Suppose A is unjustly attacking V, and using I as an “innocent shield.” In other words, A has positioned himself (or I) in such a way as to make it difficult for V to employ defensive force against A without endangering I in the process. In circumstances such as these, is it morally permissible for V to employ defensive force against A, knowing that I might very well be harmed or killed as a result?

Many people think that it is, so long as V is not trying to harm I, but merely acting in a way that he foresees is likely to harm I as a side effect of his intended goal. This, at any rate, is what the doctrine of double effect says.

But even on the doctrine of double effect (which, of course, is quite controversial), V‘s causing harm to I is only permissible if V‘s action meets certain conditions of proportionality and necessity. V isn’t allowed, presumably, to shoot and kill I in order to prevent A from scratching V‘s arm. And V might not be permitted to kill ten I‘s in order to prevent one V from dying. Necessity is trickier. If there is one and only one possible way for V to stop A, and that way involves subjecting I to risk of harm, then the necessity is obvious. But reality is rarely so neat. Usually there will be multiple ways in which V might try to stop A, some of which are harder (costlier) and some of which are easier. Suppose (to over-simplify once again), that V has just two options. (1) V can attack A in a way that subjects V to very low risks of harm, but subjects I to a very high risk of harm. Or (2) V can attack A in a way that subjects V to a very high risk of harm, and I to a very low risk of harm. Is (1) necessary?

Here’s another puzzle, which I borrow from Robert Nozick. Suppose we decide that, in a certain case, V acts permissibly in attacking A and subjecting I to risk of serious harm or death. Suppose further that I is incapable of attacking A, but that I is capable of attacking V and thus preventing V from acting in a way that threatens I. Is it morally permissible for I to attack V in self-defense? Would this mean that I and V might both legitimately attack each other, both in self-defense?

I raise these questions as a way of putting a philosophical spin on our recent discussion of the conflict in Gaza. I stayed out of that discussion for the most part, but became more interested in it after engaging in some conversation with some of our readers on our Facebook page about Anthony Gregory’s provocative article. Gregory thinks Hamas is acting wrongly when it kills innocent Israelis. But he also thinks Israel is acting wrongly when it kills innocent Palestinians. In response, many defenders of Israel noted that Hamas uses Palestinian civilians as innocent shields, and moved pretty quickly to the conclusion that therefore Israel is blameless in causing the deaths of those civilians. Maybe that conclusion is right. But I don’t think it’s as obvious or unproblematic as a lot of people have assumed.

There’s quite a large philosophical literature on these questions, and a surprisingly small libertarian one. The philosophical literature is dominated by the likes of Judith Thomson and Francis Kamm, but see this paper for an overview of some relatively recent work in the field. As for the libertarians, I haven’t seen much apart from a mention of the innocent shield problem by Murray Rothbard, and a interesting discussion here from Walter Block. As I’ve noted before, the libertarian literature is also surprisingly disconnected from the philosophical one, to the detriment of both. I’m not at all convinced that the kind of intuition-driven deontology that Kamm and Thomson employ is the best way of thinking about these matters. But whatever the flaws of their method, they ask and try to answer challenging questions about what a a principle of non-aggression commits one to, in a way that too many libertarians gloss over or ignore.

UPDATE: Of course, whenever I say “there is some issue X that libertarians ought to think more closely about” this should be read as including an exception for Eric Mack, who most likely already has thought closely about it, and written something pretty good. See, for instance, his ”Three Ways to Kill Innocent Bystanders” in Social Philosophy and Policy 1985, pp.1-26, and also his ”Rights, Just War, and National Defense,” in Machan and Rasmussen eds. Liberty for the Twenty-First Century (Rowman & Littlefield, 1995). Neither is available online, unfortunately.

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  • noiselull

    I’ll just pre-empt Stephan Kinsella’s inevitable chiming in to mention and its discussions of this and other libertarian issues,

  • Daniel Shapiro

    Matt, I am pretty sure Eric Mack has written on this topic.


      Indeed he did: “Rights, Just War, and National Defense,” in Machan and Rasmussen eds. Liberty for the Twenty-First Century (Rowman & Littlefield, 1995).

  • Peter Wize

    In consequentialist terms, not attacking A just because A is using I as an innocent shield has the disastrous consequence of encouraging aggressors to use innocent shields. In the fullness of time it would be better for there to be a publicly known policy that victims who are defending themselves will always pursue aggressors regardless of their use of innocent shields. In that way, there’d be no profit in an aggressor ever using an innocent shield, and ultimately more lives would be saved.

