Restitution

Suppose Bob paid professional killer Alice to kill him on a day of her choice in the next month. Next day, Bob changes his mind, but has no way of contacting Alice. A week later, Bob sees Alice in the distance aiming a rifle at him. Is it permissible for him to shoot Alice in self-defense?

I take it (somewhat controversially) that killing a juridically innocent person is murder even if the victim consents. Thus, Alice is attempting murder, and normally it is permissible to shoot someone who is trying to murder one. But it seems rather dastardly for Bob to shoot Alice in this case.

On the other hand, though, if Bob hired Alice to kill Carl, and then repented, shooting Alice when Alice is trying to murder Carl does seem the right thing for Bob to do if there is no other way to save Carl’s life.

What is the exact moral difference between the two cases? In both cases, Alice is trying to commit a murder, and in both cases Bob bears a responsibility for this.

I think the difference has something with duties of restitution. When one has done something wrong, and then repented, one needs to do one’s best to “undo” the wrong, repaying the victims in a reasonable manner. But there is a gradation of priority, and in particular even if one is oneself among the victims (Socrates thinks the wrongdoer is the chief victim, since in doing wrong one damages one’s virtue), restitution to others takes priority. In both cases, Bob has harmed Alice by tempting her to commit murder. In the case where Alice was hired to murder Bob, restitution to Alice takes precedence over restitution to Bob, and refraining from killing Alice in self-defense seems a precisely appropriate form of restitution. In the case where Alice was hired to murder Carl, however, restitution to Carl takes precedence, and Bob owes it to Carl to shoot Alice.

In fact, I suspect that in the case where Bob hired Alice to kill Carl, if the only way to save Carl’s life is for Bob to leap into the line of fire and die protecting Carl, other things being equal that would be Bob’s duty. Normally to sacrifice one’s life to save another is supererogatory, but not so when the danger to the other comes from one’s own murderous intent.

The morality of restitution is difficult and complex.

The need for a fine-grained deontology

It’s tempting to say that what justifies lethal self-defense is a wrongful lethal threat, perhaps with voluntariness and/or culpability added (see discussion and comments here).

But that’s not quite right. Suppose that a police officer, in addition to carrying her own gun, has her best friend’s gun with her, which she was taking in to a shop for minor cosmetic repairs. She promised her friend that she wouldn’t use his gun. Now, you threaten the officer, and she pulls her friend’s gun out, in blatant disregard of her promise, because she has always wanted to see what it feels like to threaten someone with this particular gun. The officer is now lethally threatening you, and doing so wrongfully, voluntarily and culpably, but that not justify lethal self-defense.

One might note here that the officer is not wronging you by breaking her promise to her best friend. So perhaps what justifies lethal self-defense is a lethal threat that wrongs you. But that can’t be the solution. If you are the best friend in question—no doubt now the former best friend—then it is you who is being wronged by the breaking of the promise. But that wrong is irrelevant to your lethal self-defense. Furthermore, we want an account of self-defense to justify to a general account of defense of innocent victims.

One might say that lethal self-defense is permitted only against a gravely wrongful threat, and this promise-breaking is not gravely wrongful. But we can tweak the case to make it be gravely wrongful. Maybe the police officer swore an oath before God and the community not to use this particular gun. That surely doesn’t justify your using lethal force to defend yourself against the officer’s threat.

Maybe what we want to say is that the kind of wrongful lethal threat that justifies lethal self-defense is one that wrongs by violating the right to life of the person threatened (rather than, say, being wrong by violating a promise). That sounds right to me. But what’s interesting about this is that it forces us to have a more fine-grained deontology. Not only do we need to talk about actions being wrong, but about actions being wrong against someone, and against someone in a particular way.

It’s interesting that considerations of self-defense require such a fine-grained deontology even if we do not think that in general every wrongful action wrongs someone.

