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The ethics of killing and letting die: active and passive euthanasia
  1. H V McLachlan
  1. Centre for Ethics in Public Policy and Corporate Governance, School of Law and Social Sciences, Glasgow Caledonian University, Glasgow, UK
  1. Professor H V McLachlan, School of Law and Social Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, UK; H.McLachlan{at}


In their account of passive euthanasia, Garrard and Wilkinson present arguments that might lead one to overlook significant moral differences between killing and letting die. To kill is not the same as to let die. Similarly, there are significant differences between active and passive euthanasia. Our moral duties differ with regard to them. We are, in general, obliged to refrain from killing each and everyone. We do not have a similar obligation to try (or to continue to try) to prevent each and everyone from dying. In any case, to be morally obliged to persist in trying to prevent their deaths would be different from being morally obliged to refrain from killing all other people even if we had both obligations.

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There are significant moral differences between killing and letting die.1 There are corresponding differences between active and passive euthanasia. For example, the relevant moral duties differ. Even when acts and omissions have the same outcomes, they are not thereby necessarily morally identical: how and why what is done matters. It can matter too who does it. Some of the arguments presented by Garrard and Wilkinson2 in their discussion of passive euthanasia might tend to obscure these points.3


Killing is not in all significant respects the same as letting die. For example, the absence of a ventilator kills no one. The presence of a ventilator might, in some instances, serve to counteract a cause of death. The switching off of a ventilator might, in a sense, be an indirect cause of death but it will not kill directly as, say, a heavy dose of some drugs will.46 Suppose that someone is restraining a violent thug and then ceases to do so. If the thug then murders a passer-by, it might be said that the cessation of the constraint was an indirect cause of the killing, but it was clearly not the direct cause of the death no matter how predictable the subsequent events were and whether or not they were wished for. The cessation of the constraint was not murder.

In some particular circumstances, particular people might have a moral duty to restrain particular thugs. For example, if a policeman wantonly released from his grasp an aggressive thug who was comfortably under his control, or a jailor, without authorisation, released one of his prisoners, he would be at fault and would bear some responsibility for any consequent carnage. In general, however, our moral obligations with regard to refraining from killing people are different from our obligations concerning the restraining of thugs. For one thing, we are morally obliged to refrain from wantonly killing anyone. We can hardly be morally obliged to restrain or even to try to restrain all thugs. It would be impossible to accomplish and futile to attempt such an undertaking. Similarly, our moral obligations with regard to killing people are different from our obligations with regard to letting them die. We are obliged to refrain from killing each and everyone. We do not have a similar obligation to try (far less to continue to try) to prevent each and everyone from dying. In any case, to be morally obliged to try to prevent their deaths would be different from being morally obliged to refrain from killing all other people, even if we had both obligations.

Suppose that, as a hospital patient, you were somehow able to ask someone to switch off your ventilator. If the person is, say, a visitor or a fellow patient then he should not comply with your request: to do so is none of his business. If, however, you tell the doctor who is responsible for your treatment to discontinue it, not only would he be morally permitted to switch off the machine, he would be morally obliged to do so. On the other hand, if you ask someone to kill you, whether you are a patient or not, the person will not thereby be morally obliged to kill you, whoever the person might be. The person might thereby be released from a particular moral duty to you to refrain from killing you although he might still bear other general moral duties not to kill and not to kill you.

There is a poster near my house that says: “Kill Jill?” and appears to display the alternatives: “Yes” and “No”. It is provided by the Scottish Executive and Healthy Scotland. What the promoters of this disgraceful propaganda want to suggest is that if we do not posthumously donate our organs, we are killing someone who requires a transplant in order to survive. It is morally wrong as well as illegal to kill Jill. It is not always morally wrong or illegal to refrain from doing something that might have stopped Jill from dying. Even if it is morally wrong to fail to donate your organs for posthumous transplantation, it is not a wrongful killing or, indeed, a killing of any sort. It would be absurd to make it illegal to refrain from donating our organs.7

We have a duty not to kill Jill and she has a corresponding right not to be killed. Jill does not have a similar sort of a right to receive an organ from each or any one us. It is a matter of justice that we do not kill her. It is not a matter of justice that we donate one of our organs to her. Even if we have a moral duty to be charitable and even if the fulfilment of that duty might, in some circumstances and for some people, involve donating their viable organs to those who might need them after the donors’ deaths, this duty does not correspond to a right held by anyone to receive such organs.8 9

Killing someone is not always the same as letting him die. Sometimes both are morally wrong. Sometimes both are morally right. Sometimes one is right and the other is wrong. Sometimes it would be morally more justifiable to kill someone than to let him die. My central point is that they are morally different. There are corresponding differences between active and passive euthanasia.


