Thursday, July 25, 2024

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.

16 comments:

Helen Watt said...

Alex,

By wrongfully threatening, do you mean, the facts of the case (of which I'm unaware) don't legitimise what I'm doing as the aggressor? In that case, my action doesn't seem morally wrongful so much as ill-informed. Surely it's fine to defend yourself with lethal force against me if I'm convinced (let's say, by government propaganda) that you are up to no good.

If I'm trying however inculpably to kill the (in fact innocent) living being in front of me, that seems to legitimise lethal self-defence against me. I have an aggressive intention however well-meant. In contrast, if I think I'm playing a computer game, I'm not even trying to kill a living being, let alone an innocent human being, and the right to self-defence against me doesn't seem to apply. That's not aggression however well-meant but only misguided play.

Having said that, it's tempting to say you can defend yourself with lethal force against a mad surgeon who is sincerely trying to 'help' you (by cutting off your healthy limbs etc). At least there though, the surgeon has intentions vis-a-vis you (the being in front of him) as opposed to something in a computer game.

The Shadow said...

(1) seems thoroughly unusable in practice. If someone is trying to kill me, I daresay I will often have no insight into how culpable they are, and I certainly won't have time or opportunity to assess the evidence!

Alexander R Pruss said...

Helen:

The computer game example suggests that lethal self-defense against a solipsist is wrong. For the solipsist thinks something very close to "I am just playing a video game."

I find all this very confusing and difficult. But it is clear to me that fully involuntary actions don't count as aggression in the relevant sense.

Shadow:

One might suppose that it is reasonable to assume for practical purposes that absent further evidence people are responsible for what they are in fact doing. I am not sure of that principle, though.

Aiden said...

Alex,

I think that your Alice and Bob example is either not a true example of (4) or we can precisify (4) to easily avoid the intuitive force of the example. The reason being that Alice is not the direct aggressor in this case. The direct aggressor is the virus; Alice could literally do nothing or go out of her way to attempt to prevent the spread of the disease in your example. There is nothing that Alice could do, whether voluntary or involuntary, whether culpable or not, to prevent this from happening. I believe this is the cause of the intuition we have in the example.

Suppose we change the example. Suppose Alice is infected with a lethal disease, but she can only transmit the disease by coughing on another person. Suppose also that the disease causes a madness within a person that forces them to cough on others. Now, if Alice tries coughing on Bob, it does seem to me that he's justified in using at least some force to repel her advance (following Aquinas, I doubt that it is ever justified for an individual to intentionally kill even a lethal aggressor, but set that aside for the time being). Your intuition may vary, but I imagine this example will at least not be as clear as the original.

Another example: a mad scientist unleashes a drug that causes madness within a person that drives them to murder others. If Alice is infected, and she hunts down Bob with a knife, is he not justified in using force against her? Minimally, he can surely repel her, but if he gets backed into a corner, and all he can do is stab or shoot Alice in a spot that will likely result in her death, this also seems justified to me.

So, here's a potential revision. If an agent's current *actions* (whether voluntary or involuntary) threaten one's life, then one is justified in potentially lethal methods of self-defense.

I think this is true, at least as a sufficient condition for potentially lethal self-defense. Then, the quesiton is whether past or future actions could justify lethal self-defense.

I'd love to hear your thoughts!

Alexander R Pruss said...

Good point about the virus being the aggressor rather than Alice. But it seems that to fix it all we need to do is to make clear that the virus is respiratory, so Alice spreads it by breathing.

Aiden said...

That's an interesting fix. My initial point (though I didn't make it explicit) was that if someone's mere existence is what's causing (indirectly) another's death, then lethal self-defense is not permissible, but if it goes beyond their mere existence, then it is permissible. Insofar as breathing is a normal and necessary function to remain in existence, I think my initial response still stands, though the revised category needs further revision.

Let's try "if an agent's current *extraordinary actions* (whether voluntary or involuntary) threaten one's life, then one is justified in potentially lethal methods of self-defense," where "extraordinary actions" means anything that is not necessary for one's existence. That said, I realize this is still too broad, though it does escape your fixed example. For example, if Alice will pass the disease along to Bob if she ever speaks to her children again, it doesn't seem that Bob would be justified in using lethal self-defense, even though Alice would not die if she did not do this.

Instead, let's revise "extraordinary actions" to mean something like "actions objectively directed toward harming another," and by that we mean something like "taking into account all objective facts of the situation, the actions will harm another AND the action is not a normal objective good of the 'aggressor.'"

Another simpler, though perhaps too narrow for my liking, definition of "extraordinary actions" might be something like "taking into account all *normal* objective facts of the situation, the actions will harm another." This principle, in itself, doesn't allow lethal self-defense in any of these mad scientist cases where normal facts become abnormal (eg. mere breathing will kill another), but if a drug user becomes so high that they lose their free will and attempt to stab another person, that person may use lethal self-defense.

I think I prefer the broader principle because it comes closer, in my view, to the true principle.

I wonder, how do you handle the person who was infected by a mad scientist and has no control but is trying to stab others case?

Justin O. said...

In the spaceship example, it seems if it were a reasonably foreseeable circumstance (which being marooned spaceship would be) then they would not be permitted to kill the other survivor. Foreseeability implies responsibility.

