Fourth, a capability theory of justice may need to address other ‘metrics of justice’. Within theories of justice, one strand of debate has been between those defending capabilities and functionings, on the one hand, and those defending Dworkian resources (see Dworkin 2000, 299–303; Kaufman 2006b, 125–128; Pierik and Robeyns 2007; Sen 1985b; 2009, 264–268; Williams 2002). Functionings and capabilities have also been proposed by capability philosophers as an alternative for, and improvement on, the Rawlsian social primary goods metric, which focuses on general purpose goods, such as income and wealth, opportunities and liberties, and the social basis of self-respect (Rawls 1971). Sen argues that a focus on primary goods is inherently inflexible as a metric of justice: “the primary goods approach seems to take little note of the diversity of human beings. … If people were basically very similar, then an index of primary goods might be quite a good way of judging advantage. But, in fact, people seem to have very different needs varying with health, longevity, climatic conditions, location, work conditions, temperament, and even body size. … So what is being involved is not merely ignoring a few hard cases, but overlooking very widespread and real differences” (Sen 1979a: 215–216), such as in the case of the disabled person who would not have a claim to additional resources grounded in his impairment under Rawls’s two principles of justice. Sen argues that Rawls’s difference principle would not justify any redistribution to the disabled on grounds of disability.