Garrard and Wilkinson present, in order to refute it, the “causation argument”. They write:

“Uncontentiously, euthanasia causes death. But, according to the causation argument, omissions cannot cause anything. Passive euthanasia (so-called) is an omission. So passive euthanasia cannot cause death and hence cannot really be euthanasia.”1

This argument is defective, in the view of Garrard and Wilkinson. They write:

“Most importantly, the general claim at the heart of the argument—that omissions cannot be causes—does not appear to be true. What caused the crash at the junction? One of the drivers did not signal before turning right—he omitted to signal his intentions. What caused the clever student to fail her exams? She did not bother to revise for them—she omitted to do any work. We routinely attribute causal explanatory power to a wide variety of omissions. This objection alone seriously erodes the causation argument.”1

I am uncomfortable about the bald claim that omissions can cause things to happen. Some people might say that the magnitude of the horrific shooting and killing of students at Virginia Tech in April 2007 was caused by the relative absence of guns on the campus: had more guns been present, the murderous student would have been killed before he had fired as many bullets as he managed to do. One would want more to question the point of saying this rather than its apparent tautological truth. It might be the case that we “routinely attribute causal explanatory power to a wide variety of omissions” but only, I would suggest, when we are speaking in a short-hand sort of way. For example, we might say in a particular context and in order to make a particular point that Princess Diana died because she was not wearing a seat-belt. Had she been wearing one she would, in all likelihood, still be alive. If, however, we say that what caused her death was the absence of a seat-belt, I do not think that we intend what we say to be a complete and literally true account of the situation. Failure to wear a seat-belt will not kill you. What it will do is prevent what might otherwise have killed you from killing you. There is a difference, I think, and a difference that we are often keen to stress. Brick walls and lamp-posts pose threats to passengers in moving vehicles that seat-belts and their absence do not.

We might also say that what caused Princess Diana’s death was the absence of sobriety on the part of the driver of her car. If, say, he had chosen to go to an AA meeting that day, week, month or year, things might have turned out differently. Such omissions, it might be said, were the cause of her death. With this way of talking, there is a danger of double-counting the causal factors involved in any situation. All situations would seem to be infinitely over-determined. With any event, state of affairs or occurrence it is, perhaps, tautologically true to say that it is caused by (1) its cause and (2) the absence of a preventive anti-cause. Both 1 and 2 are necessary (one might say) for the effect to ensue. 1 and 2 can, however, hardly have the same explanatory or ontological status. The cause of, say, Princess Diana’s death is something definite. What might have served as an anti-cause is limitless. Omissions are part of 2. We draw attention to them sometimes to make or remind ourselves of some particular point or other.

What caused the clever girl, cited by Garrard and Wilkinson, to fail her examinations? It was her state of ignorance at the time of her presence in the examination room. That cause could have been annihilated by the existence of a preventive anti-cause had she worked harder. Her omission to work was not, however, the cause of her failure, although it was the cause of the absence of the preventive anti-cause. What caused the crash that Garrard and Wilkinson mention? Insufficient information is provided in order for one to know.

Who, if anyone, in the situations described was at fault? How, if at all, could he, she or they have acted otherwise and better? These are different questions from that about causation. By our answers, we target particular elements in the causal narrative for particular purposes. The driver was at fault in not indicating. The girl was at fault in her failure to revise. They were at least partly responsible and culpable for the outcomes.


Garrard and Wilkinson persist. They say:

‘There are some circumstances in which omissions can clearly kill. Suppose a patient has a raging infection which the doctor can cure simply by administering antibiotics. But he negligently or malevolently does not prescribe them—he omits to provide the appropriate treatment, thereby killing the patient…. Suppose that a child is drowning in shallow water and that a passing adult, who is a strong swimmer, decides not to save her—perhaps because he hates her parents, or because he is on his way to a football match and does not want to be late. The passer-by decides not to intervene when it would have been easy for him to do so and his non-intervention kills the child. Instances such as these can be multiplied endlessly: omissions can kill. But in that case, passive euthanasia can kill even if, unlike the examples given above, it is morally permissible.’1

I agree with Garrard and Wilkinson that, contrary to a popular view, the moral status of an omission is irrelevant to whether or not it can be considered to be a cause and, in particular, I agree that it would be incorrect to say “…that only impermissible omissions can be causes.”1 For example, suppose that two people are about to drown in a nearby lake. One might be a distressed school-girl who is crying for help and the other a terminally ill person who is, and is known by us to be, peacefully ending his life. If we fail to intervene and both people die, in neither instance is our inaction a cause of the death of the person concerned. Our inaction with regard to the death of the school-girl might be wrong just as our intervention to prevent the death of the man would, I think, have been wrong.

