The first version was published in the American Philosophical Quarterly 14 (1977): 159–65 after it was read before the meeting of the American Philosophical Association, Pacific Division, 1977. A revised and expanded version appears in Values and Morals: Essays in Honor of William Frankena, Charles Stevenson, and Richard B. Brandt, pp. 47–71. ed., A. Goldman and J. Kim. Dordrecht, Holland: Reidel, 1978.