Could There Be a Solution to the Trolley Problem?

My introduction to the Trolley Problem goes back a few years, when I was watching a YouTube video of the neuroscientist Sam Harris’s talk on his then-newly published book, The Moral Landscape (2010). In his talk, Harris posed this philosophical problem to the audience as a means of demonstrating that our moral intuitions could badly fail us when they are badly needed. The full talk is well worth watching.

The Trolley Problem is a philosophical thought experiment first devised by the moral philosopher Philippa Foot in 1967. In her paper titled “The Problem of Abortion and the Doctrine of the Double Effect,” Foot wrote the following:

“[It] may rather be supposed that he is the driver of a runaway tram [trolley] which he can only steer from one narrow track on to another; five men are working on one track and one man on the other; anyone on the track he enters is bound to be killed.”

And the Trolley Problem was born. It is important to note, however, that Foot presented this thought experiment among many other variants of it, and there is no particular reason why this one has received so much attention from the philosophical and scientific communities.

In 1976 — nine years after Foot published her original paper on the Trolley Problem — the American philosopher Judith J. Thomson wrote a paper titled “Killing, Letting Die, and the Trolley Problem,” in which she introduced a second version of the Trolley Problem, making it all the more interesting:

“George is on a footbridge over the trolley tracks. He knows trolleys, and can see that the one approaching the bridge is out of control. On the track back of the bridge there are five people; the banks are so steep that they will not be able to get off the track in time. George knows that the only way to stop an out-of-control trolley is to drop a very heavy weight into its path. But the only available, sufficiently heavy weight is a fat man, also watching the trolley from the footbridge. George can shove the fat man onto the track in the path of the trolley, killing the fat man; or he can refrain from doing this, letting the five die.”

What Thomson did was essentially completing the Trolley Problem. In contemporary philosophy, Thomson’s second scenario involving the footbridge is viewed as an indispensable part of the Trolley Problem, and is included in almost all presentations of the thought experiment. After all, the second scenario is what makes the problem interesting — and incredibly puzzling.

I have noticed that, when first presented with the Trolley Problem, many people — especially those with limited background in philosophy — tend to think of all the different ways in which the obvious tragedies — namely the death of one or five individuals, depending on one’s choice — could be avoided altogether. For instance, in a real world scenario that resembles those of the Trolley Problem, one might be able to loudly warn the workmen on the tracks of the approaching trolley, in anticipation that they will move and save their lives themselves.

But that would be to miss the entire point of this thought experiment. The Trolley Problem sets up a moral dilemma, in which one is to decide whether to steer the trolley in the first scenario, and whether to push the fat man off the footbridge in the second, so that one person dies as opposed to five. Those are the only options available.

So, what is one to do?

In her 1967 paper, Foot offered her own solution to the Trolley Problem. She suggested that the morally justified action, in the first scenario, would be to steer the trolley to kill the one workman, thus saving a net four lives. In order to demonstrate this, she made a distinction between what she called “negative duties” and “positive duties.” In the broad sense, she defined negative duties as the obligation to refrain from harming others, and positive duties as the obligation to actively do good — which would be to save lives, in this case. She argued that, as a matter of principle, our negative duties are always more urgent, and weigh more than our positive duties, so that one is not justified in violating a negative duty to fulfill a positive duty.

Using this line of reasoning, one could say that the first scenario of the Trolley Problem presents a conflict between two negative duties. In other words, the driver of the trolley should ask the following: “Is it my (negative) duty to not harm one individual, or to not harm five individuals?” And the answer, according to Foot, is obviously the latter (not harming five individuals), since it leads to less harm.

In the footbridge scenario, however, one faces a conflict between a negative duty and a positive duty, namely the (negative) duty of not harming the fat man on the footbridge, and the (positive) duty of saving the lives of the five workmen on the track. In this case, Foot would argue that, since saving the lives of the five workmen requires doing significant harm to (indeed, killing) the fat man on the footbridge, one is not morally justified in doing it.

Thomson had a different point of view. Although she agreed with Foot on just what the morally superior action is in every scenario, she had her disagreements as to why one is to act in that way.

In Thomson’s view, the real distinction lied between “deflecting a threat from a larger group onto a smaller group,” and “bringing a different threat to bear on the smaller group.” Using this premise, she argued that it is morally justified to steer the trolley onto the track where there is one workman, since that would be to deflect the threat from the five workmen (larger group) to the one workman (smaller group); and that it is morally unjustified to push the fat man off the footbridge, since that would be to create an entirely new threat for him (smaller group).

Other philosophers have suggested that one ought not to use human beings as a means to save others, which is why it would be morally right to steer the trolley, and morally wrong to push the fat man. And some have questioned the very assumption that one is morally obliged to minimize harm, or to bring about the death of as few people as possible.

But the question remains: what is the ultimate solution to the Trolley Problem?

The answer, in my view, is that there is no definitive solution. Like most philosophical problems, the Trolley Problem is not designed to have a final, easy solution. It is, rather, intended to provoke thought, and create an intellectual discourse in which the difficulty of resolving moral dilemmas is appreciated, and our limitations as moral agents are recognized.

That is not to say, however, that everyone could have a perfectly legitimate opinion on the Trolley Problem, and that they would be right. Far from it. We should acknowledge that there are more or less justifiable resolutions to the Trolley Problem — or any moral dilemma, for that matter — and that it is only through reason and rational argumentation that we can converge upon them.

The ongoing discourse over the Trolley Problem is not a discourse about solutions per se — after all, there are only two ways in which one could act in both scenarios of the problem — but one that places more significance on reasons. As we saw with the argument between Foot and Thomson, most of us differ only in the reasons for which we prefer one solution to the Trolley Problem over the other. That is, in fact, what has kept the Trolley Problem alive among philosophers and scientists for nearly five decades.

I do not believe there will ever be a perfect solution to the Trolley Problem, nor a consensus as to the best possible solution. All we can hope for — and should hope for, as I have argued in this article — is to utilize the tools of philosophy, as well as the scientific method, to continue this discourse. The Trolley Problem does not have to be resolved; it merely needs to be contemplated, and be the topic of our conversations from time to time.