A forced choice between acting to cause a lesser harm and refraining while a greater harm occurs.
Foot's 1967 formulation, extended by Thomson. Widely used and widely criticised as a guide to actual moral decisions, since real choices rarely present certain outcomes and no third option.
In practice
- A committee allocating one ventilator between two patients is told the trolley case clarifies the principle, and finds neither outcome certain and a third bed possibly freeing up.
- A regulator writing an automated braking rule must settle in advance what the vehicle does, which is the rare case where the certainty the problem assumes is real.
- Possible explanations
- One explanation for the pattern of answers is the distinction between doing and allowing. Another is the doctrine of double effect, under which harm as a side effect is judged differently from harm as a means. A third is proximity, since pushing a person is more aversive than pulling a lever.
- In its favour
- It isolates moral intuitions under controlled conditions, and the broad pattern of responses recurs across many countries, which is why it remains a standard tool in moral psychology.
- Against it
- Critics argue that sacrificial dilemmas measure willingness to accept an artificial premise rather than moral judgement, and that responses correlate with traits such as callousness. Real choices rarely offer certain outcomes or only two options.
- Standing
- Widely used and widely criticised as a guide to actual moral decisions.
- Further reading
- Wikipedia
- Subject
- Decision-making & Reasoning
- Essay
- Why reasoning works the way it does