 Lippert-Rasmussen’s second objection is the “group-identification” challenge. There are any number of ways to sub-divide a given population into groups. Holding the underlying health facts fixed, different choices of group definition will correspond to different inequalities in health (of different magnitudes) inhering in the same population. Some explanation is called for, then, of the significance in justice of the particular character of one’s favored group definition. What is the relevance to justice, for example, of the apparently artificial boundary demarcating the top 1% of the income distribution in the U.S. from the bottom 1% (our opening illustration of an inequality in health)?