Philosophy
What is The trolley problem?
The trolley problem is a famous ethics thought experiment: a runaway trolley will kill five people, but you can pull a lever to divert it onto a track where it kills one. It forces a hard question — is it right to actively cause one death to prevent five?
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains the trolley problem.
Key things to understand
- 1A runaway trolley heads toward five people on the track.
- 2Pulling a lever diverts it to a track with one person.
- 3It pits saving the most lives against the act of killing.
- 4Most people pull the lever, but small variations change their answers.
- 5It's widely used to explore ethics, and now self-driving-car design.
Frequently asked questions
- What is the point of the trolley problem?
- It exposes the tension between outcomes (save five) and actions (you'd be causing a death), probing how we actually make moral choices.
- Is there a right answer to the trolley problem?
- No agreed one — it's designed to reveal conflicting moral intuitions, not to have a single correct solution.
- Why does the trolley problem matter today?
- Designers of self-driving cars and AI must encode how machines should act in unavoidable-harm situations, echoing the dilemma.