Who would you sacrifice? This is the question posed by the trolley problem – a thought experiment in ethics that puts a though decision in your hands.
The modern form of the problem was first introduced by Philippa Foot in 1967, but also extensively analysed by Judith Thomson, Frances Kamm, and Peter Unger.
The general form of the problem is this: There is a runaway trolley barrelling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them.
You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person on that second track.
You have two options:
1) Do nothing, and the trolley kills the five people on the main track.
2) Pull the lever, diverting the trolley onto the second track where it will kill one person.
Which is the most ethical choice?
In one survey, about 90% of respondents agreed that it was okay to flip the switch, letting one worker die to save five. Other studies have found similar results. These results are consistent with the philosophical principle of utilitarianism – the doctrine that actions are right if they are useful or for the benefit of a majority.
But people don’t always take this view. In a variation of the trolley problem, instead of the switch you are on a bridge under which the trolley will pass. You can only stop it by putting something very heavy in front of it.
As it happens, there is a very fat man next to you – your only way to stop the trolley is to push him over the bridge and onto the track, killing him to save five. Would you proceed?
In this case, only 10% of people said it was okay to throw the man on the tracks. Our instincts seem to tell us that deliberately causing someone’s death is different from allowing them to die as collateral damage.
Outside of the domain of traditional philosophical discussion, the trolley problem has been a significant feature in the fields of cognitive science and, more recently, of neuroethics. It has also been a topic in popular books dealing with human psychology.
The problem is also discussed with regards to the ethics of the design of autonomous vehicles.
To learn more watch the following video: