The act in the case is good in itself; it is an application of physical force in defence of a proper right, and any right supposes a compulsive power. The two effects of this double-effect act are: (a) the preservation of the defender's life, and (b) the death of the aggressor. The first effect is good because the defender has a right to his own life; the other effect is evil, not only physically for the one who dies, but morally inasmuch as the death conflicts with the dominion of God. This death, however, is an accidental effect of the act, because in general the defensive act is not directed by its nature to that death but to the preservation of the defender's life; nor does the death follow more immediately than the preservation. Thus it is not a means of the defence. Finally, the defensive act is not prohibited precisely lest that death follow: not in justice, for there is no justice in any right of the aggressor which requires from the defender an omission of defence unto the loss of life; there is no obligation in charity, since charity does not oblige us to love another more than ourselves, or to exalt the good of another above our own.
In an aggression which is merely material—say, in an attack by an insane man—the defender has a right to the infliction of such damage as is necessary and proportionate to an efficacious defence. The right of the aggressor yields to the superior right of the defender, not through the fault of the aggressor but through his misfortune. There is a collision where both rights cannot be exercised at the same time, and there is no reason obliging the defendant to forego his own right.
We may defend another against an unjust aggressor because we can assume that the attacked person communicates to us the use of his own coactive right. If the aggressor is our own father, mother, son, or daughter, or in general any one to whom charity obliges us more than to the person attacked, we are not permitted to kill our own kin because charity does not oblige us to prefer the good of an alien to the good of one of our blood. Ordinarily we are not obliged in justice or charity to defend another at the risk of our own life.
We may kill an unjust aggressor, servatis servandis, in defence of good equivalent in value to life: for example, to prevent life imprisonment, the loss of reason, a mutilation which would render us useless, the loss of a woman's chastity.
There are cases of accidental homicide, in medicine and elsewhere, which have an element of guilt in them. If a death follows accidentally upon an act which in itself is licit, and the agent uses all proper precautions, he is not morally guilty in case of an accidental death following his act. This is true even if the agent foresaw a probable death but did not intend it. If, however, the agent's primary act is illicit in itself, and an accidental death follows from this act, the agent may be guilty of homicide, provided the first act in itself is naturally likely to cause homicide. Should the first act be always dangerous, such that death commonly follows from it, like rocking a row-boat, aiming a supposedly unloaded gun at a person and pulling the trigger, striking a pregnant woman, drinking whiskey and then overlying an infant in the bed, throwing building material from a roof to a street, racing an automobile through a crowded thoroughfare, sending a crew out in a rotten ship, and so on, the accidental homicide that follows is imputable to the agent no matter how much precaution he may say he has used to avert such a death.
Suppose, secondly, the original act of the agent is illicit but such that accidental death rarely follows from it; then if he takes due precaution he is not ordinarily guilty of homicide. He has, say, stolen an automobile, and is going along the street leisurely, when a careless child runs off the sidewalk under the machine and is killed.
1. No person, then, may hasten his own death or permit any one else to hasten it.
2. No physician may in any possible condition kill a patient merely to effect euthanasia.
3. The state has no more right than the physician to permit the killing of patients to bring about euthanasia.
Were such permission given to physicians it would immediately be abused by men with even the best intentions. In all countries and in the largest cities the medical profession is swarming with quacks. What is done in crass ignorance by licensed physicians and specialists every day in the name of medicine is appalling. Professor Orth of the Pathologic Institute in Berlin makes the statement that of all the appendices that have been submitted to him for microscopic examination after removal by conservative and supposedly skilled physicians, 17 per cent. showed no disease at all, and should not have been removed. In this country the percentage of normal appendices removed because of vague abdominal pains is much larger.