David D. Friedman's Blog

"With the passing of Baroness Margaret Thatcher, the world has lost one of the great champions of freedom and liberty, and America has lost a true friend."

(From the White House statement on Thatcher's death)
 Judging by my online interaction with people from the U.K., those left of center—probably most of those I interact with—hated Thatcher. Most, I would guess, approve of Obama. Which makes Obama's praise of Thatcher, in part for the same policies for which they hate her—they, of course, would not describe her economic policies in such positive terms—interesting.
Part of the explanation is summarized by the Latin tag de mortuis nil nisi bonum—concerning the dead, nothing but good.  It is a sentiment I share. When someone about whom I have serious reservations dies, I am reluctant to interrupt the paens of praise with a sour note of criticism, and generally don't. On the other hand, looking at commentary on Thatcher's death from left of center sources other than the President, including the NYT and various writers in the U.K., I do not see much sign of such restraint.
It would appear indecorous for the President to celebrate the death of a national leader, even one he disapproved of—so far as I know, the death of Hugo Chavez was not celebrated by any official statement from the White House. But the President's statement on Thatcher's death could have been put in less fulsome terms, celebrating her role as a loyal ally of the U.S. and leaving unstated his disapproval of her economic policies. That it was not suggests that Obama sees rhetorical support for libertarian ideals as politically prudent even if his actual policies tend to go in precisely the opposite direction.

There has been a good deal of talk lately, much of it set off by a recent article in the Economist, about the fact that global temperatures have now been nearly constant for over a decade despite large increases in atmospheric CO2. Looking at the situation as a non-expert observer, it seems to me there are three possible explanations both for the recent pause and for the earlier pause from about 1940 to 1970. 
1. The theory is wrong. Warming over the past century+ is due to something other than the greenhouse effect of CO2 produced by human action.
This is possible but does not strike me as very likely.
2. The theory and models are right. Anthropogenic CO2 produces warming at about the rate implied by the IPCC models. There are, however, other factors that also affect global temperature. Recent periods of stable or falling temperature occurred because those other factors were pushing temperature down about as fast as the greenhouse effect was pushing it up.
3. The theory is right but the models are wrong—they substantially overestimate the sensitivity of temperature to CO2.
This is, I think, a more plausible variant of the previous explanation because of two of the latter's implications. The first is that the other factors are about as important, at least in the short run, as CO2, since otherwise they could not have cancelled its effect. The second is that the other factors were not adequately included in the IPCC models, since if they had been those models would not have seriously over predicted global temperatures, and they did.
As best I understand the relevant theory, sensitivity is an open question—we do not have climate models good enough to calculate it with confidence, so rely instead on deducing it from statistical data. But if global temperature depends on both CO2 and other things and the models left out or underestimated those other things, then calculations when the non-CO2 effect was pushing temperature up instead of down would tend to overestimate the CO2 effect. That seems to me consistent with the fact that temperature change over the past century is significantly positive, but at a rate much lower than what the IPCC models imply for the rest of this century. And, of course, it would explain why global temperatures for the past decade are lower than would be expected from the IPCC models and the increase in atmospheric CO2.