    • Steven Horwitz

      Yes. Second order effects matter here. It’s also possible that if V’s self-defense against A is so disproportionate to A’s aggression, and therefore kills at least I and possibly other Is, it will encourage other As to aggress against other Vs. I happen to think Peter’s scenario is more often what is happening in Gaza, but we certainly have instances of real world Vs doing exactly what I describe above and perhaps with those longer-run consequences.

      • Michael Philip

        Steve, how would you define disproportionate?

        • Steven Horwitz

          However one defines it, my claims still stands. And I was not claiming that this is what is happening in Gaza NOW, or at any specific time, but that I think it has at times, and in other places as well. What constitutes disproportionate is a debate worth having, but it’s a different debate than Matt’s point.

      • Sean II

        Another way of saying it is that V’s response is part of the recruiting campaign which turns the innocent Is of today into the aggressive As of tomorrow. From the point of view of Hamas and the whole “new class” of Palestinian leaders, that means civilian casualties are indeed a feature, not a bug.

        My father once told me there would never be an end to the troubles in Northern Ireland because “then the Provos would have to go back to being nobodies”. His prediction was off, but I think the same wisdom applies here.

        For some people in Gaza, the struggle against Israel is the only job they will ever have, the sole source of meaning in their lives, the basis for their self-esteem and social status, and a remit from the tortuous boredom of poverty.

        Why would THEY ever want it to end?

    • Marja Erwin

      Your position just means I gets killed, unless I kills V first.

      It is the road to Eichenfeld, where opposing self-defense forces start fighting, and start killing the civilians they perceive as supporting the other self-defense force. It is the rationale for total war, which, with nuclear weapons, is the worst possible consequence of which our species is capable.

      • salgaubogdan

        If I has the skill and power to kill V (who presumably is more powerful than A or else A would just engage V directly without the need of I as human shield) then I also has the power to kill A. If I has the power to kill A then I is morally allowed to do it because A is either forcing them or purposely puts them in harm’s way.

        Of course, in real world I is rarely in the position of power to resist A or V. Plus there’s also the issue of complicity and variations of the Stockholm syndrome. Can I escape from being used as a human shield? Is I deliberately acting as a human shield to help A?

        • David Odegard

          It is possible to maintain the original confines of the question that I has the power to kill A but not V. To say that because I has the power to kill A means that he must have the power to kill V is to introduce something new to the equation, something that isn’t necessarily true. What if the only reason that I has the ability to kill A but not V is the range of his short range missiles? That would put A in range but not V. In order to find an answer to the moral dilemma, one must not introduce new facts which do not answer the original question. What if paper really beats scissors after all?

        • Marja Erwin

          I’ve come across comparable situations in history, and escalating violence almost always makes things worse, and we’d do better to find ways of avoiding violence and find ways of stopping violence. If the situation involves violence, it tends to either be an unpredictable situation or an everyone-will-lose predictable one.

          So we shouldn’t be satisfied with the problem, or with violent answers to the problem, regardless of what we view of violent self-defense. I don’t judge, if it is self-defense. I don’t believe self-defense scales up from defending one’s self while being violently attacked to ordering airstrikes with weeks of pre-conflict contingency planning.


      This is a very good point. However, I wonder whether it is solely a consequentialist perspective. In other words, couldn’t a deontologist, when faced with this sort of situation, formulate a maxim along the lines of, “Act so as to minimize over the long-run the total number of innocent deaths”? Which would involve acting in self-defense despite the presence of human shields.

      • Matt Zwolinski

        Might not such a maxim involve treating people as mere means in objectionable ways – eg torturing the children of suspects terrorists, directly attacking civilian populations, etc.?


          My question was a sincere one, and I was hoping you might comment. The answer to your question might well be “yes,” but I am not sure. The reason I am uncertain is that the Kamm-style 1 vs. 5 logic (to which I subscribe), might only be intuitively compelling if we are dealing with a known, identifiable person that an agent is called upon to willfully sacrifice. Is the military commander attempting to knock-out rocket launchers (or the like) really using the unfortunate civilians nearby as a “means,” when his objective is the rockets themselves? So, maybe, the maxim I suggested is unobjectionable, and consequentialism and deontology converge on the same answer. I am happy to get your further thoughts.

          • Matt Zwolinski

            I think the usual deontological analysis would hold that civilians who are killed as the foreseen but unintended result of a legitimate military strike are not treated as means. I’m OK with that, though I think it’s possible that they are nevertheless treated in a morally impermissible way (i.e. I’m not sure that “not treating someone as a mere means” fully specifies our moral obligations). In contrast, intentionally bombing a civilian population in order to induce their government to surrender (or surrender on more favorable terms) would, according to standard deontological analysis, involve treating them as mere means.

