I was so hoping not to write anything about Brad DeLong's post on explanation v. justification -- it is, after all, my day job. But since we have started talking about it in comments, I decided that perhaps I should. It's below the fold, since it's long.
To start with the basics: explanation and justification are two quite different things. When you explain something, you try to say why it happened. You do not need to take a position on whether it was good or bad that it happened; you just try to figure out what caused it. When you justify something, you try to say why it was right that something happened. You may be interested in its causes, but only insofar as these affect the moral question involved. (E.g., if you are trying to justify someone's action, that person's motives -- what led him or her to act -- can be relevant to your justification.) Since 'why did X happen?' and 'was X justified?' are two different questions, and since there is no reason to suppose that the answers to them must be the same, explanations and justifications are completely distinct.
We can try to explain anything that happens -- earthquakes, the behavior of subatomic particles, the death of stars -- whether or not any humans or other rational agents were involved. When rational agents are involved, however, sometimes the right explanation of their conduct refers to their reasons -- why they thought that they were justified in acting as they did. This is not, obviously, a form of explanation that's available to us when we try to understand the motions of the planets: as far as we know, planets don't have views about their orbits, and wouldn't be capable of acting on those views if they had them, so trying to explain what they do in terms of "their reasons" would be silly.
We can try to explain the behavior of objects that can't appreciate reasons by talking about why they ought to do X in some cases, however: those in which we have reason to believe that the objects in question are set up in such a way that they tend to do what they have reason to do, even if they themselves don't recognize those reasons. (This line of thought comes from Daniel Dennett.) Thus, if I ask why '4' appears on my calculator screen, I might reply: well, I typed in '2+2=', and since two plus two is four, that's what appeared. Here I presuppose that my calculator is set up to answer such questions correctly, and thus that I can legitimately use this shorthand for the more complicated explanation in terms of electrons. But I would have to fall back on those more complicated explanations if my calculator broke, and '4' appeared when I had asked what the square root of three was.
When we explain the behavior of people using reasons, we normally think not just that they're set up to be able to get the right answer, as my calculator is, but also that they're capable of understanding those reasons and acting on them, as my calculator is not. So explaining via reasons isn't just a heuristic shortcut, as in the case of a calculator; explaining why someone did what she did by citing the reasons she thought she had can be just as good an explanation as explaining why my calculator does what it does by citing the gates in its chip. (Note: both my belief that I had a given reason and a gate's being in a given state are macro-level descriptions of states a being is in; neither is given in terms of the exact positions/states/velocities/etc. of particles. So objections to the first that take the form, 'but that's not stated in terms physicists would use if giving an exact description, in their terms, of the object in question' cut equally against the second.)
When we explain people's behavior in terms of reasons, what matters is not whether the reasons are good ones, but just that they believed them. If I kill you because I think you are the Antichrist, then that's my reason, false though it be; and any explanation of my action that cited only good, valid reasons would be false. The mere fact that I thought I had some reason, however, does not mean that that was why I acted. Sometimes my ostensible reasons are just rationalizations (e.g., "I just want to go into my old bar to see all my old drinking buddies, whom I haven't seen since I gave up drinking.") Sometimes they are not the real explanation of what I do, but still play a subsidiary role, since I wouldn't do what I do if I couldn't convince myself that I had some reason for doing it, however ludicrous that reason might seem from the outside.
(This is why it can be useful to convince someone that the reasons they give for what they're doing don't work, even when we think that those reasons aren't the real explanation for their actions. If you saw me about to go into my old bar, you might try to convince me that I could just as well call my old drinking buddies up and meet them at a nearby coffee shop, thereby seeing them while avoiding temptation. If you convinced me, I might have to admit to myself that seeing them wasn't my real reason for going into the bar, and that might stop me from going in.)
But sometimes, the reasons I think I have really do explain why I do what I do. I'm not acting out of some unconscious motivation; I'm not using reasons as a mere tissue of lies to cover up the sordid truth; I am, in fact, about to order a tuna melt because I am hungry, and a tuna melt is what I would most like to eat right now. In that case, you explain my action by citing my reason.
