 As is well known, Rawls starts by ascribing to the utilitarian the claim that the rationality of a certain principle of social choice can be inferred from the rationality of a certain principle of individual choice. The principle of individual choice is that, at least if no other party is affected, it is rational for an individual to incur costs for herself (or to forego benefits for herself) if doing so will spare her greater costs (or provide her with greater benefits). According to Rawls, the utilitarian holds that by parity of reasoning it is rational for a member of society to incur costs for herself (or to forego benefits for herself) if doing so will spare any member of society greater costs (or provide any member of society with greater benefits). This is the purported rational principle of social choice. Thus, we get to the utilitarian conclusion that each agent as a member of society has reason to maximize the aggregate social good even at the expense of the individual good of herself (or others).