            The problem with your maxim, I think, is that it doesn’t discriminate between these two cases. Deontologists would find (under the right circumstances) the first kind of treatment acceptable, and the latter unacceptable. But both might be permitted by your maxim, which simply tells us to minimize long-run deaths.

            It might nevertheless be true that deontology and consequentalism converge, at least in a wide range of cases. But that would only be so, I think, if we make a number of empirical assumptions and thereby remove some options (like torturing children) from the consequentialist’s table on the grounds that, as a matter of fact, we believe they will never actually minimize the number of innocent deaths.

          • MARK_D_FRIEDMAN


          • SimpleMachine88

            You don’t negotiate with terrorists due to procedural justice. Because you just don’t negotiate with terrorists ever, it’s just wrong. It’s not about utilitarianism.

  • Ethan Pooley (furball4)

    “Would this mean that I and V might both legitimately attack each other, both in self-defense?”

    Absolutely. A simpler version of this is the mistaken criminal conviction. Imagine that you are reasonably and carefully – but mistakenly – convicted of a crime and imprisoned for it. Imagine further that you are presented with a chance to escape, but must kill a guard to do so. No one in this situation has a guilty mind, yet a harm is being done. Why should the harm fall on you rather than the guard? Are you justified in killing in order to escape? What if you need only break his leg or endanger his life – not necessarily take it? What if you have to kill ten guards? A thousand?

    I would suggest that society has no enforceable claim on you to abstain from violence in your bid for freedom, but that most individual systems of morality will quickly draw their own line.

  • Michael Philip

    “Suppose A is unjustly attacking V, and using I as an “innocent shield.” In other words, Ahas positioned himself (or I) in such a way as to make it difficult for V to employ defensive force against A without endangering I in the process. In circumstances such as these, is it morally permissible for V to employ defensive force against A, knowing that I might very well be harmed or killed as a result?”

    That’s a tactical issue, not a moral one

    • Matt Zwolinski

      Can’t it be both? Was the decision to drop an atomic bomb on Hiroshima also a tactical issues and (therefore?) not a moral one?

  • martinbrock

    In reality, I can’t so easily distinguish A from V, so unless either A or V (or I) is my child or similar kin or kith, I let people kill each other as they will and don’t get involved. Everyone dies, and the vast majority of deaths are either beyond my control or none of my business. I speculate little on when I might be willing to kill myself, because only the narrowest circumstances tempt me, and when they occur, I’ll have no trouble deciding.

    As for Gaza and Tel Aviv, if my child lived in either place, I’d ask him to leave.

  • Joseph R. Stromberg

    Well dang those ole foreigners for having *people* in their cities. I’m sure there’s no population surrounding (or even near) any American command-and-control centers. Heaven forbid. They must all follow our good example and organize their society and military installations in a way that maximizes our targeting while saving such conscience as we have.

    • David Odegard

      Mark asked if the innocent bystander assumes some of the risks of being in proximity to danger. This is assuming that the innocent bystander has knowledge and ability to avoid being used as a shield; in which case, he clearly has become an informed risk-taker rather than a purely innocent person.

  • Sean II

    I really hate to bring up the Ayn Rand argument about the moral complicity of the doomed passengers on the train, but I think it must be done. Of course Matt’s thought experiment should be conducted first and separately, BUT in the end this discussion must also include a reckoning of just how innocent the various “Is” really are.

    Let’s say that in an air strike against an apartment building, the Israelis kill all of the following people:

    a) An operational commander in Hamas who is the target of the attack
    b) An active member of Al Qassam who has taken part in many rocket launches
    c) His roommate, a new recruit who has yet to finish basic paramilitary training
    d) A 15 year old boy who is thinking about joining an armed brigade next year
    e) The boy’s mother, who is actively encouraging and pressuring him to do so
    f) An elderly man who sympathizes with Hamas and sometimes acts as a lookout
    g) An apolitical black marketeer whose business includes selling weapons to Hamas
    h) An Imam who preaches publicly that anyone outside the faith may justly be killed
    I) A Fanonist educator who teaches that violence is cathartic for the oppressed.
    j) An old grandmother who taught three generations of her issue that Jews are pigs
    k) A young woman who runs a blog blending criticism of Israel with holocaust denial
    l) A young man who shares no such opinion, but cheers whenever a rocket goes off
    m) A pregnant widow who voted for Hamas because of its social-welfare policies.
    n) A middle aged businessman who does nothing to support or oppose Hamas
    o) A secular student who (discreetly) participates in Israeli/Palestinian outreach
    p) A devout Sufist who sincerely believes that all killing is an offense against god
    q) A three year old girl who does not even know what the word killing means

    The question becomes…just where on this list does innocence begin? I expect everyone would see guilt clearly in A) , B), and C), while seeing innocence clearly in O), P), and Q).