Aggression and self-defense

Let’s assume that lethal self-defense is permissible. Such self-defense requires an aggressor. There is a variety of concepts of an aggressor for purposes of self-defense, depending on what constitutes aggression. Here are a few accounts:

1. voluntarily, culpably and wrongfully threatening one’s life

2. voluntarily and wrongfully threatening one’s life

3. voluntarily threatening one’s life

4. threatening, voluntarily or involuntarily, one’s life.

(I am bracketing the question of less serious threats, where health but not life is threatened.)

I want to focus on accounts of self-defense on which aggression is defined by (4), namely where there is no mens rea requirement at all on the threat. This leads to a very broad doctrine of lethal self-defense. I want to argue that it is too broad.

First note that it is obvious that a criminal is not permitted to use lethal force against a police officer who is legitimately using lethal force against them. This implies that even (3) is too lax an account of aggression for purposes of self-defense, and a fortiori (4) is too lax.

Second, I will argue against (4) more directly. Imagine that Alice and Bob are locked in a room together for a week. Alice has just been infected with a disease which would do her no harm but would kill Bob. If Alice dies in the next day, the disease will not yet have become contagious, and Bob’s life will be saved. Otherwise, Bob will die. By (4), Bob can deem Alice an aggressor simply by her being alive—she threatens his life. So on an account of self-defense where (4) defines aggression, Bob is permitted to engage in lethal self-defense against Alice.

My intuitions say that this is clearly wrong. But not everyone will see it this way, so let me push on. If Bob is permitted to kill Alice because aggression doesn’t have a mens rea requirement, Alice is also permitted to lethally fight back against Bob, despite the fact that Bob is acting permissibly in trying to kill her. (After all, Alice was also acting permissibly in breathing, and thereby staying alive and threatening Bob.) So the result of a broad view of self-defense against any kind of threat, voluntary or not, is situations where two people will permissibly engage in a fight to the death.

Now, it is counterintuitive to suppose that there could be a case where two people are both acting justly in a fight to the death, apart from cases of non-moral error (say, each thinks the other is an attacking bear).

Furthermore, the result of such a situation is that basically the stronger of the two gets to kill the weaker and survive. The effect is not literally might makes right, but is practically the same. This is an implausibly discriminatory setup.

Third, consider a more symmetric variant. Two people are trapped in a spaceship that has only air enough for one to survive until rescue. If (4) is the right account of aggression, then simply by breathing each is an aggressor against the other. This is already a little implausible. Two people in a room breathing is not what one normally thinks of as aggression. Let me back this intuition up a little more. Suppose that there is only one person trapped in a spaceship, and there is not enough air to survive until rescue. If in the case of two people each was engaging in aggression against the other simply by virtue of removing oxygen from air to the point where the other would die, in the case of one person in the spaceship, that person is engaging in aggression against themselves by removing oxygen from air to the point where they themselves will die. But that’s clearly false.

I don’t know exactly how to define aggression for purposes of self-defense, but I am confident that (4) is much too broad. I think the police officer and criminal case shows that (3) is too broad as well. I feel pulled towards both (1) and (2), and I find it difficult to resolve the choice between them.

Against a moderate pacifism

Imagine a moderate pacifist who rejects lethal self-defense, but allows non-lethal self-defense when appropriate, say by use of tasers.

Now, imagine that one person is attacking you and nine other innocents, with the intent of killing the ten of you, and you can stop them with a taser. Surely you should, and surely the moderate pacifist will say that this is an appropriate use case for the taser.

Very well. Now consider this on a national level. Suppose there are a million enemy soldiers ordered to commit genocide against ten million, and you have two ways to stop them:

1. Tase the million soldiers.

2. Kill the general.

If you can tase one person to stop the murder of ten, then (1) should be permissible if it’s the only option. But tasers occasionally kill people. We don’t know how often. Apparently it’s less than 1 in 400 uses. Suppose it’s 1 in 4000. Then option (1) results in 250 enemy deaths.

