Monday, May 29, 2006

When is it permissible to kill in self-defence?

With regard to the first post on this blog, I'd like to raise for broader discussion the question of what constitutes material (as opposed to formal) aggression. The question can be posed without the jargon: when is it morally permissible to intend to kill someone in self-defence? One answer would be:
(A) It is morally permissible to intend to kill someone in self-defence only if that person is maliciously intending to kill (or cause grievous bodily harm to) one.
There are, however, some problems with this:
(i) it wouldn't allow one to kill in self-defence in war time (for the enemy soldiers wouldn't have malicious intent);
(ii) it also wouldn't allow one to kill in self-defence if one were about to be wrongly judicially executed (e.g. by mistaken identity);
(iii) it wouldn't allow one to kill in self-defence if one were attacked by someone acting in (what he or she thought was) *his or her own* self-defence;
(iv) it wouldn't allow one to kill in self-defence if one were subjected to grievous bodily harm by a doctor under the mistaken impression that he or she was performing a surgically beneficial procedure;
(v) most importantly, it wouldn't allow one to kill in self-defence if one were attacked by a madman or a drunk or someone under the influence of drugs;
(vi) also, it might well be that someone endangers my life maliciously without intending to kill me, e.g. if I am a shipwreck-survivor on a small plank in the open sea, someone tries to throw me off not to kill or hurt me but to save him or herself--I think that here it would be permissible to kill my assailant even though he or she doesn't intend to kill or hurt me.
At the other extreme would be this principle:
(B) It is morally permissible to intend to kill someone in self-defence only if that person would kill (or cause grievous bodily harm to) one if one weren't to kill that person.
But (B) seems too permissive for the following reasons:
(i) it would allow a mother to kill her foetus if it were endangering her life (though intended abortion is always condemned by the Vatican);
(ii) it would allow one to kill clumsy bystanders that were about to knock one in front of a bus;
(iii) it would allow one to kill a child that was playing with a handgrenade;
(iv) it would allow one to kill the person falling off a building on top of one.
Some of these cases are a bit tricky, and there is certainly controversy surrounding them.
I propose a midway principle:
(C) It is morally permissible to intend to kill someone in self-defence only if that person is about intentionally to kill (or cause grievous bodily harm to) one.
The point about (C) is that it allows one to kill people that are about intentionally to perform an action that amounts to killing or the causation of grievous bodily harm even if they do not intend to kill or cause grievous bodily harm. Thus, one may kill the person trying to tip one off the plank into the sea since he or she intends to perform the action of tipping one off, which will amount to killing or causing grievous bodily harm, even though the assailant doesn't intend to kill or cause grievous bodily harm. It will not, however, allow one to kill a child, to abort a foetus, or kill a clumsy bystander or a falling person, since they aren't intentionally about to perform an action that would amount to a killing or infliction of grievous bodily harm. It would allow one to kill a mad person or a drunk or someone under the influence of drugs provided that he or she was about intentionally to perform the action in question: there is a difference between a drunk's drunkenly pushing one over a cliff and a drunk's drunkenly falling into one knocking one over a cliff.

What do others think?

3 comments:

Joseph Shaw said...

A couple of points needing immediate clarification:

Quote: (A) It is morally permissible to intend to kill someone in self-defence only if that person is maliciously intending to kill (or cause grievous bodily harm to) one.

What does 'maliciously' mean? What does the attacker's intention need to be to satisfy this criterion?

Quote:
(C) It is morally permissible to intend to kill someone in self-defence only if that person is about intentionally to kill (or cause grievous bodily harm to) one.

What does 'intentionally to kill' mean? Again, what does the attacker's intention have to be? Not, apparantly, to kill. To perform an action which is objectively likely to result in death?

I suspect my intuitions about the cases aren't going to correspond to yours, but we can come to that later.

Daniel Hill said...

Thanks for this, Joseph.

I didn't have anything particularly in mind with my use of 'maliciously'; the idea was that it wouldn't cover legitimate cases of killing intended as such. The hangman might maliciously kill me for his own pleasure as opposed to merely carrying out the judgment of the state.

One intentionally kills someone when one performs an action that amounts to killing and one performs that action intentionally, i.e. one intends it under some description or other. Thus the person that chucks me off the plank into the sea has, ipso facto, killed me or, at least, would be accounted to have done such in a court of law. Further this person intended to chuck me off the plank. Since the chucking off the plank was the killing this person intentionally killed me even though he or she didn't intend to kill me.

Daniel Hill said...

Maybe `maliciously' in (A) can be glossed by `culpably', i.e.:
(A) It is morally permissible to intend to kill someone in self-defence only if that person is culpably intending to kill (or cause grievous bodily harm to) one.
This rules out the moral permissibility of killing infants, drunks, druggies, the honestly mistaken, and the mad. I think it should rule out killing infants, but shouldn't rule out the other four classes.