¹ Darley, John M. and Shultz, Thomas R., “Moral Rules: Their Content and Acquisition,” Annual Review of Psychology, vol. 41 (1990), pp. 525–56.CrossRefGoogle Scholar

² Piaget, Jean, The Moral Judgment of the Child (New York: Free Press, 1956)Google Scholar; Kohlberg, Lawrence, Essays on Moral Development, vol. 1, The Philosophy of Moral Development: Moral Stages and the idea of Justice (San Francisco: Harper & Row, 1981)Google Scholar; Gilligan, Carol, In a Different Voice: Psychological Theory and Women's Development (Cambridge, MA: Harvard University Press, 1982).Google Scholar Philosophical reaction appears, for example, in Rawls, John, A Theory of Justice (Cambridge, MA: Harvard University Press, 1971)Google Scholar; Kittay, Eva Feder and Meyers, Diana T., eds. Women and Moral Theory (Totowa, NJ: Rowman and Littlefield, 1987)Google Scholar; and Flanagan, Owen, Varieties of Moral Personality (Cambridge, MA: Harvard University Press, 1991).Google Scholar

³ See, for example, the journal Biology and Philosophy.

⁴ Foot, Philippa, “Abortion and the Doctrine of Double Effect,” in Foot, Virtues and Vices, and Other Essays in Moral Philosophy (Oxford: Basil Blackwell, 1978)Google Scholar; Thomson, Judith Jarvis, Rights, Restitution, and Risk: Essays in Moral Theory, ed. Parent, William (Cambridge, MA: Harvard University Press, 1986)Google Scholar, ch. 6, “Killing, Letting Die, and the Trolley Problem,” and ch. 7, “The Trolley Problem.”

⁵ A good sample of this discussion is collected in Fischer, John Martin and Ravizza, Mark, eds. Ethics Problems and Principles (Fort Worth, TX: Holt, Rinehart, and Winston, 1992).Google Scholar

⁶ There can be significant relations between these two kinds of explanation, including these: (1) Explaining why something is of value might help to explain why people value it. (2) Given an impartial-spectator theory of morality, to explain why people value something may be to explain why it is of value. (3) Certain explanations of why people value what they value may undermine the conviction that the things valued are of value.

⁷ Hume, David, Treatise of Human NatureGoogle Scholar, Book 3, part 2, section 12, “Of Chastity and Modesty.”

⁸ Expected utility is measured by the sum of the utility of each potential consequence of an option multiplied by the probability that the option will lead to that consequence. I will suppress further mention of expected utility.

⁹ Hume, , Treatise of Human NatureGoogle Scholar, Book 2, part 1, section 11, “Of the Law of Fame,” and part 2, section 7, “Of Compassion.” See also Hume, , An Enquiry Concerning the Principles of MoralsGoogle Scholar, section 5, “Why Utility Pleases.”

¹⁰ Smith, Adam, The Theory of Moral SentimentsGoogle Scholar, part 1, section 1, “Of the Sense of Propriety.” I discuss Smith's view in more detail in Harman, Gilbert, “Moral Agent and Impartial Spectator,” The Lindley Lecture at the University of Kansas (1986), Lawrence, Kansas.Google Scholar

¹¹ Smith, , Theory of Moral SentimentsGoogle Scholar, part 3, ch. 1. Smith's internal critic is Freud's superego. See Freud, Sigmund, Civilization and its Discontents, trans. Riviere, Jean (New York: J. Cape & H. Smith, 1930), chs. 8 and 9.Google Scholar

¹² For a sympathetic account of Piaget's theory and later developments, see Rest, James R., “Morality,” in Handbook of Child Psychology, 4th ed., vol. 3, ed. Mussen, Paul H. (New York: Wiley, 1983), pp. 556–629.Google Scholar

¹³ Carey, Susan, “Cognitive Development,” in Osherson, Daniel N. and Smith, Edward E., eds., “Thinking: An Invitation to Cognitive Science, Volume 3 (Cambridge, MA: MIT, 1990), pp. 146–72.Google Scholar

¹⁴ Darley, and Schultz, , “Moral Rules.”Google Scholar

¹⁵ Ibid., p. 544.

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¹⁸ Brandt, Richard B., “The Psychology of Benevolence and Its Implications for Philosophy,” Journal of Philosophy, vol. 73 (1976).CrossRefGoogle Scholar

¹⁹ Axelrod, Robert, The Evolution of Cooperation (New York: Basic Books, 1984).Google Scholar

²⁰ Posner, Richard A., The Economics of Justice (Cambridge, MA: Harvard University Press, 1981), pp. 60–115.Google Scholar

²¹ Nozick, Robert, Anarchy, State, and Utopia (New York: Basic Books, 1974), p. 41.Google Scholar

²² Dworkin, Ronald M., “Is Wealth a Value?” in Dworkin, , A Matter of Principle (Cambridge, MA: Harvard University Press, 1985), p. 240.Google Scholar

²³ Chomsky, Noam, Language and Problems of Knowledge: The Managua Lectures (Cambridge, MA: MIT, 1988)Google Scholar; Van Lehn, Kurt, “Problem Solving and Cognitive Skill Acquisition,” in Posner, Michael, ed., Foundations of Cognitive Science (Cambridge, MA: MIT, 1989), pp. 526–79.Google Scholar

²⁴ Hume, , Treatise of Human NatureGoogle Scholar, Book 3, part 2, section 2, “Of the Origin of Justice and Property”; Harman, Gilbert, “Moral Relativism Defended,” Philosophical Review, vol. 84 (1975) pp. 3–22.CrossRefGoogle Scholar

²⁵ Sober, Elliott, “Let's Razor Ockham's Razor,” in Explanation and Its Limits, ed. Knowles, D. (Cambridge, UK: Cambridge University Press, 1990).Google Scholar

²⁶ I heard a discussion about this on the radio one day, but do not have a more specific reference.

²⁷ Hercules is Ronald Dworkin's ideal judge, e.g., in Dworkin, , Law's Empire (Cambridge, MA: Belknap Press, 1986).Google Scholar

²⁸ Nozick, Robert, “Moral Complications and Moral Structures,” Natural Law Forum, vol. 13 (1968), pp. 1–50.Google Scholar

²⁹ A type of implication is “nonmonotonic” if something implied by a proposition P is not necessarily implied by the conjunction of P with something else Q. See Ginsberg, Matthew L., Readings in Nonmonotonic Reasoning (San Mateo, CA: Morgan Kaufmann, 1987).Google Scholar

³⁰ Nozick, , “Moral Complications.”Google Scholar