So maybe our choice is between tasing a million, thereby non-intentionally killing 250 soldiers, and intentionally killing one general. It seems to me that (2) is morally preferable, even though our moderate pacifist has to allow (1) and forbid (2).

Note that a version of this argument goes through even if the moderate pacifist backs up and says that tasers are too lethal. For suppose instead of tasers we have drones that destroy the dominant hand of an enemy soldier while guaranteeing survival (with science fictional medical technology). It’s clearly right to release such a drone on a soldier who is about to kill ten innocents. But now compare:

3. Destroy the dominant hand of a million soldiers.

4. Kill the general.

I think (4) is still morally preferable to causing the kind of disruption to the lives of a million people that plan (3) would involve.

These may seem to be consequentialist arguments. I don't think so. I don't have the same intuitions if we replace the general by the general's innocent child in (2) and (4), even if killing the child were to stop the war (e.g., by making the general afraid that their other children would be murdered).

Lying and killing

It initially seems to be a strange combination of views that (a) killing in defense of the innocent is sometimes permissible, but (b) lying is never permissible, not even in defense of the innocent. Yet that is the predominant view in the Christian tradition. Does this mean that truth is more valuable than life? That doesn't sound right, at least not in general.

I want to try a very speculative solution to this paradox, one I don't want to fully endorse as it raises some further problems. Thomas Aquinas has an interesting position on the lethal defense of the innocent: only officers of the state are permitted to kill intentionally, while private citizens may use defensive means that they foresee could be lethal only if they don't intend death.

Why the difference? Well, here is my crazy thought: perhaps all instances of permissible intentionally lethal defense of the innocent are effectively instances of the death penalty. In emergency situations, where there is an imminent threat to innocents, the state authorizes its officers to execute aggressors on the spot, without the usual legal safeguards. Every instance of permissible killing in a just war is an execution--we just don't call it that, because the emergency context makes very different procedures appropriate. Note, further, that as we learn from John Paul II's Evangelium Vitae, the death penalty is only permissible when there are no other means to the defense of society. Thus the intentionally lethal means to the defense of the innocent can only be deployed as a last resort. That is why, say, prisoners of war are not killed--there is no longer a need for an emergency execution once they are disarmed.

Suppose that this eccentric theory of lethal police and military action is correct. Then it is easy to see why there is a distinction between intentional killing and lying. Permissible intentional killing is an act of justice, an imposition of a just penalty on an aggressor. If we add Boethian idea that it is an intrinsic benefit to one to have justice done to one, then the aggressor is directly benefited by being punished. But even without that idea, the distinction between a defensive act of justice and a merely defensive act seems significant. There is a fine Kantian thought that just punishment constitutes a showing of respect to the person being punished; but a lie is innately disrespectful to the rationality of the person lied to.

Still, the puzzle remains. Why is it that the greater harm of death is appropriate punishment while the lesser harm of being lied to is not? But not every harm is appropriate as a punishment, and sometimes a lesser harm is inappropriate as punishment while a greater is appropriate. Sometimes, this is for reasons of dignity. Thus, it is a lesser harm to lose one's arms than to lose one's life, but judicial amputation is barbaric and contrary to the dignity of the criminal (it is hard to fully explain this intuitive judgment). Sometimes, the lesser harm just wouldn't fit the crime, or maybe ven any crime. Suppose a politician misused her office. Public infamy could be fitting punishment. But while the harm to reputation is greater in public infamy than in gossip, it just wouldn't be a fitting punishment to have officers of the court gossip about the politician behind her back. In fact, being gossiped about simply doesn't seem to be the right sort of harm to be a punishment--maybe it is the essential isolation of it from the consciousness of the person being gossiped about that makes it be inappropriate. I have the intuition that being lied to is pretty much like that--it is essentially isolated from the consciousness of the person being lied to (it's not a lie if they tell you they're lying to you!), and it just doesn't seem the right kind of harm to be a punishment.

