Print This Post Print This Post

The Switches and Skates Case:

By sheer accident, an empty trolley, nobody aboard, is starting to roll down a certain track. Now, if you DO NOTHING ABOUT the situation, your FIRST OPTION [sic], then, in a couple of minutes, it will run over and kill six innocents who, through no fault of their own, are trapped down the line. (So, on your first option, you’ll let the six die).

Regarding their plight, you have THREE OTHER options: On your SECOND OPTION, if you push a remote control button, you’ll change the position of a switch-track, switch A, and, before it gets to the six, the trolley will go onto another line, on the left-hand side of switch A’s fork. On that line, three other innocents are trapped, and, if you change switch A, the trolley will roll over them. (So, on your second option, you’ll save six lives and you’ll take three.)

On your THIRD OPTION, you’ll flop a remote control toggle and change the position of another switch, switch B. Then, a very light trolley that’s rolling along another track, the Feed Track, will shift onto B’s lower fork. As two pretty heavy people are trapped in this light trolley, after going down this lower fork the vehicle won’t only collide with the onrushing empty trolley, but, owing to the combined weight of its unwilling passengers, the collision will derail the first trolley and both trolleys will go into an uninhabited area. Still, the two trapped passengers will die in the collision. On the other hand, if you don’t change switch B, the lightweight trolley will go along B’s upper fork and, then, it will bypass the empty trolley, and its two passengers won’t die soon. (So, on your third option, you’ll save six lives and you’ll take two.)

Finally, you have a ­FOURTH OPTION: Further up the track, near where the trolley’s starting to move, there’s a path crossing the main track and, on it, there’s a very heavy man on roller skates. If you turn a remote control dial, you’ll start up the skates, you’ll send him in front of the trolley, and he’ll be a trolley-stopper. But the main will be crushed to death by the trolley he then stops. (So, on your fourth option, you’ll save six lives and you’ll take one.)

On reflection, you choose this fourth option and, in consequence, the six are prevented from dying. (Unger, LIVING HIGH AND LETTING DIE, p. 90; quoted in full by Kamm on pp. 196-7)

Is it permissible to choose the fourth option? Thoughts and discussions welcome.

The Switches and Skates Case: Is it permissible to choose the fourth option? [See The Switches and Skates Case Poll Post for details]

  • Yes (47%)
  • No (41%)
  • Not sure (12%)

Total Votes: 49


Loading ... Loading ...


  1. 1. Posted by John Alexander | August 21, 2007 10:55 pm

    If it is permissible to throw the heavy person in front of the trolley to stop it would the person at the switch be required to throw himself in front of the trolley if his weight was sufficent to stop the trolley? Is his action not praisewothy if he chooses not to do so, but to do the 4th option instead? Seems to me he would be required to throw himself in front fo the trolley and he could be criticized for not doing so if he performed the 4th option instead.

  2. 2. Posted by S. Matthew Liao | August 22, 2007 5:18 pm

    John, I think that is the conclusion that Unger wants us to reach with this case, namely, he thinks that we must generally be willing to suffer great losses or even to kill ourselves in order to prevent more suffering and deaths. See Kamm’s discussion of Unger in Chapter 6.

  3. 3. Posted by John Alexander | August 24, 2007 12:51 pm

    I had stopped reading Kamm’s book. I am lost in the maze of her nuances and intuitions and am not able to ascertain exactly what her main points are or the theory she is trying to construct; if she is trying to construct one. I did read chapter six, but I am still confused. Personally I do not find all of this minutia very impressive or helpful in understanding how I should respond to actual ethical problems. My problem I am sure. I am also recovering from partial knee replacement surgery and have not felt up to the challenge although I do continue to read the summaries and will skim the chapters as time permits.

    The point I was getting at (and should have made) in my very brief comment is, if we think that we should (ought to) sacrifice great losses, including our lives, this seems to do away with some very important ethical concepts; supererogatory, heroes, saints, above and beyond, etc, that play an important role in our ordinary moral discourse. We should all be Mother Theresa’s, etc. But this seems to be really counter-intuitive for the same reason that Singer’s solution to world poverty seems counter-intuitive. (I know she will deal with Singer later.) But, if we make use of the distinction that Urmson makes in Saints and Heroes then we seem to have a way out of this problem without having to rely on the detailed analysis of Kamm to find our way through the choices we make.

    Anyway having gotten to chapter 8, I think it would be nice if someone where to very briefly summarize the main positive points that Kamm has made. Maybe I am not alone in being lost in the maze and if we had a map maybe we could follow the path easier.

    Matthew, or anyone else for that matter, what do you make of the data that the polls have accumulated?

  4. 4. Posted by Nir Eyal | August 28, 2007 5:24 pm

    OK – so 25 people have cast their votes, and a small majority gives an answer that’s contrary to Kamm’s. 52% say (with Unger, and against Kamm) that it’s permissible to choose the fourth option, and only 40% say (with Kamm) that it’s impermissible to choose it. 8% are not sure. Even though this approximates a tie, it’s certainly not the case that the overwhelming majority agrees with Kamm.

