Notes
- . William K. Frankena, “Value and Valuation,” in The Encyclopedia of Philosophy, ed. Paul Edwards, 8 vols. (New York: Macmillan Co., 1967), 8:229–32.
- . George Edgin Pugh, The Biological Origin of Human Values (New York: Basic Books, 1977).
- . Donald T. Campbell, “On the Conflicts between Biological and Social Evolution and between Psychology and Moral Tradition,” American Psychologist 30 (1975): 1103–26 (reprinted in Zygon 11 [September 1976]: 167–208).
- . Edward O. Wilson, On Human Nature (Cambridge, Mass.: Harvard University Press, 1978).