¹ Ross, W. D., The Right and the Good (Indianapolis, IN: Hackett, 1988), 21–22Google Scholar.

² Prichard, H. A., “Does Moral Philosophy Rest on a Mistake?” in Prichard, , Moral Obligation (Oxford: Clarendon Press, 1957), 16Google Scholar.

³ The method of reflective equilibrium, as initially described by John Rawls, calls for one to consider intuitively plausible general theories that come close to systematizing one's moral judgments about particular situations, and then to adjust both one's moral judgments about particular situations and one's moral theories to bring them into harmony with each other. See Rawls, John, A Theory of Justice (Cambridge, MA: Harvard University Press, 1971), 48–49Google Scholar. The method is now often understood in a broader sense, to include any process of weighing conflicting beliefs against each other and renouncing the less plausible beliefs in order to restore coherence to one's belief system. For a defense of the method, see DePaul, Michael, “The Problem of the Criterion and Coherence Methods in Ethics,” Canadian Journal of Philosophy 18 (1988): 67–86Google Scholar.

⁴ Moore, G. E., Principia Ethica (Cambridge: Cambridge University Press, 1903)Google Scholar; Ross, The Right and the Good; Prichard, “Does Moral Philosophy Rest on a Mistake?”

⁵ See my Ethical Intuitionism (New York: Palgrave Macmillan, 2005).

⁶ See Audi, Robert, The Good in the Right (Princeton, NJ: Princeton University Press, 2004), 33–36, 48–49Google Scholar.

⁷ See Huemer, Ethical Intuitionism, 99–104; Bealer, George, “A Theory of the A Priori,” in Tomberlin, James, ed., Philosophical Perspectives 13: Epistemology (Cambridge, MA: Blackwell, 1999), 30–31Google Scholar.

⁸ The comprehension axiom states that for any well-formed predicate, there exists a set containing all and only the things to which that predicate applies. This leads to a contradiction when the well-formed predicate “is not a member of itself” is introduced.

⁹ Some philosophers argue that one's understanding of the natures of abstract objects—for example, the nature of knowledge, or of value—must lead one to have generally reliable intuitions about the properties of and relationships among these abstract objects. See Bealer, “A Theory of the A Priori,” and my Ethical Intuitionism, 122–27, for discussion.

¹⁰ Singer, Peter, Practical Ethics, 2d ed. (Cambridge: Cambridge University Press, 1993), 232Google Scholar.

¹¹ Unger, Peter, Living High and Letting Die: Our Illusion of Innocence (New York: Oxford University Press, 1996), 101–2Google Scholar. Unger does not, however, argue for a general rejection of intuition. Rather, he believes that through philosophical reasoning, we can correct the distorting influences on our intuitions.

¹² Although Singer does not describe the moral premises he favors as “ethical intuitions,” I think that is in fact what they are. See the discussion in my essay “Singer's Unstable Metaethics,” in Jeffrey Schaler, ed., Singer Under Fire (Chicago, IL: Open Court, forthcoming).

¹³ In this example, you see a child in danger of drowning in a shallow pond. Even though it will mean getting your clothes muddy and missing the lecture you were on your way to give, you clearly have a strong obligation to pull the child out of the pond. Singer thinks this is comparable to your obligation to donate money to save Third World children from malnutrition and disease (Singer, Practical Ethics, 229–46).

¹⁴ The reasoning is roughly as follows: Imagine that you have already donated most of your income to charity organizations working to relieve world poverty. Now, while walking past a shallow pond on your way to a philosophy lecture, you see a small child drowning. You could pull the child out, but doing so would get your clothes muddy and make you miss your lecture. Even so, it would be seriously wrong not to pull the child out. But, as Singer and Unger would argue, failure to save the drowning child in this circumstance is morally comparable to failure to save another starving child by sending money to UNICEF. Thus, even when you have already given away most of your money, you are still obligated to give more (Unger, Living High and Letting Die, 60–61, 135–39). Furthermore, since Singer rejects the moral significance of the distinction between killing and letting die, he holds that allowing people in the Third World to die is comparable to murder (Singer, Practical Ethics, 222–29).

¹⁵ See Mackie, John L., Ethics: Inventing Right and Wrong (New York: Penguin, 1977), 36–38Google Scholar.

¹⁶ J. Patrick Gray reports a total of 1,045 societies practicing at least occasional polygamy, compared with 186 exclusively monogamous societies; see Gray, , “Ethnographic Atlas Codebook,” World Cultures 10 (1998): 90Google Scholar.

¹⁷ Sharon Street makes these remarks regarding the biases supposedly generated by natural selection; see Street, , “A Darwinian Dilemma for Realist Theories of Value,” Philosophical Studies 127 (2006): 124Google Scholar. Her ultimate conclusion favors some form of subjectivism.

¹⁸ On (d), see Ruse, Michael, Taking Darwin Seriously (Amherst, NY: Prometheus, 1998), 145–47Google Scholar. On (e), see Dawkins, Richard, The Selfish Gene (Oxford: Oxford University Press, 1999)Google Scholar, chap. 9. Jonathan Haidt has studied attitudes toward harmless, consensual incest, as well as other victimless alleged wrongs; see Haidt, , “The Emotional Dog and Its Rational Tail: A Social Intuitionist Approach to Moral Judgment,” Psychological Review 108 (2001): 814–34Google Scholar.

