by Tim Sommers
The first part of the original trolley problem goes like this. A runaway trolley is careening towards five people tied to the tracks. There’s a lever in front of you that could divert it onto a second set of tracks. Unfortunately, there is also a person tied to those tracks. You can either do nothing and let five people die or throw the switch and kill one person – but save the five. What do you do?
The modern version of the trolley problem goes back to the 1960s, but there are variations that go back over 100 years. The trolley problem has been featured in video games, movies, tv shows, and has been a monster meme on the internet since at least 2016. MIT has a moral machine that does nothing all day and night but ask people questions based on the trolley problem – including variations suggested by users themselves. The trolley problem has been central to debates about how to program self-driving cars and “experimental” philosophers have spent a lot of time putting people in eMRI machines and asking them the trolley problem. But many other important trolley problems have not been fully explored. Here are just a few.
Sorites’ Trolley Problem
There’s no lever but the people tied to the tracks are pretty far away. Luckily, you have a wrench and can remove one piece of the trolley at a time. How many pieces do you have to remove for it to cease being a trolley? Which piece is the one piece that once removed will mean that the trolley is no longer a trolley?
Theseus’ Trolley Problem
Rather than simply removing pieces, you swap them out one at a time with brand-new, identical pieces. If you swapped them all out before the trolley hit anyone, would it still the same trolley?
Zeno’s Trolley Problem
Whether you pull the switch are not, in order to hit anyone, the trolley must travel half the distance to them, and before that it has to travel one quarter of the distance, and before that one eighth. How will the trolley ever hit anyone?
Euthyphro’s Trolley Problem
Should you throw the switch because you are commanded to do so by God or does God command you to throw the switch because it’s the right thing to do? Or does God command you to let the five die?
Anselm’s Trolley Problem
Can you prove by reason alone that there even is a trolley? Consider. If the trolley has every attribute of a good trolley to the fullest extent possible, and a trolley that exists is better than one that does not exist, mustn’t the trolley exist necessarily? Or does the fact that it is about to kill someone show that it is not good to the fullest extent possible and, therefore, does not exist?
Descartes’ Trolley
How do you know you are not dreaming the trolley?
The Inverted Spectrum Trolley Problem
When I look at the trolley it appears red to me, but how do I know it doesn’t appear blue to you?
Hume’s Trolley Problem
In the past, every careening trolley approaching people tied to tracks has killed them, but no matter how many of such instances I have observed, can I ever be sure that this trolley this time will kill the people tied to the tracks?
Sapir-Whorf’s Trolley Problem
If there’s no word for trolleys in my language, how can anyone be crushed by a “trolley”?
Parfit’s Trolley Problem
If I can teleport the trolley from the track where five people are tied to the track where only one person is tied, will it be the same trolley?
Frankfurt’s Trolley Problem
Suppose I only think I can pull the switch, but I actually can’t for some reason. But suppose I don’t even try to throw the switch, because I don’t care. Am I responsible for letting the five people die – even though I could not have done otherwise?
Nozick’s Trolley Problem
Does the existence of the trolley problem show that I am not currently in an Experience Machine that gives me whatever experiences I prefer? Or does it show that, in fact, I am in an Experience Machine and I want to see someone run over by a trolley?
Rawls’ Trolley Problem
If I were to choose the principles of justice from an “original position” behind a “veil of ignorance”, and would, therefore, choose the “difference principle” (in a just society the least well-off members should be as well-off as possible), wouldn’t I also think that people tied to trolley tracks in front of out-of-control trolleys are among the worst-off? Shouldn’t a just society, then, spend more on trolley safety?
Nozick’s Other Trolley Problem
Despite what Rawls says, aren’t these people being tied to trolley tracks as the result of their own free choices over time, and so shouldn’t we favor a minimal, night-watchman state with no government regulation of trolleys at all?
Prisoner’s Dilemma Trolley Problem
We are standing on opposite sides of the tracks as the trolley barrels towards the peopled tied to the tracks. If I throw my switch it will divert the trolley towards the one person tied to the track, if you throw your switch it will also divert the trolley towards the one. But if we both throw the switch it will divert the trolley back towards the five. So, if we want to save the five only one of us should throw the switch. But whoever throws the switch will kill someone. So, the best outcome for me is that you throw the switch, for you that I do. But the worst outcome is that we both or neither throw the switch. Given that neither of us knows for sure what the other will do and we are unable to communicate over the noise of the trolley, what should we do?
Thompson’s Trolley Problem
What if the one person tied to the track is a world-famous violin player? And she’s pregnant.
Bostrom’s Trolley Problem
Since it is overwhelmingly likely that we live in a computer simulation, is there a software work around? For example, can we make trolleys become temporarily transparent when they approach obstructions on the track?
The Self-Driving Trolley Problem
If car manufacturers announce that fully self-driving autonomous vehicles able to solve the trolley problem will be available in six months, and their stock goes up, but after the six months they just announce again that fully self-driving autonomous vehicles able to solve the trolley problem will be available in another six months, and their stock goes up; exactly what incentive do they have to stop lying about self-driving cars?
Nietzsche’s Trolley Problem
The terrible truth is that that damn trolley is going to roll down those damn tracks over and over again forever and ever. So, what? Is that supposed to make me feel better? It doesn’t. It makes everything seem futile. I should just not throw the switch and put five people out of their misery right now. Except then they will get crushed by a trolley over and over again forever. Never mind. I give up.
Last Thurdayism’s Trolley Problem
How do I know the trolley wasn’t created five minutes ago along with a bunch of fake evidence that it has existed for a long time? And why couldn’t the world come into existence five minutes later instead so I wouldn’t have to deal with this stupid impending trolley disaster?
Newcomb’s Trolley Problem
I can see one person in a transparent box on one track. On the other track there is an enormous opaque box. A perfect predictor tells me that if I divert the trolley towards the one person, there will be no one in the opaque box. But if I don’t divert it, and she has predicted correctly, there will be five people in the box. Oh, plus a million dollars.
The “Why is there Something rather than Nothing?” Trolley Problem
Because God or science or something. I don’t know. That’s not even a real question. I don’t think.
Bonus: The Liar’s Trolley Problem
The trolley track runs between two towns, Truth and Lie. Everyone from Truth always tells the truth and everyone from Lie always lies. You see the out-of-control trolley and you know there are five people tied to track on the Truth side and one tied to the track on the Lie side, but you can’t see which is which from where you are. Luckily, there is someone standing closer than you that will be able to answer one quick question before you make your decision. Unfortunately, you don’t know whether they are from Truth or Lie. What question can you ask them to figure out which side the five are on?