The difference between them and us is that they are liberated by relativism, or into relativism, while the rest of us are more likely to become its victims, since the freedom it encourages panders to our preoccupation with satisfying insatiable desires. In other words, the difference is self. Those deluded by a sense-of-self are trapped in their own self-preoccupation; ethical relativism clears the way for such people to do whatever is necessary to get what they want. Since sages and bodhisattvas are liberated from self-preoccupation, because they do not experience others as objects whose well-being is distinct from their own, relativism frees them from the formal constraints that the rest of us seem to need and allows them to get on with the task of apparently saving all sentient beings while actually doing nothing at all (a paradox embraced by both traditions).
If the issue of ethical relativism in the Zhuangzi cannot be understood without also considering the role of self, is that also the case for other types of relativism -- such as knowledge?
Being no-thing
Much of our problem with understanding the Daoist and Buddhist critiques of self comes down to envisioning an alternative. What can it mean, not to have or not to be a self? In both traditions the answer is: to become no-thing. The way to transcend this world is to forget oneself and become completely one with it, in which case one is so "empty" of any fixed form that one is able to become any-thing. That the Buddha (and our own Buddha-nature) has no fixed form by which he can be recognized is emphasized in Mahayana Buddhism, especially in the prajnaparamita sutras whose teachings are very similar to Nagarjuna's. For example, in the Diamond Sutra the Buddha says that those who attempt to see him by form or sound cannot see him, and that he is not to be recognized by any material characteristic. The other best-known Mahayana scripture, the laconic Heart Sutra, asserts that all form is emptiness (sunyata), and that realizing our emptiness liberates us from the delusion of self.
For Zhuangzi too no-thingness characterizes the Dao itself, and becoming no-thing is a return to the source from which things including us arise:
There is somewhere from which we are born, into which we die, from which we come forth, through which we go in; it is this that is called the Gate of Heaven. The Gate of Heaven is that which is without anything; the myriad things go on coming forth from that which is without anything. Something cannot become something by means of something, it necessarily goes on coming forth from that which is without anything; but that which is without anything is for ever without anything. The sage stores away in it. (ch. 23, p. 103; Graham's italics)
Having achieved this, the sage can "let the heart [xin] roam with other things as its chariot" (ch. 4, p. 71). A later chapter quotes the sage Guanyin: "Within yourself, no fixed positions:/ Things as they take shape disclose themselves./ Moving, be like water,/ Still, be like a mirror,/ Respond like an echo./ Blank! as though absent:/ Quiescent! as though transparent./ Be assimilated to them and you harmonize,/ Take hold of any of them and you lose" (ch. 33, p. 281).
The mind as a mirror is perhaps the most important metaphor in the Zhuangzi and provides one of its most-quoted passages, from the very end of the inner chapters:
"Hold on to all that you have received from Heaven but do not think you have gotten anything. Be empty, that is all. The Perfect Man uses his mind [xin] as a mirror -- going after nothing, welcoming nothing, responding but not storing."
In terms of the image, self-forgetting or mind-losing (wang xin) is the practice of polishing one's mind-mirror and keeping it clean of impurities. To say the least, such meditative techniques are also important in Buddhism, which is probably the richest of the world's contemplative traditions. Although Nagarjuna mentions little about such practices, as a monastic he was doubtless familiar with them and they provide the context within which his work must be situated, especially its emphasis on prapancopasama, the cessation of conceptual ways of understanding, which is necessary if one is to experience things as they are. Burton Watson suspects that the Zhuangzi must originally have been accompanied by similar practices to help students realize what it is talking about, yet all that survives in the text are some references to controlled breathing.
By such practices the xin of the sage becomes "the reflector of heaven and earth, the mirror of the myriad things" (ch. 13, p. 259). Nonetheless, the mirror-metaphor, like all metaphors, has its limitations. To be a perfectly-polished mirror is not quite the same as being no-thing at all: there is still a dualism between the reflector and the reflected. This may encourage the tendency of contemplative types to stand back from the world, but Zhuangzi will have none of that: "To be transformed day by day with other things is to be untransformed once and for all. Why not try to let them go? For the sage, there has never yet begun to be Heaven, never yet begun to be man, never yet begun to be a Beginning, never yet begun to be things" (ch. 25, pp. 110-111). To forget oneself completely, truly to become no-thing, means more than to reflect the transformations of things: it is to be wholly identified with them, to be them -- in which case there are no things and no transformations, since "that which is without anything is for ever without anything" (quoted above). Such a world is not a collection of things but is composed of events. Evidently someone who realizes she is no-thing remains no-thing even as she playfully assumes this or that form. When there is no thing or self that exerts itself to do things, there is the spontaneity (ziran, "so of itself") of actions that are experienced as no actions (wu wei), of transformations that are just as much non-transformations.