  In a much-quoted passage, Sidgwick claimed that rational egoism is not arbitrary: “It would be contrary to Common Sense to deny that the distinction between any one individual and any other is real and fundamental, and that consequently ‘I’ am concerned with the quality of my existence as an individual in a sense, fundamentally important, in which I am not concerned with the quality of the existence of other individuals: and this being so, I do not see how it can be proved that this distinction is not to be taken as fundamental in determining the ultimate end of rational action for an individual” (Sidgwick 1907, 498).  This can be interpreted in various ways (Shaver 1999, 82–98; Phillips 2011, ch. 5).