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« Jessica Moss on Plato and Aristotle on Weakness of Will | Main | Alison Gopnik on Hume and Buddhism »

September 01, 2013



Great episode. This discussion reminds me of the famous Milgram experiment which found that proximity to the victim also affects moral decisions. Pulling a lever to divert a train is easier than pulling a lever to drop someone through a trap door because you're further removed from the victim. And pulling a lever to drop someone through a trap door is easier than putting your hands on that person and pushing them to their death for the same reason. There is something about human psychology that makes it so the more removed we are from the victim, the less guilty we feel.


I am not sure why there is confusion about the difference between the two versions of the problem.

In the original version, the actual *means* of saving the five people is the switch, not the person tied to the alternative track. If no one were tied to the other track, switching tracks would still save the five people. As mentioned in the podcast, it is an undesired and secondary consequence that the person on the alternative track will die if the track is switched.

In the second version, however, the means is killing the fat man. The fat man must die in order to save the five people down on the tracks. No fat man, no way to save the other people.

So in the first case, most people would switch the track for utilitarian reasons, but, in the second case, most refuse to push the fat man for deontological reasons.

What am I missing? What is the philosophical difficulty in distinguishing between the two versions?

Akim McMath

Interesting discussion. However, I am unconvinced that the Doctrine of Double Effect (DDE) explains the difference in intuitions. In particular, I can't understand how the DDE would explain our intuitions in the looping variant, as discussed in Thomson's article, "The Trolley Problem". Imagine the trolley is hurtling towards the five workers who are working on a loop. If you flip the switch, the trolley will go the other way around the loop, hitting a very fat man who will stop the train before it gets to the workers. Most people believe you should pull the switch. However, it seems to me that you are intentionally killing the fat man. Any thoughts?

David Edmonds

Hi Everyone.

Thanks for your comments. Good points. SB, there is a variation called The Loop, which I didn't have time to go into, but which AkimMcMath mentions. AkimMcMath, for reasons which are in the book, I do not think Loop undermines the DDE.

David Edmonds

ps: I should say, SB, that Loop has been used to show that your explanation does not work - I think you're on the right, ahem, tracks...


How about this? In the original fat man problem, the fat man is outside the scenario, whereas in Loop, the fat man is down on the tracks and therefore "involved".

In other words, perhaps most people refuse to throw the fat man from the bridge because by doing so, they would literally be throwing him into a dangerous situation. In Loop, however, the fat man, by being on the tracks, is already part of a dangerous situation and this takes away at least some of the guilt involved in switching the direction of the trolley. That is, by being on the tracks, the fat man becomes less innocent and, in a way, even complicit in the situation and is therefore less worthy of being saved.

Akim McMath

I was afraid of the "it's in the book" response. Now I've got to wait until 6 October. Looking forward to it.


You could test the validity of my last claim by combining the original fat man problem with the Loop:

What if you first saw someone push the fat man from the bridge onto the Loop track? Would you still be as likely to switch the direction of the trolley, killing the fat man and saving the five people? Or would seeing the fat man being pushed off the bridge make him seem more like an innocent bystander and cause you not to throw the switch?

Chad Jordahl

Is it not a problem that pushing the fat man seems less that certain to succeed? I know I can't avoid thinking that the plan might fail, which makes me even less inclined to support the idea.



For the thought experiment to work, I think you have to assume that pushing the fat man off the bridge will definitely stop the trolley.

Chad Jordahl

SB - I agree, but I've never seen how these questions are asked out in the real world. Are respondents told to assume the push will succeed?

When academics try to make sense of the numbers, it seems they must take into account that some people who say they wouldn't push the fat man were influenced by these practical considerations, even if they're advised not to. Maybe it's not all moral reasoning. Who knows, perhaps the effect is small. Or maybe not.

Jim Vaughan

Excellent episode - and article!

Aquinas "double effect" may go some way, yet I am puzzled why Kant's "kingdom of ends" is mentioned so little in Trolleyology. Deontology, not Utilitarianism holds the key, doesn't it?

We resist throwing the fat man onto the tracks because people are "ends in themselves" never just "means to an end"!

To directly use the fat man as the means to stop the train offends that principle. Its the same argument as harvesting the organs of one healthy person to save 5. It disrespects his autonomy and "personhood".

The loop and "lazy susan" situations are more difficult, as he does become the indirect means, yet our actions only directly involve changes to the track (and someone must get squished first anyway). The track, not the man are our means of intervention.

Playing around further, it feels unethical to use only his legs to stop the train (so he is only injured) for the same reason. Likewise persuading him to jump onto the track in the path of the trolley. Yet, it feels OK to persuade him to risk his life by jumping onto the trolley to operate the brake. There is no disrespect in the latter.

Doesn't a similar issue operate with the crying baby too? Stifling her disrespects her personhood, and right to live, the complication being that she is also the cause of the problem.

I cannot think of a situation which refutes Kants "kingdom of ends" as an intuitive and rational guiding ethic, so I disagree with Peter Singer, that we should override it!

From the work of Josh Greene, perhaps we have Kantian, and Utilitarian ethical decision making areas, which will often conflict. Are there ones for Aristotle or Levinas too?

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