“Thou shalt not kill the innocent.” The movement to protect children before they’re born rests on this moral command, assuming that the child, from the moment he starts to exist, is an innocent human person.
There are many routes that the opposition takes to get around this argument, many of which target humanity and personhood. One that may come as a surprise is the proposal that the child is not innocent. And if that’s the case, then the mother’s act of killing the child can be classified as an act of self-defense.
Now, I know what you’re thinking: “How in the world can that child be anything other than innocent?”
Here’s a proposed answer: the concept of innocence isn’t restrictive to being innocent in the will—what some call formal innocence. It also extends to behavior (called material innocence).
For example, when I freely choose to behave in a way that doesn’t infringe on your natural right to exercise freedom and life, I am both formally innocent (innocent in my will) and materially innocent (innocent in my behavior). Both my will and my behavior are consistent with what’s naturally owed to you: exercise of freedom and life.
This distinction is important because it’s possible for someone to be innocent in his will (formal innocence) but not in his behavior (materially unjust). Consider, for example, a mentally crazed person who might aggressively attack me, thereby behaving in a way that conflicts with my exercise of freedom and life. Obviously, this person would be formally innocent because he isn’t choosing to attack me—his insanity (whatever the cause might be) impedes him from freely using his intellect and will.
His behavior, however, is not innocent. As mentioned above, the behavior is such that it conflicts with my natural right to exercise my freedom and life. The aggressive behavior destroys what St. Thomas Aquinas calls the “equality of relations” (Summa Theologiae II-II:79:1), which is naturally due to me. Philosophers call this kind of aggression material aggression—that’s to say, the behavior, or the material stuff, is aggressive, but the person himself, in his will (which is a power of his substantial form called the rational soul), is not.
Now, most people intuit that we’re justified in defending ourselves against a person who fits the mold of a material aggressor (someone who’s innocent in will but not in behavior). And if the behavior goes so far as to pose a threat to my life, and there’s no other way for me to defend my life, then I’m justified even in deliberately killing him.
Some might reject this intuition, thinking that we’re never permitted to deliberately kill anyone, or at least not someone who is materially innocent, and that an assailant’s death (even if only formally innocent) can only be an unintended side-effect. But others have argued, and in my judgment correctly, that we are morally permitted to kill the material aggressor, since the aggressor’s behavior itself is not innocent. On this view, nature’s prohibition against killing the innocent would not apply.
It’s here where some people try to justify abortion, arguing that the child in the womb is not innocent, at least in a scenario where the child’s presence poses a threat to the mother’s life. On this supposition, it would seem that the child fits the “material aggressor” description: he’s an aggressor only in behavior (using the mother’s body and growing in the womb) and not in will. Since the baby is at least materially an aggressor (even though not intentionally or formally), the mother’s act of killing, so it’s argued, would be a justified act of self-defense.
What should we make of this argument?
Well, for the material aggressor argument to succeed, the child’s behavior must be outside the natural order of the “equality of relations.”
So what’s the nature of the child’s behavior in the womb? He’s doing what nature directs him to do: grow, develop, and take in nutrients from his mother. This is nature’s blueprint for how social rational animals are to live their lives at those stages of development—and so it cannot possibly be outside the order of the “equality of relations” that nature demands for the mother and child.
Think about it. If a baby’s growth, development, and nutrition in the womb were of themselves aimed at ending a mother’s life (thereby aimed at undermining the “equality of relations”), then nature would be contradicting itself: directing a woman to be a mother (insofar as she is naturally helping the child grow, develop, and be nourished) and not be a mother (insofar as the child’s growth, development, and nourishment are leading to her death, a point after which she will no longer be a mother) at the same time and in the same respect. Assuming that nature wouldn’t be self-defeating in such a fundamental thing as human life itself, we can affirm that the baby’s natural behavior in the womb isn’t outside the order of the “equality of relations.”
So the baby’s behavior is no more aggressive than the mother’s act of breathing in oxygen. When the mother chooses to take in oxygen with a breath, she is not thereby guilty of formal aggression against others who need oxygen. The reason is that such behavior is not aimed at bringing about death in others. Such behavior is natural to the mother (and us) and thus within nature’s order. This is the opposite of defective or disordered behavior.
In a scenario where the mother’s life is at risk, the threat isn’t due to any disordered behavior on the part of the child, like in the case of a material aggressor. Rather, it is due to some other defect, like the child being in the wrong place (e.g., in the fallopian tube, an example of what’s called an ectopic pregnancy) or an illness that the mother has (cancer, pulmonary hypertension, etc.). In such cases, the baby still can’t be deliberately killed. But his death may be an unintended side-effect of an act that of its nature treats the pathological condition.
Given what we’ve said above, it is clear that a baby within a mother’s womb can’t possibly be a material aggressor. There’s no behavior on the part of the baby that of itself is or could be defective or disordered, thereby undermining the “equality of relations” that nature demands for the mother concerning the exercise of her life. As such, there is no case where a mother’s choice to kill her child can be considered as an act of self-defense.