Introduction
Whether there is a morally significant difference between killing and letting die is contentious. The consequentialist approaches this by rejecting this distinction, arguing that only outcomes ultimately matter — a thoroughly utilitarian point of view. Philippa Foot challenges this view by arguing that there is a morally significant distinction between doing harm and merely letting it occur. By Foot, those who deny the existence of this distinction fail to recognise the asymmetry between the duty not to harm and the duty to provide aid.
I argue that Foot successfully identifies this moral distinction as a feature of moral agency — where initiating harm typically holds greater moral weight than failing to prevent it — while also recognising that Foot ultimately fails to represent this distinction as a decisive principle.
Doing Harm vs. Allowing Harm
Foot's argument observes that moral practices treat distinct kinds of actions as more serious than others, even when outcomes are identical. Killing someone would typically be viewed as morally worse than simply allowing them to die. According to Foot, killing involves initiating a harmful causal chain of events, whereas letting someone die consists in permitting such a process to continue (Foot, 2002). The difference elucidates on the asymmetry between negative and positive duties. Negative duties prevent us from harming others, whereas positive duties require us to provide aid. Foot says that negative duties are stronger. Thus, violating a negative duty is worse than failing to complete a positive duty.
This explains why certain moral intuitions are resistant to cut-and-dry consequentialist reasoning — as in the transplant case, wherein a doctor could kill a healthy patient and distribute their organs to save five others. Even if doing this would maximise the overall lives saved, most people would regard the action as morally impermissible. Foot's framework explains that killing the patient violates the negative duty not to harm.
Rejections from Consequentialism
Consequentialists would reject the claim that this distinction exists. On consequentialist views, actions should be evaluated solely on the value of their outcomes. Thus, if killing one person would prevent several deaths, then the killing may appear morally justified. The contention between both perspectives is even more evident in trolley-problem style cases. Thomson's analysis highlights the difficulty of explaining why diverting a trolley onto a track where it kills one person is permissible, whilst pushing someone onto the track to stop the trolley killing five people seems impermissible (Thomson, 1976). These cases suggest that differences in agency — doing versus allowing harm — can shape moral judgement independently of consequences.
Foot's theory captures this feature of moral reasoning by emphasising the difference between initiating and permitting harm, explaining why some actions remain prohibited even when they would produce better outcomes.
Responsibility and Limits
Despite the distinction's appeal, it also faces challenges. Kagan argues that drawing a decisive moral boundary between doing and allowing harm can obscure the morally relevant similarities between actions (Kagan, 1989). A moral agent may deliberately structure their behaviour so that a harmful outcome occurs without directly inciting the chain of harm. If the agent knowingly allows a preventable harm to occur when intervention would be easy, the moral difference between active harm and their behaviour seems lesser.
Quinn also argues that the moral importance of doing versus allowing depends heavily on intention rather than on the physical form of the action itself (Quinn, 1989). Certain cases can blur the boundary because agents can manipulate the causal structures of the action to avoid direct responsibility whilst still bringing about the harmful consequences.
Moral Agency
Further challenges arise when we consider indirect harm. McMahan argues that removing barriers to harm — such as withdrawing life-sustaining aid — can sometimes count as killing rather than allowing one to die (McMahan, 1993). If withdrawing this aid initiates a new causal chain which leads to death, the classification becomes unclear. The distinction between doing and allowing therefore often depends on how these causal processes are described. However, moral evaluation cannot depend on subtle discrepancies in cause alone. If two actions have the same moral outcome through similar causes, treating them as morally distinct is arbitrary.
Foot's Insights
Despite these criticisms, Foot's central tenet remains persuasive. There is a distinction between killing and letting die which demonstrates that actively initiating harm carries greater moral weight than failing to prevent it. This helps explain why certain consequentialist conclusions seem impermissible. By emphasising the moral significance of agency, Foot provides an account of why actively causing harm violates stronger moral boundaries than allowing harm to occur.
Conclusion
Foot succeeds in demonstrating that there is a distinction between killing and letting die which relies on the moral aspect of agency. However, the distinction is not universal enough to stand as a decisive moral principle. Cases involving responsibility for actions can be ambiguous — some killings can seem to have the same moral weight as simply letting die — and therefore we cannot draw this distinction as an absolute.
Bibliography
Foot, P. (2002). Moral Dilemmas and Other Topics in Moral Philosophy. Oxford: Oxford University Press.
Kagan, S. (1989). The Limits of Morality. Oxford: Oxford University Press.
McMahan, J. (1993). "Killing, Letting Die, and Withdrawing Aid." Ethics 103(2).
Quinn, W. (1989). "Actions, Intentions, and Consequences: The Doctrine of Doing and Allowing." The Philosophical Review 98(3).
Thomson, J. J. (1976). "Killing, Letting Die, and the Trolley Problem." The Monist.