¹ This formulation is inspired by Hirose, Iwao, “Aggregation and the Non-Utilitarian Moral Theories,” Journal of Moral Philosophy 4, no. 2 (2007): 275–86, at 275CrossRefGoogle Scholar.

² For excellent discussions of such points, see, e.g., McMahan, Jeff, “Killing and Equality,” Utilitas 7, no. 1 (1995): 1–29CrossRefGoogle Scholar; McMahan, , “Cognitive Disability, Misfortune, and Justice,” Philosophy and Public Affairs 25, no. 1 (1996): 3–34CrossRefGoogle Scholar; McMahan, , The Ethics of Killing (Oxford: Oxford University Press, 2002), esp. chap. 3CrossRefGoogle Scholar; Holtug, Nils, “Equality for Animals,” in Ryberg, Jesper, Petersen, Thomas S., and Wolf, Clark, eds., New Waves in Applied Ethics (New York: Palgrave Macmillan, 2008)Google Scholar; and Vallentyne, Peter, “Of Mice and Men: Equality and Animals,” in Holtug, Nils and Lippert-Rasmussen, Kasper, eds., Egalitarianism (Oxford: Clarendon Press, 2007), 211–37Google Scholar.

³ The familiar examples here are Tom Regan and Peter Singer. See, e.g., Regan, Tom, The Case for Animal Rights (Berkeley: University of California Press, 1983)Google Scholar; Regan, , Defending Animal Rights (Urbana: University of Illinois Press, 2001)Google Scholar; Regan, , “Empty Cages: Animal Rights and Vivisection,” in Cohen, Andrew I. and Wellman, Christopher Heath, eds., Contemporary Debates in Applied Ethics (Malden, MA: Blackwell, 2005), 77–90Google Scholar; Singer, Peter, “All Animals Are Equal,” Philosophical Exchange 1, no. 1 (1974): 103–16Google Scholar; and Singer, , Animal Liberation (New York: Random House, 1975)Google Scholar.

⁴ See, e.g., Nils Holtug, “Equality for Animals”; and Vallentyne, “Of Mice and Men: Equality and Animals.”

⁵ See Milo, Ronald, “Contractarian Constructivism,” The Journal of Philosophy 92, no. 4 (1995): 181–204CrossRefGoogle Scholar, for a helpful discussion of metaethical contractarianism. Normative and metaethical contractarianism are logically independent; contractarianism in one sense does not presuppose contractarianism in the other. Metaethical contractarianism is basically an account of the truth-makers of moral claims. On Milo's view of contractarianism as a metaethical theory, for instance, contractarianism is in part “a theory about the ontological status of moral wrongness” (ibid., 190). The theory holds “that the moral wrongness of acts is constituted by their being prohibited by the norms chosen by the hypothetical contractors” (ibid., 202). A normative contractarianism, by contrast, will specify principles for determining the moral rightness or wrongness of acts (ibid., 189).

⁶ Though my discussion focuses on contractarian accounts, much of it may apply as well to contractualist theories. For the contractualist/contractarian distinction, see Darwall, Stephen, “Introduction,” in Darwall, , ed., Contractarianism, Contractualism (Malden, MA: Blackwell, 2003)Google Scholar; and Cudd, Ann, “Contractarianism,” Stanford Encyclopedia of Philosophy,http://plato.stanford.edu/entries/contractarianism/Google Scholar.

⁷ Hypothetical consent thus need not merely be a “heuristic”; principles can be justified because agents would agree to them in hypothetical choice situations. For a related discussion, see Stark, Cynthia A., “Hypothetical Consent and Justification,” The Journal of Philosophy 97, no. 6 (2000): 313–34, at 326–29CrossRefGoogle Scholar.

