An Irrelevant Consideration: Killing versus Letting Die

Michael Tooley

Many people hold that there is an important moral distinction between passive euthanasia and active euthanasia. Thus, while the AMA maintains that people have a right "to die with dignity," so that it is morally permissi­ble for a doctor to allow someone to die if that person wants to and is suffering from an incurable illness causing pain that cannot be suffi­ciently alleviated, the AMA is unwilling to countenance active euthanasia for a person who is in similar straits, but who has the misfortune not to be suffering from an illness that will result in a speedy death. 

A similar distinction with respect to infanticide has become a com­monplace of medical thinking and practice. If an infant is a mongoloid, or a microcephalic, and happens also to have some other defect requiring corrective surgery if the infant is to live, many doctors and hospitals believe that the parents have the right to decide whether the surgery will be performed, and thus whether the infant will survive. But if the child does not have any other defect, it is believed that the parents do not have the right to terminate its life. 

The rationale underlying these distinctions between active and passive euthanasia, and between active and passive infanticide, is the same: the idea that there is a crucial moral difference between intentionally killing and intentionally letting die. This idea is admittedly very common. But I believe that it can be shown to reflect either confused thinking or a moral point of view unrelated to the interests of individuals. 

Two sons are looking forward to the death of their nasty but very wealthy father. Tired of waiting, they decide, independently of one another, to kill their father. The one puts some poison in his father's whiskey, and is discovered doing so by his brother, who was just about to do the same thing. The latter then allows his father to imbibe the deadly drink, and refrains from administering an antidote which he happens to have. The one son killed his father. The other merely allowed him to die. Did the former do something significantly more wrong than the latter? 

My own view is that the actions are morally equivalent, since I think that the following general principle-which may be referred to as the moral symmetry principle-is sound:


Let C be a causal process that normally leads to an outcome E. Let A be an action that initiates process C, and B be an action that stops process C before outcome E occurs. Assume further that actions A and B do not have any other morally significant consequences, and that E is the only part or outcome of C which is morally significant in itself. Then there is no moral difference between perform­ing action A, and intentionally refraining from performing action B, assuming identical motivation in the two cases.

This principle implies that, other things being equal, it is just as wrong intentionally to refrain from administering an antidote to someone who is dying of poisoning as it is to administer the poison, provided that the same motive is operative in both cases. And, more generally, it follows that the distinction between killing and intentionally letting die is not in itself a morally significant one. 

Some people find this hard to accept. However, it has been my experi­ence that those who are inclined to reject the moral symmetry principle often do so because of a failure to understand exactly what it does and does not imply. Let me begin by considering an objection which, though badly confused, helps to clarify the principle. The criticism in question claims that the moral symmetry principle can be shown to be mistaken by the following counterexample. It involves considering these two actions: 

Action M:         An individual refrains from giving information to the enemy even though he knows that the enemy will torture a child as long as he refuses to divulge the information. 

Action N:         An individual tortures a child in order to induce the enemy to give him information. 

The contention is that it is "surely monstrous" to view these two actions as morally equivalent. The intuitive appeal of this position is obvious. Whether it will stand up under critical reflection is quite another matter. The crucial point, however, is that this example is just not relevant to the moral symmetry principle. That principle states, very roughly, that it is as wrong intentionally to refrain from interfering with a causal process leading to some morally significant result as it is to initiate the process. It does not assert that it is as wrong to refrain from preventing someone else from initiating a causal process as it is to initiate it oneself. So it does not imply that actions M and N are morally, equivalent. 

One might try to argue that although the moral symmetry principle does not imply that actions such as M and N are morally equivalent, one can formulate a generalized moral symmetry principle which does have this implication, and which ought to be accepted by anyone who is willing to accept the original principle. One can certainly formulate such a principle. The difficulty is to justify the claim that anyone who accepts the original principle ought to accept the generalization of it. For it would seem that if intentionally refraining from preventing someone else from doing something and doing it oneself are morally equivalent actions, then preventing someone else from doing something and intentionally refrain­ing from doing it oneself are also morally equivalent actions.' But the intuitive feeling of most people would surely be that the mere fact that when one prevents someone else from doing something one is interfering with someone's action, whereas when one merely refrains from doing something oneself one is not, is a morally relevant difference. Thus there is a prima facie case against any extension of the moral symmetry principle that would have the consequence that intentionally refraining frorn pre­venting someone else from doing something is morally equivalent to doing it oneself. I certainly do not wish to assert that this prima facie case case cannot be overcome. However, any argument that succeeded in overthrowing it would ipso facto give one reason to reject the contention that it is "monstrous" to treat actions M and N as morally equivalent. 

What the objection to the moral symmetry principle has in effect done is to confuse that principle with consequentialism in ethics. If consequen­tialism is true, then so is the moral symmetry principle. But the converse is emphatically not the case. It is very important to realize that one can accept the moral symmetry principle without committing oneself to a consequentialism position. 

