This article reviews the reasons scholars hold that driverless cars and many other AI equipped machines must be able to make ethical decisions, and the difficulties this approach faces. It then shows that cars have no moral agency, and that the term ‘autonomous’, commonly applied to these machines, is misleading, and leads to invalid conclusions about the ways these machines can be kept ethical. The article’s most important claim is that a significant part of the challenge posed by AI-equipped machines (...) can be addressed by the kind of ethical choices made by human beings for millennia. Ergo, there is little need to teach machines ethics even if this could be done in the first place. Finally, the article points out that it is a grievous error to draw on extreme outlier scenarios—such as the Trolley narratives—as a basis for conceptualizing the ethical issues at hand. (shrink)

Questions of what a self-driving car ought to do if it encounters a situation analogous to the ‘trolley problem’ have dominated recent discussion of the ethics of self-driving cars. This paper argues that this interest is misplaced. If a trolley-style dilemma situation actually occurs, given the limits on what information will be available to the car, the dynamics of braking and tyre traction determine that, irrespective of outcome, it is always least risky for the car to brake in a straight (...) line rather than swerve. (shrink)

The trolley problem, first described by Foot (1967) and Thomson (The Monist, 59, 204–217, 1976), is one of the most famous and influential thought experiments in deontological ethics. The general story is that a runaway trolley is threatening the lives of five people. Doing nothing will result in the death of those persons, but acting in order to save those persons would unavoidably result in the death of another, sixth person. It appears that, depending on the situation, we have different (...) moral judgments about the permissibility of action. We will review and systematize all the proposals in the literature of the past 35 years that have attempted to grasp our moral intuitions in a simple deontological principle. In particular, seventeen proposals will be classified: six algorithmic, seven psychological, and four other invalid accounts. This review and classification sheds light on some subtle differences and clarify a few issues. (shrink)

In this paper, we argue that solutions to normative challenges associated with autonomous driving, such as real-world trolley cases or distributions of risk in mundane driving situations, face the problem of reasonable pluralism: Reasonable pluralism refers to the fact that there exists a plurality of reasonable yet incompatible comprehensive moral doctrines within liberal democracies. The corresponding problem is that a politically acceptable solution cannot refer to only one of these comprehensive doctrines. Yet a politically adequate solution to the normative challenges (...) of autonomous driving need not come at the expense of an ethical solution, if it is based on moral beliefs that are (1) shared in an overlapping consensus and (2) systematized through public reason. Therefore, we argue that a Rawlsian justificatory framework is able to adequately address the normative challenges of autonomous driving and elaborate on how such a framework might be employed for this purpose. (shrink)

It has been claimed that the recent wave of neuroscientific research into the physiological underpinnings of our moral intuitions has normative implications. In particular, it has been claimed that this research discredits our deontological intuitions about cases, without discrediting our consequentialist intuitions about cases. In this paper I demur. I argue that such attempts to extract normative conclusions from neuroscientific research face a fundamental dilemma: either they focus on the emotional or evolved nature of the psychological processes underlying deontological intuitions, (...) in which case the arguments rely on a blatantly fallacious inference, or they appeal to the (alleged) moral irrelevance of the factors to which deontological intuitions respond, in which case the neuroscientific results end up playing no role in the overall argument. (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 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)

Though sometimes maligned, “trolleyology” offers an effective means of opening and framing, not only classes in ethics, but indeed any introductory philosophy course taking a broadly “puzzle-based” approach. When properly sequenced, a subset of the thought experiments that are trolleyology’s stock-in-trade can generate a series of puzzles illustrating the shortcomings of our untutored moral intuitions, and which thus motivate the very enterprise of moral theorizing. Students can be engaged in the attempt to resolve said puzzles, inasmuch as they’re accessible and (...) compelling, and their resolutions generally easy to achieve. Once thus engaged, students can be directed to the fact that they had already rolled up their sleeves and begun “doing philosophy.” In this way, engagement with trolleyological puzzles can serve as a “microcosm” for philosophy more broadly, illustrating the processes of critical thinking that are likewise the stock-in-trade of philosophers across many different domains of inquiry. (shrink)

Book reviewed in this article: Greation and Abortion: A Study in Moral and Legal Philosophy. By Frances M. Kamm.

Paradox Lost covers ten of philosophy’s most fascinating paradoxes, in which seemingly compelling reasoning leads to absurd conclusions. The following paradoxes are included: The Liar Paradox, in which a sentence says of itself that it is false. Is the sentence true or false? The Sorites Paradox, in which we imagine removing grains of sand one at a time from a heap of sand. Is there a particular grain whose removal converts the heap to a non-heap? The Puzzle of the Self-Torturer, (...) in which a series of seemingly rational choices has us accepting a life of excruciating pain, in exchange for millions of dollars. Newcomb’s Problem, in which we seemingly maximize our expected profit by taking an unknown sum of money, rather than taking the same sum plus $1000. The Surprise Quiz Paradox, in which a professor finds that it is impossible to give a surprise quiz on any particular day of the week... but also that if this is so, then a surprise quiz can be given on any day. The Two Envelope Paradox, in which we are asked to choose between two indistinguishable envelopes, and it is seemingly shown that each envelope is preferable to the other. The Ravens Paradox, in which observing a purple shoe provides evidence that all ravens are black. The Shooting Room Paradox, in which a deadly game kills 90% of all who play, yet each individual’s survival turns on the flip of a fair coin. Each paradox is clearly described, common mistakes are explored, and a clear, logical solution offered. Paradox Lost will appeal to professional philosophers, students of philosophy, and all who love intellectual puzzles. (shrink)

Self-driving cars currently face a lot of technological problems that need to be solved before the cars can be widely used. However, they also face ethical problems, among which the question of crash-optimization algorithms is most prominently discussed. Reviewing current debates about whether we should use the ethics of the Trolley Dilemma as a guide towards designing self-driving cars will provide us with insights about what exactly ethical research does. It will result in the view that although we need the (...) ethics of the Trolley Dilemma as important input for self-driving cars, the route towards simply implementing it into automated cars is blocked. (shrink)

A recent study of moral intuitions, performed by Joshua Greene and a group of researchers at Princeton University, has recently received a lot of attention. Greene and his collaborators designed a set of experiments in which subjects were undergoing brain scanning as they were asked to respond to various practical dilemmas. They found that contemplation of some of these cases (cases where the subjects had to imagine that they must use some direct form of violence) elicited greater activity in certain (...) areas of the brain associated with emotions compared with the other cases. It has been argued (e.g., by Peter Singer) that these results undermine the reliability of our moral intuitions, and therefore provide an objection to methods of moral reasoning that presuppose that they carry an evidential weight (such as the idea of reflective equilibrium). I distinguish between two ways in which Greene's findings lend support for a sceptical attitude towards intuitions. I argue that, given the first version of the challenge, the method of reflective equilibrium can easily accommodate the findings. As for the second version of the challenge, I argue that it does not so much pose a threat specifically to the method of reflective equilibrium but to the idea that moral claims can be justified through rational argumentation in general. (shrink)

In this paper, we investigate how data about public preferences may be used to inform policy around the use of controversial novel technologies, using public preferences about autonomous vehicles (AVs) as a case study. We first summarize the recent ‘Moral Machine’ study, which generated preference data from millions of people regarding how they think AVs should respond to emergency situations. We argue that while such preferences cannot be used to directly inform policy, they should not be disregarded. We defend an (...) approach that we call ‘Collective Reflective Equilibrium in Practice’ (CREP). In CREP, data on public attitudes function as an input into a deliberative process that looks for coherence between attitudes, behaviours and competing ethical principles. We argue that in cases of reasonable moral disagreement, data on public attitudes should play a much greater role in shaping policies than in areas of ethical consensus. We apply CREP to some of the global preferences about AVs uncovered by the Moral Machines study. We intend this discussion both as a substantive contribution to the debate about the programming of ethical AVs, and as an illustration of how CREP works. We argue that CREP provides a principled way of using some public preferences as an input for policy, while justifiably disregarding others. (shrink)

Intuition—spontaneous, nondeliberative assessment—has long been indispensable in theoretical and practical philosophy alike. Recent research by psychologists and experimental philosophers has challenged our understanding of the nature and authority of moral intuitions by tracing them to “fast,” “automatic,” “button-pushing” responses of the affective system. This view of the affective system contrasts with a growing body of research in affective neuroscience which suggests that it is instead a flexible learning system that generates and updates a multidimensional evaluative landscape to guide decision and (...) action. With this latter view in mind, I revisit some of the classic hypothetical scenarios used in experimental moral psychology. (shrink)