⁸ This is a clear point of departure between contractarianism and contractualism. The Rawlsian agreement, for instance, models certain moral conceptions of what should constrain principles of justice. Contractarian agreements have no such commitments since moral notions are supposed to emerge out of the agreement. See Rawls, John, A Theory of Justice (Cambridge, MA: Belknap Press of Harvard University Press, 1971)Google Scholar. David Gauthier, by contrast, assigns no moral constraints to the bargaining situation. On his view, while fairness and impartiality characterize the bargaining situation and coercion is ruled out, these conditions are necessary for making any agreement possible. Otherwise agents would not come to the table. See, e.g., Gauthier, David, Morals by Agreement (Oxford: Clarendon Press, 1986), chaps. 6–7Google Scholar. The Hobbesian agreement lacks even the modest constraints Gauthier proposes. See Hobbes, Thomas, Leviathan, ed. Macpherson, C. B. (New York: Penguin Books, 1968), chaps. 6, 14, 17, 21Google Scholar. For the distinction between “constrained” and “unconstrained” contract theories, see Morris, Christopher W., “Justice, Reasons, and Moral Standing,” in Coleman, Jules L. and Morris, Christopher W., eds., Rational Commitment and Social Justice: Essays for Gregory Kavka (New York: Cambridge University Press, 1998), 186–207, at 189CrossRefGoogle Scholar.

⁹ In this discussion, I use “agent,” “human,” and “person” more or less interchangeably, though there will likely be a significant difference between what qualifies as a “human being” and what qualifies as an “agent” or a “person.” This would matter when considering how contractarianism might assess the moral status of children or the disabled. I pass over this issue here, though there will be connections among various contractarian accounts for each case. But for a discussion of children, see Cohen, Andrew I., “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” Journal of Applied Philosophy 24, no. 2 (2007): 188–201, esp. sections 3–4CrossRefGoogle Scholar; and on the status of the disabled within contractualism, see Hartley, Christie, “An Inclusive Contractualism: Obligations to the Mentally Disabled,” in Brownlee, Kimberley and Cureton, Adam, eds., Disability and Disadvantage: Re-examining Topics in Moral and Political Philosophy (New York: Oxford University Press, forthcoming)Google Scholar.

¹⁰ Here I assume that no nonhuman animals are rational agents. Dolphins and some of the great apes might be rational agents to some extent, but I concentrate on exploring the moral status of animals that are not at all rational agents or persons. On the personhood of dolphins, see White, Thomas, In Defense of Dolphins (Malden, MA: Blackwell, 2007)CrossRefGoogle Scholar. On the place of morality among primates other than humans, see, e.g., de Waal, Frans, “Morally Evolved: Primate Social Instincts, Human Morality, and the Rise and Fall of ‘Veneer Theory,’” in his Primates and Philosophers (Princeton, NJ: Princeton University Press, 2006), 1–82Google Scholar.

¹¹ Gauthier admits as much; see Morals by Agreement, 268, 285.

¹² For some instances of this worry, see Carruthers, Peter, The Animals Issue: Morality in Practice (Cambridge: Cambridge University Press, 1992)CrossRefGoogle Scholar; DeGrazia, David, Taking Animals Seriously (Cambridge: Cambridge University Press, 1996)CrossRefGoogle Scholar; Hooker, Brad, Ideal Code, Real World: A Rule-Consequentialist Theory of Morality (Oxford: Oxford University Press, 2003), 7–9, 66–70Google Scholar; and Nussbaum, Martha, “Beyond the Social Contract: Toward Global Justice,” The Tanner Lectures on Human Values 24 (2004): 413–507Google Scholar. A related version of this objection concerns the status of the disabled in contractarian theory. See, e.g., Kittay, Eva Feder, Love's Labor (New York: Routledge, 1999)Google Scholar. Cynthia A. Stark recently considered a related worry about how to adapt Rawlsian contract theory to accommodate the disabled. See Stark, , “How to Include the Severely Disabled in a Contractarian Theory of Justice,” Journal of Political Philosophy 15, no. 2 (2007): 127–45CrossRefGoogle Scholar.