In order to reinforce my contention that any moral difference between actions M and N, rather than counting against the moral symmetry principle, merely reflects the fact that one's obligation to prevent others from doing something may not be as great as one's obligation to refrain from doing it oneself, consider actions that are similar to h1 and N except that the relevant effects are achieved directly rather than by influencing someone else's action:

 Action M*:     One is confronted with a machine that contains a child and a military secret. The Machine is so constructed that unless one pushes a button, the child will be tortured and the secret will be destroyed. If one pushes the button, the child will emerge un­harmed, but the secret will be transmitted to the enemy. One refrains from pushing the button.

 Action N*:    One is confronted with a similar machine. This time, however, it is so constructed that unless one pushes a button, a secret will be transmitted to the enemy, while a child will emerge unharmed. If one pushes the button, the secret will be destroyed, but the child will be tortured. One pushes the button.

 Although the moral symmetry principle does not quite entail that actions M* and N* are morally equivalent, I believe that anyone who accepts that principle would agree that there is no moral difference between M* and N*. Doubtless there are some philosophers who would also characterize this view as "monstrous." And some philosophers have tried to argue that there is, at least, significant moral difference between acting and refrain­ing from acting; however, all the arguments that I have seen in support of this contention seem to me to be either unsound or else not relevant to the claim that the distinction is significant in itself: 

But what is one to say about the feeling-which is admittedly fairly widespread-that there is a morally significant difference between acting and refraining from acting? I do not want simply to dismiss this feeling, even though I would maintain that appeal to such "moral intuitions" does not constitute a good way of arriving at sound moral principles. What I want to do is to try to show how the feelings in question may rest upon certain confusions. 

The place to begin is by distinguishing the following two questions:


 1. Is the distinction between killing and intentionally letting die morally significant in it? 

 2. Are there other factors which make it generally the case that killing someone is more seriously wrong than intentionally letting someone die? 

The answer to the second question is surely yes. In the first place, the motive of a person who kills someone is generally more evil than the motive of a person who merely lets someone die. A person may let someone die out of laziness or apathy, and though I would insist that such inaction is seriously wrong, it is surely not as seriously wrong as the action of a person who kills someone else because he wants him dead. Secondly, the alternative to letting someone die-saving his life may involve considerable risk to the agent, or a very large expenditure of society’s resources. This will rarely be true of refraining from killing someone. Thirdly, if one person forms an action that normally results in the death of a person, there is little likelihood that the person will survive. While one merely refrains from saving someone’s life, there is often a substantial chance that she will survive in some other way.

             These three factors-motive, cost to the agent and/or society, and the probability that death will result from one’s action or inaction-all tend to make it the case that an attempt to kill someone will generally be more seriously wrong than intentionally refraining from saving someone’s life. It is these factors that make the difference, rather than the difference between killing and letting die. People are right in thinking that killing is generally morally worse than merely letting someone die. Where they go wrong is in failing to notice that there are factors involved that can explain this difference in perfectly satisfactory fashion. And, as a result, they mistakenly conclude that the difference between killing and letting die must be morally significant in itself.  

Let the conclude my case against the distinction by mentioning an example which isolates the interfering variables, and thus raises in a vivid way the issue of whether there really is any significant moral difference between acting and intentionally refraining from acting. Imagine a machine containing two children, John and Mary. I f one pushes a button, John will be killed, but Mary will emerge unharmed. If one does not push the button, John will emerge unharmed, but Mary will be killed. In the first case one kills John, while in the second case one merely lets Mary die. Does one really wish to say that the action of intentionally refraining from pushing the button is morally preferable to the action of pushing it, even though exactly one person perishes in either case? The best action, it would seem to me, would be to flip a coin to decide which action to perform, thus giving each person an equal chance of surviving. But if that isn't possible, it seems to me a matter of indifference whether one pushes the button or not.

 If there is no intrinsic difference between killing and intentionally letting die, where does this leave the distinction between active and passive euthanasia?  There are two possibilities that need to be considered. The first is that even if neither active nor passive euthanasia is wrong in itself, it may be that legalizing the former would have undesirable con­sequences, as Yale Kamisar and others have contended.' I do not think that this line of argument is sound; however it is certainly one that deserves very serious consideration. 

The second possibility is one that arises if one holds both that there is no intrinsic difference between active and passive euthanasia and that euthanasia is, nevertheless, wrong in itself, on the grounds, say, that a person does not have a right to kill even himself in order to put an end to unbearable suffering. Such a view would be compatible with the accep­tance of passive euthanasia in some cases, though not in all. For while one would be committed to holding that passive euthanasia, like active euthanasia, was wrong in it, there might be circumstances in which the former was morally justified. The cost of keeping a person alive, for example, might be so great that allowing him to die would be the lesser of' evils.

