1. The Classic Problem

A trolley is heading down a track with 5 people tied down to it. There is an alternate track it can go down with only 1 person tied down to it. You’re standing next to a lever which can redirect the trolley to the track with only one person. Do you pull the lever and make the switch, killing one person to save 5?

My answer: Of course you do. People who say don’t pull the lever are afraid that you pulling the lever will put that person’s blood on your hands, whereas you doing nothing means the death of the 5 people wasn’t necessarily your fault. But for me, you’re still making the choice to do nothing when you have the ability to pull the lever, so it’s just as bad as pulling the lever to kill 5 people instead of 1. So the obvious answer is to pull the lever.

Now let’s get onto some interesting ones. I promise they won’t be the classic alternate versions you’re used to.

2. Theseus’ Trolley

Same setup as before, except now there’s about 10,000km between where the track splits and where the second man is tied down. If, during the long journey, a team of engineers on the trolley replace each part bit by bit – replace a plank of wood here, a nail there – until every single original piece has been replaced with a new one, is the trolley that kills the man the same one that you diverted? 

The key here is that the trolley is moving as a single entity the entire time and any given replacement at one time is only a small part. If you replace a car’s tire, for example, you can’t say it’s an entirely new car. But what if you replace the windshield wipers next month? Is it a new car now? What about if you replace the seats inside with leather? Taking one replacement at a time, there seems to be no change in the entity called ‘the trolley’ at all. However, over time, once every single original piece has been replaced, is it still the original

3. Driverless Trolley

The trolley system has been privatized and monopolized by the Edison corporation and all but automated away using AI. You drive an automated trolley down a track and see a track straight ahead that has a person on it.

Very energy-efficient

The trolley is programmed to brake when it detects an obstacle and so you sit back and decide to let the trolley stop itself. Too late, you realise the detection system hasn’t worked, and you go to slam the brakes, but the damage is done. The trolley runs over and kills the person. Who is responsible for his death?

Should the company be held liable for a detection software that didn’t work in this one circumstance? Or are you to blame for not stopping the trolley when you had the chance to? Often these trolley problems are criticized for not actually being applicable or relevant in the real world, and thus the conclusions are not based on anything tangible. This one, however, will only become increasingly pertinent with the rise of automated vehicles, and how we as a society choose to answer this question will have very real legal implications.

4. The Riemann Trolley

A trolley is heading down a track with a countably infinite number of people on it. If it continues down that path, it would literally kill infinitely many people. 

There is another track, however. For every nth individual on the first track, there are n individuals tied together on the second track. In other words, you have 1 + 2 + 3 + 4+… people on the second track.

According to the analytical continuation of the Riemann Zeta Function, this expression is equivalent to -(1/12). Do you trust this track to continue down the path of infinitely many people or do you pull the lever to revive one twelfth of a person? 

If you don’t know about the this expression or the Riemann Hypothesis at all, 3blue1brown has an AMAZING video on this topic which, if you take your time to watch through and understand, is immensely rewarding even for mathematical laymen.

5. The Trolleyologist

A trolley is headed down an empty track. However, you have the option to divert the trolley to another track where a philosopher who constantly asks you trolley questions is tied down. How fast do you pull the lever?