Chapter 2 builds on research across the social sciences to provide a parsimonious approach to the study of fairness reasoning “in action.” In Western democracies, it argues, reasoning about the fairness of redistributive social policies implies two types of fairness evaluation: (1) how fair is it for some to make (a lot) more money than others in the marketplace and (2) how fair is it for some to receive more in benefits than they pay in taxes? Each question calls to mind a different norm of fairness: the proportionality norm, which prescribes that individual rewards be proportional to effort and talent, or the reciprocity norm, which prescribes that cooperative behavior be rewarded more than uncooperative behavior. Agreement with these two norms is quasi-universal. Where people differ is with regard to their fairness beliefs, that is, their assessment of the status quo as more or less deviating from what these norms prescribe.