The trolley problemBy HallvardLillehammer (Ed.), Cambridge: Cambridge University Press. 2023. ix + 267 pp. £74.99 (hb)/£26.99 (pb) ISBN: 9781009255592

Abstract

The Trolley Problem, edited by Hallvard Lillehammer, is worth reading for a number of reasons. The Trolley Problem has sparked heated philosophical debate for over four decades, as well as scientific research, pop-culture references and memes. Sadly, among all this the actual questions the Trolley Problem set out to illustrate sometimes have a tendency to disappear into the background. As several of the authors in this volume point out, the Trolley Problem is sometimes thought to refer to the single case in which a Bystander has to choose whether to turn a runaway trolley onto a side-track. This is somewhat of an (over)simplification. For most writing on it, the Trolley Problem is about finding convincing explanations of the difference in permissibility between different cases featuring trolleys—such as the classic case, where someone is faced with the choice of switching a runaway trolley to a sidetrack, or the ‘Bridge’ case, where someone is faced with the choice of pushing a person off a bridge to stop a trolley. However, there are several different interpretations of the problem in circulation, and this may contribute to the confusion. One reason to recommend this volume, part of Cambridge University Press's ‘Classic Philosophical Arguments’ series, is that it does a genuinely good job of cutting through some of the noise. Its twelve chapters offer a range of reflections on the Trolley Problem, ‘trolleyology’, and related issues. Given the variety of issues covered, space does not permit me to discuss any one chapter in great detail. Instead, for the purposes of this review, I will comment on some more general points. First, however, I will briefly outline the range of topics covered in this volume. It encompasses traditional (deontological) discussions of the Trolley Problem, as well as virtue ethical approaches, moral psychology, cross-cultural empirical analysis, and applied philosophy. The first chapter, by Lillehammer, provides a helpful overview of the history of the Trolley Problem, and includes reflections on Foot, Thomson and Kamm, as well as a response to Barbara Fried's important critique of the Trolley Problem (see Fried, 2012). The first set of chapters, by William J. FitzPatrick, Peter A. Graham, F.M. Kamm, Dana Kay Nelkin and Samuel Rickless, and Fiona Woollard, tackle various aspects of the Trolley Problem from a broadly deontological perspective. In his chapter, FitzPatrick argues that Judith Jarvis Thompson (in)famous change of heart with regards to the classic case was unwarranted. Instead, he suggests that the problem can be explained by appeal to reasonable norms of shared risk. Next, Graham focuses on the question of whether it is merely permissible or obligatory to turn the trolley in the standard case. He takes aim at Helen Frowe, who argues that it is obligatory. Contrary to Frowe, Graham maintains that it is (merely) permissible to turn the trolley by appealing to previous work by Kamm (2007, 2016). Following Graham, Kamm herself agrees and offers a clear and characteristically detailed discussion of some of the key arguments for her view that it is permissible to turn the trolley from an explicitly non-consequentialist perspective. It is a particularly useful and concise overview of some of her recent work on this topic and would therefore serve well to introduce people (for example, students) to her work. Taking a slightly different angle, Nelkin and Rickless, as well as Woollard, focus on the Doctrine of Double Effect (DDE) and Doctrine of Doing and Allowing (DDA)—both often used to attempt to explain the difference in permissibility between various trolley cases. Nelkin and Rickless argue, importantly, that classical formulations of trolley cases fail to take risk into account. By drawing on Warren Quinn's interpretation of the DDE (Quinn, 1989), which distinguishes between direct and indirect harmful agency, they argue that a probabilistic version of the principle can be constructed to deal with these more complex cases. On the other hand, Woollard focuses on the DDA, another principle often wheeled out to help resolve the Trolley Problem. Woollard argues that the relationship between the DDA and the Trolley Problem is, however, considerably more complex. Specifically, the DDA should not be understood as a solution to the problem, but nor should the Trolley Problem be considered a proof that the DDA is morally irrelevant. Rather, her analysis suggests that an additional principle is needed—a sister principle to the DDA—to explain common intuitions about these cases. Following this set of deontological investigations, the contributions to this book take (somewhat) more unexpected approaches. Liezl van Zyl considers the Trolley Problem from a virtue ethical perspective. She makes a number of important points that those writing on Trolley Problems should take into serious consideration. Her virtue ethical analysis of the ‘Bridge’ case is particularly worth noting. Van Zyl claims it is unlikely that a moderately virtuous person would, when faced with such a situation, look at a fellow human being on the bridge and think of them as a ‘heavy object’ that can be used to stop the trolley. As she notes, her students—when presented with a less leading example of the Bridge case—come up with standard suggestions: ‘[the men] should yell out, blow a whistle, wave their arms, run toward the workmen, look for a heavy object further down the track, etc. So far, none of them have proposed that [Bystander] should consider pushing the big man onto the track.’ (p. 128) Her overall argument is that proponents of virtue ethics can support common intuitions about trolley cases, including Bridge. However, this is for very different reasons than those appealed to by deontologists. The next two chapters are an interesting debate between, on the one hand, Guy Kahane and Jim Everett and on the other, Joshua D. Greene. Kahane and Everett consider the use of Trolley Problems in contemporary psychological research, and the way this research has often been framed in terms of a contrast between deontological and utilitarian approaches to morality. They claim this framing is misleading—first, because some of the responses researchers classify as ‘utilitarian’ are at best tangentially utilitarian (and more often self-interested or simply consequentialist) and second, because they suspect it is difficult to generalize from these kinds of cases to more general claims about moral reasoning. Greene, on the other hand, has done extensive psychological research using trolley problems and related cases and he can quite rightly be considered a pioneer in this particular area of the field. Here he argues (pace Kahane and Everett, but also several other critics) that the empirical study of how people react to Trolley Problems has significantly improved our understanding of the psychological mechanics of moral judgment. He claims in particular that his empirical research has demonstrated the evidential or justificatory limitations of intuitions about moral dilemmas. Natalie Gold, in her chapter, also draws on a number of empirical studies, but her interest in those studies looking at how people from different (cultural) backgrounds respond to Trolley Problems. She provides a critical and detailed survey of this literature and shows that the picture that emerges from these studies is mixed. It is possible to conclude from these studies that there do exist differences in judgment about trolley cases between cultures, but the number of studies that can be used for this analysis is relatively small. Moreover, Gold argues, it is plausible to think of these differences as evidence for ethical constructivism. Finally, the last two chapters focus on the application of Trolley Problems to two areas within applied philosophy: Sven Nyholm considers the ethics of self-driving cars, and Ezio Di Nucci considers the Trolley Problem in the context of healthcare, and specifically the COVID-19 pandemic. Both offer interesting, critical, discussions of the use (and occasional abuse) of Trolley Problems in the context of applied ethics, public policy, and law. In this volume, there are a number of overarching themes and issues that come to the fore, which mean that while there certainly is value in picking it up to read just one or the other chapter, it would also be rewarding to read the whole book—or at least the sets of chapters corresponding to one's area of academic interest. This is the second reason why this volume is worth reading. However, as noted at the outset, it is not always clear in the wider literature what the Trolley Problem actually is. And this book, perhaps surprisingly, does not provide a clear answer to that question either. Indeed, it is interesting to note that even in a book about the Trolley Problem, different chapters offer subtly different explanations. For example, Woollard—like Lillehammer and some of the other contributors—points to the issue of explaining the difference in perceived permissibility between the classical case and cases such as Bridge. Thus, in Woollard's words, the real Trolley Problem ‘is to explain why you are permitted to turn the trolley [in the classic trolley case] when there are many cases where intuitively you are not permitted to kill one person to save five’ (p. 101). But FitzPatrick offers a subtly different interpretation: he suggests that the relevant problem is the question ‘What is it about the sort of diversion involved in [the standard case] that makes for an exception to the usual proscription against killing some to save others (assuming we accept some version of that non-consequentialist constraint in the other cases)?’ (p. 27). Finally, going against the grain somewhat, Graham identifies the question of whether it is merely permissible or required to turn the trolley as the central problem of concern. One might perhaps wish that the authors had ensured a bit more consistency between their explanations of what exactly the problem is, and the slight shifts in explanation may confuse someone coming to this area with little background knowledge. That being said, we also have here a great illustration of the complex and somewhat slippery nature of the puzzle posed by the Trolley Problem. Through reading this volume, it becomes clear just how rich a thought experiment Foot and Thomson's invention really is—rather than a single Trolley Problem, it becomes clear there are multiple serious moral issues raised by these apparently simple cases. And as the chapters by Greene and Kahane and Everett highlight, pursuing an empirical, utilitarian approach is not a guarantee you can entirely avoid them—though the issues faced by experimental philosophers and psychologists when trying to make sense of the Trolley Problem may be somewhat different, of course. Whether this is an issue with the volume will depend a lot on the audience, I suspect. As noted, for someone coming at this with little background knowledge, or someone really keen to find out what, precisely, the Trolley Problem is, the ambiguity could create confusion. If assigned as part of, for example, an undergraduate course, it may therefore require some careful explanation by the instructors. However, for philosophers working in ethics, metaethics and relevant areas of applied ethics, this volume is a useful resource on the various issues raised by the Trolley Problem. Finally, this volume—while generally of high quality—contains a number of particularly outstanding or otherwise noteworthy chapters. These alone make it worth picking up, whether for a class or a particular research project. As already mentioned, Kamm's chapter provides a clear and comparatively accessible introduction to her recent work on Trolley Problems. For those interested in the relation between the DDE, the DDA, and Trolley Problems, the chapters by Nelkin and Rickless and Woollard provide plenty of material to work with. The chapters by Kahane and Everett and Greene should be at home on reading lists for many introductions to experimental philosophy or moral psychology. And finally, the chapters by Nyholm and Di Nucci provide interesting insights in their respective areas of applied philosophy. In sum, it is likely not the case that every chapter in this volume will be of interest to everyone, but that is somewhat to be expected with edited volumes which cover a range of areas. What this book does offer is a wide ranging discussion of one of contemporary moral philosophy's most iconic puzzles, which—much like the Trolley Problem itself—can offer many different things to many different people.