I have seen two sorts of defenses offered for the virulently hostile response that many people gave to Steve Landsburg's recent post. One is that one shouldn't talk about rape, or shouldn't use it in hypotheticals,  because it will rouse bad memories in people who have been victims of rape or for other reasons along similar lines. I find that argument unconvincing, and suspect that most of those using it would reach a different conclusion if they were doing the talking and expressing the proper views on the subject. 
The other defense is that Landsburg was not offering an interesting puzzle, since the answer was obvious, hence that the only explanation of his post was that he was trying to shock people, and trying to shock people by talking about a sensitive subject is juvenile and rude. Alternatively, that Landsburg was not offering an interesting puzzle but thought he was, which shows how stupid he is.
Hence this post.
Argument 1 for why the answer is obvious, popular with libertarians:
The unwanted but physically harmless rape is obviously wrong because it violates the victim's property right in her own body.
When I look out the window and see the light in a neighbor's window, the fact I can do so shows that photons whose existence he caused have trespassed on both my property and my retina. We don't see that as obviously wrong.
Why? One obvious answer, although not the only possible one, is that the trespassing photons do no damage—we would react differently if what was trespassing was a megawatt laser beam. But that answer gets us back to Landsburg's puzzle: If physical trespass to someone's body did no damage, would it also not count as a violation of the victim's rights? More generally, how do we figure out what rights, in property or anything else, who has? 
In my view, anyone who thinks that problem is trivially easy has not thought very hard about it. Any philosopher who thinks so should find another line of work. Which brings me to ...
Argument 2, popular with philosophers:
The puzzle is uninteresting because we already know that utilitarianism, at least of a simple sort, is obviously wrong.
Perhaps I missed it, but I am not aware of any proof, by philosophers or other people, of what moral philosophy is the right one. Absent such a proof, the fact that a particular candidate implies a conclusion that feels wrong to us admits of at least three different explanations:
A. The candidate is wrong.
B. Our moral intuition is wrong.
C. The argument from assumptions to conclusion is wrong. 
Part of what makes an argument like the one Landsburg offered interesting is that it forces us to think about those explanations. Responding with "we already know the right answer to the fundamental questions of moral philosophy," which is not what anyone I saw said but what a number of people appeared to be implying, is not a good answer. My long post on the subject was arguing C—that the conclusion Landsburg sketched did not follow from the implicit assumptions, for somewhat complicated (and, I thought, interesting) reasons.
I could go on to list other arguments for why the answer to the puzzle is obvious, but I have not seen any that struck me as convincing, and two unconvincing ones are sufficient.
Showing why particular arguments that his puzzle is uninteresting are wrong does not tell us what is interesting about it. One answer to that question is that one of the most intriguing facts that comes out of the economic analysis of law is that the legal rules that economic theory implies are efficient—loosely speaking maximize utility—often if not always resemble the rules implicit in both existing law and existing moral beliefs. If that is true, it is surely interesting, in part because it suggests some possible conjectures about where law and moral beliefs come from. And it also suggests the project of looking at places where law or moral beliefs fail to fit what economic efficiency appears to imply, and trying to see if one of my answers A, B, or C explains the difference.
One implication of that project is that  it is a mistake to claim, as some philosophers (and economists) do, that wicked pleasures ought not to count in the utilitarian calculus. If you put your moral beliefs in at the beginning of the analysis, it is not very interesting to get them out at the end. It is much more interesting if you put in something much simpler, if you treat the benefit that the pickpocket gets from the money he steals from you on precisely the same terms as the loss to you from having it stolen, and yet end up with something that looks like rather like your intuitions of right and wrong. As you do—for a defense of that claim, see my Law's Order.
It is possible that I am being unfair to Landsburg's critics, since this is an area I have worked and written in for many years, so the point may be more obvious and interesting to me than to them. On the other hand, if an intelligent academic makes an argument that seems pointless to you, trying to figure out why he thinks it interesting, even asking him, seems a more appropriate response than most of the responses Landsburg got.

And even for someone who has never thought about the economic analysis of law, figuring out why we make the moral judgements we do, why we reach different conclusions about what can be seen as similar cases, ought to be interesting.

