Consider this case: my rival is sure to win the coveted Wise Prize for Living Philosophers, unless he dies before a given date—in which case the lucrative award will go to me. Fortunately for me, he lies comatose in the hospital, and his condition is deteriorating. Unfortunately for me, he is being sustained by a variety of life-support equipment, and he will not die in time for me to win in his stead. Seizing my chance, I sneak into his room late at night, and turn the machinery off. He breathes a last breath—and dies. I have killed him.
Contrast this with the following case: after months of seeing their comatose son kept alive through the use of exotic and resource-consuming medical equipment, the parents decide it would be better to let their son die than to meaninglessly prolong his deteriorating life. The proper legal/medical boards add their consent, the duly authorized doctor disconnects the life-support machines—and the boy dies. After months of prolonging life, the doctor has allowed him to die.
Not everyone, perhaps, will agree with the intuitive judgments I have offered about these two cases. But many, I think[,] will be inclined to accept them. When I maliciously unplug my rival's life-support machines, I kill him; when the doctor—acting out of due concern for all those involved—disconnects the machines preserving the comatose boy, she merely allows him to die. This, at least, is the way that many people would like to describe the cases.
It is rather puzzling, however, how the judgments about both cases can be maintained. For the two cases seem structurally similar. The medical condition (we can suppose) of the two patients is the same. In both cases, the life-preserving machinery is turned off, and death is the outcome; had the machines continued to operate, neither patient would have died. How can the cases differ according to the doing/allowing distinction?
One difference between the two cases, of course, is the fact that the second case involves a doctor, who—it might be suggested—may have special obligations or rights by virtue of her professional role. But even if such differences can help justify different moral evaluations of the two cases, it is not clear how the fact that the agent in the second case is a doctor can affect the question of what it is she does. If I have killed my rival, how can it be denied that the doctor—justifiably or not—has killed the comatose boy?
Those who support the claim that the doctor merely allowed the boy to die will argue that the medical staff had been providing aid, and then—after careful consideration—stopped providing aid. And to refrain from giving aid is not to kill—it is merely to allow to die. So it might be said. Yet what the doctor did was turn some machines off—and this is just what I did when I killed my rival. Left plugged in, each set of machines would have continued to aid its patient. The doctor took steps to see that this would not happen; so did I. How can we treat the cases differently?
(Shelly Kagan, The Limits of Morality, Oxford Ethics Series, ed. Derek Parfit [Oxford: Clarendon Press, 1989], 101-2 [italics in original])