¹³ See, e.g., Kant, Immanuel, The Metaphysics of Morals, ed. and trans. Gregor, Mary (Cambridge: Cambridge University Press, 1996), 192–93CrossRefGoogle Scholar; Kant, “Duties Toward Animals and Spirits” (c. 1780), in Infield, Louis, trans., Lectures on Ethics (New York: Harper and Row, 1963), 239–41Google Scholar. See also Christine Korsgaard's discussion of Kant's views in Korsgaard, “Fellow Creatures: Kantian Ethics and Our Duties to Animals,” The Tanner Lectures on Human Values, presented at the University of Michigan, February 6, 2004, available at http://www.tannerlectures.utah.edu/ijklm.html.

¹⁴ Working in a contractarian framework, Jan Narveson suggests that animals at most enjoy an indirect moral status, most notably as property. See, e.g., Narveson, , Moral Matters (Orchard Park, NY: Broadview Press, 1999), chap. 6Google Scholar.

¹⁵ Depending on the specific version of contractarianism, there might be no meaningful way to describe some behavior toward animals as mistreatment until norms forbidding some behavior emerge from an agreement.

¹⁶ See, e.g., Hooker, Ideal Code, Real World, 67–68.

¹⁷ Kant puts this well when he speaks of how cruelty toward animals blunts a “shared feeling of their suffering and so weakens and gradually uproots a natural disposition that is very serviceable to morality in one's relations with other people.” Kant, The Metaphysics of Morals, 192–93.

¹⁸ For a related discussion, see Hooker, Ideal Code, Real World, 68–70.

¹⁹ Much would also depend on how we describe the contractors; how much they know about people's psychologies; their beliefs about the power of education, inculcation, and example to inspire people to develop certain dispositions; and, perhaps most importantly, the specific theory of rationality built into the contractarian theory. If rationality were purely instrumental, then contractors' particular ends would govern their decision on the relevant candidate moral norm. If rationality has an end (or ends), then, depending upon what those ends were, people might be committed to treating animals in a certain way. For a related discussion of whether Hobbesian reason has an end of its own, see Cohen, Andrew I., “Warmongers, Martyrs, and Madmen Versus the Hobbesian Laws of Nature,” Canadian Journal of Philosophy 32, no. 4 (2002): 561–86, esp. 576–81CrossRefGoogle Scholar.

²⁰ See, e.g., Gauthier, Morals by Agreement, 269.

²¹ For a related discussion, see Narveson, Jan, “Gauthier on Distributive Justice and the Natural Baseline,” in Vallentyne, Peter, ed., Contractarianism and Rational Choice (Cambridge: Cambridge University Press, 1991), 127–48, at 141–42Google Scholar.

²² Chris Morris draws a similar distinction between direct and indirect moral objects in “Justice, Reasons, and Moral Standing,” 191.

²³ I assume here that beneficence is the sort of moral consideration that can be owed. Whether the prospective beneficiary can also be a claimant of it is another matter. For a related discussion of disconnecting rights from demands, see Badhwar, Neera, “The Circumstances of Justice: Pluralism, Community, and Friendship,” The Journal of Political Philosophy 1, no. 3 (1993): 250–76, at 266–71CrossRefGoogle Scholar. See also Christopher Morris's discussion of the place of beneficence in contract theory in “Moral Standing and Rational-Choice Contractarianism,” in Vallentyne, ed., Contractarianism and Rational Choice, 76–96, at 93–94.

²⁴ Of course, particular substantive moral theories might insist that moral status cannot vary in this fashion. A theory may say, for instance, that if some entity has direct moral status, it has that with respect to all persons.

²⁵ This account of primary and secondary moral standing owes much to Christopher W. Morris. See Morris, “Moral Standing and Rational-Choice Contractarianism”; Morris, , “A Contractarian Account of Moral Justification,” in Sinnott-Armstrong, Walter and Timmons, Mark, eds., Moral Knowledge (Oxford: Oxford University Press, 1996), 215–42Google Scholar; and Morris, “Justice, Reasons, and Moral Standing.”

²⁶ If animals can agree to mutual restraint with human beings, then they might acquire primary moral standing. I see little convincing evidence that animals can do so. In any case, the number of types of animals that are candidates for having such advanced rational abilities is narrower than the scope of animals we typically regard as being owed our direct moral consideration. I know of one argument that many animals can agree to restraint and are thus eligible to be contractors. See Tucker, C. and MacDonald, C., “Beastly Contractarianism: A Contractarian Analysis of the Possibility of Animal Rights,” Essays in Philosophy 5, no. 2 (2004), available at http://www.humboldt.edu/~essays/tucker.htmlGoogle Scholar.