    Where does that leave the thesis that Kamm bases partly on this case? Should we reject that thesis? Should we count this against it? Should we count it strongly against it? Kamm seems to think that philosophers should seek intuitions introspectively, rather than by checking other people’s intuitions. Should we say then that her answer is true for her (given her introspection) and false for the majority of poll participants?

    Kamm does mention that this case may sway some because it has a “sorites structure: Creating a series with (supposedly) slight differences between each member of the series gets us to equate the two extremes of the series, which we know to be distinguishable.” (p. 200). As mentioned in a previous post, I wish she developed this interesting response further. Some of Unger’s cases elicit new intuition only by tempting us to make invalid, e.g. sorites, moves. Such cases do not show that all intuitions are worthless (as Unger may seek to show), just that some, induced by Unger in these contrived cases, are worthless. Compare: the fact that when you are sober you see one finger and when you are drunk you see two fingers doesn’t show that your vision is always worthless; the most it can show is that it is worthless when you are drunk.

  5. 5. Posted by Mike Otsuka | August 28, 2007 7:12 pm

    Some of Unger’s cases elicit new intuition only by tempting us to make invalid, e.g. sorites, moves. Such cases do not show that all intuitions are worthless (as Unger may seek to show), just that some, induced by Unger in these contrived cases, are worthless. Compare: the fact that when you are sober you see one finger and when you are drunk you see two fingers doesn’t show that your vision is always worthless; the most it can show is that it is worthless when you are drunk.

    That’s right. So a thoroughgoing sceptic needs to argue that there’s no such thing as sober moral intuitions about cases – i.e., intuitions formed in epistemically reliable circumstances.

    One thing such a sceptic might argue is that intuitions about cases are unreliable because (i) they’re biased by the influence of intuitions about other cases or (ii) unbiased in that respect but therefore unreliable in a different way because uninformed. See the exchange of comments between Guy and me in this thread for a bit more on this.

    Or a sceptic might draw on Kahneman and Tversky’s experimental data in order try to argue that our intuitions are unreliable because there’s always more than one true and equally valid way of describing a given case, and our intuitions will vary depending on how the case have been described to us (‘framed’). Ch. 14 of Kamm’s book takes up this challenge.

  6. 6. Posted by Nir Eyal | August 28, 2007 9:04 pm

    Mike, thank you for yours. The skeptic may indeed point to these biases and to other types of bias: cultural biases, financial interests, perceptual biases…

    One thing though: The fact that bias significantly affects people’s reported “intuitions” about a case does not always make these “intuitions” worthless for ethical inquiry. So long as we know the direction and the strength of the relevant bias, we can correct for it, and use the “intuitions” propitiously. By analogy, humidity at 66% and wind at 5 km/h create a known bias. Under such conditions, if it feels as though the temperature is 36°C, the actual temperature is 31°C. The problem arises only when knowledge about the nature of the bias is amiss. If we don’t have a clue how humid it is, we can’t use the “temperature” we feel in order to glean what the real temperature is.

  7. 7. Posted by Dave Simon | September 3, 2007 12:14 am

    In response to the first commenter’s post: Why would we have to be willing to throw ourself in front of the trolley to choose option four? The main distinction between the fourth option and the other options is the *active* element. That is, in the fourth option we seem to be *causing* the death of the person (i.e., choosing to turn on the skates), whereas in the other options we are faced with a choice where death is imminent regardless of our action. But that is really a bit of handwaving. The fact that we *turn on* the skates is no more important than the fact that we *change* or *toggle* the switch.

    I’m not sure we have to place ourselves in the shoes of the skater to decide whether or not we should choose the fourth option. Would *we* be willing to die to save the other people is not the question in the hypothetical, nor is it a relevant moral question–at least not here. The question is meant to appeal to your intuitive consequentialist notions, I think. While the example isn’t particularly illuminating, I think the relevatist approach you take here is not merited.

  8. 8. Posted by John Alexander | September 4, 2007 8:46 pm

    Thanks for your comments
    I am not sure that I see any relativism here. Your suggestion that my example is ‘not the question in the hypothetical’ may be correct, but it is certainly an implication of accepting choosing the 4th option, so it does seem to be relevant. If we think we should perform the action that results in the least amount of harm, or reduces harm for the most people, then if throwing myself in front of the trolley will accomplish this then it seems that I ought to do so. But, most, including myself, would reject this conclusion. It seems a supererogatory (permissible) action at best, not obligatory. If I would reject sacrificing myself, then I should not choose the fourth option.

    I agree that this example is not particularly illuminating, but then I have that problem with most of Kamm’s examples.

Post a comment

Name: (required)

Email Address: (required) (will not be published)



(Spamcheck Enabled)

This work is licensed under a Attribution-NonCommercial-NoDerivs 3.0.