 The rationale for the use-per-need view might appeal to an argument from function of the following sort: “The (main) function of health-care services is to prevent and cure illness, i.e., to meet health-care needs. A distribution of health-care services that is not determined by the distribution of health-care needs is therefore unreasonable in some important sense. One sense in which it is unreasonable is that it would defeat the purpose of meeting health needs to provide access in ways not determined by the level or kinds of need people have. Another sense in which it is unreasonable is that it ignores similarities and differences—here in health status—between persons which, given the function of health care, ought to be relevant to establishing its reasonable distribution. Ignoring such relevant similarities and differences is what it means for a distribution to be inequitable.” A version of this argument is clearly foreshadowed in Bernard Williams’ (1971: 27) now classic discussion of equality in which he concluded that, “leaving aside preventive medicine the proper ground of distribution of medical care is health; this is a necessary truth.”