    But what of the space in between?

    • good_in_theory

      Ah, if C is in I guess we should include every israeli who has and will serve in the idf in the ‘guilty’ stack…

      • Sean II

        Not so fast. The IDF uses conscription. Al Qassam is a volunteer force. Hardly a mark in Israel’s favor for libertarians, but it makes a difference in moral terms for the individuals involved.

        We can be sure C) has voluntarily chosen to put himself in a situation where he might kill someone.

        • good_in_theory

          One can avoid conscription by putting forth an objection of conscience or moving. The penalty for objecting tends to be a dozen or so weeks in prison. Easy enough.

          • Anthony Gregory

            The fact that Israel uses a slave army is very damning to that state, but a mitigating factor when considering the morality of the individual soldiers. Nevertheless, a slave has no more right to commit murder than anyone else does—it is only that his doing so might be more understandable.

          • good_in_theory

            If the coercive penalties deployed by the state of Israel against those who refuse to serve are to mitigate the culpability of those who chose to serve, then what excludes the coercive circumstances under which Palestinians might ‘choose’ to participate in Hamas from mitigating the culpability of their own choices?

            By what criteria do we naturalize some forms of coercion and not others? It’s not unlikely that it is much easier for an Israeli to avoid complicity than it is for a Palestinian to do the same, both in terms of the coercive sanctions faced and the capacities possessed to avoid the present circumstances for something more morally tolerable.

          • David Odegard

            I have agreed with you in 90% of your remarks about the war in Afghanistan, but you really have gone too far in saying that Israel has a slave army. And Israel has a legitimate claim to self protection.

          • David Odegard

            To use the original formula for this thread: Israel is the victim of a Hamas missile (I realize you will say that Israel is actually the aggressor, but a comprehensive look at the overall history since ’48 will prove you wrong). starting again: Israel is the (V)ictim of a Hamas missile. Can (I)nnocent Lebanese people kill their leaders, the (A)ggressor Hamas, and call it self defense? I would say yes they can kill their leaders since Hamas (A) is putting them in a perilous situation and since Israel (V) has an obligation to protect herself from missile attacks. The same question is this, can a woman who is being held by the hair with a gun to her head and being shuffled off to a car by a bank robber legitimately stab her assailant if she has the option? Yes. Better if she could disarm him, but that goes outside the parameters of the original question.

    • Anthony Gregory

      The thing is, if we’re going to defend collateral damage of Palestinians, we end up on the road to defending terrorism against any people who have an aggressive government.

      I would have thought it an uncontroversial point among bleeding heart libertarians that the U.S. has waged aggressive wars, that people murdered in US wars are among the greatest victims of American government. It makes no sense to regard victims of the IRS and DEA as sympathetic, innocent people but assume the worst of the millions slaughtered in US foreign policy. The US government is an enemy of liberty. It is evil. It seizes American wealth by force. It kidnaps and detains hundreds of thousands of people. And, worst of all, it kills people in large numbers abroad.

      I would further assume that most bleeding heart libertarians would regard Obama’s drone bombings in Pakistan, to take one example, as a clear cut case of mass murder. I would also assume it would be uncontroversial among bleeding hearts that if anyone has a right to defend themselves against aggression, foreigners fighting off US forces invading and killing people in their neighborhoods have this right.

      So where does that bring us? Let’s look at a possible list of targets of al Qaeda:

      a) An operational commander of the military
      b) An active drone pilot
      c) An American training to be a drone pilot
      d) A 15 year old boy who is thinking about joining the Marines
      e) The boy’s mother, who is actively encouraging and pressuring him to do so
      f) An elderly man who sympathizes with the US empire and sometimes acts as a lookout
      g) An apolitical defense contractor whose business includes selling weapons to the US government
      h) A Randian who preaches that it’s legitimate to kill Arab civilians
      I) An educator who encourages enrollment in the US armed forces
      j) An old grandmother who has taught that three generations of victims of US wars had it coming
      k) A young woman who runs a blog blending criticism of Islam with denial of the atrocities committed by the US
      l) A young man who shares no such opinion, but cheered the Iraq war
      m) A pregnant widow who voted for Obama because of its social-welfare policies.
      n) A middle aged businessman who does nothing to support or oppose US wars
      o) A student who (discreetly) participates in American/Iranian outreach
      p) A devout Christian who sincerely believes that all killing is an offense against god
      q) A three year old girl who does not even know what the word killing means

      Not only do I think it would be murder to target O, P, and Q, I think it would be murder to target anyone from d onwards, and I would say the same about the examples Sean II lists to which I attempted here to find an American analog.