Discussing with my daughter the flap over Steve Landsburg's recent post, I commented that the people who were angry about it, mostly online, struck me as either stupid or evil. Either they were too stupid to see that he was actually raising an interesting puzzle or they saw that he was doing so but pretended not to, in order to have an excuse to attack someone they disliked or disagreed with.
Her response was that I was wrong, that my mistake was not realizing the degree to which many other people were different from me. To me, ideas are real, important, and sufficiently interesting that my reaction to an argument that appears to prove some frightening or ugly conclusion is to be neither frightened or angry but intrigued. Lots of people don't react that way—and if you see the conclusion of an argument as frightening or ugly, it isn't surprising if you skip over the fact that it raises an interesting puzzle or are too willing to assume that whoever offered the argument must agree with its conclusion.
I am not sure if she is correct or not, but it did start me thinking about other arguments which I find intriguing despite the fact that their implications are disturbing. None of them has the same emotional loading as an argument about rape, but all of them have implications that strike me as more serious, in various directions, than the implications of the argument Landsburg made. Here are three examples:
1. Moral nihilism: 
I have sketched elsewhere my view of the nature of moral philosophy, what Michael Huemer (and, I assume, other professional philosophers) refers to as intuitionism. I read Huemer's book on the subject in part in the hope that he could offer an adequate rebuttal to the best argument against that position that I knew of, since I didn't have one. I still don't, although he thinks he does.
The argument (which I believe was once offered by someone commenting here) is simple. I have moral intuitions—I perceive some acts or outcomes to be good or bad. My preferred explanation is that they really are perceptions of a (non-physical) truth. An alternative explanation is that they are beliefs that got hardwired into my brain by evolution because having those beliefs resulted in increased reproductive success in the environment in which my distant ancestors evolved. That explains the same data, my intuitions, without requiring any additional assumptions, since I already believe in evolution and recognize that some characteristics of how the brain processes information are best explained in that way.
If that argument is correct, not only is there nothing wrong with raping an unconscious victim, there is nothing wrong with doing anything to anyone—right and wrong are merely illusions. I find it impossible to believe that conclusion, but I have no adequate argument against it.
Unless you count this one.
2. We are all brains in vats:
Assume that the growth in wealth and technology that has occurred over the past century continues into the far future. In the world of a thousand years from now, an obvious form of entertainment, the equivalent of movies, books and video games, is simulation—Sim City on steroids—and in that world they will have the wealth and technology to simulate people, and worlds full of people, down to the neuron. A period of history of particular interest, and so particularly likely to be simulated, is the period when mankind made the great technological leaps that made possible the world of a thousand years hence. There will be thousands, millions, perhaps billions of simulations of that period, fully populated with simulated people who believe they are real.
What are the odds that you and I are in the one real version of the present instead of one of the millions of simulated ones?
3. There is no reason to expect the future to resemble the past. At all.
Consider the inductive hypothesis, the claim that the future resembles the past. It is essential to all of science, indeed to virtually all of our attempt to make sense of reality. Without that assumption, the fact that stones fell down when we dropped one yesterday gives us no reason to expect that, if we drop another stone today, it will fall down instead of up. 
Do we have any reason to believe the hypothesis? It is true that it has held, so far as we can tell, through the entire history of the universe. Unfortunately, that argument is circular. In the past, the future resembled the past—each day, stones fell in the same direction. But unless we already know that the future is going to resemble the past, the fact that the inductive hypothesis held in the past is no evidence that it will hold tomorrow.

