 Gauthier (1986: 140–141, 152–153) suggests that cooperative surplus might be split according to the ratio of the parties’ “individual relative benefit from cooperation”. Each party’s relative benefit from exchange is measured by their next best option. If A and B generate $10 of cooperative surplus, and A could have earned $3 acting independently of B, while B could have earned $4, then the maximum A can claim of the surplus is $6 consistent with inducing B’s willing cooperation, and the maximum B can claim is $7 for a parallel reason. When the $10 surplus is split based on a 6:7 ratio, each party receives such benefits as she would expect apart from cooperation and, in addition, receives a share of the surplus proportionate to her potential for benefiting from the exchange. Gauthier defends the proposal as a solution to a bargaining problem confronting self-interested rational agents, but it is morally contestable. It remains unclear why a party should receive more just because they had a better alternative, since the availability of an attractive alternative may be a function of brute luck. Moreover, Gauthier’s principle does not guarantee that parties receive a share commensurate to sacrifice or productive contribution (Van Parijs 1996).