General epistemological skepticism about the reliability of interpersonal comparisons of welfare cannot be warranted. It cannot be that we are never warranted in making interpersonal comparisons of welfare. If magnitudes of welfare exist and we sometimes make confident judgments about these magnitudes, then there is no reason to deny that we can sometimes make reliable judgments of this sort. Depending on what things have intrinsic or extrinsic value, we will have a variety of means by which to measure value directly or indirectly. According to OU [Objective Utilitarianism], liberty has great extrinsic value, and liberty can presumably be measured directly by the absence of legal, physical, and perhaps psychological restraints. Pleasure and pain can be measured by a variety of indices (e.g., introspective reports and nonlinguistic behavior). Basic well-being can be measured by a variety of nutritional, medical, and psychological criteria. Respect for persons can be measured (in a way that relies on moral theory, of course) by a variety of social, psychological, and economic indices. Many questions about the appropriate methods of measurement, of course, can be best addressed only after one has fully articulated the components and conditions of human welfare. There is no reason, however, to claim that we cannot now make some highly accurate comparisons of the welfare of different individuals or groups.
(David O. Brink, Moral Realism and the Foundations of Ethics, Cambridge Studies in Philosophy, ed. Sydney Shoemaker [Cambridge: Cambridge University Press, 1989], 255)