In a recent post, I argued that Robert Bork, in an old and famous law review article, and Steven Landsburg, in a recent and now infamous blog post, were making two sides of the same point, in both cases arguing that our legal rules (and, for many of us, our moral intuitions) were inconsistent in treating essentially similar cases differently. Various commenters on my post pointed in what I think is the right direction for explaining the puzzle and justifying the legal, and perhaps the moral, difference.
The first step is an old distinction in the economic analysis of law between property rules and liability rules, two different solutions to the problem of efficient allocation. Under a property rule, something belongs to someone and other people can use it only with his permission. The role of the legal system is to impose costs on those who use it without his permission large enough so that they won't. My control over my car is regulated by a property rule, as demonstrated by what happens to someone who steals it and gets caught.
Under a liability rule, in contrast, people are permitted to do things that impose costs on others, but have to pay for them. My use of my car to impose a risk of collision on other drivers is regulated by a liability rule. Unlike the case of a property rule, I don't need their permission to use their cars as possible unintended targets for mine. But if I do dent their cars and it is my fault, I am supposed to pay for the repairs. The role of the legal system is to estimate the cost and make me pay it.
Why do we use property rights to control who drives my car but liability rights to control how it is driven? The standard response is that, under property rights, things are moved to their highest valued use via market transactions—if ownership or use of my car is worth more to you than to me, you ought to be able to offer me a price to buy or rent it that I am willing to accept. Under liability rules, they are moved to their highest valued use via litigation, actual or potential. 
Controlling who drives a car by market transactions is reasonably simple and straightforward, as demonstrated every day by car dealers and rental agencies. Controlling how it is driven would either require me to buy permission from everyone else on the road to impose a cost of damage on their car, if they had a property right not to have such a risk imposed on them, or require them to buy a guarantee from me to drive carefully, if I had a property right to drive my car as I wished, whatever the risk to others. Neither is practical, since what I am imposing is a highly dispersed cost, a very small risk on each of a very large number of people.
Controlling who drives a car by a liability rule would mean that someone in a hurry to get to the airport would be entitled to hotwire my parked car, drive it to the airport, and leave it there—and it would be up to me to sue him for the cost and inconvenience imposed on me. That would create substantial costs, since I would have to identify the guilty party and sue him, and provide a very inaccurate and inexpensive control mechanism, since a court would have to somehow estimate the cost to me. Some of those problems exist for using a liability rule to control how I drive, but they arise only when I actually run into someone, which (fortunately) does not happen very often, and it is usually obvious at that point who was the driver. So it makes sense to use a property rule to control who drives the car but a liability rule to control how he drives it.
(For a more detailed account, see Chapter 5 of my Law's Order, under the subhead "Property or Liability Rules.")
The discussion so far leaves open one question of some importance: If we use a property rule, who owns the property? From the standpoint of economics, there are two different approaches to answering it.
One is that property should start out belonging to the person who created it, in order that people will have a suitable incentive to create things. The other is that property should belong to the person who can most easily control it, in order to minimize the cost of enforcing property rights.

We use the first rule for deciding who owns my car. It started out as the property of the Honda corporation, which built it, was sold by them to a dealer and by the dealer to me. We use the second approach for deciding who owns me.

