The Trolley Problem and Reversibility

by casebash 3 min read30th Sep 201527 comments


The most famous problem used when discussing consequentialism is that of the tram problem. A tram is hurtling towards the 5 people on the track, but if you flick a switch it will change tracks and kill only the one person instead. Utilitarians would say that you should flick the switch as it is better for there to be a single death than five. Some deontologists might agree with this, however, much more would object and argue that you don’t have the right to make that decision. This problem has different variations, such as one where you push someone in front of the train instead of them being on the track, but we’ll consider this one, as if it is accepted then it moves you a large way towards utilitarianism.

Let’s suppose that someone flicks the switch, but then realises the other side was actually correct and that they shouldn’t have flicked it. Do they now have an obligation to flick the switch back? What is interesting is that if they had just walked into the room and the train was heading towards the one person, they would have had an obligation *not* to flick the switch, but, having flicked it, it seems that they have an obligation to flick it back the other way.

Where this gets more puzzling is when we imagine Bob having observed Aaron flicking the switch? Arguably, if Aaron had no right to flick the switch, then Bob would have obligation to flick it back (or, if not an obligation, this would surely count as a moral good?). It is hard to argue against this conclusion, assuming that there is a strong moral obligation for Aaron not to flick the switch, along the lines of “Do not kill”. This logic seems consistent with how we act in other situations; if someone had tried to kill someone or steal something important from them; then most people would reverse or prevent the action if they could. 

But what if Aaron reveals that he was only flicking the switch because Cameron had flicked it first? Then Bob would be obligated to leave it alone, as Aaron would be doing what Bob was planning to do: prevent interference. We can also complicate it by imagining that a strong gust of wind was about to come and flick the switch, but Bob flicked it first. Is there now a duty to undo Bob's flick of the switch or does that fact that the switch was going to flick anyway abrogate that duty? This obligation to trace back the history seems very strange indeed. I can’t see any pathway to find a logical contradiction, but I can’t imagine that many people would defend this state of affairs.

But perhaps the key principle here is non-interference. When Aaron flicks the switch, he has interfered and so he arguably has the limited right to undo his interference. But when Bob decides to reverse this, perhaps this counts as interference also. So while Bob receives credit for preventing Aaron’s interference, this is outweighed by committing interference himself - acts are generally considered more important than omissions. This would lead to Bob being required to take no action, as there wouldn’t be any morally acceptable pathway with which to take action.

I’m not sure I find this line of thought convincing. If we don’t want anyone interfering with the situation, couldn’t we lock the switch in place before anyone (including Aaron) gets the chance or even the notion to interfere? It would seem rather strange to argue that we have to leave the door open to interference even before we know anyone is planning to do so. Next suppose that we don’t have glue, but we can install a mechanism that will flick the switch back if anyone tries to flick it. Principally, this doesn’t seem any different from installing glue.

Next, suppose we don’t have a machine to flick it back, so instead we install Bob. It seems that installing Bob is just as moral as installing an actual mechanism. It would seem rather strange to argue that “installing” Bob is moral, but any action he takes is immoral. There might be cases where “installing” someone is moral, but certain actions they take will be immoral. One example would be “installing” a policeman to enforce a law that is imperfect. We can expect the decision to hire the policeman to be moral if the law is general good, but, in certain circumstances, flaws in this law might make enforcement immoral. But here, we are imagining that *any* action Bob takes is immoral interference. It therefore seems strange to suggest that installing him could somehow be moral and so this line of thought seems to lead to a contradiction.

We consider one last situation: that we aren't allowed to interfere and that setting up a mechanism to stop interference also counts as interference. We first imagine that Obama has ordered a drone attack that is going to kill a (robot, just go with it) terrorist. He knows that the drone attack will cause collateral damage, but it will also prevent the terrorist from killing many more people on American soil. He wakes up the next morning and realises that he was wrong to violate the deontological principles, so he calls off the attack. Are there any deotologists who would argue that he doesn’t have the right to rescind his order? Rescinding the order does not seem to count as "further interference", instead it seems to count as "preventing his interference from occurring". Flicking the switch back seems functionally identical to rescinding the order. The train hasn’t hit the intersection; so there isn’t any casual entanglement, so it seems like flicking the switch is best characterised as preventing the interference from occurring. If we want to make the scenarios even more similar, we can imagine that flicking the switch doesn't force the train to go down one track or another, but instead orders the driver to take one particular track. It doesn't seem like changing this aspect of the problem should alter the morality at all.

This post has shown that deontological objections to the Trolley Problem tend to lead to non-obvious philosophical commitments that are not very well known. I didn't write this post so much as to try to show that deontology is wrong, as to start as conversation and help deontologists understand and refine their commitments better.

I also wanted to include one paragraph I wrote in the comments: Let's assume that the train will arrive at the intersection in five minutes. If you pull the lever one way, then pull it back the other, you'll save someone from losing their job. There is no chance that the lever will get stuck out that you won't be able to complete the operation on trying. Clearly pulling the lever, then pulling it back is superior to not touching it. This seems to indicate that the sin isn't pulling the lever, but pulling it without the intent to pull it back. If the sin is pulling it without intent to pull it back, then it would seem very strange that gaining the intent to pull it back, then pulling it back would be a sin.