²⁷ Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals.”

²⁸ Here I pass over several complicating scope issues, such as how many animals are the subject of the agreement, whether all animals of a given type are thus protected, and whether the relevant moral protections are all of the same stringency for all agents prospectively bound. On related themes, see Cohen, Andrew I., “Dependent Relationships and the Moral Standing of Nonhuman Animals,” Ethics and the Environment 13, no. 2 (2008)CrossRefGoogle Scholar.

²⁹ See related discussion in Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” secs. 3–4.

³⁰ I make the simplifying assumption that no other moral constraints bind agents regarding the animal.

³¹ See Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” secs. 5–6.

³² Rawls, A Theory of Justice, 13.

³³ Morris, Christopher W., “The Relation between Self-Interest and Justice in Contractarian Ethics,” Social Philosophy and Policy 5, no. 2 (1988): 119–53, at 123CrossRefGoogle Scholar.

³⁴ See Gauthier, Morals by Agreement, 87; and Morris, “The Relation between Self-Interest and Justice in Contractarian Ethics,” 123.

³⁵ For discussion, see Morris, “The Relation between Self-Interest and Justice in Contractarian Ethics,” 123–24; Morris, “Moral Standing and Rational-Choice Contractarianism,” 90–92; and Peter Vallentyne, “Contractarianism and the Assumption of Mutual Unconcern,” in Vallentyne, ed., Contractarianism and Rational Choice, 71–75.

³⁶ Vallentyne, “Contractarianism and the Assumption of Mutual Unconcern,” 73 (emphasis in the original).

³⁷ Ibid., 73–74.

³⁸ The preferences need not be “considered” preferences, despite Gauthier's suggestions. See Gauthier, Morals by Agreement, 29–38. For a critique of the appeal to such considered preferences, see Murray, Malcolm, “Unconsidered Preferences,” South African Journal of Philosophy 17, no. 4 (1998): 346–53CrossRefGoogle Scholar.

³⁹ I am grateful to Brad Hooker and Ellen Frankel Paul for pressing versions of this worry.

⁴⁰ To be more precise, in such a case the weight at the bargaining table of demands by the animals' advocates would not be enough to give contractors reason to endorse norms protecting such animals.

⁴¹ Perhaps, for instance, human beings simply do not owe any moral consideration directly to Gila monster lizards. If we can make sense of the notion of gratuitously torturing a Gila monster, and if such torture is wrong, at most it wrongs other human beings. But since Gila monster saliva produces compounds useful for treating diabetes (see, e.g., http://www.centerwatch.com/patient/drugs/dru879.html), one can imagine contractors insisting on moral norms that forbid the gratuitous destruction of any (and especially all) Gila monsters.

⁴² For a discussion of the possibility that the contract may endorse defective norms, see Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” sec. 6.

⁴³ For a discussion of some of the conditions of “owing to,” see ibid., sec. 5.

⁴⁴ This seems to be much of the reason Jan Narveson rejects the moral considerability of animals. See Narveson, “Gauthier on Distributive Justice and the Natural Baseline,” 141–42.

⁴⁵ By appealing to the apparatus of secondary moral standing, the contractarian can allow for owing direct moral consideration to infants. A similar sort of unilateral constraint might apply between human persons and nonhuman animals. See Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” secs. 3–4.

⁴⁶ This example is purely illustrative and not meant to presuppose that beneficence is necessarily a contractarian moral virtue or that it can be owed. For related discussion, see Morris, “Moral Standing and Rational-Choice Contractarianism,” 93–95.

