You've heard this one before:
TROLLEY
A runaway trolley is coming down the track. It is headed towards five people who cannot get out of its way. A Passerby realizes that he can save the five by throwing a switch and diverting the trolley down a siding, but he also realizes that if he does so, the trolley will kill a Lone Man standing on the siding.
Should you divert the trolley? Lots of folks say, "Yes!" Whether or not they are right is an interesting problem but it is not what philosophers call "The Trolley Problem". That problem involves a different case:
FAT MAN
A runaway trolley is coming down the track. It is headed towards five people who cannot get out of its way. A passerby realizes that if he pushes a nearby fat man onto the tracks his bulk will stop the trolley before it hits the five, though the fat man himself will be killed.
Most people, including those who think it is okay to turn in TROLLEY, think that it is not okay to push the FAT MAN. "The Trolley Problem" is how to reconcile these two answers. In both cases it seems you can do something that will save five people but only by killing one. How can anyone think it okay to turn in TROLLEY but wrong to push the FAT MAN? What difference is there between the two stories that can possibly make a moral difference?
In the almost forty years since Judith Jarvis Thomson first posed the problem in this form there have many attempts to solve it but none is generally accepted as successful. Indeed a general consensus seems to have developed that the "folk intuitions" (as philosophers call them) about the difference between these cases are simply irrational.
Thus a Utilitarian like Peter Unger can argue that, since there is no difference, it must be morally okay to go around doing things like pushing fat men under trolleys so long as it promotes the general happiness.
Meanwhile Judith Jarvis Thomson concludes that, since there is no difference between the cases, it must be wrong to turn in TROLLEY and so FAT MAN represents a reductio ad absurdum of Utilitarianism.
Both sides explain away "folk intuitions" that the cases are somehow different as a psychological aberration. Folks feel better about killing other folks in TROLLEY-- this theory goes-- because they are more comfortable with throwing a remote switch in TROLLEY than they are with the up close shoving that FAT MAN requires. There are even psychological "experiments" and (God help us) neural imaging studies that are supposed to explain (away) these folksy confusions.
In a conflict between folk intuitions and philosophical theory I'll bet on the folk every time. In this post, I'm not going to take a position on whether or not it is permissible to turn in TROLLEY or push the FAT MAN. My goal instead is to show that, as described, there are subtle but important differences between the FAT MAN and TROLLEY cases; differences that can make a moral difference in other circumstances, but differences that have, hitherto, gone overlooked by philosophers.
We begin with some different thought experiments.
SACRIFICING OTHERS
A runaway trolley is coming down the track. It is headed towards a Lone Man on the tracks who cannot get out of the way. However that man is standing by a switch which, if thrown, will divert the trolley down a siding. In that case the man will be safe but he can also see that, in that case, five people standing on the siding will be killed.
Is it morally permissible for the man to throw the switch? If it is permissible, what of this:
SHIELDING ONESELF
A man sees that someone is about to shoot him. To protect himself, he grabs an innocent bystander and uses her as a shield.
Now there is a line of thought that says that when one's life is in danger, anything goes. The philosopher Hobbes seems to have held something like this position. But this seems to me to throw morality out the window when it may be most required. It seems to me that SHIELDING ONESELF and SACRIFICING OTHERS are clearly impermissible and in what follows I'm going to assume you agree with me.
Now consider.
SELF DEFENSE
A runaway trolley is coming down the track. Luckily there is no one in its path. A passerby, Burns, sees this but he also notices that Homer, someone he hates, is standing on a siding. Burns realizes that if he throws a nearby switch, the trolley will be diverted down the siding killing Homer. Homer can see all this too and when he sees Burns moving towards the switch he correctly guesses his intent. Homer cannot get out of the way but he is not defenseless: he has a gun. He draws it and shouts "Stop or I'll shoot!". But Burns ignores him and keeps moving the switch.
Assuming all these facts, I expect you to agree with me that it would be morally permissible for Homer to pull the trigger. It seems an ordinary case of self-defense albeit against an unusual attack.
Now for the interesting case:
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