This chapter defends a non-consequentialist approach to justifying harming innocent nonthreatening people. The discussion centers on variations of cases where either a trolley driver or a bystander may redirect a trolley so that it kills one person, rather than five people towards whom it is headed. The article begins by critically examining other non-consequentialist proposals for why turning the trolley may be justified in both types of cases. It then defends seven principles, which together comprise the “Doctrine of Productive Purity” (DPP). The DPP implies that interpersonal harms may be justified by what produces them as opposed to by the goods they produce as in consequentialist views. The article contrasts the DPP with threshold deontology and considers how those whom one might permissibly harm may still permissibly resist such harm. The chapter concludes by considering limits of the DPP, the moral significance of the DPP for relations between people, and a new trolley problem that has implications for the killing/letting die distinction.

Philippa Foot offered her original Trolley Case, where a driver will unavoidably kill either five or one, neither to present a moral quandary nor to pose any special problem for moral theory. Its purpose was simply to illustrate how her theory of duties – which she deployed to defend non-consequentialist intuitions about various other cases of harmful agency – could also handle cases like this one where consequentialist verdicts seem apt. The Trolley Problem arose when Judith Jarvis Thomson modified the case, using the bystander variation to raise difficulties for Foot. Intuitively, it seems that the bystander may equally turn the trolley, but that would amount to killing one to save five, which was ruled out by Foot’s theory (even though it allowed a driver to kill one to avoid killing five). That was the Trolley Problem, which amounted to a challenge to explain why the bystander trolley case is an exception to the usual prohibition against killing some to save others for the greater good. For decades Thomson saw it as a legitimate challenge and offered plausible ways of meeting it. Later, however, she changed her mind, concluding that it is not permissible for the bystander to turn the trolley after all. In this chapter, I begin by examining the relevant background, refining the understanding of the Trolley Problem, and considering basic methodological issues in this area of normative ethics. I then develop a solution to the Trolley Problem along with a diagnosis of what went wrong in Thomson’s later attempt to show that there was never really a Trolley Problem to begin with. In the end I hope to have shown why there was indeed an important theoretical challenge posed by the Trolley Problem and how it can be resolved in a principled way with minor revisions to Foot’s original theory.

The Trolley Problem is not only one of the most widely discussed puzzles in moral philosophy. It is also one of the most controversial with respect to its perceived importance. At the one end of the spectrum there are those who consider it to reveal facts that belong at the very center of our moral understanding. At the other end of the spectrum there are those who consider it to be an example of contemporary philosophy at its most pointless. In this chapter, I critically address this dispute by tracing the discussion of the problem from its earliest formulation on the work of Philippa Foot, Judith Thomson, and Frances Kamm. Then I discuss a number of the most important criticisms of these discussions, drawing on the work of Barbara Fried. In doing so, I describe not only the actual causes of the problem’s continuing interest but also the underlying justification and rationale for that interest to which that history gives evidence.

Chapter 6 responds to five objections to double effect from proponents of the Irrelevance Theory, the theory that an agent’s intentions and motivating reasons are not fundamentally relevant to assessments of moral permissibility. The objections are the following: (i) It is mysterious why something in the agent’s mind should matter for the moral permissibility of her bodily actions; (ii) the PDE leads to inconsistent judgments about cases; the PDE is objectionable from the perspective of the deliberating agent, either (iii) insofar as it makes the moral permissibility of doing things such as dropping bombs turn on the agent’s intentions rather than objective features of her situation or (iv) insofar as it requires a deliberating agent to focus her attention inward on her own mental states rather than on the world; (v) the PDE sometimes has absurd implications for how we ought to respond to agents with bad intentions. I argue that none of these objections seriously damage the PDE.