Full Idea
Rawls claims that utilitarianism applies to the problem of many interests a method appropriate for one individual. A single person may accept disadvantages in exchange for benefits, but in society other people get the benefits.
Gist of Idea
Utilitarianism inappropriately scales up the individual willingness to make sacrifices
Source
report of John Rawls (A Theory of Justice [1972], p.74,104) by Thomas Nagel - Equality §7
Book Reference
Nagel,Thomas: 'Mortal Questions' [CUP 1981], p.119