In the late twentieth century, theorists’ attention was drawn to a new way of thinking about individuals’ relative level of advantage or well-being. Instead of assessing either of these on the basis of the resources (such as income and wealth) available to people or on the basis of what they have achieved (by way of satisfying their interests, preferences, or plans, as utilitarians would, or by way of functioning in one way or another, as Aristotle did), the new thought was to do so on the basis of what people are able to do or to be: on the basis, that is, of their capabilities. Amartya Sen (1982) introduced this idea of capabilities partly via a critique of Rawls’s reliance on the idea of primary goods, and speciically of his suggestion that income and wealth can serve to index inequalities for purposes of the difference principle. Consequently, it is sometimes thought that the “capabilities approach” that has grown up around Sen’s constructive suggestions and those of Martha Nussbaum is inimical to Rawls’s approach. Nussbaum, however, has recently written that since “for Rawls the primary goods are just one element in a highly complex overall theory, it is perhaps best not to invoke his theory” as a foil for the capability approach (2011, 56–57).