      I will be accused of moral equivalency, yet in material terms, the US government certainly poses as much a threat to innocent people as Hamas does. It has murdered thousands of people in multiple countries that it has no moral claim by any standard to even wage war with. Yet nothing the US government has done—and I think it has clearly murdered more innocent people than Hamas has—could justify 9/11 or other terrorist attacks on American soil, and even certain attacks against US bases where there are civilians and children present would be morally problematic.

      I don’t see how we can argue that Hamas is guilty of using human shields and not conclude the same about the US government. I don’t see how any consistent ethic could justify Israel’s assault on Gaza without also justifying reckless attacks against Israelis and Americans.

      • Gordon Sollars

        The key to your argument is the term “reckless”. Reckless attacks against human shields are presumably impermissible, whether in Gaza or the U.S. Likewise, attacks that inflict collateral damage on innocents in the U.S. might be permissible, if the attacks are not “reckless”. Haven’t at least some of Israel’s targets in Gaza, or the U.S.’s targets in Afghanistan, been in your category (A)? Or is the problem that too much of the targeting is incorrect and thus “reckless”?

        • Anthony Gregory

          It is possible that some of Israel’s targets, and some of America’s in Afghanistan, are not so reckless. I still oppose those bombings as a strategy. But when dozens of children are killed in a response to the murder of four people, red flags should go up automatically.

          • Anthony Gregory

            But the whole Afghanistan war has been unlibertarian since the beginning. If I’m discussing matters with libertarians who aren’t thoroughly antiwar, I could see why we might disagree.

          • Gordon Sollars

            “whole”? The attack was initially against al-Qaeda leadership in Afghanistan. How was that unlibertarian?

          • Anthony Gregory

            Well, it was a war, that involved taxing, bombing, invading, flexing jurisdictional power, central planning. State war is unlibertarian. al Qaeda is bad, but virtually none of the people killed in Afghanistan had any direct involvement in 9/11.

          • Gordon Sollars

            Well, my being able to drive to the grocery store on public roads involves taxing and central planning, but I don’t think I must grow my food in my backyard until all such evils have passed away. As to your second point, I agree; the plan went off the rails almost immediately. But “virtually” is not the same as “none”, and “from the beginning” starts just a little too soon.

          • Anthony Gregory

            The “plan” was almost inevitably going to go “off the rails.” It was a _war_, which is another word for state-coordinated mass murder. There was no reason for anyone with a tittle of skepticism and knowledge about the US government to assume for a moment that if Bush launched an invasion of Afghanistan, it would become a protracted, bloody, tragic conflict. Even if it achieved some semblance of justice in its first couple days—which it didn’t since innocents were killed in those days, and the 9/11 perpetrators were not—the predictable outcome of the US military response—years of war and occupation—rendered the entire thing indefensible.

            Driving on roads is not comparable to waging a war. Even the most just foreign war imaginable is more akin to the government seizing land by eminent domain, borrowing money to start building a road, and burying a few people under the rubble while building it. It is unlibertarian thoroughly, if anything is.

          • Gordon Sollars

            Many things are “unlibertarian”, some among them being public roads and state wars. If your point is that some things are more unlibertarian than others, I agree; but, in an imperfect world, the best action available to us sometimes might be unlibertarian. That is why I am suspicious of your, “Even if it achieved some semblance of justice in its first couple
            days—which it didn’t since innocents were killed in those days, and the
            9/11 perpetrators were not”. Unless the possibility of killing innocents means that you cannot act at all, then there will be some actions that kill innocents and fail to reach the guilty.

            Was it impermissible for the U.S. government to attempt to capture or kill bin Laden by *any* means, simply because the U.S. government is “unlibertarian”? For example, suppose that drones were used instead of an invasion? Or, consider the actual killing of bin Laden. Several others were killed along with him, including an unarmed woman. Supposing she was innocent, was the action impermissible?

          • Gordon Sollars

            Dozens of children only? Or in addition to a target related to the murdered four people?


        You seem unwilling or unable to disentangle the factual issue of which countries wage wars of aggression from the philosophical question of whether the victim nation (whatever nation that happens to be) is entitled to engage in self-defense if even a single innocent person is harmed.

        Since you never answered this example on the previous thread, I will repeat it here:

        I am a black man living in the Jim Crow South. My only “crime” is the color of my skin. A large mob of KKK has come to lynch me and torch my house with my family still in it. But I have a suprise for these bastards. I have a “little friend,” in the form of a Tommy Gun with plenty of ammo.

