The right to life implies a correlative duty in all other persons not to take the life of the unborn child, except in two cases: viz., (i) the case in which the child commits aggression against the life of another person; or (ii) the case in which the continued life of the child and the continued life of another person are mutually incompatible because of the existential circumstances. These cases involve: (i) the privilege of self-defense, which permits a victim of aggression to defend his own life, even if that defense requires taking the aggressor's life; and (ii) the privilege of self-preservation, which permits an innocent individual to take the life of another innocent individual in an 'emergency' situation in which both cannot survive, and the survival of one depends upon the denial to the other of the means of survival. The question is: Does abortion come within either exception to the duty of every individual to respect and preserve the life of every other individual?

I. Abortion is not an exercise of the privilege of self-defense, since the unborn child is not an aggressor.

A. Aggression involves an act of will or an act of negligence. It can never arise from an act that is caused by existential forces beyond an individual's control. I.e., there cannot be aggression if human action, in the sense of purposeful behavior, is not involved at all.

B. The creation of the fertilized egg and its attachment to the uterine wall are not "acts" of the unborn child in the sense of being purposeful. They are the result of existential biological forces independent and beyond the control of the child (although not of the father and mother), and brought into play by the combined acts of the father and mother.

C. Since the unborn child cannot rationally be held responsible for its own creation, it cannot rationally be held to have committed aggression by coming into -- indeed, being brought into existence. Aggression implies responsibility; and no human being is responsible for his own creation.

D. Since the unborn child is not and cannot be an aggressor, the mother cannot invoke the privilege of self-defense against its continued existence in the one place in which, at that stage in its development as a human being, it is both logically and biologically appropriate for it to be. (N.B.: whether the father in a rape situation is guilty of aggression is another matter. In any event, his guilt cannot rationally be imputed to the child.)

II. Abortion is not an exercise of the privilege of self-preservation, since, in the usual case, the mother's life is not endangered by the pregnancy.

A. A privilege of self-preservation arises only in those situations in which the lives of two or more equally innocent persons are in jeopardy, and not all of them can be saved.

B. Pregnancy is not such a situation in the normal case. Were it so in extraordinary cases, the mother would have a privilege to defend her own life through abortion, or to choose to give up her life to save the child (assuming this could be done medically). In such a situation, neither the state nor even the father of the child would have any right or privilege to interfere with the mother's decision.

III. In sum, since abortion does not come within the two recognized exceptions to the right to life, and is inconsistent with the right as far as the unborn child is concerned, abortion must itself be a form of aggression repugnant to libertarian principles.

(Dr. Vieira is an attorney practicing constitutional law.)