An Animated Introduction to the Famous Thought Experiment, the “Trolley Problem,” Narrated by Harry Shearer

You don’t have to get too deep into the study of ethics before you run across the trol­ley prob­lem. It comes up so read­i­ly that it hard­ly needs an intro­duc­tion: a run­away train is on course to col­lide with and kill five peo­ple work­ing on the tracks, but you can pull a lever that will switch it to anoth­er sec­tion of track on which stands only one per­son. Do you pull it? Accord­ing to a pure­ly util­i­tar­i­an inter­pre­ta­tion, you should, since one life lost sure­ly beats five lives lost. But faced with the deci­sion, real indi­vid­u­als tend to strug­gle: not pulling the lever feels like let­ting five peo­ple die, but pulling it feels like mur­der­ing one.

What if you could stop the train by push­ing one espe­cial­ly large indi­vid­ual off a bridge into the train’s path, stop­ping it but killing him? Few say, or at least admit, that they would do it. But why not? The Har­ry Shear­er-nar­rat­ed ani­ma­tion above, a part of BBC Radio 4 and The Open Uni­ver­si­ty’s series on the his­to­ry of ideas, con­sid­ers what our respons­es reveal about how we think eth­i­cal­ly.

“What the trol­ley prob­lem exam­ines is whether moral deci­sions are sim­ply about out­comes, or about the man­ner in which you achieve them,” says Shear­er. “Lots of peo­ple say they would switch the points, but they would­n’t push the man off the bridge. Are they sim­ply incon­sis­tent… or are they on to some­thing?

The TED-Ed video just above, writ­ten by edu­ca­tor Eleanor Nelsen, gets deep­er into what they might be on to. “The dilem­ma in its many vari­a­tions reveals that what we think is right or wrong depends on fac­tors oth­er than a log­i­cal weigh­ing of the pros and cons,” says Nelsen. “For exam­ple, men are more like­ly than women to say it’s okay to push the man over the bridge. So are peo­ple who watch a com­e­dy clip before doing the thought exper­i­ment. And in one vir­tu­al real­i­ty study, peo­ple were more will­ing to sac­ri­fice men than women.” The study of “Trol­ley­ol­o­gy,” a sub­ject since Philip­pa Foot first artic­u­lat­ed the prob­lem in 1967, now finds “researchers who study autonomous sys­tems” col­lab­o­rat­ing with philoso­phers “to address the com­plex prob­lem of pro­gram­ming ethics into machines.” Alter­na­tive­ly, of course, they could just put the ques­tion to the near­est two-year-old.

Relat­ed Con­tent:

How Can I Know Right From Wrong? Watch Phi­los­o­phy Ani­ma­tions on Ethics Nar­rat­ed by Har­ry Shear­er

What Is Free­dom? Watch Four Phi­los­o­phy Ani­ma­tions on Free­dom & Free Will Nar­rat­ed by Har­ry Shear­er

48 Ani­mat­ed Videos Explain the His­to­ry of Ideas: From Aris­to­tle to Sartre

Oxford’s Free Course A Romp Through Ethics for Com­plete Begin­ners Will Teach You Right from Wrong

Watch a 2‑Year-Old Solve Philosophy’s Famous Eth­i­cal “Trol­ley Prob­lem” (It Doesn’t End Well)

Based in Seoul, Col­in Mar­shall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.