Rawls’s theory of justice concerns the scope of required equalities and permitted inequalities engendered by the basic social structure of a society: the distributive justice of “the way in which the major social institutions it together into one system, and how they assign fundamental rights and duties and shape the division of advantages that arises through social cooperation”(PL 258).Within this basic structure individuals act so as to secure an actual allocation of determinate goods to each participant. Arguments concerning this subject require an index of benefits and burdens that allows publicly accessible interpersonal comparisons of citizens’ well-being, in the relevant sense, among representative members of various social groups: “the idea is to find a practicable public basis of interpersonal comparisons in terms of objective features of citizens’ social circumstances open to view” (CP 454–455).

Rawls’s answer is to focus on how the basic structure of society distributes social primary goods. These arise out of institutions – that is, legal powers and immunities: