Crashes involving self-driving cars at least superficially resemble trolley dilemmas. This article discusses what lessons machine ethicists working on the ethics of self-driving cars can learn from trolleyology. The article proceeds by providing an account of the trolley problem as a paradox and by distinguishing two types of solutions to the trolley problem. According to an optimistic solution, our case intuitions about trolley dilemmas are responding to morally relevant differences. The pessimistic solution denies that this is the case. An optimistic (...) solution would yield first-order moral insights for the ethics of self-driving cars, but such a solution is difficult to come by. More plausible is the pessimistic solution, and it teaches us a methodological lesson. The lesson is that machine ethicists should discount case intuitions and instead rely on intuitions and judgments at a higher level of generality. (shrink)

Consider three cases: -/- Turn: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me. -/- Hurl: A trolley is about to kill five innocent strangers. You can hurl me at the trolley, saving the five and paralyzing me. -/- TurnHurl: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me. You can instead hurl me at (...) the trolley, saving the five and paralyzing me. -/- Most find the following four claims intuitively plausible: -/- (1) It is permissible to turn the trolley onto me in Turn. (2) It is impermissible to hurl me at the trolley in Hurl. (3) It is impermissible to turn the trolley onto me in TurnHurl. (4) It is permissible to hurl me at the trolley in TurnHurl. -/- But how does turning go from permissible to impermissible, and hurling from impermissible to permissible, when both alternatives are available? I argue that such “secondary permissibility” claims are explained by contrastive consent. Even if I do not consent to being harmed, it is likely I’ll consent to being hurled at the trolley rather than being turned onto. (shrink)

This paper deals with the core version of the Trolley Problem. In one case many people favor an act which will bring about the death of one person but save five other persons. In another case most people would refuse to “sacrifice” one person in order to save five other lives. Since the two cases seem similar in all relevant respects, we have to explain and justify the diverging verdicts. Since I don’t find current proposals of a solution convincing, I (...) propose an alternative one according to which —but not —violates two forms of equality. I also test the underlying egalitarian principle against other cases. I argue that it offers a good explanation and also a normative justification of our intuitive verdicts about the cases. (shrink)

This paper argues against the view that trolley cases are of little or no relevance to the ethics of automated vehicles. Four arguments for this view are outlined and rejected: the Not Going to Happen Argument, the Moral Difference Argument, the Impossible Deliberation Argument and the Wrong Question Argument. In making clear where these arguments go wrong, a positive account is developed of how trolley cases can inform the ethics of automated vehicles.

Trolley cases are widely considered central to the ethics of autonomous vehicles. We caution against this by identifying four problems. Trolley cases, given technical limitations, rest on assumptions that are in tension with one another. Furthermore, trolley cases illuminate only a limited range of ethical issues insofar as they cohere with a certain design framework. Furthermore, trolley cases seem to demand a moral answer when a political answer is called for. Finally, trolley cases might be epistemically problematic in several ways. (...) To put forward a positive proposal, we illustrate how ethical challenges arise from mundane driving situations. We argue that mundane situations are relevant because of the specificity they require and the scale they exhibit. We then illustrate some of the ethical challenges arising from optimizing for safety, balancing safety with other values such as mobility, and adjusting to incentives of legal frameworks. (shrink)

This paper defends the use of imaginary cases in normative theorizing. Imaginary cases are used as a part of an argument and should be assessed in terms of the role they play within arguments. The paper identifies five ways in which they are used and then uses some of the best examples to bring out how they contribute to debates. While not directly akin to empirical experiments, criticisms of imaginary cases can be represented in terms of the well‐known distinction between (...) internal and external validity in social science experiments. While imaginary cases can suffer from internal and external validity problems, these do not constitute a decisive critique of their use as a method of analysis. Criticisms of imaginary cases should detail the precise form in which they are used, and why any particular use is invalid, internally or externally, in the context of the argument for which the case is presented. (shrink)

Reflective equilibrium —the idea that we have to justify our judgments and principles through a process of mutual adjustment—is taken to be a central method in philosophy. Nonetheless, conceptions of RE often stay sketchy, and there is a striking lack of explicit and traceable applications of it. This paper presents an explicit case study for the application of an elaborate RE conception. RE is used to reconstruct the arguments from Thomson’s paper “Turning the Trolley” for why a bystander must not (...) divert a runaway trolley from five workmen onto one. Analyzing Thomson’s resulting position with the RE-criteria has two main results: Firstly, the adjustment of one of her commitments can be defended. Secondly, no justified position in RE was reached. With respect to RE as a method, the main results from this application are: There is at least one conception of RE that is sufficiently specified to be applicable; the RE criteria put real constraints on the process of justification; and an explicit application of RE has benefits in terms of clarity while at the same time providing guidance for how the justificatory process could be continued. (shrink)

In this paper, I approach the trolley problem from a different angle, and align the perspective with non-Western models of philosophy as instruction for life. I argue that the trolley problem is an...

In light of the magnitude of interpersonal harm and the risk of greater harm in the future, Ingmar Persson and Julian Savulescu have argued for pharmacological enhancement of moral behaviour. I discuss moral bioenhancement as a set of collective action problems. Psychotropic drugs or other forms of neuromodulation designed to enhance moral sensitivity would have to produce the same or similar effects in the brains of a majority of people. Also, a significant number of healthy subjects would have to participate (...) in clinical trials testing the safety and efficacy of these drugs, which may expose them to unreasonable risk. Even if the drugs were safe and effective, a majority of people would have to co-operate in a moral enhancement programme for such a project to succeed. This goal would be thwarted if enough people opted out and decided not to enhance. To avoid this scenario, Persson and Savulescu argue that moral enhancement should be compulsory rather than voluntary. But the collective interest in harm reduction through compulsory enhancement would come at the cost of a loss of individual freedom. In general, there are many theoretical and practical reasons for scepticism about the concept and goal of moral enhancement. (shrink)

The doctrine of double effect and the many other principles that philosophers have advanced to remedy the doctrine’s defects were meant, in the words of Warren Quinn, "to capture certain kinds of fairly common intuitions about [a set of canonical] pairs of cases." Both cases in each pair “have the same consequential profile,” in that "agents bring about the same good result at the same cost in lives lost or harm suffered." But they exhibit differing deontological characteristics, leading the “common (...) intuitions” to which Quinn refers to deem one but not the other case in each pair permissible. Over time, though, the body of cases has ballooned to embrace ever more complex situations about which intuitions are far less shared, and the principles advanced to explain those intuitions do not necessarily generate the “common” permissible/impermissible distinctions in each canonical pair. My goal is to offer a principle that does so, and to suggest that it reflects a unique deontology. (shrink)