the realm of the Infinite, take your final rest therein.The translation by Fung Yu-lan:
Referring to the right and the wrong, the 'being so' and the 'not being so': if the right is really right, we need not dispute about how it is different from the wrong; if the 'being so' is really being so, we need not dispute about how it is different from 'not being so.' … Let us forget life. Let us forget the distinction between right and wrong. Let us take our joy in the realm of the infinite and remain there.The translation by Wing-tsit Chan:
We say this is right or wrong, and is so or is not so. If the right is really right, then the fact that it is different from the wrong leaves no room for argument. If what is so is really so, then the fact that it is different from what is not so leaves no room for argument. Forget the passage of time (life and death) and forget the distinction of right and wrong. Relax in the realm of the infinite and thus abide in the realm of the infinite.The translation by A C Graham:
Treat as 'it' even what is not, treat as 'so' even what is not. If the 'it' is really it, there is no longer a difference for disputation from what is not it; if the 'so' is really so, there is no longer a difference for disputation from what is not so.Commentary on Zhuangzi by Brook Ziporyn (from Zhuangzi: The Essential Writings pp.xvi-xvii)
The question Zhuangzi faces is indeed among the most fundamental human problems: How should I live my life? Which of the alternate courses should I take as my guide? How is it that I come to choose one course over another? Given that there are alternate ways to see things, why do I, and why should I, see things the way I do rather than another way and thus follow one path rather than another? Zhuangzi’s response to this problem, simply stated, is this: This question can never be answered in the terms in which it has been put, because our understanding consciousness can never know why it sees things one way rather than another, can never ultimately ground its own judgments, and is actually in no position to serve as a guide for living. To consciously weigh alternatives, apply your understanding to making a decision about what is best, and then deliberately follow the course you have decided on—this is the fundamental structure of all purposive activity and conscious knowledge, the basis of all ethics, all philosophy, all politics, all human endeavors at improvement, and this is precisely what Zhuangzi seems to consider ridiculous and impossible. Knowledge is unreliable; Will is unreliable; Tradition is unreliable; Intuition is unreliable; Logic is unreliable; Faith is unreliable. But what else is there?