Reflective equilibrium has been criticized for various reasons ever since the publication of Rawls’ A Theory of Justice. Recent empirical research into moral decision-making poses new challenges to RE because it questions the reliability of moral intuitions. This research might discredit moral intuitionism in general and RE in particular insofar as it ascribes epistemic value to moral intuitions. These findings suggest, for instance, that moral intuitions vary with cultural background, gender or framing. If it could be shown that all or (...) certain kinds of moral intuitions are unreliable, this would diminish the plausibility of the claim that they provide good reasons to believe in the truth of their content, especially given the growing evidence that professional philosophers are just as biased and susceptible to distorting factors as lay people. In this paper I critically discuss three recent defenses of RE against this unreliable intuitions objection. Two of these defenses argue that the UIO misses its target, because RE does not depend on intuitions, or because the relevant considered judgments in RE are not intuitions. The third defense grants that RE depends on intuitions and that some Rawlsian considered judgments are intuitions. But it argues that the notion of considered judgments can be revised, and that wide reflective equilibrium has the means to adopt the criticism because it can use information about unreliable intuitions and exclude those from further consideration. I argue that the first two defenses do not succeed. The third defense is the most promising one. However, I argue that this defense also fails. In this defense, RE is not a distinctive moral epistemic theory: different versions of RE would be conceivable, all of which are deeply problematic. I conclude with a discussion of the broader philosophical implications of the UIO, specifically whether or not accepting the UIO would warrant skepticism regarding moral knowledge. (shrink)

In the Trolley Case (Figure 1), as devised by Philippa Foot and modified by Judith Jarvis Thomson, a runaway trolley (i.e. tram) is headed down a main track and will hit and kill five unless you divert it onto a side track, where it will hit and kill one.

In the Trolley Case (Figure 1), as devised by Philippa Foot and modified by Judith Jarvis Thomson, a runaway trolley (i.e. tram) is headed down a main track and will hit and kill five unless you divert it onto a side track, where it will hit and kill one.

Self-driving cars hold out the promise of being safer than manually driven cars. Yet they cannot be a 100 % safe. Collisions are sometimes unavoidable. So self-driving cars need to be programmed for how they should respond to scenarios where collisions are highly likely or unavoidable. The accident-scenarios self-driving cars might face have recently been likened to the key examples and dilemmas associated with the trolley problem. In this article, we critically examine this tempting analogy. We identify three important ways (...) in which the ethics of accident-algorithms for self-driving cars and the philosophy of the trolley problem differ from each other. These concern: the basic decision-making situation faced by those who decide how self-driving cars should be programmed to deal with accidents; moral and legal responsibility; and decision-making in the face of risks and uncertainty. In discussing these three areas of disanalogy, we isolate and identify a number of basic issues and complexities that arise within the ethics of the programming of self-driving cars. (shrink)

Self‐driving cars hold out the promise of being much safer than regular cars. Yet they cannot be 100% safe. Accordingly, they need to be programmed for how to deal with crash scenarios. Should cars be programmed to always prioritize their owners, to minimize harm, or to respond to crashes on the basis of some other type of principle? The article first discusses whether everyone should have the same “ethics settings.” Next, the oft‐made analogy with the trolley problem is examined. Then (...) follows an assessment of recent empirical work on lay‐people's attitudes about crash algorithms relevant to the ethical issue of crash optimization. Finally, the article discusses what traditional ethical theories such as utilitarianism, Kantianism, virtue ethics, and contractualism imply about how cars should handle crash scenarios. The aim of the article is to provide an overview of the existing literature on these topics and to assess how far the discussion has gotten so far. (shrink)

The philosophical–ethical literature and the public debate on autonomous vehicles have been obsessed with ethical issues related to crashing. In this article, these discussions, including more empirical investigations, will be critically assessed. It is argued that a related and more pressing issue is questions concerning safety. For example, what should we require from autonomous vehicles when it comes to safety? What do we mean by ‘safety’? How do we measure it? In response to these questions, the article will present a (...) foundation for a continued discussion on these issues and an argument for why discussions about safety should be prioritized over ethical concerns related to crashing. (shrink)

Autonomous vehicles must be programmed with procedures for dealing with trolley-style dilemmas where actions result in harm to either pedestrians or passengers. This paper outlines a Rawlsian algorithm as an alternative to the Utilitarian solution. The algorithm will gather the vehicle’s estimation of probability of survival for each person in each action, then calculate which action a self-interested person would agree to if he or she were in an original bargaining position of fairness. I will employ Rawls’ assumption that the (...) Maximin procedure is what self-interested agents would use from an original position, and then show how the Maximin procedure can be operationalized to produce unique outputs over probabilities of survival. (shrink)

Studies suggest that people's moral intuitions are sensitive to morally irrelevant factors, such as personal force, spatial distance, ethnicity or nationality. Findings of this sort have been used to construct debunking arguments. The most prominent champion of this approach is Joshua Greene, who has attempted to undermine deontology by showing that deontological intuitions are triggered by morally irrelevant factors. This article offers a critical analysis of such empirically informed debunking arguments from moral irrelevance, and of Greene’s effort to undermine deontology. (...) One problem with arguments from moral irrelevance concerns the hierarchy between the targeted case-specific intuitions and the more general intuitions about which factors are morally (ir)relevant. If we assume that general intuitions always take precedence over case-specific intuitions, arguments from moral irrelevance become dialectically useless. By contrast, if we assume that both case-specific and general intuitions should be taken seriously, particularly sweeping debunking projects, such as Greene’s, are unlikely to go through. Another problem concerns the experimental aspect of arguments from moral irrelevance. Empirically informed arguments from moral irrelevance have been presented as examples of how empirical moral psychology can advance moral theory. But arguments from moral irrelevance can also be constructed from the armchair. And basing these arguments on empirical findings about laypeople’s intuitions is even counterproductive. (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.

Peter Unger’s book has both substantive and methodological aims. Substantively, it aims to prove the following four claims in the following order: we must, in general, suffer great losses of property to prevent suffering and death; we may, in general, impose such losses on others for the same goals; we may, in general, kill others to prevent more deaths; and we must, in general, kill ourself to prevent more deaths. Methodologically, it aims to show that intuitive judgments about cases that (...) would be presented as evidence against the four substantive claims—the standard technique of nonconsequentialists arguing against consequentialists—are worthless because we can construct cases that generate the opposite intuitive judgment; further, we can show that the factors that distinguish the cases yielding such different intuitions are not morally significant; and hence, we must decide which judgments are correct by consulting such general moral values as the importance of reducing suffering and death. Thus, Unger offers an error theory of nonconsequentialist restrictions on harming others and prerogatives not to make large sacrifices to aid. This error theory is based on the psychological effects of morally insignificant factors. (shrink)

Ethical theory often starts with our intuitions about particular cases and tries to uncover the principles that are implicit in them; work on the ‘trolley problem’ is a paradigmatic example of this approach. But ethicists are no longer the only ones chasing trolleys. In recent years, psychologists and neuroscientists have also turned to study our moral intuitions and what underlies them. The relation between these two inquiries, which investigate similar examples and intuitions, and sometimes produce parallel results, is puzzling. Does (...) it matter to ethics whether its armchair conclusions match the psychologists’ findings? I argue that reflection on this question exposes psychological presuppositions implicit in armchair ethical theorising. When these presuppositions are made explicit, it becomes clear that empirical evidence can (and should) play a positive role in ethical theorising. Unlike recent assaults on the armchair, the argument I develop is not driven by a naturalist agenda, or meant to cast doubt on the reliability of our moral intuitions; on the contrary, it is even compatible with non-naturalism, and takes the reliability of intuition as its premise. The argument is rather that if our moral intuitions are reliable, then psychological evidence should play a surprisingly significant role in the justification of moral principles. (shrink)

Future weapons will make life-or-death decisions without a human in the loop. When such weapons inflict unwarranted harm, no one appears to be responsible. There seems to be a responsibility gap. I first reconstruct the argument for such responsibility gaps to then argue that this argument is not sound. The argument assumes that commanders have no control over whether autonomous weapons inflict harm. I argue against this assumption. Although this investigation concerns a specific case of autonomous weapons systems, I take (...) steps towards vindicating the more general idea that superiors can be morally responsible in virtue of being in command. (shrink)

The prospective introduction of autonomous cars into public traffic raises the question of how such systems should behave when an accident is inevitable. Due to concerns with self-interest and liberal legitimacy that have become paramount in the emerging debate, a contractarian framework seems to provide a particularly attractive means of approaching this problem. We examine one such attempt, which derives a harm minimisation rule from the assumptions of rational self-interest and ignorance of one’s position in a future accident. We contend, (...) however, that both contractarian approaches and harm minimisation standards are flawed, due to a failure to account for the fundamental difference between those ‘involved’ and ‘uninvolved’ in an impending crash. Drawing from classical works on the trolley problem, we show how this notion can be substantiated by reference to either the distinction between negative and positive rights, or to differences in people’s claims. By supplementing harm minimisation with corresponding constraints, we can develop crash algorithms for autonomous cars which are both ethically adequate and promise to overcome certain significant practical barriers to implementation. (shrink)

This discussion attempts to show that the elusive solution to the trolley problem lies hidden in the solution to another perennial problem in moral philosophy: the ducking puzzle. The key to solving the ducking puzzle is an important, but overlooked, exception to our obligation not to harm others, an exception for , which, it is argued here, is also the key to solving the trolley problem.

The introduction of self-driving vehicles gives rise to a large number of ethical issues that go beyond the common, extremely narrow, focus on improbable dilemma-like scenarios. This article provides a broad overview of realistic ethical issues related to self-driving vehicles. Some of the major topics covered are as follows: Strong opinions for and against driverless cars may give rise to severe social and political conflicts. A low tolerance for accidents caused by driverless vehicles may delay the introduction of driverless systems (...) that would substantially reduce the risks. Trade-offs will arise between safety and other requirement on the road traffic system. Over-reliance on the swift collision-avoiding reactions of self-driving vehicles can induce people to take dangerous actions, such as stepping out in front of a car, relying on its fast braking. Children travelling alone can violate safety instructions such as the use of seatbelts. Digital information about routes and destinations can be used to convey commercial and political messages to car users. If fast passage can be bought, then socio-economic segregation of road traffic may result. Terrorists and other criminals can hack into a vehicle and make it crash. They can also use self-driving vehicles for instance to carry bombs to their designed places of detonation or to wreak havoc on a country’s road system. (shrink)

In some cases people judge it morally acceptable to sacrifice one person’s life in order to save several other lives, while in other similar cases they make the opposite judgment. Researchers have identified two general factors that may explain this phenomenon at the stimulus level: (1) the agent’s intention (i.e. whether the harmful event is intended as a means or merely foreseen as a side-effect) and (2) whether the agent harms the victim in a manner that is relatively “direct” or (...) “personal”. Here we integrate these two classes of findings. Two experiments examine a novel personalness/directness factor that we call personal force, present when the force that directly impacts the victim is generated by the agent’s muscles (e.g., in pushing). Experiments 1a and b demonstrate the influence of personal force on moral judgment, distinguishing it from physical contact and spatial proximity. Experiments 2a and b demonstrate an interaction between personal force and intention, whereby the effect of personal force depends entirely on intention. These studies also introduce a method for controlling for people’s real-world expectations in decisions involving potentially unrealistic hypothetical dilemmas. (shrink)

In this article I explain why cognitive science (including some neuroscience) matters for normative ethics. First, I describe the dual-process theory of moral judgment and briefly summarize the evidence supporting it. Next I describe related experimental research examining influences on intuitive moral judgment. I then describe two ways in which research along these lines can have implications for ethics. I argue that a deeper understanding of moral psychology favors certain forms of consequentialism over other classes of normative moral theory. I (...) close with some brief remarks concerning the bright future of ethics as an interdisciplinary enterprise. (shrink)

No one has done more over the past four decades to draw attention to the importance of, and attempt to solve, a particularly vexing problem in ethics—the Trolley Problem—than Judith Jarvis Thomson. Though the problem is originally due to Philippa Foot, Thomson showed how Foot’s simple solution would not do and offered some solutions of her own. No solution is uncontroversial and the problem remains a thorn in the side of non-consequentialist moral theory. Recently, however, Thomson has changed her mind (...) about the problem. She no longer thinks she was right to reject Foot’s solution to it. I argue that, though illuminating, Thomson’s current take on the Trolley Problem is mistaken. I end with a solution to the problem that I find promising. (shrink)

The recent progress in the development of autonomous cars has seen ethical questions come to the forefront. In particular, life and death decisions regarding the behavior of self-driving cars in trolley dilemma situations are attracting widespread interest in the recent debate. In this essay we want to ask whether we should implement a mandatory ethics setting for the whole of society or, whether every driver should have the choice to select his own personal ethics setting. While the consensus view seems (...) to be that people would not be willing to use an automated car that might sacrifice themselves in a dilemma situation, we will defend the somewhat contra-intuitive claim that this would be nevertheless in their best interest. The reason is, simply put, that a PES regime would most likely result in a prisoner’s dilemma. (shrink)

One of the reasons why most of us feel puzzled about the problem of abortion is that we want, and do not want, to allow to the unborn child the rights that belong to adults and children. When we think of a baby about to be born it seems absurd to think that the next few minutes or even hours could make so radical a difference to its status; yet as we go back in the life of the fetus we (...) are more and more reluctant to say that this is a human being and must be treated as such. No doubt this is the deepest source of our dilemma, but it is not the only one. For we are also confused about the general question of what we may and may not do where the interests of human beings conflict. We have strong intuitions about certain cases; saying, for instance, that it is all right to raise the level of education in our country, though statistics allow us to predict that a rise in the suicide rate will follow, while it is not all right to kill the feeble-minded to aid cancer research. It is not easy, however, to see the principles involved, and one way of throwing light on the abortion issue will be by setting up parallels involving adults or children once born. So we will be able to isolate the “equal rights” issue and should be able to make some advance... (shrink)