sources for requiring cooperation than Zhu recognizes. But that may be of little import, as Zhu also charges that cases commonly thought to raise issues of fair play fall instead under the purview of consent. I turn now to that issue. 7 Incidentally, although Zhu attributes the actual consequences argument to George Klosko, I think Klosko has something more like my argument in mind. See The Principle of Fairness and Political Obligation, Rev. ed. (Lanham, Md.: Rowman & Littlefield, 2004), 42. Hart also clearly rejects the appeal to actual consequences as the basis of a duty to play fair. Immediately after stating the principle of fair play, he writes: "In social situations of this sort... the obligation to obey the rules is something distinct from whatever other moral reasons there may be for obedience in terms of good consequences (e.g., the prevention of suffering); the obligation is due to the cooperating members of the society as such and not because they are human beings on whom it would be wrong to inflict suffering." "Are There Any Natural Rights?," Philosophical Review 64, no. 2 (1955): 185. Other common-sense defenses of fairness also explicitly reject the need for additional bad consequences to render unfair rulebreaking morally problematic. See Gerald F. Gaus, Social Philosophy (London: M. E. Sharpe, 1999), 184–85. 8 Zhu, "Fairness, Political Obligation, and the Justificatory Gap," 307–308. 5Playing Fair and Following | doi 10.1163/17455243-46810054 journal of moral philosophy (2016) 1-8 <UN> 2 Consent and Fair Play Both consent and fair play are transactional principles. They account for the transfer or creation of rights relationships between persons by appeal to some interaction between them. As a result, the two principles have a similar structure with similar parts. On consent theory, one commits to an agreement by the offering of a "sign of consent"-an act that, "because of the context in which the act was performed, including the appropriate conventions (linguistic or otherwise)...counts as 