Here is a thought experiment that Amartya Sen (born 1933, Nobel Prize in Economics 1998) used to devastating effect. Imagine two people. Person A earns $30,000 a year and is healthy, educated, politically free, and able to participate fully in social life. Person B also earns $30,000 a year but has a chronic illness that requires expensive treatment, lives in a society that discriminates against her gender or caste, lacks access to the education that would let her convert her income into a good job, and is excluded from political participation.
By standard economic measures, A and B are identical. Same income, same welfare. But their actual lives are radically different. B is poor in a way that income statistics completely miss.
This is the central problem Sen diagnosed with welfare economics and development theory in the 1970s and 1980s: the obsessive focus on resources (income, wealth, commodities) as the measure of human welfare ignores the enormous variation in people's ability to convert resources into actual lives. A pregnant woman needs more food than a non-pregnant woman to achieve the same nutritional status. A person in a wheelchair needs more income to achieve the same mobility. An illiterate person cannot convert access to a library into education. Resources are means, not ends, and the relationship between means and ends is wildly variable across individuals and social contexts.
Sen proposed replacing the focus on resources with a focus on capabilities: what a person is actually able to do and to be. A capability is a real freedom, not just a formal right but a genuine opportunity. The capability to be well-nourished. The capability to be educated. The capability to move freely. The capability to participate in political life. The capability to appear in public without shame.
This framework, developed in works including Inequality Reexamined (1992) and Development as Freedom (1999), goes by the name the capability approach. Its central claim is that development, whether of individuals, communities, or nations, should be understood as the expansion of real freedoms, not the accumulation of resources or the growth of GDP. A country that doubles its GDP while keeping women excluded from education and political life has not developed in the relevant sense. A country with modest income but high levels of education, health, political freedom, and social participation is genuinely more developed.
The slogan that captures it: "Development as Freedom." Poverty is not just low income. It is the deprivation of real freedoms, of capabilities. And justice is not just redistribution of resources. It is so that that people can actually live lives they have reason to value.
One of the things that makes Sen's framework philosophically rich is that it is explicitly pluralist about what capabilities matter. He does not give a single master value (utility, resources, primary goods) and reduce everything else to it. Different capabilities matter for different reasons, and the framework is designed to accommodate the genuine diversity of things that matter in a human life. This makes it less mathematically tractable than utilitarian or Rawlsian frameworks, but, Sen argues, more honest about the actual complexity of human welfare.
Quick reflection
Think about your own life. If someone wanted to measure how well you are doing, and they had your income and wealth figures, how much of the picture would they have? What capabilities — real freedoms to do and be things — would they miss? Make a list of five or six things you are actually able to do and be that matter to your quality of life and cannot be read off from your income.