One could hold—as Roman law did—that I belong to my parents (actually, under Roman law, my father—or his father if still alive), on the grounds that they created me. The problem with that approach, economically speaking, is that it is easy for me to control myself (at least as long as there are no bowls of potato chips within easy reach), hard for anyone else to control me. If I want my arm to move, I move it. For you to get my arm to move, supposing you are my owner, is a more difficult, indirect and costly process. That, economically speaking, is the argument against slavery.
Sometimes the two approaches are in conflict. Consider the case of copyright law. Giving me the right to control people who want to copy my book and charge them for doing so gives me a suitable incentive to write books. But controlling their copying is much easier for them to do than for me to do. How much easier depends on technology, which is why we have moved, over about a century, to a situation where copyright could be enforced without copyright law, as in the case of English authors collecting royalties for books published in America a century or so ago, to one where it is becoming increasingly difficult to enforce copyright in digital works even with copyright law.
How does all of this apply to the puzzle raised by Landsburg and Bork? Being more prudent than Landsburg, or perhaps less courageous, I start by replacing his example with a less emotionally loaded one that I think raises the same issues.
You happen to know that I am going to be out of town for a few months, perhaps because I have mentioned my plans on my blog. Coincidentally, you are going to be in town for the same few months, in need of a place to stay. Conveniently, one of your hobbies is picking locks. I leave, you move in. Shortly before I return you, being a considerate guest, tidy the place up, leaving it in exactly the same condition you found it in and so, arguably, imposing no cost on me. 
You only make one small mistake—not noticing the video camera unobtrusively located on a high shelf in the living room, plugged in, running, and feeding a very large hard drive. 
Just as in Landburg's example, the act violates existing rights but imposes no material cost. As in that example, it might impose a psychic cost—I may be upset to find that someone else has been living in my house without my permission. And, as in that example, it is illegal. Should it be?
It should. The reason it should is that the use of houses is better allocated by a property rule than by a liability rule. The liability rule, under which you are not liable because you imposed no cost, or at least no cost of a sort reasonably measurable by a court, is difficult to enforce, given that not all empty houses have security cameras running and not all trespassers are easily identified, located and sued. Further, the cost to me is better measured by the price I am willing to accept for the use of the house than by a court's estimate, in part because that includes the subjective cost to me of knowing that my house has been occupied and any secrets it contained, perhaps my stash of porn, revealed, a cost hard to prove or measure in court.
A further argument, pointed out by commenters on my earlier post, is that a property rule makes it possible for me to charge you for your use of my house, which in turn affects my incentive to make the house available—my earlier point about allocating property to its creator. The ability to collect rent on the house when I am not using it reduces the cost to me of spending a quarter visiting at GMU and so makes me more willing to do so—and should, since the availability of the house for you to occupy is a real benefit produced by my absence.
I think I have now answered Steve Landsburg's puzzle. The difference between his example (or mine) of an action that imposes only subjective costs and his example of an activity such as reading pornography, or Bork's of using contraception, that imposes only subjective costs, is not the nature of the harm. The difference is that in the one case the cost is of a sort that can be measured, the action controlled, via a property rule. In the other, it is not. 
More precisely, the property rule under which I have a right to read porn and you can only stop me by offering to pay me not to do so produces its result by ignoring the cost my porn reading imposes on you, since, as with the case of risks imposed by careless driving, including that cost requires an unworkable contract between all of the prudes and all of the would-be consumers of porn. The property rule under which you have a right to forbid me, or anyone else, from reading porn, produces its result by ignoring the cost your ban imposes on me, for the same reason. Neither property rule gets the cost/benefit calculation correct, but the former rule is a great deal less expensive to enforce than the latter, which is an argument for it. 
What about a liability rule? That is the point at which the subjective nature of the harm comes in. It is true that, from the standpoint of economics, all harm is ultimately subjective—having my arm broken or my car dented would not be a cost under sufficiently bizarre assumptions about my preferences. But some subjective costs are a lot easier to measure externally than others. When I claim damages for my wrecked car, there are market prices out there for repairing or replacing it that provide a court with a reasonable basis for estimating the cost. When I announce that your reading of porn, or oil drilling in a wilderness I never plan to visit, inflicts large psychic harm on me, there is no such basis for checking my claim.
I think I have now answered Bork's argument as well as Landsburg's. Insofar as air pollution imposes measurable costs in ill health or increased laundry bills, it is possible to use a liability rule or something similar to measure those costs and charge the polluter for them. But if my use of contraception imposes only immeasurable psychic costs on you, that approach does not work. A property rule takes account of such costs, since they are reflected in the prices people are willing to pay or accept, but a property rule assigning the right to either the would-be user of contraception or the opponent of his use does not work to reflect those costs because of their dispersed nature. And, between the two alternative property rules, there is a strong presumption for the one that libertarians prefer, since it requires no expensive and intrusive apparatus to enforce it.
Bork, unfortunately, is no longer around to read my answer, but Landsburg is, and probably will.
In my earlier post, I commented that explaining why I thought Bork was wrong would require a different and longer post. I have now written it, and it did—about twice as long.

A recent blog post commenting on one of mine asserts that:

David Friedman at his appropriately entitled blog “Ideas” compares contemporary patent litigation with feudal warfare.

What I compared it to was a feud system, a legal system whose rules are enforced by the threat of private force, something very common in the historical record. "Feud" and "feudal" sound the same, which makes it easy to confuse them, but the words are unrelated in both meaning and etymology.
The same mistake as interpreting "niggardly" as a racial slur.
---feudal (adj.) 1610s, from Medieval Latin feudalis, from feudum "feudal estate," of Germanic origin (cf. Gothic faihu "property," Old High German fihu "cattle;" see fee). Related to Middle English feodary "one who holds lands of an overlord in exchange for service" (late 14c.).feud (n.) c.1300, fede "enmity, hatred, hostility," northern English and Scottish; perhaps from an unrecorded Old English word or else from Old French fede, from Old High German fehida "contention, quarrel, feud," from Proto-Germanic *faihitha noun of state from adj. *faiho- (cf. Old English fæhð "enmity," fah "hostile;" German Fehde "feud;" Old Frisian feithe "enmity;" see foe). Sense of "vendetta" is early 15c. Alteration of spelling in 16c. is unexplained.(Both from the Online Etymology Dictionary)

A charming, reasonably sensible, but somewhat tongue in cheek essay by a fellow economist.