¹⁹ Ruse, Taking Darwin Seriously, 252–54; Street, “A Darwinian Dilemma.”

²⁰ Sinnott-Armstrong, Walter, Moral Skepticisms (Oxford: Oxford University Press, 2006), 195–204CrossRefGoogle Scholar.

²¹ Ted Bundy killed dozens of young women across the United States during the 1970s, becoming one of history's most notorious serial murderers.

²² According to the coherence theory of justification, a belief is justified, if at all, by virtue of the way it fits together with the rest of one's belief system. This “fitting together” is usually understood as a matter of supporting and being supported by other beliefs, being explainable in terms of one's other beliefs, and so on. See BonJour, Laurence, The Structure of Empirical Knowledge (Cambridge, MA: Harvard University Press, 1985), 93–101Google Scholar.

²³ The probability of as many as two of the six witnesses picking the same incorrect license plate number by chance (assuming random selection from six-digit alphanumeric sequences) is about one in 145 million.

This kind of argument is advanced by BonJour, The Structure of Empirical Knowledge, 147–48, and Lewis, C. I., An Analysis of Knowledge and Valuation (La Salle, IL: Open Court, 1946), 346Google Scholar. See Olsson, Erik, Against Coherence (Oxford: Clarendon, 2005)Google Scholar, for an extended discussion of the conditions under which coherence produces confirmation. Note that the argument requires that the witnesses be more reliable than chance, but not that they be more than 50 percent reliable. Note also that I do not hereby embrace a coherence theory of justification, since I do not claim that coherence is either necessary or sufficient for justification; I claim only that coherence can ratchet up the level of justification that intuitions start with.

²⁴ See JPollock, ohn and Cruz, Joseph, Contemporary Theories of Knowledge, 2d ed. (Lanham, MD: Rowman and Littlefield, 1999), 195–96Google Scholar, for the distinction between rebutting and undercutting defeaters.

²⁵ Singer, Practical Ethics, 170–73.

²⁶ Presumably, Singer would not back this point up, as I would, with a realist conception of ethics, since his sympathies lie more in line with noncognitivism. I discuss the resulting tension between his metaethical views and his ethical methodology in my “Singer's Unstable Metaethics.”

²⁷ See, respectively, Dancy, Jonathan, Moral Reasons (Oxford: Blackwell, 1993)Google Scholar; Sidgwick, Henry, The Methods of Ethics, 7th ed. (Indianapolis, IN: Hackett, 1981)Google Scholar; and Ross, The Right and the Good.

²⁸ In this example, one must choose between allowing a runaway trolley to run over and kill five people, and flipping a switch to send the trolley onto another track, where it will run over and kill one person. See Foot, Philippa, “The Problem of Abortion and the Doctrine of the Double Effect,” Oxford Review 5 (1967): 5–15Google Scholar.

²⁹ DePaul expresses doubt on this score in “The Problem of the Criterion and Coherence Methods in Ethics.”

³⁰ Michael Tooley employs the latter principle in his defense of abortion and infanticide; see Tooley, , “Abortion and Infanticide,” Philosophy and Public Affairs 2 (1972): 37–65Google Scholar.

³¹ Axiological additivity principles claim that value can be added along some dimension—for example, that the value of a pair of people's lives is equal to the value of the first person's life plus the value of the second person's life; or that the value of some event is equal to the value of the first half of the event plus the value of the second half of the event.

³² This is a special case of the “availability heuristic,” discussed in Tversky, Amos and Kahneman, Daniel, “Availability: A Heuristic for Judging Frequency and Probability,” in Kahneman, Daniel, Slovic, Paul, and Tversky, Amos, eds., Judgment under Uncertainty: Heuristics and Biases (Cambridge: Cambridge University Press, 1982), 163–78CrossRefGoogle Scholar.

³³ David Lewis discusses this kind of case in “Causation,” in Lewis, , Philosophical Papers, vol. 2 (Oxford: Oxford University Press, 1986), 159–214Google Scholar.

³⁴ Rachels, Stuart, “Counterexamples to the Transitivity of Better Than,” Australasian Journal of Philosophy 76 (1998): 71–83Google Scholar. Rachels takes his series of cases to provide a counterexample to the transitivity principle. I take it, instead, to illustrate certain biases in our evaluations of the cases.

³⁵ See my “Non-Egalitarianism,” Philosophical Studies 114 (2003): 147–71, for an argument against welfare egalitarianism based mainly on formal intuitions. See Parfit, Derek, Reasons and Persons (Oxford: Clarendon, 1987), 419–30Google Scholar, for an argument (though Parfit does not endorse the argument) based mainly on formal intuitions for “the repugnant conclusion” that, for any world of very happy people, some world with a much larger population of people with lives barely worth living would be better. See also Unger, Living High and Letting Die, 88–94, for an argument that our intuitions about sacrificing individuals to produce greater benefit violate the principle of independence of irrelevant alternatives.

³⁶ Mackie, Ethics, 30–35.

³⁷ See Harman, Gilbert, The Nature of Morality (New York: Oxford University Press, 1977), 94–95Google Scholar. However, I argue in Ethical Intuitionism (176–79) that even demands for consistency and coherence are problematic for ethical antirealists.

³⁸ I discuss the issue in greater detail in my “A Paradox for Moderate Deontology” (unpublished manuscript).