        Sadly, several members of the KKK have brought their young children along to see the fun and to educate them in how you treat blacks who dare to live in your town (there are the ones dressed in the pillowcases instead of sheets). As the mob attacks, I have only two choices: (i) do nothing and die or (ii) open fire with my automatic weapon, saving my family but probably killing some of the little ones.

        I say, the black man in my case has a right of self-defense. He didn’t endanger these kids, and doesn’t want to harm them. The parents must take full responsibility for what happens to them. If you disagree, please justify your position. Now, how in principle does my case differ from that of a military commander fighting a purely defensive, and thus just war, who is faced with essentially the same situation? Please explain that to me.
        If you have difficulty identifying naked wars of aggression that have been waged in the last century that are analogous to my KKK case, let me know. But the identity of these wars is irrelevant for purposes of getting the philosophical principle right.

        • Gordon Sollars

          Your case could differ if the military commander – or his civilian superiors, if any – had resources beyond the black man’s automatic weapon in relation to the aggregate force of the other side. In general, I am not sure how many “moving parts” an analogy must have to be “essentially the same situation” as the military commander’s. And, of course, some would claim that even getting that right would not be enough to properly analogize to the Israel/Palestine case, as that case might not represent a “purely defensive” war. What if the house was a duplex, and the black man’s grandfather had locked the KKKer’s grandfather out years ago? Oh, and let’s add that significant portions of the KKKers and the black man’s family believe that the duplex was given to them by God.

          • MARK_D_FRIEDMAN

            With all due respect, I think you are making the same mistake as Anthony. My argument has nothing to do with Israel/Gaza or Israel/anyone. Imagine whatever you think of in your mind as a people or nation fighting a purely defensive war: I can cite some examples if this would help, but it shouldn’t be necessary. Then ask, if this people/nation could ONLY defend itself by means of tactics that involved unintentionally kiling the innocent, i.e. they are killed as an unavoidable side-effect of trying to defend (as in my KKK case). Then, ask, would this be morally permissible? Subject, if you like, to the condition that the number of innocents killed is not wildly disproportionate to the number of those under attack by the aggressor nation, i.e. in my case there were not 1000 children being killed by the Tommy gun.

          • Gordon Sollars

            Sorry, but I thought you had weighed in using the Israel/Palestine example; looking back, it was a post above yours that mentioned Hamas. I am happy to put that example aside.

            I would use Nozick’s “principle 7″: an action A is impermissible if another action B is available with less wrongness than A such that the extra wrongness of A over B is more than the extra rightness of A over B. (And, it gets more complicated when we consider that A is often part of a larger course of action.) (I think that that formulation is more helpful, believe it or not, than trying to make sense of “wildly disproportionate”.) So, the killing of the innocent might not be impermissible, depending on what other actions were available. In trying to determine the rightness and wrongness of A and B on an interval scale, context *really* matters.

          • MARK_D_FRIEDMAN

            As a general decision-strategy it seems quite reasonable. The devil, however, is in the details, i.e. filling in what counts as “wrongness” and “rightness.” Aye…there’s the rub.

          • Gordon Sollars

            Yes – Nozick was pretty clever. ;-) I think we have to start with some initial assessment of the rights and wrongs and argue from there. Also, action A, here the “defensive” action that harms innocents, might remain permissible because of the unavailability of B, *unless* the actor takes some steps to create conditions for B. Must the actor try to create the conditions for B? I think so, if the moral “cost” of a *policy* of doing A is “large”.

          • MARK_D_FRIEDMAN

            I think “pretty clever” is a huge understatement.

          • David Odegard

            I have to agree with the way the original question was posited. When you attribute A, I, and V to real life situations we all already have valuations on who they are. What if a black man hunted down a gathering of KKK peacefully assembled, could he then “stop the hate” by mowing them all down?
            The question is rightly put: Can I (innocent) kill A (agressor) to protect himself from the unintended risk to life presented by V (victim) AS SELF DEFENSE? knowing that V has to defend himself from A.
            Answer this question first. Then you may introduce another question such as: What parameters of risk are acceptable to endanger I in order to save V? Introducing real life values such as Palestinians and Israelis clouds the issue because to the typical muslim Jews are worth less than zero. Remember, they hated Jews Before the creation of the nation of Israel. So to them “I” no longer has any value. It clouds the whole question.

          • MARK_D_FRIEDMAN

            I don’t really disagree with you. But, I think hypothetical examples are helpful in illutsrating what the acceptance of an abstract principle commits one to. I agree that the specifics can influence our emotions, but nonetheless this can be corrected for in the way you just suggested, i.e. with counter-cases. Yours doesn’t really do that, however, because the black man would be clearly the agggressor. A more neutral case would be if a KKK person (acting innocently at the time) was holed up in his house and attacked by a mob of African-Americans in the Jim Crow South. Here, I would deliver the same verdict.

