The Capabilities Approach to Justice

Core Idea

The capabilities approach (Sen, Nussbaum) shifts focus from resources or utility to what people are actually able to do and be. Justice requires substantive freedoms—health, education, political participation, practical reason. Rather than assuming everyone needs identical resources, it recognizes people need different support to achieve equivalent capabilities. This bridges rights-based and welfare-based theories by emphasizing human flourishing and real freedoms.

Explainer

From your study of the capabilities approach as a welfare framework, you know the basic idea: Sen and Nussbaum propose that we evaluate well-being not by how many resources people have or how satisfied their preferences are, but by what they are actually able to do and be — their capabilities. A capabilities approach to justice takes this framework and asks: what must a just society guarantee? Which capabilities are so fundamental that their absence constitutes an injustice, not just a misfortune?

Martha Nussbaum answers with a list of central human capabilities — bodily health, bodily integrity, the use of senses and imagination, emotional development, practical reason, political participation, control over one's environment, and others. These define the threshold no just society should leave any person below, because they are preconditions of a distinctly human life. Crucially, this is a floor, not a ceiling: justice requires that every person reach a minimum threshold of each central capability, not that capabilities be equalized. Someone with extraordinary capabilities does not need to be reduced; someone falling below the threshold has a justice claim on the society.

The framework's most powerful insight is that converting resources into capabilities is uneven. A person using a wheelchair needs more resources to achieve the same mobility capability as an ambulatory person. A woman in a society that restricts her movement and autonomy cannot convert formally equal legal rights into real freedom to pursue her projects. This means justice cannot be simply about distributing equal resources — it must attend to conversion factors: the individual, social, and environmental conditions that determine what people can actually do with resources. This bridges rights-based theories (which emphasize formal entitlements) and welfare-based theories (which track outcomes) by insisting on substantive, not merely formal, freedom.

The approach also draws a careful distinction between capabilities (real opportunities) and functionings (actually achieved states). A just society guarantees capabilities — the real freedom to live in various ways — but does not compel particular functionings, preserving individual choice. Someone who can eat well but chooses to fast retains the capability; justice requires the capability, not the achievement. The main challenge the approach faces is specifying which capabilities belong on the mandatory list, and by whom. Sen deliberately avoids a fixed list to preserve flexibility across democratic communities; Nussbaum's list has been criticized as reflecting particular cultural values. This tension between universal requirements and cultural plurality is one of the central debates within the capabilities tradition.