Preventing the greatest harm should guide action.
One death may be required when it is the only way to save five.
Ethics
Is it ever right to sacrifice one person to save many?
The problem in miniature
A switch and a barrier
A runaway trolley will kill five people unless you divert it onto a side track where one person stands. Pulling a switch saves five and leads to one death. Now alter one feature: the trolley can be stopped only by pushing a person into its path. The numbers are unchanged, but the person is no longer a foreseen casualty on another route; their body is used as the means of rescue. Many people judge the cases differently. The puzzle is not a survey of instinct but a test of which moral difference can justify that change.
Why this is difficult
The pressure comes from more than one direction.
People must not be used merely as instruments.
Some beneficial outcomes remain impermissible because of how they are produced.
Intended harm differs from foreseen harm.
The agent's plan matters, even where the physical outcome and number of deaths match.
Philosophers in the conversation
Different routes through the same problem.
Jeremy Bentham and J. S. Mill
Utilitarian reasoning evaluates actions through their effects on well-being. Saving five rather than one initially seems decisive, but the calculation must include every consequence: fear, trust, rules and future behaviour, not simply the immediate body count. These indirect effects can therefore become morally decisive.
Immanuel Kant
Kantian ethics asks whether a person's rational nature is respected as an end. Deliberately using someone as a tool for others' survival appears to violate that demand, even when the resulting world contains less suffering overall. The constraint protects each individual against aggregate calculation.
Philippa Foot
Foot introduced the trolley comparison while examining duties and the doctrine of double effect. Her cases distinguish what an agent intends from harmful effects they foresee, making the structure of the action — not only the total result — morally relevant.
Judith Jarvis Thomson
Thomson develops trolley variants to test rights, agency and the moral significance of redirecting an existing threat. Her work shows how small changes in who acts, who owns a threat and how a person is involved can unsettle a simple numerical answer.
Key ideas
Language for thinking more precisely.
- Utilitarianism
- The view that right action is determined by producing the best overall consequences.
- Deontology
- An approach in which duties or constraints can limit what outcomes permit.
- Intention
- The result an agent acts to produce, not every effect they foresee.
- Double effect
- A principle distinguishing intended harm from harm foreseen as a side effect.
- Omission
- Allowing an outcome by not acting, contrasted with bringing it about through action.
- Rights
- Protected claims that can constrain how individuals may be treated for collective benefit.
Follow the question through the curriculum
Continue with a unit or lesson.
Reconsider your answer
The opening question has changed.
Physical closeness and personal action strongly affect judgement, but those feelings may track a real difference in agency — or merely a bias produced by vivid contact.
Would your answer change if you had to act personally, and should emotional distance ever make a moral difference?