“Utilitarianism can be usefully characterized (following an analysis proposed by Bernard Williams and Amartya Sen) as involving three ideas. First, consequentialism: The right choice is the one that produces the best overall consequences. Second, sum-ranking: The way we aggregate the satisfactions of different persons into a social whole is simply by adding them all up (rather than, say, by focusing on getting the worst-off person as high up as possible, or by insisting on some constraints on how unequal people can be allowed to be). Third, some substantive view of what the good for a person is, such as pleasure, or the satisfaction of desire. Sidgwick, like Bentham, opts for pleasure, though he is much more sensitive than Bentham to the difficulties involved in comparing different pleasures of the same person and the even greater difficulty involved in comparing the pleasures of different people.”
“Utilitarians typically commend the choice of pleasure as the goal by pointing to the alleged ubiquity of the pursuit of pleasure (not the best and surely not the only way to justify a central ethical value, one might have thought). They then encounter a difficulty: If what each person pursues, and should pursue (according to them), is maximal personal pleasure, how are we going to defend the view that the right goal for society is the greatest happiness of the greatest number? And how, having defended the view, are we going to convince people that it is that goal, rather than the egoistic goal, that they should pursue, since for many people pursuing overall happiness will involve personal sacrifice? Mill had a lot of difficulty with the philosophical argument, and he needed ultimately to depart from strict Utilitarianism in order to solve it to the extent that he did; but he was optimistic about the social process, believing that civic education could produce people who really did think of the happiness of others as an integral part of their own happiness. Sidgwick was hung up on this problem all his life; he called it the "dualism of practical reason,” and in the end he believed that he had failed to solve it--unless life after death should turn out to produce a coincidence between personal happiness and service to others. But he made much more headway than his predecessors on the philosophical side of the issue, with his probing work on ethical methodology and his defense of a perspective of impartiality ("the point of view of the Universe") as the right place from which to make ethical judgments. (Schultz rightly notes that Sidgwick owes a considerable debt to Kant, although it is scarcely acknowledged, and to the Kantian idea that one must not favor one's own case but rather must test one's own actions by thinking about how they would look as universal features of the world.)”
From Martha Nussbaum, ‘Epistemology of the Closet’ in The Nation June 6, 2005.