Sunday, 15 April 2012

Trolley problems

A train is rushing out of control down the track. 5 people are tied to the track, unable to get out of its way. If the train is allowed to continue, they will all be killed. Watching from a nearly signal-box, you are given an opportunity to influence the scenario. A pull of a lever will divert the train, and send it into a side-track, where there is only one person tied up. The five people will be saved; however, the one person will be killed if the train is diverted. Do you pull the lever?
From a utilitarian perspective, there is only one good answer - pull the lever, minimizing the cost to human life. The consequences are what matter, and in this case, pulling the lever will mean that 1 person dies instead of 5 people. However, a person may still have some worries about pulling the lever nonetheless - for in pulling the lever, you make yourself directly responsible for a person's death. Considered in isolation, removing the 5 people on the original track from the scenario, your act is equivalent to murder.

 Whether any human is 'stop-a-train fat' is a separate question...

The scenario can be tweaked to isolate differing moral intuitions in different cases. Consider:
  1. The scenario remains the same, except that the single person on the side-track is your brother. Divert?
  2. You stand on a bridge above the railway. There are 5 people on the track who will be killed by the train. However, the train can be stopped by pushing a fat guy standing on the bridge alongside you into its path, and then the 5 people will be saved. Push him? (most find this a harder choice than the original example).
  3. The same scenario obtains as in (2), except the fat guy is a villain, who was responsible for the train being out of control in the first place. Push?
  4. The same scenario obtains as in (2), except the fat guy is your brother. Push?
Discussion of these examples has been widespread in philosophy and online. The philpapers survey (see previous post) reported that almost 70% of philosophers would pull the lever in the original case.

I think I’d probably pull the lever in the original scenario, and push the fat bloke in both 2 and 3 (though the fact that he’s a villain doesn’t seem to affect things particularly). At least, I think doing these things would be the right thing to do, whether or not I had the courage to do them myself. However, the family cases raise some of the most profoundly difficult moral dilemmas in moral philosophy. It’s a tough question as to whether one’s personal relationships should affect one’s moral outlook in such tricky cases.


  1. ' However, a person may still have some worries about pulling the lever nonetheless - for in pulling the lever, you make yourself directly responsible for a person's death'

    Surely by NOT pulling the lever you are still responsible for people's deaths? You were effectively the arbiter of their fates and subsequently chose to let them die.

    Great post though, a classic problem

  2. Thanks, John! You're right - except, had you not been on the scene, the 5 would have died regardless. So in not pulling the lever, you have made no difference. Whether moral difference depends on other factors, like you state, is an interesting one.

  3. you could argue that god intended for the 5 to die anyway (lets throw a Christian spanner into the works. =D )

  4. You would have to provide a convincing argument for the existence of god. Good luck with that.

  5. I think dyslexic-chyc (hi!) highlights an interesting point concerning God's plan and our free will. If we say that 'evil (eg. men crushed by train) happens in the world as part of God's plan for a greater good', then this would seem to suggest that we SHOULDN'T BOTHER to intervene to stop evil, as we then get in the way of God's plan for a greater good.

    This is a criticism of any attempt to provide justification of evil in light of God's assumed existence, I think.

  6. I think, Tom B (hellooo!!!), that it is entirely possible that this hypothetical God could have put those individuals there specifically to test a hypothesis about human reactions.... what conclusions would he draw from our behaviour I wonder....

  7. He he. I wonder what conclusions we would draw from his sick enjoyment in using human beings like rats as test subjects...

  8. hmm... clearly the conclusions we can draw is that god is indeed a scientist. I find this more comforting that the idea of his as judge jury ans executioner. =D xx


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