Judith Jarvis Thomson: Trolley Problems & Moral Theory

Biography

Judith Jarvis Thomson was born on October 4, 1929, in New York City. She studied at Barnard College and then at Cambridge University, where she was a student of the logician and philosopher G.E.M. Anscombe. She earned her doctorate in philosophy from Columbia University in 1959. Thomson taught at Boston University and then spent most of her career at the Massachusetts Institute of Technology, where she became one of the most influential moral philosophers in the English-speaking world. She was president of the American Philosophical Association and held professorships that recognized her standing as a leader of analytic moral philosophy. Her papers "A Defense of Abortion" (1971) and "Killing, Letting Die, and the Trolley Problem" (1976) are among the most widely taught works in modern philosophy, and her 1990 book The Realm of Rights developed a systematic rights-based moral theory. Thomson died on November 20, 2020, in Cambridge, Massachusetts.

Historical Background

Thomson worked at the height of the analytic tradition in ethics, when the field was dominated by the confrontation between utilitarianism and deontology. Her immediate context was the revival of applied ethics in the 1960s and 1970s: the civil rights movement, the Vietnam War, and debates about abortion and medical ethics pushed philosophers to engage with concrete moral problems. Philippa Foot had introduced the trolley problem in 1967; Thomson took it up, transformed it, and made it the most productive thought experiment in the history of moral philosophy. Her work also belongs to the tradition of rigorous, ordinary-language analysis: she was known for her devastating counterexamples, her surgical precision, and her willingness to overturn both consequentialist and deontological orthodoxies. She came of age in a profession that was just beginning to admit women, and she became one of its most formidable figures.

Core Ideas

The Trolley Problem

Thomson made the trolley problem her own. In "Killing, Letting Die, and the Trolley Problem" (1976), she added the fat man variant and the loop variant to Foot's original case, and she used them to argue that the doctrine of double effect — the intended/foreseen distinction — cannot explain our moral judgments. Her analysis concluded that what matters is not the distinction between doing and allowing, but the structure of people's rights: the fat man has a right not to be pushed, and the one on the side track has a right not to be used as a means, but the one in the loop's path may have no such right. Thomson's rights-based reading of the trolley problem turned a curiosity about intuitions into a test bed for the foundations of deontology.

The Violinist Argument

In "A Defense of Abortion" (1971), Thomson wrote the most famous thought experiment in bioethics. You wake up to find yourself plugged into a famous violinist who needs your kidneys for nine months. Thomson argued that you may unplug: the violinist's right to life does not include a right to the use of your body without your consent. The argument was designed to show that even granting the fetus a full right to life, the conservative conclusion about abortion does not follow. Its deeper lesson is about the limits of rights: a right to life is a right not to be killed, not a claim on the bodies and resources of others. The violinist case transformed the abortion debate and made Thomson a public figure in moral philosophy.

Rights and the Limits of Moral Theory

Thomson's mature philosophy, developed in The Realm of Rights (1990), is a systematic rights-based theory of morality. She argues that our rights are claims that others may not interfere with our lives, bodies, and property in specified ways, and that these rights constrain what may be done to us even for the sake of the greater good. Her account is deontological in spirit but unusual in method: she works from case to case, testing theories against carefully constructed examples, and she is equally critical of utilitarian arithmetic and of rigid Kantian formalism. She also defended the distinction between killing and letting die as morally significant in some contexts, while insisting that the full story is more complex than either side of the classic debate supposed.

Major Works

"A Defense of Abortion" (1971) is the most anthologized paper in contemporary ethics. "Killing, Letting Die, and the Trolley Problem" (1976) created the modern trolley literature. "Rights and Compensation" (1980), "The Trolley Problem" (1985), and "The Realm of Rights" (1990) developed her systematic moral theory. "The Right to Privacy" (1975) is a classic of legal and moral philosophy. Her collected papers in Rights, Restitution, and Risk (1986) and Goodness and Advice (2001) display the full range of her work, from metaphysics of persons (she defended the thesis that we are material beings, in "People and Their Bodies") to the ethics of everyday life.

Philosophical Influence

Thomson's influence is difficult to overstate. She created the modern trolley problem industry: her variants are used in ethics courses, psychology laboratories, and the design of autonomous systems, and the terms "fat man," "loop variant," and "Thomson's switch" are standard vocabulary in moral philosophy and moral psychology. Her violinist argument restructured the abortion debate, forcing defenders and critics of abortion to argue at the level of rights and bodily autonomy rather than of mere personhood. Her rights-based ethics is a leading alternative to both consequentialism and Kantianism in contemporary deontology. She was also one of the most admired teachers and critics of her generation, known for the clarity and force of her objections. When ethicists test a new theory, they still ask what Thomson would say.

Related Concepts

Thomson's work is inseparable from the trolley problem and its fat man and loop variants, and from the violinist case. Her rights-based ethics engages deontology, utilitarianism, and meta-ethics. Her great interlocutor was Philippa Foot, and her work connects to decision-making and responsibility.