⁴⁷ The “exclusionary scope” of a reason refers to how many first-order reasons it excludes from counting in the balance of reasons. For related discussions, see Raz, Joseph, Practical Reason and Norms (London: Hutchinson and Co., 1975)Google Scholar; , Raz, The Authority of Law (Oxford: Clarendon Press, 1979)Google Scholar; Raz, , The Morality of Freedom (Oxford: Clarendon Press, 1986)Google Scholar; and Raz, , “Facing Up: A Reply,” Southern California Law Review 62 (1980): 1153–1235Google Scholar.

⁴⁸ Here I suppose that these three parameters all influence the same metric: moral standing. It might be analytically more complete to speak of three different parameters of moral standing that track the three varying factors (number of agents, which considerations, and stringency). This level of precision is not required for the analysis of welfare conflicts that I offer below.

⁴⁹ Here I need not take a stand on whether the contract necessarily includes and thus binds all persons. Having enough agents might be enough to secure the mutual restraint contractors seek. See related discussion by Kavka, Gregory S. in “The Reconciliation Project,” in Copp, David and Zimmerman, David, eds., Morality, Reason, and Truth (Totowa, NJ: Rowman and Allanheld, 1984), 297–319, at 306–7Google Scholar; Morris, “A Contractarian Account of Moral Justification,” 226; and Cohen, “Warmongers, Martyrs, and Madmen Versus the Hobbesian Laws of Nature,” sec. VIII.

⁵⁰ All this will be true even if the relevant moral norms do not necessarily generate decisive (or indeed any) reasons. For related discussion, see Morris, “A Contractarian Account of Moral Justification,” esp. 226–33.

⁵¹ My conception of responsiveness comes from Iwao Hirose, “Aggregation and the Separateness of Persons,” paper delivered at Georgia State University, April 9, 2007, pp. 3–4.

⁵² These formulations draw from Hirose, “Aggregation and the Separateness of Persons,” 3–4. To be clear, the contract is not necessarily saying that all choice situations involving the welfare of two or more entities express responsiveness in a way that generates moral reasons. But insofar as the contract would endorse some option(s) as morally preferable in such situations, it would thereby express (or at least be consistent with) responsiveness. Whether the contract would say that any possible resolution to conflict situations must also be a function of moral norms would depend on whether the theory (or a substantive doctrine to which it is married) has any commitments on the pervasiveness of morality. For related discussion, see Scheffler, Samuel, “Morality's Demands and Their Limits,” The Journal of Philosophy 83, no. 10 (1986): 531–37CrossRefGoogle Scholar. The theory's commitments on this issue do not ultimately seem to matter much for the important cases involving conflict, for at least in some such cases the contract would resolve the conflict by endorsing one option as morally preferable.

⁵³ Responsiveness also says nothing about what a moral theory would say properly counts as a benefit or a harm (or, similarly, a gain or a loss). To simplify the discussion, I shall assume there is a criterion of gain/loss that is sufficiently robust so as to command a consensus that resolves the bulk of cases involving putative gain/loss. This is not to claim there would be no difficulties in determining what this criterion might be. If it is not available in some handy form prior to agreement, it would need to be a product of the contract.

⁵⁴ Obviously, there are various other possible combinations that would be instances of rivalrous welfares, such as: a gain to one entity requires forgoing a gain to another, or, a gain to one individual comes with an opportunity cost of forgoing an additional gain to another entity that otherwise stood to gain in any case, and so forth.

⁵⁵ The conclusions of the contract will significantly hang on the structure of the coalitions at the bargaining table. As Christopher Morris notes, however, coalition theory is underdeveloped—especially for the purposes of generating a determinate contractarian moral theory. See his discussion in “Justice, Reasons, and Moral Standing,” 192, 202–3. See also Milo, “Contractarian Constructivism,” esp. sec. III.

⁵⁶ See, e.g., Hume, David, A Treatise of Human Nature (1739; Oxford: Clarendon Press, 1951), III.2.2Google Scholar.; , Hume, An Enquiry Concerning the Principles of Morals (1777; Oxford: Clarendon Press, 1975), III.1Google Scholar; Morris, “Moral Standing and Rational-Choice Contractarianism,” 79–80, 86; Morris, “A Contractarian Account of Moral Justification,” 220; Gauthier, Morals by Agreement, 113–16; and Rawls, A Theory of Justice, 126–30.