If this is right, then there is a clear and obvious difference between explanation and justification. So why do people tend to confuse the two? One easy reason is that both, when applied to people, can cite the reasons why those people did what they did. They will, of course, cite them in different ways: what matters for explanation is just that the people whose conduct we're trying to explain thought they had those reasons; when we're trying to justify what they did, on the other hand, what matters is whether the reasons were good ones. Moreover, both try to show that something is in some sense necessary: explanations try to show why something had to happen, given the circumstances and the antecedent causes; justifications try to show that something is rationally required. Both the role of reasons and the form of necessity appealed to in explanation and justification are different, but people aren't always completely clear about this.
Another reason is that when I explain someone's actions by citing her reasons, I make her action more comprehensible than it might otherwise have been. And there are people who think that this is somehow tantamount to excusing what she does. I think this is wrong: citing people's reasons for e.g. becoming terrorists may make them comprehensible, but it will generally make their decisions seem like a comprehensible and completely wrong decision. Likewise --oh, let's be utterly implausible -- suppose that Edward carries out a decades-long vendetta against me, which I find incomprehensible, since I can't recall ever even meeting him. Someone who knows him might tell me that actually I did, once, and said something he took the wrong way, and that he's the sort of person who stays up at night rehearsing slights and thinking of all the withering comebacks he might have made and plotting what to do in revenge, and that all of this explains his conduct towards me. This makes it comprehensible, but not at all OK.
There are other reasons, though, that require longer explanations, so I'll address them in sections.
Is responsibility zero-sum? People sometimes think that if one person is responsible for something, no one else can be responsible for it; or (alternatively) that there is a fixed amount of responsibility for each thing, such that if I am partly responsible for something you did, your responsibility must be lessened. More briefly: they think that that responsibility is zero-sum. If someone thought this, then she might see any attempt to say that I am to any degree responsible for something you did as tantamount to partially excusing you. If she also thought that my playing some role in the process that led to your acting as you did meant that I was partly responsible for what you did, then to explain your action as due to anything other than your uncaused choice would be to partially excuse you.
In fact, moral responsibility is not zero-sum. To use an example I've used before: imagine that Sebastian is preparing for some really, really important thing at work, and I, knowing this, show up the night before bearing pizza, beer, and some really great movies, and Sebastian says: gee, hilzoy, I have this really important thing to do. Suppose that I don't just leave, but continue to try to tempt him into watching movies with me, and eventually he gives in. And suppose that, as a result, he tanks on his important brief/presentation/whatever. Am I responsible for this? I think I am, at least partly: had I not shown up, he might well have done his preparation. Does this imply that Sebastian is not responsible for it? No: I didn't hold a gun to his head or anything. He chose to yield to the temptation I offered, and he shouldn't have. I can (correctly) think that I am partly responsible for Sebastian's screwing up his presentation (or whatever) without thinking that this diminishes his responsibility in any way.
To quote (slightly revised) a comment I wrote some months back: There are lots of situations in which I can blame myself or someone else for putting in place the conditions in which X would happen, even when the actual perpetrator of X is a different person. For instance, suppose a military commander ordered his or her troops to put down their weapons, take off their body armor, put big signs on that said 'American Soldier! Unarmed!' in Arabic, cuff their hands behind their backs, and march through Fallujah. And suppose further that, not surprisingly, a lot of these soldiers were killed. Obviously, it's violent people in Fallujah who actually did the killing. But does that in some way mean that the commander is blameless? Not according to me.
More specifically: who killed the soldiers? Individuals in Fallujah. Did the commander kill them? No. She may have 'as good as killed them', or 'consigned them to their death', but she did not kill them. The Fallujans did that, and are responsible for it. But who was unbelievably stupid, and criminally casual about those soldier's lives? The commander: she did that, and is responsible for what she did. Who is responsible, not for killing them or for stupid deployment orders, but for their deaths? I would say: both the killers in Fallujah and the commander. Both did things they should not have done, given what they knew at the time. Both the orders and the actions contributed to the deaths (if no Fallujans were inclined to kill American soldiers, the soldiers could have marched in this stupid way without being killed; if these orders had not been given, the fact that Fallujans were so inclined would not have led to people being killed.)