The difficulty with this account is that modeling intentionally lethal police and military action as a form of the death penalty suffers from serious problems. The main one is that we have good reason to think that many enemy soldiers, even if their side is opposed to justice, are likely to be non-culpable, because they are likely to be ignorant of the fact that their side is opposed to justice. Perhaps, though, in an emergency situation--and a war is always an emergency--the evidential standards can be much lower, and so we don't need to examine culpability. Another problem is that this account will not allow the police to engage in intentionally lethal action against a clearly insane attacker. But perhaps that's the right conclusion.

Intending material conditionals and dispositions, with an excursus on lethally-armed robots

Alice has tools in a shed and sees a clearly unarmed thief approaching the shed. She knows she is in no danger of her life or limb—she can easily move away from the thief—but points a gun at the thief and shouts: “Stop or I’ll shoot to kill.” The thief doesn’t stop. Alice fulfills the threat and kills the thief.

Bob has a farm of man-eating crocodiles and some tools he wants to store safely. He places the tools in a shed in the middle of the crocodile farm, in order to dissuade thieves. The farm is correctly marked all-around “Man-eating crocodiles”, and the crocodiles are quite visible to all and sundry. An unarmed thief breaks into Bob’s property attempting to get to his tool shed, but a crocodile eats him on the way.

Regardless of what local laws may say, Alice is a murderer. In fulfilling the threat, by definition she intended to kill the thief who posed no danger to life or limb. (The case might be different if the tools were needed for Alice to survive, but even then I think she shouldn’t intend death.) What about Bob? Well, there we don’t know what the intentions are. Here are two possible intentions:

1. Prospective thieves are dissuaded by the presence of the man-eating crocodiles, but as a backup any that not dissuaded are eaten.

2. Prospective thieves are dissuaded by the presence of the man-eating crocodiles.

If Bob’s intention is (1), then I think he’s no different from Alice. But Bob’s intention could simply be (2), whereas Alice’s intention couldn’t simply be to dissuade the thief, since if that were simply her intention, she wouldn’t have fired. (Note: the promise to shoot to kill is not morally binding.) Rather, when offering the threat, Alice intended to dissuade and shoot to kill as a backup, and then when she shot in fulfillment of the threat, she intended to kill. If Bob’s intention is simply (2), then Bob may be guilty of some variety of endangerment, but he’s not a murderer. I am inclined to think this can be true even if Bob trained the crocodiles to be man-eaters (in which case it becomes much clearer that he’s guilty of a variety of endangerment).

But let’s think a bit more about (2). The means to dissuading thieves is to put the shed in a place where there are crocodiles with a disposition to eat intruders. So Bob is also intending something like this:

3. There be a dispositional state of affairs where any thieves (and maybe other intruders) tend to die.

However, in intending this dispositional state of affairs, Bob need not be intending the disposition’s actuation. He can simply intend the dispositional state of affairs to function not by actuation but by dissuasion. Moreover, if the thief dies, that’s not an accomplishment of Bob’s. On the other hand, if Bob intended the universal conditional

4. All thieves die

or even:

5. Most thieves die

then he would be accomplishing the deaths of thieves if any were eaten. Thus there is a difference between the logically complex intention that (4) or (5) be true, and the intention that there be a dispositional state of affairs to the effect of (4) or (5). This would seem to be the case even if the dispositional state of affairs entailed (4) or (5). Here’s why there is such a difference. If many thieves come and none die, then that constitutes or grounds the falsity of (4) and (5). But it does not constitute or ground the falsity of (3), and that would be true even if it entailed the falsity of (3).

This line of thought, though, has a curious consequence. Automated lethally-armed guard robots are in principle preferable to human lethally-armed guards. For the human guard either has a policy of killing if the threat doesn’t stop the intruder or has a policy of deceiving the intruder that she has such a policy. Deception is morally problematic and a policy of intending to kill is morally problematic. On the other hand, with the robotic lethally-armed guards, nobody needs to deceive and nobody needs to have a policy of killing under any circumstances. All that’s needed is the intending of a dispositional state of affairs. This seems preferable even in circumstances—say, wartime—where intentional killing is permissible, since it is surely better to avoid intentional killing.

