Skip to content
Know.itKnow.it
Create an animated lesson
On request

This article is free to read. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

What is the trolley problem?

PhilosophyLesson on requestFree to read

Quick answer

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?

Key things to understand

  1. A runaway trolley heads toward five people on the track.
  2. Pulling a lever diverts it to a track with one person.
  3. It pits saving the most lives against the act of killing.
  4. Most people pull the lever, but small variations change their answers.
  5. It's widely used to explore ethics, and now self-driving-car design.

People also ask

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.