Measuring freedom: towards a solution to John Rawls’ indexing problem

Suppose a principle of distributive justice states that social institutions should maximize the freedom of the least well-off. Understanding how to do so would be easier if freedom only depended on one good, like income. If it depends instead on a composite index of social primary goods, a question arises: Which combination of social primary goods can maximize the freedom of the least well-off? This is John Rawls’ indexing problem. Solving it requires addressing two related problems. The first consists in evaluating, in theory, under which conditions it is acceptable to substitute goods, that is, their substitution rates. The second consists in evaluating which acceptable substitutions are feasible in practice. This article proposes a framework to think clearly about this indexing problem within a Rawlsian, resourcist conception of distributive justice. I conclude by discussing a path towards solving the indexing problem. While further empirical exploration is needed, plausible assumptions about social regimes suggest that maximizing the freedom of the least well-off is likely to require giving them access to a social position with a balanced combination of social primary goods.