I disagree on the first point that lethal self-defense requires a lethal aggressor. Lethal self-defense could be justified when a person has a reasonable objective belief of an unlawful lethal threat (meaning there is some objective evidence of an imminent lethal threat) and the person has a personal subjective feeling of an imminent unlawful lethal threat at the time. That leaves open that a person could be genuinely mistaken about the other's intent at the time.

Alexander R Pruss said...

Justin:

On the first one point, suppose that to get to your destination you have to sail through pirate-infested seas, and you have morally weighty reasons to get to your destination. It's reasonably foreseeable that a pirate will attack you, but you are still permitted to use lethal force to repel the pirate's lethal force.

On the second point, it depends on internalist/externalist questions. On a more internalist view one might say that reasonable belief is enough to justify lethal self-defense. On a more extenralist view one might say that a real threat is needed to justify lethal self-defense, but reasonable belief makes you non-culpable.

Christopher Michael said...

Wait, why not just (5) wrongfully threatening one's life?

This deals with the police officer, disease, and air cases nicely, while also avoiding the major problem with requiring culpability, which is that it is clearly permissible to defend oneself against a mentally incapacitated person.

If we are worried about how to construe "wrongfully" in the involuntary cases, make it conditional: (6) threatening, either wrongfully, or, if involuntarily, then in a manner which if it were voluntary would be wrongful, one's life.

Alexander R Pruss said...

Suppose that someone has implanted remotely controlled electrical stimulators in your muscles, and is using your muscles to attack me. That might satisfy your (6), but doesn't seem enough for lethal self-defense against you.

Christopher Michael said...

I guess that's where we disagree! I think self-defense against involuntary attacks is clearly justified, and accepting the contrary commits me to a weird and unintuitive skepticism about whether I can defend myself in any case, because I can't know the mental state of my attacker and whether it has undermined his will.

Alexander R Pruss said...

In the completely involuntary case, I don't even think we can say that it's an attack by the individual in question. Suppose that you're walking under a cliff, and Alice and Bob are at the top. Alice picks up Bob and throws him at you. Alice is attacking you, but Bob is not. The case of remotely controlled muscles seems hardly different.

I think that apart from special cases it is pretty easy to know that people are acting voluntarily, though it may be very hard to know that they are acting culpably. If I see someone shooting arrows at a tree, barring very special circumstances (them moving jerkily as if they were sleepwalking, or having electrical devices hooked up to their muscles, or my having observed them taking mind-altering drugs), I will take myself to know (of course fallibly) that they are doing so voluntarily, and I will in fact know it, absent special circumstances. The same is true if they are shooting arrows at a person.

Complex physically well-coordinated involuntary action is in fact quite rare.

Christopher Michael said...

In the case of throwing Bob, I agree that there's a sense in which Bob is not attacking me. But even in that case it is clear to me that, if I could prevent Alice from killing me using Bob by harming Bob, I may harm Bob in that way.

I suppose part of what I'm saying is that I don't think the action theory on the part of the "aggressor" really matters. The moral principle underlying self-defense is that I am morally entitled to prevent any unjustified contact by means proportionate to the force of that contact, no matter how involuntary on the part of the "aggressor". The state of mind of the aggressor plays no role in the moral analysis, I don't think.

Alexander R Pruss said...

In the case of involuntary things, I think "unjustified" is a category mistake. Take a case where it's the wind that "throws" Bob at you. It makes no sense to talk of Bob's flight as justified or unjustified (except maybe insofar as one can talk about God's permission of the event--but God's permission is always justified). In the case where Alice throws Bob, we only get to use "justified" and "unjustified" with respect to Alice's action, not Bob's flight.

If you think it's OK to use lethal force to stop Bob in the case where Alice threw him at you, because it's an unjustified flight, then you might as well say that it's OK to use lethal force to stop Bob in the case where you threw him at yourself, because it's equally unjustified!

Christopher Michael said...

So let "unjustified" simply mean "not morally justified", and thus include both wrongful contacts and amoral contacts. My claim is that I am morally entitled, by my duty of self-preservation, to prevent (by proportionate force) all such contacts that do me harm or threaten harm.

This moral entitlement can be defeated by my being the immediate cause of the contact (such as when I throw Bob at myself in a way that leaves Bob totally innocent in the contact) for the same reason I cannot kill another to save myself from dying at my own hand, but it cannot be defeated merely by the innocent mental state of the cause. The goods secured by self-defense simply don't depend on the state of mind of the cause of the pending harm, and to think otherwise seems to me to slip into the error that what justifies self-defense is a right to punish an aggressor, which gets punishment wrong. The right to self-defense isn't a right to punish, which is why it ceases when the aggression ceases, even though the aggressor remains punishable for his aggression.

Alexander R Pruss said...

But this would include the case where you are trapped with an innocent person in a sealed room. Breathing is (normally) an involuntary activity, and hence amoral. The other person is thus unjustifiedly (in your sense) poisoning your air with carbon dioxide, and hence on your account you are permitted to use lethal force against them. But that seems wrong.

(Note: If correct, this calculation shows that, for appropriate room dimensions, carbon dioxide will kill you before lack of oxygen gets you: https://www.reddit.com/r/askscience/comments/yyg20/if_i_was_in_an_airtight_room_would_i_die_first/ )

Objection: Production of carbon dioxide is not contact.

Response: It seems no less contact than hitting someone on the head with a rock.