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Winchester Lectures: Kamm and Permissibility

In her first Winchester Lecture, ‘Who Turned the Trolley?’, presented in Oxford on 21 October, Frances Kamm discussed some of the recent views of Judith Thomson on so-called trolley cases

Consider a case in which you are a bystander, watching a runaway trolley heading for five people. You are able to switch the trolley onto a track heading for only one person. Both Kamm and Thomson believe that you are (at least) permitted to turn the trolley onto the track with one person. 

Now consider a second case, similar to the first, except that here there is a third track, and you are on it. Thomson believes that, though it is permissible for you not to switch the trolley onto your track, it is impermissible for you to switch the trolley from the five to the other single person. You, the agent, she believes, should pay the cost of doing the good deed.

Against this, Kamm offered a moral separability principle which she called Strong Claim 1: ‘If it is permissible to impose a cost on someone for some end were there no alternative, it need not become impermissible to do so merely because one does not impose the cost on someone else when one should’.

So in the second case, Kamm suggests, it is permissible for you to turn the trolley towards the one.

But the logic of Strong Claim 1 seems to rule this out. Should we can take to be equivalent to is required to, and is required to to be equivalent to is not permitted not to. In other words, if you are imposing a cost, then it is impermissible not to impose it on yourself, which is Thomson’s view.

What this suggests, perhaps, is that the language of permissibility and impermissibility alone is not sufficient to capture certain intuitions about trolley cases. Consider, for example, the notion of moral goodness. We might say that turning the trolley towards yourself would be morally best (which is consistent with its being permissible for you not to do it), while turning it towards the one would be morally better than leaving it to kill the five. In other words, if you’re not going to turn it towards yourself, you should at least turn it towards the one rather than leave it to kill the five.

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4 Comment on this post

  1. Your logic is impeccable, Roger, but I wonder whether you go far enough.
    If we agree that turning the trolley towards oneself is morally best, we acknowledge that oneself is morally good. As we know nothing at all out the moral goodness of the other one person (and agree that the trolley should be turned towards one of the single persons rather than the the group of five), isn’t it our DUTY to maximise the likelihood of moral goodness’ being preserved and thus direct it towards the other person ?

  2. That’s a nice point, Anthony! It reminds of Aristotle’s suggestion in Nicomachean Ethics 9.8 that the virtuous person will, in a battle, stand back and allow his colleague to do the courageous thing and rush at the enemy. One important feature of these imaginary examples is that one has to assume everything else is equal — so we are meant to assume equality of moral goodness. But what about the case you describe ? I suppose it might be claimed that, given that it’s unlikely the other one will ever do anything so morally remarkable, you should sacrifice yourself now while you have the chance. In general, I think the value of virtue — which was a major topic of discussion in ancient philosophy, as well in the first half of the C20 — is worth a lot more attention than it now gets in ethics. So thanks again for bringing this up.

  3. Marco Antonio Azevedo

    Hi Roger,

    Sorry if I’m late. In my opinion, you are right: what seems to follow from Thomson/Kamm problem on trolleys is that the language of permissibility and impermissibility alone is not sufficient to capture certain intuitions about trolley cases. The intuition is that it is better, advisable, morally best perhaps to turn the trolley into yourself, even though it is not impermissible to turn the trolley into the other in both cases. How is it possible? If we accept Anthony’s claim, then whatever we ought to do is obligatory, but this simply eliminates the distinction between what is permissible and what is obligatory (that is, moral permissibility would be equivalent to moral obligation). What I think to capture all our intuitions is that we cannot blame morally the person who does not turn the trolley into her, even though we can (and in fact do) morally criticize her. My suspicion here is that we should follow a difference Scanlon suggested between substantive responsibility and attributability, with the amendment that we can rightly attribute moral responsibility without attributing substantive responsibility (as I think is the right view on the matter). Substantive and attributive responsibilities are not hence equivalent notions.


    1. Thanks, Marco. I like the distinction between blame and moral criticism. That to me seems a difference in degree rather than kind, however.

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