        • Anthony Gregory

          “If you have difficulty identifying naked wars of aggression that have been waged in the last century that are analogous to my KKK case. . . ”

          That’s not my difficulty. I can think lots of wars that would qualify as naked aggression—including lots of wars waged by the US. I keep going back to the US as an example because I think some of the ethical implications of defending collateral damage could conceivably include the legitimization of anti-American terrorism. I don’t like the idea of being held liable for the criminal actions of my own government.

          But to answer your hypothetical—sure, fire at the lynch mob. Aim for the heads of the adults, however. But if you are shooting in a way that is putting innocent kids at risk, then I have to say I sympathize with those kids. I can’t really say you have a right to shoot those kids without saying those kids have no right not to be shot. But they do have a right not to be shot.

          What if some terrorist put a gun to your head and threatened, credibly, to kill a thousand people unless you murdered one child? Concede for the sake of argument that you can trust him on this. Would you kill the child? If you did so, most people would probably place a “higher” blame on the shoulders of the terrorist. They might understand why you did it. But it would still be murder. This example is more extreme but it nevertheless illustrates a point: we might feel compelled to act in immoral ways to stop something horrible from happening, and others might sympathize, and most people might hold back a lot of blame due to the circumstances, but it doesn’t mean the act itself is morally pure.

          I too would probably violate rights in extreme circumstances. But that’s what I would be doing: violating rights. I should have to grapple with those moral consequences personally. One reason to oppose state acts of violence where we might be sympathetic to individuals committing that violence is that the state tends to isolate the actor from the moral implications of his actions. There might be lifeboat scenarios where otherwise good people violate rights and we can understand why. This is not a good reason to let the state violate rights.

          • MARK_D_FRIEDMAN

            Thanks for the answer and analysis, but I don’t think it fully answers my argument. The question in my hypothetical and in the case of national self-defense in a just war is not whether, as you say, the act is “morally pure” or even whether it violates some other person’s rights. That standard demands too much and takes an implausible absolutist stance on the nature of rights.

            Are you familiar with Joel Feinberg’s famous “Cabin” case about the lost hiker in a blizzard who will die unless he breaks into a cabin to take shelter. The owner refuses permission, but common sense says that this unimpeachable property right gets overriden by the hiker’s need to live. The property right is not absolute.

            Of course we have sympathy for the innocent kids in my example, but that doesn’t mean that the black man acts wrongly, that he should be condemned, for defending himself and his family. I believe that 100% of the blame goes to the parents who brought their kids to see the “show.” And that it seems to me is the real issue.

            Alter you case a bit. Assume that the number is not 1000, but 7.5 billion. Of course I should kill the kid. Call it “murder” if you like, but are you seriously going to criticize me for saving the entire human race? I think I would be acting rightly, even if my action isn’t “pure.” Again, rights are not absolute.

            The argument that “the state tends to isolate the actor from the moral implications of his actions” is unconvincing. I posited a purely defensive war, and presumably the military commander understands the justice of the cause for which he/she is fighting. The issue is in such a case is whether self-defense is justified if it inadvertently costs innocent lives. I don’t see how the decision of a senior military commander is different in this regard than the black man in my KKK case.

      • Sean II

        Anthony, I’d also love an answer to my question from the last thread, which I’ll rephrase thus:

        Since you obviously think Israel produces too many civilian casualties in its response to Hamas, please tell me how you determine what is acceptable and what is not, in that respect. How many civilian casualties is too many?

        15,000 civilian contractors aboard the second Death Star – too many?

        10 prisoners held in the brig of Luftwaffe base during the blitz – too many?

        1 girl picking daisies beside a malfunctioning ICBM silo that will directly kill 3 million people and accidentally start a worldwide nuclear exchange if it isn’t immediately destroyed – too many?

        I just really want to clarify, for me and everyone else in this conversation, whether you’re rejecting outright any kind of consequentialist math here, because it really sounds like you are.

      • Sean II


        You were right to answer me in this way, and I’m glad you did. This puts us back to the ground we should never have left…back to the question, not of how these societies defend themselves in terms of military tactics, but of whether they deserve to be defended.

        Because apart from that, you’re absolutely right: there is no other difference between my list and yours.

        If you’re interested, I explain myself at greater length in my second comment over in the Chartier “Some Principles” thread.

  • Peter Lewin

    Matt admirably characterizes the issues. It is complicated enough if the consequences of any action were certain, but infinitely moreso when, as is the case, they are very uncertain. In highly uncertain situations, the burden of proof becomes very important. who has to show what to justify their actions and what counts as evidence?