The basic view of moral responsibility underlying this is: if you do something which you have every reason to believe could lead to some bad outcome, and if, given what you know at the time, you should not do this thing, and if it does lead to the bad outcome, then you are responsible for that outcome. If you didn't know, and this isn't due to e.g. stupidity but to non-culpable ignorance, you are of course not to blame. If you knew it would lead to the bad outcome but you had a good reason to believe that every other alternative would be worse, you are responsible for choosing to do something that would lead to X, but you should not be blamed for that choice, since it wasn't the wrong one. (E.g., if the reason the commander gave the idiotic orders was that that really was the only way to prevent terrorists from blowing up the whole world, she should not be blamed.)
This general view explains why responsibility is not zero-sum. The fact that some bad decision of mine helped to produce some state of affairs does not imply that no bad decision of anyone else's helped to produce it as well.
But if responsibility is not zero-sum, then when someone says, for instance, that some foreign policy mistake of ours contributed to the rise of terrorism, or that our decision to go into Iraq with too few troops contributed to the breakdown of order and the murder of innocent Iraqis, what she says does not imply, in any way, that anyone else is less responsible for those things. Specifically, it doesn't imply that the perpetrators of terrorism are less than fully responsible for terrorism, or that Iraqi insurgents are not fully responsible for what they do.
Confusing different reasons for criticizing claims about responsibility. Just because something is true doesn't mean that it's OK to say it in a given situation. For instance: suppose you decide to play blind man's buff on a fifth-floor balcony, and end up falling over the railing onto the sidewalk below, and, as luck would have it, I am standing nearby. And suppose that instead of calling an ambulance, or yelling for a doctor, or tending to your wounds myself, I say: that was really stupid of you, or: I just finished cleaning this sidewalk, and now you've gotten blood all over it. Both of these statements might be perfectly true. It was stupid. I did just finish cleaning the sidewalk. You did get blood all over it.
Just because they're true, however, doesn't mean that there are not other grounds for criticizing me for saying them. I am heartless, more concerned with pointing out your failings than with saving your life, etc. (To amuse yourselves while hammering home the central point, just think of the many, many occasions on which it would be wrong to recite the multiplication tables, true though they be. In the middle of a fight with your spouse, for instance.) In all such cases, the appropriate criticism is not that the person saying these things is saying something false, but that the act of saying it reveals her motives for saying it, or her character more generally, to be in some way bad.
I think that some conservatives tend to make assumptions about liberals that lead them to hear claims about e.g. any possible American role in the genesis of al Qaeda as just this sort of utterly inapt statement. If my first response to the sight of you bleeding on the sidewalk should be to tend to your wounds, not to tell you how dumb you were, then by the same token my first response to 9/11 should have been to tend to, or (if I wasn't in a position to help directly) at least to mourn with, the dead and injured and those who loved them. It should not have been to point out America's role (if any) in the genesis of terrorist movements; and anyone whose first response to 9/11 was not horror but blaming America would, I think, have shown real moral ugliness.
I think that some conservatives make assumptions about liberals that lead them to think that liberals who try to explain such things do so for all the wrong reasons. (Liberals have stereotypes about conservatives too, of course, but they tend not to get tangled up with explanation and justification.) Rush Limbaugh, for instance, thinks that liberals always want to empathize with anyone they can see as 'downtrodden', however loathesome that person might be; that liberals despise America and think that America is responsible for all the world's evils; and that we think that no one from another culture is ever responsible for anything. If you think that liberals are like this, and you hear a liberal say that American policies in the Middle East contributed in some way to the development of al Qaeda or the motives of terrorists, you might well be inclined to think the worst of that person. But that would be because you assumed the worst to begin with.
This matters, since I think there are some very good reasons for wondering whether we, in particular, are in any way responsible for various bad things that happen. Quoting something I said a while ago: This may be easier to see in the case of a person focussing on his or her own responsibility: when several people are to blame for something, and one of them is me, I should (I think) start by focussing on my role, because while blaming other people may be fun in a sort of cheap way, I am the only person whose actions are under my control, and therefore when I figure out what each of us did to bring something bad about, I am the one whose flaws I can begin directly to try to rectify, and whose mistakes I am likely to repeat unless I learn from them.