⁵⁷ Again, not all conflict situations necessarily have one or any morally preferable outcome, because not all situations of conflict are moral conflict; and not all moral conflicts necessarily have determinate or unique moral resolutions. For related discussion, see Foot, Philippa, “Moral Realism and Moral Dilemma,” The Journal of Philosophy 80, no. 7 (1983): 379–98CrossRefGoogle Scholar.

⁵⁸ Again, the criterion of gain/loss would depend significantly on the findings of the rich literature on rational choice. I propose setting such controversies aside by supposing that whatever criterion contractors select would still present them with a possibility where human and animal welfares would potentially be in conflict.

⁵⁹ On whether and how an animal's death counts as a setback to its welfare, see Jeff McMahan, The Ethics of Killing, sec. 1.2.

⁶⁰ See, e.g., Narveson, Jan, “Moral Problems of Population,” The Monist 57, no. 1 (1973): 62–86CrossRefGoogle Scholar; Narveson, , “Utilitarianism and New Generations,” Mind 76, no. 301 (1967): 62–72CrossRefGoogle Scholar; Parfit, Derek, Reasons and Persons (Oxford: Clarendon Press, 1984), 370, 394Google Scholar; Broome, John, Weighing Lives (Oxford: Oxford University Press, 2004), chaps. 8–9CrossRefGoogle Scholar; and Vallentyne, Peter, “Critical Notice of Child Versus Childmaker: Future Persons and Present Duties in Ethics and the Law by Melinda Roberts,” Noûs 34, no. 4 (2000): 634–47CrossRefGoogle Scholar.

⁶¹ Of course, this might be an argument against structuring the contractarian choice situation in a way to rule out non-person-affecting criteria for morally considerable welfare, but my task here is not to defend contractarianism but to explore the moral logic it features for resolving conflicts between persons and animals. See related discussion about cross-generational ties in Gauthier, Morals by Agreement, chap. 9; but see also worries about Gauthier's approach in Kavka, Gregory, “The Problem of Group Egoism,” in Hooker, Brad, ed., Rationality, Rules, and Utility: New Essays on the Moral Philosophy of Richard B. Brandt (Boulder, CO: Westview Press, 1993), 149–63Google Scholar. My thanks to Harry Dolan for correspondence on this issue.

⁶² I assume here that only animals, and likely only sentient creatures, can have welfares. See Cohen, “Contractarianism, Other-Regarding Attitudes, and the Moral Standing of Nonhuman Animals,” 192; Taylor, Paul, “Frankena on Environmental Ethics,” Monist 64, no. 3 (1981): 313–24CrossRefGoogle Scholar; Feinberg, Joel, “The Rights of Animals and Unborn Generations,” in Blackstone, W., ed., Philosophy and Environmental Crisis (Athens, GA: University of Georgia Press, 1974), 43–68Google Scholar; and DeGrazia, Taking Animals Seriously. But nothing in my account hangs on this assumption. If, contrary to my belief, plants or rocks can have welfares, then, after setting out some ontology of entity, we could explore whether contractors would endorse an entity-affecting or a non-entity-affecting criterion of welfare.

⁶³ Here I am happy to avoid the more accurate but clumsier “non-nonhuman-animal-affecting.”

⁶⁴ Certain maximizing requirements for welfare may then threaten a “repugnant woodpecker conclusion,” but I do not pursue that matter here.

⁶⁵ There would be further complications in understanding how, if at all, such a perfectionist criterion applies to nonhuman animals. If it applies to animals, it might not be a loss to the gazelle when a lion hunts and kills it. This would seem to require an implausibly robust non-animal-affecting criterion of welfare.

⁶⁶ Here I have assumed there would no place for partial perfectionist criteria of gain/loss. Any such partial criterion would not rule out conflict entirely; it would merely restrict opportunities for conflict. The criterion would rule out only certain prospective changes to welfare as genuine gains or losses. Contractors would then have to have agreed to a norm that disqualifies only certain putative gains from being genuine. If only certain gains are ruled out, then either we can capture the effects of ruling out such putative gains by appealing to various substantive constraints (as I discuss at present in the text), or contractors could agree that some such gains simply are not really gains. Again, I confess I do not see why contractors would agree to this latter notion.

