Indian economist, philosopher, and 1998 Nobel laureate whose work has reshaped welfare economics, development studies, and political philosophy. Sen grew up in Bengal during the 1943 famine — a childhood experience that informed his career-defining demonstration, in Poverty and Famines (1981), that famines rarely result from absolute food shortages; they result from collapses in "entitlements" (income, employment, market access) that leave specific groups unable to command the food that exists. The implication — that democracies with free presses almost never suffer famines — has become canonical.
His deeper contribution is the capability approach, developed over several decades and given its clearest statement in Development as Freedom (1999). Against both utilitarian welfarism (which measures well-being by preference-satisfaction) and resourcist views (which measure it by income or primary goods), Sen argues that what matters is what people are actually able to do and be — the real freedoms, or capabilities, they enjoy. A disabled person who needs twice the income to achieve the same mobility is not equally well-off as an able-bodied peer with the same bank balance; measuring freedom in terms of capabilities captures this where other metrics do not. The approach has reshaped the UN's Human Development Index and much of international development practice.
Sen has also written carefully about the Indian intellectual tradition, collective choice theory (where his early work on Arrow's impossibility theorem is technically foundational), and the parochialism of Western political philosophy. He has been a friendly but persistent critic of John Rawls.