Sunday, September 28, 2008

The old runaway cable car

The basic plot is this: you're operating a cable car and the brakes fail while going downhill. There is a fork coming up and you can pick to switch to the other line or stay on your current. On your current track are three people who will be hit. On the other is one person. To clear up the inevitable questions: you have no other options except to hit three people or switch and hit one person. They are as generic as people go, so you aren't picking between friends/family and strangers or another race or anything like that. Oh right, and anyone you hit will die.

At first glance it's pretty simple: it's a matter of two evils, one greater, one lesser. Killing one person is less bad than killing three people. In other words: switch to the other track.

But let's look at it some other ways.

For the person on the other track, he is in no danger. His life is safe. Fate rolled the dice and put him on the safe track. From his perspective, switching to hit him is a great injustice. It's as if he dodged a bullet, breathed a sigh of relief, and then it ricocheted into his skull.

For the people on your track, their lives are already gone. What can they say? Kill him instead, we are more people, we are more important, let him die, not us! That seems rather selfish. Imagine further that there is only one person there. He'll still want you to switch tracks, even without the justification of numbers.

Jumping back, let's look at you again. Your choice can be rephrased as killing three through inaction or killing one through action. You choose to kill one or do nothing to save three. Now which sounds worse? Do we attack the people outside the burning build because they don't rush in again to pull out others? In general we're surprisingly tolerant of inaction. But action, that's a big deal, especially when it involves death. Think of historical examples of people who have killed others for a greater good. Stalin is an excellent example, having millions killed to protect the State. Yet despite what he would call great action, we call him a monster. Hitler killed millions of Jews and other 'undesirables' in order to save the German race from being polluted. He too, is a monster.

While a quick check of numbers shows that it makes sense to switch the car to kill one rather than three, from a larger perspective it looks like a horrible thing to do. Society attacks those that kill for the greater good but is merciful to those who do nothing and let fate run its course. Powerful men have switched the cable cars in their nations and become monsters.

Personally, I'd switch the track, but I'd still feel horrible.