Also, if I am to blame for something, this may imply things about my obligations in the future, which I need to know about. (E.g., if I ran you over while drunk, I might need to do what I can to help you recover. And it's much more important for me to know what I owe in this way than to know what, say, Newt Gingrich might owe, since I am me, and if I conclude I owe something, I can just decide to pay up. Regrettably, I do not have this sort of control over Newt Gingrich.)
For both sorts of reasons, it's normally more important for me to figure out whether I am responsible for something than whether someone else is. I think something similar is true in the case of one's country: as citizens in a democracy, we can try to fix any problems we discover, and we can also try to bring it about that we as a country live up to our obligations. So I think that while it's always a mistake (a) to blame someone, or some country, when that person or country is not actually to blame, it is not at all a mistake (b) to concentrate on what you or your country is to blame for, as opposed to what some other person or country is to blame for, when you or your country are in fact among those responsible.
I think that when people complain about 'blaming America first', sometimes they're rightly complaining about (a), but sometimes they're wrongly complaining about (b). And it's really, really important to separate the two. If we don't, we may prevent ourselves from rushing to blame American first, but we will also make it impossible to learn from our mistakes, and to do what we have to do to make sure that nothing like 9/11 ever happens again.
One other point about Brad DeLong's post. I think he is wrong to say that when we explain people's actions, we are thinking of them "as stimulus-response zombie-automata, who act in certain predictable ways when circumstances push certain of their buttons", and not "as rational analysts and moral agents." Explaining my behavior in terms of my reasons does not imply thinking that I act because "circumstances push my buttons". If I decide, after a lot of thought, not to take an interesting job offer because, despite the interesting new colleagues I would have there, I do not want to move to Peoria, this can be a perfectly good explanation of my actions whether or not my taking these to be the most relevant considerations, and weighting them as I do, is causally determined by anything. Whether or not I have free will, in any remotely plausible sense of that term, I can still decide to stay because I do not want to move to Peoria; if I do, then that explains my action.
The key point for Brad, I think, is what he says next: "We consider them "as they are, and not as we would wish them to be." We do this, as I said, because we are explaining their behavior, and explaining their behavior requires that we consider the reasons that they thought they had, insofar as these figure in the explanation. It does not require that we consider the reasons they would have had had they been perfectly informed and perfectly moral, unless we have some antecedent reason to believe that they are perfectly informed and perfectly moral. (That Christians generally believe they can make those assumptions about God explains why they think that they can infer things about his motives by asking, for instance, what an omniscient, omnipotent, and perfectly good being would have had in mind when He created so many beetles.) This just follows from the fact that what we are trying to do is to explain.
I think Brad also misstates things, or at least gives a misleading impression, when he goes on to say this: "Most of the consequences of our actions are the reactions they induce in other people. Thus key to figuring out how we should act is to understand what their hot buttons are, and how we can push the right ones to generate the reactions that we want to produce the consequences we desire."
When I try to affect your conduct, I can, of course, just see you as a thing to be manipulated as I see fit. Thus, if I need money, I might just ask myself: what, of all the things I might do now, would be most likely to lead you to give me the money I want? Maybe I should pull a gun on you; maybe I should tell you some lie about how I desperately need to get to San Francisco to see my ailing grandmother before she dies; maybe I should tell you the truth, which is that I want to buy some CDs but I don't feel like paying for them myself. If I think of you as a thing (in this case, a thing like an ATM, which I want to produce money for me), all that matters is what's most effective.
On the other hand, I could see you as a person: someone who generally tries to make up her mind on the basis of reasons, and who has the right to do so; or, in short, as someone who is capable of self-government, and has the right to govern her own life. (I might think that because this is how I view myself, and I can't see any relevant differences, in this respect, between you and me.) If I regard you thus, it will make a number of differences in how I treat you, of which two are relevant here.
