Part I: The Classic Train Track Dilemma, or: The Trolley Problem
Imagine that you’re at a train station “open house” of sorts. People are there to admire trains and see how they operate. No trains are scheduled to run that day, so people are scattered all over the place.
There are some people gathering at the station; some standing on the tracks; and some, like you, standing on the hills admiring the scenery.
Suddenly you spot a train hurtling toward and about to hit a group of about fifty people, all of whom are unaware of it. You shout out to them, but whatever sound you make is drowned out by the party atmosphere down there. You estimate that if nothing is done, at least 90% will be killed.
It just so happens that you’re standing near a switch that, if flipped, would throw the train on to another set of tracks and save these fifty people. However, you notice that on the other set of tracks there stands a group of five people. By flipping the switch, though you could save the fifty, you’d almost certainly kill these five.
What do you do?
PART II – The Train Track Dilemma, Revisited
Now, before you make a decision, let’s throw in another spanner into your already-jammed-up-moral works. Being a train enthusiast, you spot something, on the tracks leading to the fifty, that looks a lot like a device that serves to limit speeds of trains as they approach the station.
It appears to be engaged, meaning that there is a possibility that the train will slow down sufficiently enough such that those fifty could possibly get out of the way. But you don’t know that — it might just be some rubbish or party prop.
You estimate a 50% chance that it is a speed limiter that works, saving those fifty; and a 50% chance that it isn’t one, allowing the train to go on at full speed, killing those fifty.
What now? Do you flip the switch? If you do, you could well be sentencing the five to death for the sake of fifty who might not even be at risk.