Killing in self-defense: it is moral to intend the death of the aggressor?

I’m beginning to see the fittingness of the title ‘Vox Nova’ for the group blog at They have new things to say on matters of faith and morals — new because these things are not found in Tradition, Scripture, Magisterium. For example, this post claims that killing in self-defense becomes intrinsically evil when the killing is done with a handgun.

Like so many commentators, he uses the term ‘intrinsic evil’ without really knowing what that term means.

An act consists of three fonts: 1. intention, 2. moral object, 3. circumstances. The second font of moral object actually consists of three things; moral object is the short-hand way of describing that font.

The second font is
a. the knowingly chosen act itself,
b. with its inherent moral meaning (its moral nature or moral ‘species’), as determined by:
c. the moral object (the proximate end, in terms of morality, toward which the act is inherently ordered).

The act itself is what Pope John Paul II in Veritatis Splendor calls the ‘concrete act’. Now a ‘concrete act’ can be interior or exterior. But in either case, there is a knowingly chosen act, whether an interior decision of the mind and heart, or an exterior action that includes an interior choice. Both interior acts and exterior acts are an exercise of intellect and free will; they are knowingly chosen acts. So the concrete act is always knowingly chosen.

But the chosen act also has an inherent moral meaning before God. When evaluated in terms of the love of God and neighbor, a knowing choice will always be either morally licit (at least morally permissible) or morally illicit — a sin. Every sin is a type of offense against the love of God and neighbor. This inherent moral meaning is also called the moral species, which is the type of act in terms of morality.

Theft can be committed in a myriad of different ways, in terms of the exterior concrete act. What makes each of these very different actions the same type (species) of act, namely theft? It is the inherent ordering of the act toward a particular end, in this case the end of depriving the owner of his goods. Why is expropriation not the same as theft? It is because God is the First Owner of all goods. The deprivation of goods from an owner in the case of expropriation is indirect; it is a consequence in the third font (circumstance), not the moral object of the second font.

Self-defense differs from murder in a similar way. Murder can be committed in a myriad of different ways, in terms of the exterior concrete act. What makes all of these ways the same moral species is the inherent ordering of the act toward a particular evil moral object, the deprivation of life from an innocent human person. When the act is directly ordered toward that end, in other words, when the end is [morally] proximate to the act, and the act is deliberately chosen, then that act is called murder.

Intrinsically evil acts are always direct and voluntary. In other words, intrinsically evil acts are always intentionally chosen (deliberately chosen), and the moral object is always the direct (i.e. proximate) result of the chosen act.

Indirect killing is not murder because the deprivation of life is in the circumstance, not in the moral object. So if the military in a just war attacks a military target, but reasonably anticipating that there will be some civilian deaths, the deprivation of life of those innocents is in the circumstance, not in the moral object. So the act is not intrinsically evil. Nevertheless, all three fonts must be good for an act to be moral. So the reasonably anticipated good consequences of such an act must outweigh the reasonably anticipated bad consequences.

Self-defense is not murder because the person who is killed is not innocent. The chosen act is inherently ordered toward the good end of preserving the life of the innocent victim of the attack. The death of the attacker is a bad consequences in the circumstance; for the loss of any human life, even a guilty person, is a bad consequence.

Now a moral question arises based on the assertion of St. Thomas Aquinas that a person acting in self-defense must not intend the death of the attacker; he can only intend to defend himself. But if we analyze Thomas’ assertion in terms of the three fonts of morality, we see that this point by St. Thomas is in the first font, not the second or third. The defender cannot intend the death of the attacker as an intended end. More generally, it is always immoral for anyone to intend any type of moral or physical evil (harm or disorder) as an end. So St. Thomas is correct on that point.

But his point has been misunderstood and misrepresented in this post at Vox Nova.

It is never moral to intend moral evil or physical evil as an end. And it is never moral to intend or to choose moral evil as a means. However, physical evil may be intended as a means to a good end, if the bad consequences of that means are outweighed by the good consequences of the end. For example, a physician may intend to amputate a limb (intended means, physical evil in the circumstances) in order to save a life (intended end, good moral object). Similarly, a person killing in self-defense may intend to use the means of killing the attacker (physical evil, but not moral evil) to achieve the end of self-defense.

In moral theology, the term intention is used to refer to the intended end, the first font of morality. Each font is a type of end. But all that is intended must be morally good. One and the same intention may include a means as well as an end.

Saint Thomas Aquinas: “…the will is moved to the means for the sake of the end: and thus the movement of the will to the end and its movement to the means are one and the same thing.” (Summa Theologica, I-II, Q. 12, A. 4; see also A. 1-3.)

The means and the end must both be morally good. A good end does not justify the use of an immoral means. However, a good end may justify the use of a means which is morally good, but includes a physical evil (harm). Therefore, when a person kills in self-defense, although he may not intend the death of the aggressor as the intended end, he may morally intend the death of the aggressor as a means.

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