But isn’t it paradoxical to think there is a moral difference between setting up a human guard and a robotic guard? Yet a lethally-armed robotic guard doesn’t seem significantly different from locating the guarded location on a deadly crocodile farm. So if we think there is no moral difference here, then we have to say that there is no difference between Alice’s policy of shooting intruders dead and Bob’s setup.

I think the moral difference between the human guard and the robotic guard can be defended. Think about it this way. In the case of the robotic guard, we can say that the death of the intruder is simply up to the intruder, whereas the human guard would still have to make a decision to go with the lethal policy in response to the intruder’s decision not to comply with the threat. The human guard could say “It’s on the intruder’s head” or “I had no choice—I had a policy”, but these are simply false: both she and the intruder had a choice.

None of this should be construed as a defence in practice of autonomous lethal robots. There are obvious practical worries about false positives, malfunctions, misuse and lowering the bar to a country’s initiating lethal hostilities.

Deontology and double effect

This post continues the line of investigation from an earlier post. There I supposed that you're a police officer and you saw that Glossop was very likely to be about to murder Fink-Nottle, and the only way to stop him was to shoot Glossop in the head. Glossop was pointing a shotgun at Fink-Nottle, and your credence that he was about to shoot was 0.9999. I took it for granted that under circumstances like that it was permissible to kill Glossop. But on deontological grounds, I also assumed it was wrong to kill one person to save 9999 innocents. This did not seem to fit with standard decision theory, but I managed to make it fit.

I now consider a variant. In Gotham there are right now 10000 setups like the Glossop and Fink-Nottle story, each observed by a different police officer. You are the police chief. You know that in 9999 of the cases, the person in the Glossop role is about the murder the person in the Fink-Nottle role. But in the remaining one case, they are just amateur actors rehearsing a scene.

Should you order by radio all of your officers to shoot the Glossops in the head? There are arguments on both sides.

Pro: Each of the 10000 cases is just like the original case. So if in the original case, the officer should shoot Glossop, each of your 10000 officers should shoot. But if that's what each should do, that's what you should tell each to do.

Con: You know that by ordering all 10000 Glossops to be shot, you will be killing one innocent man (and 9999 guilty ones, but surely that doesn't make it better) in order to save 9999 Fink-Nottles. By deontology, this is wrong.

I think the Con argument is flawed. The death of the innocent Glossop differs from the deaths of the guilty Glossops. The deaths of the guilty Glossops are a means to saving the Fink-Nottles. The death of the one innocent Glossop isn't a means to saving any of the Fink-Nottles. We should take your issuing of the order "Shoot" to be intended to kill the 9999 guilty Glossops, with the death of the innocent Glossop a side-effect. (Admittedly, this is a bit awkward because you are ordering the innocent Glossop to be shot.) The side-effect is not intended, proportionality is met if the ratio 9999:1 is high enough (if not, change the numbers), and it seems likely that the Principle of Double Effect will justify the action.

I think the Pro argument, perhaps with some refinement, is convincing. This means that deontologists must find a way to block the Con argument. But it seems that the only relevant difference between this case and cases where ordering shooting is wrong on deontological grounds is the structure of intentions. So the above case provides support for the kind of focus on intentions that is essential to the Principle of Double Effect.

Pacifism and trolleys

In the standard trolley case, a runaway trolley is heading towards five innocent people, but can be redirected onto a side-track where there is only one innocent person. I will suppose that the redirection is permissible. This is hard to deny. If redirection here is impermissible, it's impermissible to mass-manufacture vaccines, since mass vaccinations redirect death from a larger number of potentially sick people to a handful of people who die of vaccine-related complications. But vaccinations are good, so redirection is permissible.

I will now suggest that it is difficult to be a pacifist if one agrees with what I just said.

