The Trolley Problem

Introduction

You've probably heard of it before. The most famous thought experiment in philosophy, but if you haven't, it goes like this...

The Trolley Problem

History

This dilemma is a common retelling of the thought experiment known as "the trolley problem". Originally thought of by Phillipa Foot in 1967, the trolley problem is designed to ask what we should do when the interests of human beings conflict.

Consequentialist Approaches

Many people don’t see the dilemma here. Kill one instead of five, right? Isn’t it obvious? You want to choose actions that avoid the most pain and create the most pleasure by saving lives. This line of thinking is known as “Consequentialism”, where actions are picked purely based on what will lead to the best consequences.

This line of thinking is a slippery slope, however. Philosopher Judith Jarvis Thomson poses a variant of Phillipa Foot's Trolley Problem...

The Mafia Trolley Problem

In this variation, you are taking into consideration the accountability of each person on the track. If you kill the five mafia members because they are guilty, where does it end?

• Would you kill a regular person over a doctor because the doctor is more able to save other people?
• Would you kill an adult over a child because of their life span?
• Or a man over a woman because women live longer?

One website that tests out your bias through trolley problem variations such as Thomson's is The Moral Machine.

I think you get my point though... Where do you draw the line? Most people start feeling uncomfortable making these decisions. "Playing God".

More Variations

Things get more complicated however when you contrast it with some other variations of the thought experiment.

The Fat Man Trolley Problem

In surveys when this question is asked, most people say that they would not push the large man. But what's the difference? In both situations you're killing one to save five. Is it different just because you feel more responsible for the death?

Phillipa Foot poses a similar dilemma known as the transplant problem...

The Transplant Problem

While most people says that they would flip the switch, many don't think it is justified to harvest someone’s organs against their will, or push someone in front of a trolley. But why not? In each of these cases, it’s a matter of killing one to save five.

Some philosophers say that the difference is consent. This patient did not consent to the transplant, and so a doctor cannot operate. However, as Judith Jarvis Thomson points out:

Judith Jarvis Thomson

One of the other variants Judith Jarvis Thomson provided was the Mayor Variant.

The Mayor Trolley Problem

Does the fact that you made a promise make it acceptable to kill five instead of one? Wouldn’t sacrificing the one create the best consequence? Here enters “Deontology”, the belief that some rules and principles are more important than consequences alone.

Deontology

Deontological theories tend to explain this dissonance between the trolley problem and the other thought experiments. Agent-centred deontology for example, suggests that you have more of an obligation to the people you are personally responsible for, such as the convalescent you made a promise to. Or if you were a parent and your kids were on one track, you'd have more of an obligation to protect them as their wellbeing is your responsibility while a stranger's is not.

Another theory, "The Doctrine of Doing and Allowing" states that it is worse to do harm than to allow it. This theory explains why you might be permitted to “let die” in the Trolley Problem but are not permitted to "kill" in The "Fat Man" Problem or The Transplant Problem.

Similarly, "The Doctrine of Double Effect" states that you are permitted to do an action with a negative consequence, if the good outweighs the bad and the good thing is not the same as the bad thing. For example, you are permitted to divert the track in the trolley problem because you’re saving five lives, the death of one is merely an unfortunate by-product. In the words of Phillipa Foot:

Phillipa Foot

This might also be why you are not permitted to push the large man, as his death is inherently part of your plan, not just a by-product. If he didn't get run over, then you would have failed.

These deontological theories are not without flaw however. Phillipa Foot has pointed out that one could argue that it wasn't their intention for the man to die, they just wanted his body to slow down a 40-tonne vehicle travelling at 50km/h... "if he happened to die because of that, that's not on me."

Real-World Applications

It’s easy at this point to say that “trolleyology” is too abstract, with no real-world value. Many people also criticise the thought experiments for being too sterile—people would likely act differently in real life.

However, there are many situations in the real world where people sit down and make decisions based on what they cannot see in front of them. Whether it's a runaway trolley, a self-driving car, or even something that doesn't involve murdering people with runaway vehicles.

The point of thought experiments such as the trolley problem is to provide "edge cases" where our values and intuition are inconsistent and lead to unexpected results. Having these simple case studies help keep ourselves accountable for our ethical decisions. But given the endless permutations of harm and consequence, is this dilemma ultimately solvable, or is the 'right' choice inherently unknowable?