Does it even have a meaning beyond self=interest? From Instapundit
If you’re interested in the question of whether morality can exist without God, you might enjoy Arthur Allen Leff’s discussion in Unspeakable Ethics, Unnatural Law. Or, in shorter and more pungent form, his treatment in Memorandum From The Devil. Also, these — especially the latter — are two of the best-written law review articles ever.