Imagine a variant where the one person on the side-track isn't innocent at all. Indeed, she is the person who set the trolley in motion against the five innocents, and now she's sitting on the side-track, hoping that you'll be unwilling to get your hands dirty by redirecting the trolley at her. Surely the fact that she's a malefactor doesn't make it wrong to direct the trolley at the side-track she's on. So it is permissible to protect innocents by activity that is lethal to malefactors.

This conclusion should make a pacifist already a bit uncomfortable, but perhaps a pacifist can say that it is wrong to protect innocents by violence that is lethal to malefactors. I don't think this can be sustained. For protecting innocents by non-lethal violence is surely permissible. It would be absurd to say a woman can't pepper-spray a rapist. But now modify the trolley case a little more. The malefactor is holding a remote control for the track switch, and will not give it to you unless you violently extract it from her grasp. You also realize that when you violently extract the remote control from the malefactor, in the process of extracting it the button that switches the tracks will be pressed. Thus your violent extraction of the remote will redirect the trolley at the malefactor. Yet surely if it is permissible to do violence to the malefactor and it is permissible to redirect the trolley, it is permissible to redirect the trolley by violence done to the malefactor. But if you do that, you will do a violent action that is lethal to the malefactor.

So it is permissible to protect innocents by violence that is lethal to malefactors. Now, perhaps, it is contended that in the last trolley case, the death of the malefactor is incidental to the violence. But the same is true when one justifies lethal violence in self-defense by means of the Principle of Double Effect. For instance, one can hit an attacker with a club intending to stop the malefactor, with the malefactor's death being an unintended side-effect.

This means that if it is permissible to redirect the trolley, some lethal violence is permissible. What is left untouched, however, by this argument is a pacifism that says that it is always impermissible to intend a malefactor's death. I disagree with that pacifism, too, but this argument doesn't affect it.

Who is a combatant?

Jus in bello prohibits deliberate killing of non-combatants. But who is combatant? Plainly, a uniform a combatant does not make. If a dictator decreed that all toddlers are to wear military uniforms, that would not make them into combatants. Nor would they be combatants if he issued them with guns which they never fired. (The question of what should be done if they did shoot is a more involved one.)

I find particularly challenging the case of people pressed into military service who have the intention to refrain from violent acts. Under compulsion, they wear a uniform and carry a gun, but are no more combative than an unarmed toddler. In World War II, only 15-20% of American soldiers themselves along the line of fire would fire at the enemy in any given battle, even if the engagement lasted two or three days (I got this from Grossman's book on killing; Grossman doesn't say if the same 80-85% of soldiers were refraining from shooting in different engagements).

Suppose, then, that you are fighting a just war, and know (e.g., from intelligence reports) that 80% of enemy servicemen have a personal commitment either never to shoot or to shoot only in the air, and are wearing the uniform and carrying weapons under compulsion. You have an armed enemy serviceman in your gunsights. You do not have time to observe him long enough to figure out if he is one a uniformed pacifist or a soldier. Is it licit to shoot him?

If not, then justly waging wars against enemies whose soldiers are likely to be like that seems nigh impossible. On the other hand, how can it be licit to shoot someone who is more likely than not as innocent of bellicose activity as any conscientious objector? If you are a police sniper who sees in the distance five people, one of whom you know is a terrorist about to trigger a bomb via remote control and the other four are innocent bystanders, surely you are not permitted to pick off all five when you can't tell which one is the terrorist.