First, while I will think that I could cause you to give me money in all sorts of ways, the only ones that are morally acceptable are the ones that involve giving you reasons to decide to do so. Thus, what matters is not: what will be the most effective way of getting money out of you? but: what should I do, given that I think of you as a person who has the right to decide for herself what to do with her money? In this case, I will regard violence and deception as out of bounds. I might try telling you the truth, but if I don't think you'd be particularly inclined to subsidize my desire to get CDs without paying for them, I might also not bother. Thus, thinking of you as a person puts constraints on what it's morally acceptable for me to do to you in pursuit of my goals.
(Two notes on these constraints: (1) I do not take them to be absolute. There are all sorts of ways of arguing either that they could be overridden in cases where huge consequences are at stake, or that they can be (partially) waived by people who do not themselves respect the right of self-governance in others. (E.g., that it might be OK to kill someone who was trying to kill you, on the grounds that she had waived her right to have her capacity for self-governance respected, at least in this case, by showing that she herself rejected the principle that grounds that right.) Second, this is meant to be a rough sketch of complicated issues; the fact that I am using deontological language should not be taken to imply that the position I'm sketching is necessarily deontological. I think it's possible to make the same basic point in quite different terms; it's just that explaining its deontological, consequentialist, virtue-based, and other variants would be needlessly complicated. Do you want this post to be even longer? I didn't think so.)
Second, if I think of you as a person who has the right to decide what to do with her life generally, I will also not think of you, generally, as a tool for maximizing my (already given) preferences, but as someone who is engaged (broadly speaking) in figuring out what to do with her life, just as I am. If I think of you as a tool, I take it that my preferences should govern what happens, and yours are of interest only insofar as they allow me to manipulate you. But if I regard you as someone who is, like me, capable of self-governance, then I will regard your preferences and mine as (other things equal) on a par. (Other things equal means: if my preference is for world peace and yours is for watching other people suffer, we can say that mine is better. But it's not better just because it's mine.)
This means that if I regard you as a person capable of self-governance, I won't just think that there are constraints on how I use you to get what I want; I will think that you are not someone I should regard primarily as an instrument at all. You have the right to decide what to do with your life. When I offer you what I think are reasons to do something, I should not think of them simply as causal interventions in the course of your life, interventions which I have to limit to those I actually believe, but as considerations that I think you might actually be interested in, since they are true. I should also think that you might have interesting and insightful things to say to me, things I might not have thought of. I should think of you, that is, as someone with whom I am (or could be) in dialogue, whose goals I might adopt as my own, and from whom I can learn.
None of this conflicts with the idea that I can causally intervene in your life. Obviously, I can; and obviously, people are both objects whose trajectory I can (sometimes) alter and beings who share with me a capacity for self-governance. The question is not which of these is true (both are), but how I should regard people, which conception of them should govern my dealings with them.
(What does 'regard' mean here? Consider: it is true that any of my readers would probably, if suitably killed, prepared, and preserved, provide nutritious food for my cats for months to come. Nonetheless, when I write this, I do not regard any of you as potential cat food, nor am I primarily guided by the thought: what can I write that will have the greatest likelihood of causing my readers to become a series of nutritious meals for Nils and Annika? I do not regard you thus even though I believe that it is true that, properly killed and tinned, you would make good cat food. I do not regard you thus even while I am constructing this example, and therefore explicitly thinking about your potential as cat food.)
The reason that, when I am thinking about what to do, I think about what someone is likely to do, and not what she has most reason to do, is just that I am making up my mind, not hers. What I am going to do is what I am trying to decide; for these purposes, I have to think of it as something that has yet to be determined, since what I do will depend on my choice, which I am still in thee process of making. What you do, however, is something I can take as given: what you do is, for these purposes, part of the background against which I have to make up my mind. That I treat your conduct and mine differently, in these ways, has nothing to do with which of us (if any) I think are 'really' zombies, and which I take to be autonomous agents, and everything to do with the fact that I am making up my mind, not yours. (If you and I were talking about what you should do next, I would treat your future action differently.) I can think that neither of us is a zombie who responds solely to stimuli, and it wouldn't affect this point at all.
Well, I could go on (and on, and on), and in fact I already have, so I'll just stop here.