¹ I do not use “utopian” in a pejorative way, or as an indication that the specified social arrangement is infeasible. Some contemporary political philosophers explicitly contrast “utopian” with “realistic” theory ( Valentini, Laura, “Ideal vs. Non-ideal Theory: A Conceptual Map,” Philosophy Compass 7, no. 9 [2012]: 654–64, at 654;CrossRefGoogle Scholar see also Jubb, Robert, “Tragedies of Non-ideal Theory,” European Journal of Political Theory 11 [2012]: 229–46, at 230CrossRefGoogle Scholar). However, traditional utopian thought was often concerned with viable institutional schemes. (See Goodwin, Barbara and Taylor, Keith, The Politics of Utopia [London: Hutchinson, 1982], 210–14;Google Scholar Timothy Kenyon, “Utopia In Reality: ‘Ideal’ Societies in Social and Political Theory,” History of Political Thought 3 [January 1982]: 123–55.) As I use it, a utopian theory is a type of “ideal theory,” which may well be implementable. Karl Kautsky famously praised More’s Utopia as articulating a socialist ideal that satisfied important “realization” constraints. Karl Kautsky, Thomas More and His Utopia (London: Lawrence and Wisehart, 1979 [1888]), 249.

² Rawls, John, A Theory of Justice, rev. ed. (Cambridge, MA: Harvard University Press, 1999), 65–73.Google Scholar

³ Cohen, G. A., Rescuing Justice and Equality (Cambridge, MA: Harvard University Press, 2008), 33, 48.CrossRefGoogle Scholar “The incentives argument has something in common with the kidnapper argument . . . ” (ibid., 41).

⁴ Cohen, G. A., Why Socialism? (Princeton, NJ: Princeton University Press, 2009), chap. 2.Google Scholar

⁵ Brennan, Jason, Why Not Capitalism? (New York: Routledge, 2014), 71.CrossRefGoogle ScholarPubMed

⁶ See Fourier, Charles, Design for Utopia: Selected Writings of Charles Fourier, trans. Franklin, Julia (New York: Schocken, 1988);Google Scholar Robert Owen, A New View of Society, and Other Writings (London: Dent, 1972 [1813]); Edward Bellamy, Looking Backward (New York: Dover, 1996 [1880]); Peter Alekseevich Kropotkin, Mutual Aid: A Factor of Evolution (London: W. Heinemann, 1907).

⁷ I consider the effects of relaxing (iii), the non-accommodation clause, in Section II.B.

⁸ See Bicchieri, Cristian, The Grammar of Society (Cambridge: Cambridge University Press, 2006), esp. chap. 1.Google Scholar

⁹ Thomas Hobbes, Leviathan, ed. Edwin Curley (Indianapolis, IN: Hackett, 1994), 61 (chap. 11, para. 21). Cf. Cohen, Rescuing Justice and Equality, 6.

¹⁰ See William Godwin, An Enquiry Concerning Political Justice, and its Influence on General Virtue and Happiness, two vols. (London: G. G. J. and J. Robinson, 1793). Thomas Malthus targeted Godwin’s rather extreme claim that passions, including that for sex, would wither away. Thomas Robert Malthus, Malthus — Population: The First Essay (Ann Arbor, MI: Ann Arbor Paperback, 1959 [1798]).

¹¹ Passmore, John, The Perfectability of Man (London: Duckworth, 1971), 200.Google Scholar

¹² Berlin, Isaiah, The Roots of Romanticism (Princeton, NJ: Princeton University Press, 1997), 23.Google Scholar

¹³ Rawls, Political Liberalism, expanded edition (New York: Columbia University Press, 2005), xxiv.

¹⁴ According to Rawls, reasonable judgments so often are at odds because: (i) the evidence is often conflicting and difficult to evaluate; (ii) even when we agree on the relevant considerations, we often weigh them differently; (iii) because our concepts are vague, we must rely on interpretations that are often controversial; (iv) the manner in which we evaluate evidence and rank considerations seems to some extent the function of our total life experiences, which of course differ; (v) because different sides of an issue rely on different types of normative considerations, it is often hard to assess their relative merits; (vi) in conflicts between values, there often seems to be no uniquely correct answer (Rawls, Political Liberalism, 56–57). For Haidt’s view, see The Righteous Mind: Why Good People Are Divided by Politics and Religion (New York: Pantheon, 2012).

¹⁵ See Richerson, Peter J. and Boyd, Robert, Not by Genes Alone (Chicago: University of Chicago Press, 2005), chaps. 1–3.Google Scholar It has been said that children can be understood as “cultural sponges.” Mesoudi, Alex, Cultural Evolution (Chicago: University of Chicago Press, 2011), 15.CrossRefGoogle ScholarPubMed We often do not understand precisely the benefits of our cultural practices, but because culture is largely transmitted via imitation, people often do not have to know why something is done, only that it is the done thing around here. Whereas intelligent primates such as chimps tend to figure out problems for themselves, human infants appear to have a much stronger tendency to simply copy what they observe being done, copying “stupid” acts which the chimp apparently sees as pointless. See Victoria Horner and Andrew Whiten, “Causal Knowledge and Imitation/Emulation in Chimpanzees (Pan Troglodytes) and Children (Homo Sapiens),” Animal Cognition 8 (2005): 164–81.

