By Michael Dorf
The latest issue of the New York Review of Books includes a review by Cass Sunstein of the new book, Would You Kill the Fat Man? The Trolley Probelm and What Your Answer Tells Us About Right and Wrong, by David Edmonds. (Only the very beginning of the review is available for free online. The rest is behind a subscription paywall, so if you're not a NYR subscriber, you'll have to trust me for my description.) The title of the book refers to a famous hypothetical scenario in moral philosophy, a variant of the so-called "trolley problem." In this post, I'll very briefly explain the problem, and then suggest that Sunstein's otherwise fair-minded review omits (express) discussion of an important feature of moral reasoning.
A) In the classic trolley problem, you see a trolley hurtling out of control towards five people tied to the track. You stand by a switch. If you throw the switch, you can divert the trolley to a second track, but there is one person tied to the second track. Do you throw the switch, resulting in the death of the one but the sparing of the five?
B) In the fat-man variant of the trolley problem, you are standing on a footbridge overlooking a track, where you see a trolley hurtling out of control towards five people tied to the track. Next to you is a (very) fat man. If you push him off the footbridge, his mass will block the trolley before it can run over the five. Do you push the fat man, resulting in his death but the sparing of the five?
People have various moral intuitions in the two cases. Act-utilitarians think it morally permissible or even obligatory to throw the switch and to push the fat man, because in both cases, the action leads to a better result: the death of only one, rather than five. Some act/omission deontologists think it morally impermissible to throw the switch or to push the fat man because in each case, they would be deliberately acting in a way that causes a death, rather than merely failing to act to save five lives. Most interestingly, many people (including me) think that it is morally permissible to throw the switch but morally impermissible to push the fat man. The book, the review, and the substantial literature on "trolleyology" explore the reasons for these intuitions (and others regarding still more variants), in order to discern either what morality really entails or, as in Sunstein's case, to question whether this whole method of inquiry is likely to lead to moral truth.
I'll come to what I think Sunstein omits shortly, but first, I should give the standard explanation for what I called the most interesting pair of intuitions--that it's permissible to throw the switch but not to push the fat man. The explanation goes under the heading of a doctrine--originally traceable to Catholic theology but now part of the general philosophical discussion--called "double effect." The doctrine allows that it is sometimes morally permissible to intentionally take an action that has as its aim averting one evil, even though it will also cause some other evil.
Real-world applications of the double-effect doctrine include pain medication that has the side effect of killing the patient (which is distinguished from taking an overdose for the express purpose of suicide), causing "collateral" deaths of civilians in wartime (so long as the use of force targets military combatants and collateral deaths are not disproportionate), and more controversially, abortion.
In trolleyology, throwing the switch is an instance of double effect, because the person who throws the switch intends thereby to divert the train in order to save the five, even though doing so will have the regrettable side-effect of killing the one. Pushing the fat man is not an instance of double effect, because the fat man's death is not a side-effect of saving the five; it is the means of doing so.
As I said, Sunstein's review is generally fair, although he himself appears to be a rule-utilitarian. He thinks that if there is a moral distinction between throwing the switch and pushing the fat man, it is one that has to do with following general rules that, in the aggregate lead to the greatest good for the greatest number, even if, in particular cases, following such rules leads to bad results. Thus, he acknowledges that there is overall utility in following a rule that one should not push people off of bridges into the path of hurtling trolleys, and that perhaps the benefits of following that rule, as a rule, outweigh the costs of occasionally forgoing the greater good of saving trolley passengers.
But Sunstein ends on a note of skepticism. The moral intuitions we have, he says, are heuristics that developed in ordinary circumstances. They may be "misfiring" in odd cases like the fat-man problem. Put differently, perhaps the rule that a rule-utilitarian ought really to be following is not "don't push people off of footbridges in front of trolleys" but "don't push people off of footbridges in front of trolleys unless doing so will avert a greater harm." The fat-man problem, in this view, shows that our intuitions do not perfectly map onto the right rule-utilitarian rules.
Yet Sunstein's skeptical account of trolleyology omits any express discussion of what is usually a key feature of deontological reasoning and indeed, of moral reasoning more generally. Deontologists do not typically say that each of our moral intuitions generalizes into a true moral principle. After all, our intuitions sometimes tug in different directions. Thinking about Jim Crow may lead one to think that legal distinctions based on race are wrong, but then thinking about race-based affirmative action in public universities may lead one to modify that principle to say something like race-based legal distinctions that subordinate traditionally disadvantaged minorities are generally wrong, but that ameliorative race-based distinctions are more often acceptable. Or not. One might conclude that color-blindness is the right principle after all.
My point here is not to argue for any particular principle, but to note that trolleyology is not just about exploring our intuitions; it's about trying to find principles that reconcile our intuitions, and then, if that cannot be done, abandoning some of our intuitions in favor of more deeply held ones. It aims at reflective equilibrium, not naked intuitionism. Thus, the title of the post: We want to reflect on the fat man, not simply react to his case.
Sunstein titles his review "How Do We Know What's Moral?", and he implies in it that the method of interrogating our intuitions is not a reliable means of finding out. But he comes up short in two ways: First, his contention that our pre-reflective moral intuitions can be wrong is not an indictment of deontology, because deontology is not committed to the correctness of pre-reflective moral intuitions.
Second, to the extent that Sunstein's argument is more radical--i.e., to the extent that he thinks that our moral intuitions have nothing to do with moral truth but are simply heuristics that conferred survival value on groups of humans--Sunstein undermines not simply deontology but all of morality, including all forms of utilitarianism. After all, the claim that morality consists of maximizing utility is itself an appeal to moral intuition--a kind of meta-heuristic. If the intuition that it is wrong to push the fat man is simply a misfiring of a hard-wired rule that conferred evolutionary advantage, then so is the intuition that it is wrong to abstain from simple actions that could save more lives than they sacrifice.
The reduction of morality to heuristics is a kind of global moral skepticism that swallows all morality, not just deontology. Sunstein's (implicit) argument against double effect and deontology thus throws out the baby with the bathwater. If he really is a moral skeptic, then he would have no moral problem with throwing out a baby, but I don't read him to embrace moral skepticism, except perhaps inadvertently.