⁶⁷ See Hirose, “Aggregation and the Separateness of Persons,” 3; and Broome, Weighing Lives, 135–36. See also Gauthier, Morals by Agreement, 235–36.

⁶⁸ For a splendid discussion of problems with speciesism, see Norcross, Alastair, “Puppies, Pigs, and People: Eating Meat and Marginal Cases,” Philosophical Perspectives 18, no. 1 (2004): 229–45CrossRefGoogle Scholar.

⁶⁹ The contract can reach this conclusion regardless of its commitments on whether the relevant criterion for chicken welfare is chicken-affecting or non-chicken-affecting. It need only hold that the life of any such chicken is below some baseline for making the life worth living. For related discussion, see John Broome's account of the “neutral level” of human existence in Weighing Lives, chaps. 10, 13. If no human life is worth living, interspecies welfare comparisons might be further complicated but certainly not impossible. See Benatar, David, Better Never to Have Been: The Harm of Coming into Existence (Oxford: Oxford University Press, 2006)CrossRefGoogle Scholar.

⁷⁰ Norcross might raise such an objection. See, e.g., his “Puppies, Pigs, and People: Eating Meat and Marginal Cases.”

⁷¹ Human health likely generates a wide but not absolute substantive exclusionary constraint. Contractors might agree to discount the suffering of animals confined for the purposes of experimentation to develop some pharmaceutical or consumer product to benefit humans, even if, on some measures of welfare, the setback to animals exceeds the benefit to human beings. This discount might not, however, exclude what contractors would deem inappropriate or gratuitous animal discomfort, such as pain that can be avoided without jeopardizing the integrity of a study. Examples of norms restricting such inappropriate treatment are found in the various animal use and care principles governing research universities in the United States.

⁷² I take no stand here on whether the contract would reach this conclusion by aggregating the frogs' welfare setbacks or by saying that the welfare gain to Lou from any given incremental roll forward in the car is not as weighty as the welfare setback to each frog hurt as the car proceeds along that increment.

⁷³ See, e.g., Gauthier, Morals by Agreement, 208–11, 221–23.

⁷⁴ See, e.g., Narveson, Jan, The Libertarian Idea (Philadelphia, PA: Temple University Press, 1988)Google Scholar; Gauthier, Morals by Agreement, chap. 7; and the essays in Vallentyne, ed., Contractarianism and Rational Choice, esp. those in part II.

⁷⁵ I discuss this right to do wrong in “Virtues, Opportunities, and the Right to Do Wrong,” Journal of Social Philosophy 28, no. 2 (1997): 43–55.

⁷⁶ Presumably, the contract would also indicate what counts as a “harm.” Here I set aside the issues of the mechanics of the contractors' settling on a notion of harm and what the content of the notion is likely to be.

⁷⁷ See, e.g., Regan, The Case for Animal Rights, 308. See also Regan, Tom, “Animal Rights, Human Wrongs,” in Zimmerman, Michael E. et al. , eds., Environmental Philosophy, 4th ed. (Upper Saddle River, NJ: Prentice Hall, 2005), 41–55Google Scholar.

⁷⁸ To be clear, in the case of Regan's example, the circumstances of justice might no longer obtain between the person in question (along with her advocates), and those persons who advocate for the Siberian tigers.

⁷⁹ See related discussion by Morris in “Justice, Reasons, and Moral Standing,” 200–203.

⁸⁰ Ibid., 201.

⁸¹ For related discussion, see Milo, “Contractarian Constructivism.”

⁸² See also Morris, “Justice, Reasons, and Moral Standing,” 207 n. 46.

⁸³ But see related discussions of slavery in Gauthier, Morals by Agreement, chap. 7; Morris, “Moral Standing and Rational-Choice Contractarianism,” 87–89, 93–95; and Morris, “Justice, Reasons, and Moral Standing,” 192–94.