Judith Jarvis Thomson

Judith Jarvis Thomson (1929–2020) was an American moral philosopher whose work transformed several domains of applied ethics, most notably the philosophy of abortion, the ethics of self-defense, and the metaphysics of rights. Her 1971 paper "A Defense of Abortion" — which introduced the famous violinist thought experiment — is among the most widely cited and debated papers in twentieth-century philosophy. But Thomson's deeper contribution lies in her methodological approach: she treated moral philosophy not as the articulation of general principles but as the analysis of concrete cases, and she showed that intuitions about specific scenarios could be more philosophically productive than abstract axiomatic systems.

Thomson's work on rights challenged the simplistic framing of moral conflicts as zero-sum competitions between competing rights. Her analysis of the trolley problem — and of the distinction between doing harm and allowing harm — revealed that our moral intuitions are sensitive to the structure of agency, not merely to the arithmetic of outcomes. A bystander who diverts a trolley to save five lives at the cost of one acts permissibly, Thomson argued; a surgeon who harvests the organs of one healthy patient to save five acts impermissibly. The difference lies not in the numbers but in the relational structure of the action.

This structural sensitivity connects Thomson's moral philosophy to the study of mental heuristics and causation. The same cognitive structures that organize our moral intuitions — the distinction between action and omission, between intended and merely foreseen consequences, between direct and indirect harm — are the structures that organize our causal and probabilistic reasoning. Thomson did not set out to contribute to cognitive science, but her work provides a philosophical foundation for understanding why human judgment is organized around relational structures rather than outcome maximization.