In late twentieth-century philosophy, the debate over how to measure justice and well-being took a new direction. The American philosopher Martha Nussbaum (b. 1947), together with the economist Amartya Sen, brought a fundamental objection to the dominant measures — approaches that gauge a country's wealth by income per capita and a person's welfare by the resources they hold.

The core of the objection is this: resources are not an end but a means. Two people may have the same income, but if one is disabled, ill, or subject to discrimination, what they can actually do with that income differs greatly. The true measure of justice, then, is not the money in people's hands but what they can really do with it and with social conditions — what kind of life they can lead. Nussbaum calls this "capabilities": a person's freedom to do and to be the things they value.

Nussbaum departed from Sen by adding a concrete list to this approach. She set out the basic capabilities that every society must secure for a life worthy of human dignity: life; bodily health and integrity; the senses and thought; emotions; practical reason; affiliation with others; play; control over one's environment. A society cannot be counted just unless it provides its members this minimum threshold. This is not an abstract principle but a practical framework that directly influences development policy, women's rights, and disability rights.

Nussbaum's work brought philosophy together with economics, law, and development studies; instruments such as the United Nations Human Development Index drew on this thinking. Inspired by ancient Greek ethics (Aristotle's concept of the "good life," eudaimonia), Nussbaum redefined philosophy not as merely an abstract analysis but as a pursuit aimed at improving the concrete lives of people.