I would, however, deny that “omissions can clearly kill” although I would concede that omissions can indirectly lead to deaths insofar as they might fail to prevent them. More importantly, I would stress that actively to kill someone is significantly morally different from failing to do something that would have prevented the person from dying. Even when both are morally wrong and equally morally wrong they are different moral wrongs. The doctor’s failure to prescribe antibiotics was wrong especially if it was malevolent, but it was a wrongful omission rather than a wrongful killing. To drown a child is illegal and murder. To fail to save a child is not (and should not be) to commit murder even if it sometimes is to be guilty of failing to fulfil a duty of care. There is a moral difference between drowning a child yourself and failing to save a drowning child. There is and should be a legal distinction. Sometimes, one could save one child from drowning only by neglecting some other drowning child. Contrariwise, it is not the case that one can avoid murdering one particular child only by murdering another one.

Suppose that you are walking by a lake in which 10 children are swimming happily. You have a legal and a moral duty towards each child not to drown him and each has a moral and legal right not to be drowned by you. None has a legal right against you to be saved from drowning. Suppose that, simultaneously, each of the children has a violent coughing fit and each one will drown unless he is rescued by a passer-by. If you are the only passer-by and you, somehow, realise the peril that each child is in then it might or might not be praiseworthy if you risked your own life by trying to save one of the children. If you are a non-swimmer and have children of your own at home and a sick wife to care for then the action might be foolhardy and blameworthy even if not criminal. Even if the action is praiseworthy it is clearly not legally obligatory. It is far from obvious that, even if you can swim, it is morally obligatory to try to save a child. Even if you are morally obliged to try to save a child, it is noteworthy that none of the children has a corresponding moral right against you that you try to save him. You cannot save them all. You cannot even reasonably try to save them all.

Suppose that a doctor stood at the side of the lake as the children were drowning. If he realised that one of the children was one of his patients, he would be no more morally or legally obliged than any one else who stood there to save that child or, indeed, to save a child. If the doctor realised that one of his own children was in danger of drowning, however, he would have a moral obligation to try to save her even if some other children could be more readily saved by him. He might even have a legal obligation to try to do so.

If you were in such a situation and you stood by while all 10 children drowned, then, whether or not your non-intervention was morally blameworthy, it was not the partial cause of the death of each child nor the complete cause of the death of any one of them. It was not a causal factor. Perhaps you should have entered into the situation causally but you did not. If you were in such a situation but only one child was in danger of drowning and you could have saved him easily and safely then your non-intervention would have been no more causally significant but hugely more morally reprehensible.


Garrard and Wilkinson also consider “…a supplementary argument that is sometimes used to back up the causation argument. This asserts that in cases of (so-called) passive euthanasia, it is the disease itself which causes death, rather than the withholding or withdrawing of treatment. So, in the context of terminal illness, failing to delay the death need not amount to causing it”.1 I disagree with Garrard and Wilkinson and consider this supplementary argument to be perfectly sound. My previous analogy of switching off a ventilator and restraining a violent thug serves to support it.5

Garrard and Wilkinson continue:

“The thought here seems to be that the real or underlying or fundamental cause of death is the disease (not the withdrawing or withholding of treatment) and this idea is (supposedly) bolstered by the fact that, were it not for the disease, the patient would not have presented to the healthcare professional in the first place and so questions about withdrawing or withholding treatment would not even have arisen. This supplementary argument though is also flawed. For as Devlin rightly suggests, if this argument works at all then it “proves too much”, since it applies both to acts and omissions, both to active and passive euthanasia. For one might in the same way argue that, even in cases of active euthanasia, the underlying or fundamental cause of death is the disease (and on the same grounds—that were it not for the disease, the patient would not have presented to the healthcare professional in the first place).”1

Devlin’s reported comment is wide of the mark. To kill and to let die are different and readily distinguished in the example that Garrard and Wilkinson put forward in order to support a different conclusion. We can distinguish between the presence of actual causes and the absence of preventive anti-causes. Similarly, we can draw a meaningful distinction between active and passive euthanasia. If a motor car is on an incline, gravity will cause it to move downhill. The use of a hand-brake will retard the motion. The absence of a hand-brake does not, however, in the same sense, cause the vehicle to move downhill any more (or less) than does the absence of sufficiently powerful superglue on its wheels. Similarly, treatment might have retarded the death of the patient in this example but its absence was not a cause of his death in the way that his underlying illness was. The withdrawal of treatment will not be fatal for someone who does not require it. The absence of a hand-brake will not cause a stationary car to move if it is parked on a horizontal surface.


Despite what Garrard and Wilkinson’s arguments might seem to suggest, there is an important conceptual difference between killing and letting die. They play a different part in causal narratives. This enables us to make a meaningful legal distinction between active and passive euthanasia. Furthermore, active euthanasia is morally different from passive euthanasia. Although killing and letting die might be the same in the respect of being right or wrong in some particular circumstances, they differ with regard to how and why they are right or wrong. The moral duties at issue are different. They are duties to do different things: different people can possess them differently with regard to different people.


The author is grateful for help from James Marr, Darragh Hare and John Coggon.


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  • Competing interests: None.

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