    I suspect that one reason that there has not been too much distinctively libertarian writing on this subject is that it is not a distinctively libertarian issue. In other words, the philsophical doctrines that come into play here, just war theory, doctrine of double effect, etc. cut across libertarian/non-libertarian lines.

    Nozick didn’t write much about the issues Matt raises, but in his 1978 review of Walzer’s book Just and Unjust Wars [available in Nozick's Socratic Puzzles], he characteristically did raise an interesting point:

    “And when guerillas operate in an area, living in the midst of civilians whose presence is a moral shield for the guerillas and an extra moral restraint on the means those attacking the guerillas may use, do the civilians have any responsibility to get out of the way?

    If someone shoots at passersby from the window of my office and the police arrive to cope with him and while not being kept a prisoner there, I insist on staying…then if I do get hurt as the gunman is overpowered, is none of that my fault?”

    I trust that the potential relevance of this commentary to the recent Gaza hostilities is sufficiently obvious that I don’t need to spell it out.

    • martinbrock

      The relevance to hostilities in Tel Aviv is equally obvious.

    • David Odegard

      I agree Mark. Please comment on my thread post above in answer to the idea that Israel has a “slave” army.

  • T.Cushman

    IN the main scenario, A is is a homo hostis generus if it uses human shields as a defensive maneuver. If it is a state, than A is, in Rawlsian terms, an outlaw state if we adhere to The Law of Peoples. V is justified in retaliating against A even if A uses I as a shield, but it has an obligation to try to do as much as possible to mitigate against harming I. But it should not be compelled to do so if its existence is at stake. It is better if if it does, but not a perfect duty, especially in extremely hostile and dangerous situations. As applied the the case of Israel, it could be argued that Israel, as a decent society in Rawls’ terms, goes out of its way to avoid harm to I, but can never do so perfectly. It does so at the cost of harm to itself since many more Israeli soldiers are killed than would be the case otherwise if V acted without some moral obligation to mitigate harm against I. The moral crime here that preempts all other actual or potential crimes is the use of I as a shield by A. This violation of the laws of war mitigates any other just claim by A, especially because I is not a belligerent, but is an innocent party. And as an innocent party, the answer to question of whether I has the right of self-defense against V should be recast as: should I be allowed to use violence against A for using I against its will as a tool in war? The legitimate target of I is A, but since I is usually a non-belligerent, without the means of violence, the issue of whether it would be just to attack A or V is probably moot.

  • Gordon Sollars

    As to Nozick’s question whether two persons can fight each other in
    self-defense, the answer has always seemed to me obviously “yes”. Why would
    A’s aggression limit I’s right to self defense against A or V?

    As to proportionality and necessity, Nozick’s Principle VII from his “Moral Complications and Moral Structures” is relevant to the discussion. Whether V’s killing I (or even A) – and, of course, I’s killing V (or A) – is permissible depends on the set of actions available. As Dennett notes, moral rules are often employed as “conversation stoppers”, that is, as statements meant to cut off an analysis or discussion that threatens to swamp our limited cognitive abilities to assess all the relevant facts. Many, if not most, of the participants in this discussion seem *sure* that Hamas or Israel is wrong. This view is usually “established” by use of an analogy that is far less complex than the actual situation.

    • David Odegard

      I want to clarify that A and V are not equals in the equation. I cannot justly kill V like I can A. The unjust actions of A and the Innocence of V are parts of the equation. I realize that in a real life conflict like Israel vs. the Jew hating Muslims of the World, the injustice and innocence become VERY blurry.

  • good_in_theory

    If toy examples are the game, what if we start, “Suppose A is justly attacking V”. Or “Suppose A cannot attack V (justly or unjustly) without also endangering I.” Or… In other words, such examples naturalize assumptions in an entirely unhelpful way.

    • Matt Zwolinski

      You can start your own examples any way you like. But I don’t quite see your criticism of mine.

  • Javier

    Matt says: “I’m not at all convinced that the kind of intuition-driven deontology
    that Kamm and Thomson employ is the best way of thinking about these

    I’m curious: what’s your alternative to “intuition-driven deontology”?

    As a side note, I think libertarians who are interested in questions about war should take a look at David Rodin’s excellent book War and Self-Defense.

  • SimpleMachine88

    It’s not that simple, there are four people. “Israel” is not one actor, there’s the government and the people, and the government has a responsibility to protect it’s people at all costs. It may not refrain from doing so. A person can turn the other cheek, but a nation cannot.

    • martinbrock

      Nonsense. People subject to the United State would be far better off today if the state had done precisely nothing in response to 9/11. An extremely measured response might have been better than nothing, but turning the other cheek would have been far better than the response that actually occurred.

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