A core interest of social science is the study of stratification--inequalities in income, power, and prestige. Few persons would care about such inequalities if the poor, powerless, and despised were as happy and fulfilled as the wealthy, powerful, and admired. Social research often springs from humanistic empathy and concern as much as from scholarly and scientific curiosity. An economist might observe that black Americans are disproportionately poor, and investigate racial differences in education, employment, and occupation that account for disproportionate poverty. A table comparing...