Depth 1 · 34 s
The lever and the bridge
A runaway tram heads for five workers. Pull a lever and it kills one instead - most people would. Push a stranger off a bridge to stop it - most would not. The results are the same. So what is the difference?
About this video
A runaway tram, a trolley in America, is racing down a track with its brakes gone. Ahead, five workers are on the track and can't get out of the way. You are standing next to a lever: pull it, and the tram switches onto a side track, where there is one worker. What should you do?
Nobody expects to meet a runaway tram. The story is made up on purpose, to test an idea, like a fair test in science where everything is kept the same but one thing. A made-up case used to test an idea is called a thought experiment. This one was first told by the English philosopher Philippa Foot in 1967, and the American philosopher Judith Jarvis Thomson later named it the trolley problem. Most people who hear it say they would pull the lever, and their reason is about results: one dies instead of five.
Now change one thing. There is no lever. You are on a bridge over the track, next to a very large stranger, and the only way to stop the tram is to push him off in front of it. He would die; the five would be saved. The results are exactly the same, yet most people say they would not push, and many say it would be clearly wrong. Why?
People have given many answers. In the first case the one worker dies as a side effect of saving the five; in the second the stranger is used, his body the thing that stops the tram. Pushing someone with your own hands seems different from moving a lever. The stranger has a say over his own body. Nobody has found an answer everyone accepts, and this video won't pick one. But the puzzle suggests that results may not be all that matters. This video goes with The Runaway Trolley lesson of Ethics Level 1 on Knaph.
This video shows depth 1 of The trolley problem.
Learn The trolley problemTranscript
- 0:00A runaway tram. Five workers ahead. Its brakes have gone.
- 0:05Pull the lever, and it turns to one worker instead. Most people would pull.
- 0:11Now you're on a bridge. The only way is to push a large stranger.
- 0:17The same results, one for five. Yet most people would not push.
- 0:23Used, not a side effect? Your own hands? His own body? Nobody agrees.
- 0:29Same results, different feelings. Maybe results aren't all.