The Trolley Problem

A philosophical thought experiment.

"The Trolley Problem, or Would You Throw the Fat Guy Off the Bridge?: A Philosophical Conundrum"
— Thomas Cathcart

Imagine yourself being the operator of a tram or trolleybus moving quickly down the tracks. Suddenly you see you are heading toward five people standing on the line in front of you, just beyond a junction. They seem oblivious to their fate. As you approach you see one person on the alternative line. The brakes are not working, the tram is careening out of control, and your only option is to switch lines. What do you do?

The experiment forces one to weigh action against inaction in a way that can be easily explored. I say "easily" because it's not always such a simple issue. Whole books have been written about it, including one by Thomas Cathcart cited above.

The question as stated raises two questions as you have but two choices. If you take no action, five people will die. If you switch to the other line, one person dies. An early form of the problem was set in a questionnaire by Frank Chapman Sharp in 1905 but it has been discussed by many people for years. This particular form (and associated conundrums) first really came to attention in 1967 through philosophy professor Philippa Foot in a series of debates about abortion. Since then others have written about and discussed the trolley problem and it has escaped from academia into the public consciousness.

Since then it has become a staple of any kind of moral or ethical discussion as it sets no boundaries; there is no absolute, correct answer and many variants exist. The traditional number is one (anonymous) person versus five, but introducing various other criteria, such as knowing the one person, or having the five be serial killers. In some problems the one is a pregnant woman or a world-famous surgeon. You get the idea; changing the parameters does transcend the issue.

it's become almost a meme, to the point of having a scene in The Good Place, in which the demon Michael makes the problem real for Chidi. It's almost embarrassingly difficult to watch someone actually having to make the decision as suddenly the thought experiment becomes concrete, and Chidi cannot remain detached. I found the scene on YouTube, for your delight.

Other forms of the dilemma are also available, some requiring a particularly deliberate agency, as in this one:

As before, a trolley is hurtling down a track towards five people. You are on a bridge under which it will pass, and you can 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. Should you proceed?

In this scenario, there's also a clear public issue. You are clearly visible to a crowd and your actions will be weighed and judged by them. You cannot simply anonymously push a lever to solve it, you must actually push someone to their death in order to resolve the issue. Suddenly ethics and moral philosophy will become very personal, as you are distinctly attached to the action.

In a similar vein you are a surgeon specialising in transplant surgery. A homeless drug addict is brought into the emergency room, on the brink of death. Do you save him or leave him in a brain-dead state so his organs can be harvested to possibly save or improve the lives of others?

Making it personal also has an effect on one's view. If the one person is a close family member or a lover, many more people will choose to sacrifice the five, because now social good has to be weighed against personal benefit. The permutations are seemingly endless, and some of them are explored in an online game form at https://neal.fun/absurd-trolley-problems/. Have fun killing people.

The real world problem: autonomous vehicles

There's been a rash of interest in the trolley problem when designing and developing automatic driving systems for cars. Designers are having to really consider the implications of dealing with complex situations in traffic. Consider that you as a driver may have been in a situation where you have to make a split-second decision to create one situation by avoiding another. I've had this a few times. Avoid the pedestrian by driving into a situation in which I might hit another vehicle. Hit the squirrel rather than swerve and hit a parked car. But these are situations that software developers are having to face, and code for. How to do it? How much more valuable are the occupants of the driven vehicle worth? What the value of other road users, pedestrians or cyclists? This is in addition to actually recognising these elements in software. Of course, much research has been done into the implications, the how and the why. It is a rabbit hole I was reluctant to go down, but there's an introduction to it on Wikipedia along with links to various papers whose abstracts I admit gave me a headache.

And finally, SMBC webcomics has an unusual take on it!

Now as a disclaimer, I am not a philosophy major and I'm unequipped to delve into the different schools of thought. I hope that someone is, and is willing to navigate the thorny topic and write that it up here.

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