We shall focus on moral theories that are solely concerned with promoting the benefits (e.g., wellbeing) of individuals and explore the possibility of such theories ascribing some priority to benefits to those who are worse off—without this priority being absolute. Utilitarianism (which evaluates alternatives on the basis of total or average benefits) ascribes no priority to the worse off, and leximin (which evaluates alternatives by giving lexical priority to the worst off, and then the second worst off, and so on) (...) ascribes absolute priority to the worse off (i.e., favors even a very small benefit to a worse off person over very large benefits to large numbers of better off people). Neither extreme view, we assume, is plausible. (shrink)

The difference principle, introduced by Rawls (1971, 1993), is generally interpreted as leximin, but this is not how he intended it. Rawls explicitly states that the difference principle requires that aggregate benefits (e.g., average or total) to those in the least advantaged group be given lexical priority over benefits to others, where the least advantaged group includes more than the strictly worst off individuals. We study the implications of adopting different approaches to the definition of the least advantaged group and (...) show that, if acyclicity is required, several seemingly plausible approaches lead to something close to leximin. We then show that significant aggregation is possible, if the least advantaged group is defined as those with those with less benefits than some strictly positive transform of the lowest level of benefits. Finally, we discuss the implications of requiring that, in comparing two alternatives, the cutoff for the least advantaged group of one alternative be the same as that for the other alternative. (shrink)

in Intergenerational Equity and Sustainability, edited by John Roemer and Kotaro Suzumura, (Palgrave Publishers Ltd., forthcoming 2007), ch.11.