 My response to this second attempt to ascribe at least limited moral significance, albeit of a derived variety, to the distinction between active and passive euthanasia, is to reject the view that active euthanasia is wrong in itself. What I should argue, ultimately, is that there must surely be some justification for the institution of morality, some reason for society to accept moral rules. And what reason more plausible than that the accep­tance of a certain set of moral rules accords better with the interests of people than the acceptance of some other set of moral rules, or none at all? But some moral rules that people accept, or have accepted, are clearly such as do not serve the interests of individuals e.g. various sexual prohibitions, such as that against masturbation. The prohibition of active euthanasia seems to be another case of a moral point of view which does not further the interests of individuals living together in society. Why, then, has this moral point of view been accepted? The answer here, as in the case of the traditional sexual outlook of Western society, is found in the powerful influence of the Christian churches.' This historical point deserves to be kept firmly in view when one is reflecting upon the morality of euthanasia. Many otherwise thoughtful people somehow lose sight of the fact that what they refer to as "moral intuitions" regarding euthanasia sprang originally from a certain theological outlook, one that is no longer taken seriously by most people who have taken the trouble to examine its credentials carefully and impartially. 

In conclusion, then, it is far from clear that the commonly accepted distinction between active and passive euthanasia is morally significant. This has been, admittedly, a very brief survey of the relevant issues. In some cases I have been able to do little more than touch upon them in passing. However, I have tried to argue, in some detail, that the distinc­tion between killing and letting die is not morally significant in itself. If this is right, then the reason that is most commonly offered for holding that there is a morally significant difference between active and passive euthanasia is in fact unsound.


From KILLING AND LETTING DIE, edited by Bonnie Steinbock, Prentice-Hall, 1980, pp. 56-62. Reprinted by permission of Michael Tooley.



See, for example, "Moral and Ethical Dilemmas in the Special-Care Nursery," by Raymond S. Duffand A.G.M. Campbell in 77reNew England journal of Medicine, 289 (Oct. 25, 1973), 890-94, and "Dilemmas of 'Informed Consent' in Children," by Anthony Shaw in The New England journal of Medicine, 289 (Oct. 25, 1973), 1). 886.

 I appealed to a closely related principle in my papers discussing abortion and infanticide. See pages 58-60 of "Abortion and Infanticide" Philosophy & Public Affairs, 2 (Fall 1972), 37-65, and pages 84-86 of "A Defense of Abortion, and Infanticide" i n J. Feinberg, ed., The Problem of Abortion (Belmont, CA: Wadsworth Publishing Co., 1973), 51-92, for some remarks that are relevant to the present principle as well. My view is that when actions A and B are related in the way indicated, it is true both that performing A is morally equivalent to intentionally refraining from performing B, and that performing B is morally equivalent to intentionally refraining from performing A, assuming the same motivation in both cases. 

This objection was advanced by Philip E. Devine in his paper "Tooley on Infanticide," read at the Eastern Sleeting of the American Philosophical Associa­tion in Atlanta, December 1973. 

This is surely very reasonable. But if justification is wanted, one can argue that (1) if actions Q and R are morally equivalent, then so are the actions of intention­ally refraining from Q and intentionally refraining from R, and that (2) the action of intentionally refraining from performing some action Q is equivalent to per­forming action Q. 

There is some relevant discussion by Bernard Williams in Utilitarianism: For and Against, by J. J. C. Smart and Bernard Williams (Cambridge: Cambridge University Press, 1973) pp. 82-100. 

The argument offered by Daniel Dinello in his article "On Killing and Letting Die" seems simply unsound. The argument advanced by P. J. Fitzgerald, on the other hand, in his article "Acting and Refraining," [see bibliography for publish­ing information] appears irrelevant to the contention that the distinction is mor­ally significant in itself. For a vigorous defense of the view that the distinction is not in itself morally significant, see Jonathan Bennett's paper "Whatever the Consequences." Bennett's article is slightly marred by an inadequate analysis of the distinction between acting and refraining, but this does not affect his central contentions. 

Yale Kamisar, "Euthanasia Legislation: Some Non-Religious Objections," in Euthanasia and the Right to Death, ed. A. B. Downing, (Los Angeles: Nash Publish­ing Co., 1969). 

For a discussion that helps to bring out the extent to which contemporary Western aversion to voluntary euthanasia reflects the influence of the Christian church, see Raanan Gillon's article, "Suicide and Voluntary Euthanasia: Historical Perspective," in Euthanasia and the Right to Death, ed A. B. ])owning (Los Angeles: Nash Publishing Co., 1969). Also very helpful in this regard is the discussion by Glanville Williams in Chapter VII I of his book, The Sanctity of Life and the Criminal Law.

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