¹⁶ See Kohlberg, Lawrence, The Philosophy of Moral Development (New York: Harper and Row, 1981), part two.Google Scholar

¹⁷ I have considered in more depth the relation between agreement on principles and disagreement on interpretations, in my “On Justifying the Liberties of the Moderns,” Social Philosophy and Policy 25 (2007): 84–119. It is important that in moral matters, when we disagree, we cannot suspend judgment; something must be done. It is not at all clear that such suspension is the proper policy even in purely epistemic matters. For a general overview of the “peer disagreement” literature in epistemology, see the essays in The Epistemology of Disagreement, ed. David Christensen and Jennifer Lackey (New York: Oxford University Press, 2013).

¹⁸ A referee objects: if “you already believe Assumption 4, then you will rightly find it dystopian that dissenters would be treated so disrespectfully. But if you instead believe that in utopia all competent moral agents would agree, then you really are going to think the dissenter in utopia is incompetent. The dissenter should be regarded much the way we regard Holocaust deniers or flat earthers or rabid racists who advocate lynching — there’s some serious failure of reasoning going on here and they really would be more competent if they were able to think as others think.” The reader takes (for sake of analysis) the argument based on The Moral-Epistemic Homogeneity of Utopia as modus ponens — the conclusion indeed follows. I am suggesting that the conclusion shows the argument form to be modus tollens: if any dissenting conclusion about justice implies that “there’s some serious failure of reasoning going on here” we should reject the premises that got us to what I cannot help but see as an objectionably dystopian conclusion. This apparently confirms the adage that one person’s modus ponens is another’s modus tollens.

¹⁹ To remind readers of a basic but fundamental point: preferences are simply pairwise rankings of alternatives, not a type of mental state (such as a desire) that generates such rankings; and utility is a mathematical representation of how well a choice satisfies an ordered ranking, not a sort of goal or value. See here my On Philosophy, Politics, and Economics (Belmont, CA: Wadsworth-Thomson, 2008), chap. 2.

²⁰ Cohen, Rescuing Justice, 175ff.

²¹ Immanuel Kant, The Metaphysical Elements of Justice, 2nd edition, ed. and trans. John Ladd (Indianapolis, IN: Hackett, 1999), 116 [sect. 43]. Emphasis added.

²² Ibid.

²³ Of course each could seek to force the other to do the just thing, but then we have what Kant thought of as a lawless state of nature.

²⁴ Cohen, Why Not Socialism? 42.

²⁵ Luce, R. Duncan and Raiffa, Howard, Games and Decisions (New York: John Wiley and Sons, 1957), 90–94.Google Scholar

²⁶ This phrase comes from Rawls, Political Liberalism, 157, 163.

²⁷ “Stronger” because this view does not build in special accommodation to the conclusions of others.

²⁸ See my Order of Public Reason (Cambridge: Cambridge University Press, 2011), 163–79. Compare Bicchieri, The Grammar of Society, chap. 1.

²⁹ This is a broad definition of a convention that does not require that Alf and Betty are playing a strict coordination game, though it encompasses such games. To get more precise, the maximization condition would have to be spelled out, but it would take us too far astray. On the narrower, more classic notion of a convention, see Lewis, David, Convention: A Philosophical Study (Cambridge, MA: Harvard University Press, 1969).Google Scholar See also Sugden, Robert, The Economics of Rights, Co-operation and Welfare (Oxford: Blackwell, 1986);Google Scholar Hardin, Russell, David Hume: Moral and Political Theorist (New York: Oxford University Press, 2007), chap. 4.CrossRefGoogle Scholar

³⁰ H. Musgrave Wilkins, A Literal Translation of the Eclogues and Georgics of Virgil (London: Longmans, Green and Co., 1871), 94ff.

³¹ Sometimes this seems suggested by Joseph H. Carnes in his utopian egalitarian market scheme, as if the motivation by each to do her social duty would be enough. However, overall he sees the need for rather more explicit socialized incentives, a matter I take up in Section IV.C. See his Equality, Moral Incentives, and the Market: An Essay in Utopian Politico-Economic Theory (Chicago: University of Chicago Press, 1981), 8. The hope that a division of labor could be the spontaneous upshot of free egalitarian choices is an enduring theme in utopian thought, such as in Fourier’s scheme or Bellamy’s socialist utopia.

³² Cohen, Rescuing Justice, 123.

³³ Read as “a is preferred to o.”

³⁴ See, for example, Sen, Amartya, “Maximization and the Act of Choice” in his Rationality and Freedom (Cambridge, MA: Harvard University Press, 2002): 159–205.Google Scholar

³⁵ Thus we cannot say that two first choices are “equal,” that is, that the players are indifferent between, say, all play a and all play b. That would require a complete ranking. For those worried by the apparent assumption of indifference, and so completeness, in Figure 3, I consider at some length how to model this sort of choice under incompleteness in The Order of Public Reason, 303–10.