I see five solutions to this problem:

1. Drop the moral prohibition against killing innocent people who aren't any danger to anybody. This seems clearly wrong.
2. Prohibit lethal engagement in such situations. This makes much of what most people would consider the just conduct of war impossible. But perhaps double effect would still allow use of weapons not targeted at particular individuals, with the intention of killing the guilty.
3. Argue that by wearing uniform and carrying a gun on the side of injustice in a war, one has made oneself a part of an unjust war effort, and that in and of itself makes one a combatant. After all, even if one is not shooting oneself, one is boosting the war effort by providing a certain amount of cover for those who are shooting, etc. And anybody who is boosting the war effort on the side of injustice may be fairly shot. This seems mistaken. If our own POWs were forced to wear enemy uniform, and at gunpoint mixed with enemy troops, we would not consider them combatants on the enemy side--i.e., traitors--as long as they refrained from shooting at us. And the nationality of compelled uniformed people should make little moral difference here.
4. Follow Germain Grisez in saying that even in wartime, it is always wrong to intentionally kill anybody, guilty or innocent. But one can use guns and bombs and the like to intentionally make enemy soldiers incapable of harming us, and we can do this by the Principle of Double Effect (PDE) without intending that the enemy soldiers die. Their death is not a means to our goal of self-protection. All we need for self-protection is that they be out of commission for the course of the war. If this is correct, then it does not matter if 4/5 of the enemy is uniformed and pacifists, since their deaths are "collateral damage", just like the deaths of civilians standing near the enemy HQ when the HQ is bombed. But is this plausible? While some weapons can be thought of as disabling the enemy, with the enemy's death an unintended side-effect (e.g., if I hit an attacker over the head with a club, then it is plausible to suppose that I do not intend to kill him, but merely put him out of commission; if he dies, that's an unfortunate side-effect). But it feels like a stretch to use this kind of justification for all weapons. Suppose a sniper shoots an enemy soldier in the head. Let us say, with Grisez, that this is to disable the enemy soldier. But how is the sniper disabling the soldier? By destroying the brain. And how does destroying the brain disable the soldier? By killing him, it seems. And so the killing is intended, as a means, contrary to Grisez. Now maybe one can argue that one is merely trying to destroy the parts of the brain involved in fighting, and the fact that one destroys the whole brain is a mere unintended side-effect. This feels sophistical. And, anyway, if it is wrong to kill the innocent, it seems to be also wrong to intentionally destroy healthy portions of their brains.
5. Use another Double Effect line of justification. One aims at the enemy serviceman's heart and fires, say. But one isn't intending that the enemy serviceman be dead, or even that his heart be unable to oxygenate his body sufficiently for fighting (as per the previous suggestion). Rather, one is intending a conditional effect: One is intending that this serviceman be dead, or at least that this heart be unable to oxygenate his body sufficiently for fighting, if he is genuinely a combatant. One doesn't know that he is a uniformed pacifist (if one knew that, shooting him would be plainly wrong), and one's intended goal can be conditional. This solution strikes me as the least unsatisfactory of the five, but is not that satisfactory. It would allow the police sniper to shoot the five people one of whom is a terrorist. On the other hand, this solution coheres with the following intuition: It makes relatively little moral difference whether you throw a grenade at five people, killing them at once, or shoot each one individually. (Though the latter may be much more traumatic.) But it could be licit to throw a grenade at five people, four of whom were innocent and one of whom was a terrorist about to kill many people.

Here is an interesting and, I think, important conclusion. When deciding whether the proportionality condition in jus ad bellum holds--whether the war would eliminate more evils than it would cause--one needs to count among the evils the many non-bellicose enemy soldiers who would die as a result of the war. This can have real consequences. Suppose that one estimates that if an invading force is unopposed, they will murder 500,000 of one's people, some soldiers and some non-soldiers, but will cause no other evils. Suppose, further, that by opposing them, one will be able to reduce the death-toll on one's own side to 100,000, but one will need to kill a million enemy soldiers to do so. In killing a million enemy soldiers, one might be killing 800,000 completely innocent and non-bellicose people. Here, the proportionality condition would not seem to be met--one kills 800,000 innocent people to save 400,000. One should instead surrender. Unless, of course, one can argue that the enemy will not stop at killing the 500,000, which in practice is likely. But in any case, one must take into account the innocent death toll among enemy soldiers into account when figuring out if a war is licit.