In his brilliant (and, sadly, unfinished) Ethics, Dietrich Bonhoeffer states that the "first task of Christian ethics is to invalidate [the] knowledge [of good and evil]," because the "knowledge of good and evil shows that [man] is no longer at one with his origin." I take this to mean that our necessarily contingent conceptions of good and evil are only approximations of what we would know if we achieved unity with God--they serve as guidance to us in our fallen state. As Bonhoeffer puts it, it is "only in the unity of his knowledge of God that [man] knows of other men, of things, and of himself." Or from a Buddhist perspective, only that which is not subject to arising and cessation can be truly known, and only through that which is not subject to arising and cessation can anything be truly known. Only through the emptiness that is the source of our consciousness can we know the Emptiness out of which and into which all dependent existence evolves; only through the divinity of our soul can we know God.

Good and evil, like all other dualities, are only necessary or possible in our state of separation from or forgetting of God or Brahman or nibanna or whatever you'd prefer to call it. Like all other dualities, good and evil are based on illusion and will ultimately be inadequate. We'll never find a universal ethics. But I'm not advocating that we simply abandon the idea of good and evil. As this old story from Vedanta Hinduism quoted by Ken Wilber in A Brief History of Everything illustrates, this is a complicated issue:

A man goes to an enlightened sage and asks, of course, for the meaning of life. The sage gives a brief summary of the Vedanta view, namely, that this entire world is nothing but the supreme Brahman or Godhead, and further, your own witnessing awareness is one with Brahman. Your very Self is in a supreme identity with God. Since Brahman creates all, and since your highest Self is one with Brahman, then your highest Self creates all...

Off goes the gentleman, convinced that he has understood the ultimate meaning of life, which is that his own deepest Self is actually God and creates all reality. On the way home, he decides to test this amazing notion. Heading right toward him was a man riding an elephant. The gentleman stands in the middle of the road, convinced that, if he's God, the elephant can't hurt him. The fellow riding the elephant keeps yelling, "Get out of the way! Get out of the way!" But the gentleman doesn't move--and gets perfectly flattened by the elephant.

Limping back to the sage, the gentleman explains that, since Brahman or God is everything, and since his Self is one with God, then the elephant should not have hurt him. "Oh, yes, everything is indeed God," said the sage, "so why didn't you listen when God told you to get out of the way?"

As long as we believe ourselves to be distinct selves, we need ways to support each other and protect ourselves from each other. The practical question that this suggests is: How are we in our fallen state, separated from God, to define good and evil? Over the millennia of recorded history, there have been countless attempts to resolve this issue through revelation, reasoning, and feeling, and, as I've said, none have achieved universal acceptance. Perhaps the closest we have to a universal doctrine is the "Golden Rule" from Jesus' "Sermon on the Mount": "All things whatsoever ye would that men should do to you, do ye even so to them." Here we have the intersection of revelation, reasoning, and feeling--that is, it was revealed to us by Jesus (echoing the earlier Jewish prophets and later echoed by Muhammad), it's easily understood and commonsensical, and it feels right and fair. But as a practical guide to daily behavior, this precept suffers many shortcomings (most clearly demonstrated by the Freudian critique that because we can't be shown to love ourselves in any real way, our self-regard doesn't provide a useful basis for our behavior toward others).

What if instead of a practical guide, we took this to be an exhortation? Rather than simply looking to what we want or need or feel and applying that to others, what if we aspired to that part of ourselves that actually transcends the distinction between ourselves and others? What if instead of identifying with the man standing in the road, we sought to identify with him, the elephant, and its rider? This isn't to say that we should act, like Winnicott's omnipotent infant, as if the whole world were simply an extension of our selves. We should act as if we and what we act upon were aspects of the same whole, manifestations of the same emptiness.