³⁶ Cohen, Rescuing Justice, 123.

³⁷ On the rule-destroying effects of undermining empirical expectations, see Bicchieri, Cristina, Norms in the Wild (Oxford: Oxford University Press, 2016), chaps. 3–4.Google Scholar

³⁸ Hobbes, Leviathan, 23 (chap. 5, para. 3).

³⁹ Recall here the passage from Hobbes in Section II.B, which Cohen quotes.

⁴⁰ Gauthier, “Public Reason,” Social Philosophy and Policy 12 (1995): 19–42, at 27. Emphases added.

⁴¹ Ibid.

⁴² Ibid., 31. Emphasis in original.

⁴³ Ibid., 25.

⁴⁴ Jean-Jacques Rousseau, A Discourse on Political Economy in The Social Contract and Discourses, trans. G. D. H. Cole (London: J. M. Dent and Sons, 1923), 256–57. Emphasis added.

⁴⁵ “When therefore the opinion that is contrary to my own prevails, this proves neither more nor less than that I was mistaken, and that what I thought to be the general will was not so. If my particular opinion had carried the day I should have achieved the opposite of what was my will; and it is in that case that I should not have been free . . . . This presupposes, indeed, that all the qualities of the general will still reside in the majority . . . ” (Rousseau, The Social Contract, in The Social Contract and Discourses, 112).

⁴⁶ Hobbes, Leviathan, 245–46 (chap. 32, para. 2).

⁴⁷ Ibid., 246. “But in any business, whereof a man has not infallible science to proceed by, to forsake his own natural judgment, and be guided by general sentences read in authors, and subject to many exceptions, is a sign of folly, and generally scorned by the name of pedantry” (ibid., 27 [chap. 5, para. 22]).

⁴⁸ I argue for this conclusion in some depth in my Contemporary Theories of Liberalism: Public Reason as a Post-Enlightenment Project (London: Sage, 2003), 71ff. See more generally Jean Hampton’s Hobbes and the Social Contract Tradition (Cambridge: Cambridge University Press, 1986), chap. 7.

⁴⁹ Cohen, Rescuing Justice, 43.

⁵⁰ See Cohen, Why Not Socialism? 39ff. Or, as Sidney and Beatrice Webb put it, “The Worship of God is replaced by the Service of Man” (Soviet Communism: A New Civilization, third edition in one volume [London: Longman’s, Green and Co., 1944], 913).

⁵¹ Carnes, Equality, Moral Incentives, and the Market, 8.

⁵² Wiles, P. J. D., Economic Institutions Compared (New York: Wiley, 1977), 27.Google Scholar

⁵³ Carnes, Equality, Moral Incentives, and the Market, 122.

⁵⁴ Cf. Cohen: “The Carnes system is Utopian partly because it relies entirely on non-self-interested choice” (Why Not Socialism? 65). This does not seem to be Carnes’s view. More accurately, Carnes’s system avoids appeal to what Wiles called “Benthamite incentives” — an exchange of work for some private good outside of working hours (Economic Institutions Compared, 15).

⁵⁵ Jean-Jacques Rousseau, The Government of Poland, trans. Willmoore Kendall (Indianapolis, IN: Bobbs-Merrill, 1972), 87. See also Chapman, John W., Rousseau —Totalitarian or Liberal? (New York: Columbia University Press, 1956), 60ff.Google Scholar

⁵⁶ Harinck, Fieke, De Dreu, Carsten K. W., and Van Vianen, Annelies E. M., “The Impact of Conflict Issues on Fixed-Pie Perceptions, Problem Solving, and Integrative Outcomes in Negotiation,” Organizational Behavior and Human Decision Processes 81 (2000): 329–58, at 330.CrossRefGoogle Scholar They also considered a third type of dispute, “a negotiation about an intellective problem,” that is, where “interdependent individuals or groups hold incompatible positions that are rooted in different interpretations of an objectively verifiable problem” (ibid.). All emphases in original.

⁵⁷ See also Greene, Joshua, Moral Tribes: Emotion, Reason and the Gap between Them and Us (New York: Penguin, 2013), 86–88.Google Scholar

⁵⁸ See Haworth, A., “Planning and Philosophy: The Case of Owenism and the Owenite Communities,” Urban Studies 13 (1976): 147–53, at 153;CrossRefGoogle Scholar Kumar, Krishan, “Utopian Thought and Communal Practice: Robert Owen and the Owenite Communities,” Theory and Society 19 (1990): 1–35, at 18.CrossRefGoogle Scholar

⁵⁹ This may be a more basic feature of humans than enjoying camping. See Greene, Moral Tribes.

⁶⁰ Cohen, Why Not Socialism? 40.

⁶¹ Immanuel Kant, “What is Enlightenment?” in On History: Immanuel Kant, ed. Lewis White Beck (Indianapolis, IN: Bobbs-Merrill, 1957): 3–10, at 3.