My friend Steve Landsburg appears to have entered a competition with my friend John Lott over who can make the most politically incorrect argument. John's old entry was an article arguing that the fact that rich criminals were less likely to be convicted than poor criminals was evidence for, not against, the efficiency of the legal system (my discussion of that article is in chapter 15 of my Law's Order, under the subhead "Should the Rich Pay Higher Fines"). Steve's new one, which has gotten a good deal more attention, is a blog post asking why rape of an unconscious victim who suffers no injury in the ordinary sense should be illegal.
Reading attacks on Steve's piece, it occurred to me that I had seen the essential point before—from the other side, in an old article by Robert Bork which explained, among other things, why he was not a libertarian. It is a long time since I read it, and when I recently reread it I discovered that it was not mainly about the part I remembered, but that particular argument was what impressed me, since I am both a libertarian and an economist and the argument appeared to show that the two were inconsistent with each other.
Bork's argument, in my words not his, goes as follows:
When I pollute the air I am injuring other people, so it is legitimate for the legal system to respond by penalizing me. What makes it an injury is not the fact that I affect the air but that the effect does harm; one could imagine an effect, such as a change in the ratio of two stable isotopes of trace gases in the atmosphere, that would not matter to anyone and so would not be seen as an injury or a proper subject for legal action.
Harm, however, is ultimately subjective, since it depends on the preferences of the harmed individual.  When I smell the roasting ribs from my neighbor's barbecue, that isn't harm because I enjoy the smell. When the smoke from the barbecue makes me cough that is harm, because I don't like coughing—and would be harm even if the smoke had no adverse effect on my health. From the point of view of economics, "harm X" simply means "lower X's utility."
Suppose that, instead of polluting my neighbor's air, I engage in behavior that he disapproves of—read pornography, use contraceptives, work on Sunday. That too causes him disutility. Since the defining characteristic of harming someone is lowering his utility, I am harming him. Since I am harming him, my activity is just as much a legitimate target for legal action as my polluting his air would be. Hence the libertarian principle that I have a right to engage in what Mill referred to as self-regarding actions, actions that only affect me, is either false or empty. Either I don't have a right to read porn if doing so offends others without affecting them, or their offense counts as an effect of what I am doing so my reading porn isn't really a self-regarding action and there is no reason in principle why it shouldn't be banned.
When I first read it, it struck me as an interesting and persuasive argument for a conclusion I disagreed with—explaining why I thought it was ultimately wrong would take a different, and longer, post than this. 
Steve Landsburg's piece, responding in part to the Steubenville rape case, makes the same argument from the other side. We—at least Steve (and I)—don't feel that the argument for banning pornography or contraception is a legitimate one. Our reason is that the "harm" in those cases is purely subjective—I haven't actually done anything to you, so your unhappiness at my self-regarding behavior is your problem, not mine, and you have no right to use the legal system to make me conform to your wishes. And even if you argue that I have done something to you—acted in a way that resulted in your knowing what I was doing, knowledge that pained you—that doesn't count, because "knowledge that pains you" isn't injury in the same sense as causing you to get cancer is.
Which gets us to the part of Steve's post that gives lots of people reason, or excuse, to attack him. Suppose an unconscious woman is raped in a way that results in no injury—in the Steubenville case, "rape" actually consisted of digital penetration. She only finds out it happened several days later, at which point the harm is purely subjective, consists of her being offended at the knowledge that it happened. Why is this different from the subjective harm suffered by the person offended at someone else reading pornography? It feels different—to me and obviously, from his post, to Steve. But is it different, and if so why?
That, it seems to me, is an interesting question, one relevant to both law and  morality. It is ultimately the same question raised by Bork, although from the other side. Bork was arguing that the harm caused by the use of contraception and the harm caused by air pollution were ultimately of the same sort, that it was legitimate to ban pollution hence legitimate to ban contraception—his article was in part an attack on Griswold v. Connecticut, the Supreme Court case that legalized contraception, a fact I had forgotten when I started writing this post. Landsburg is arguing that rape that does only subjective harm is of the same sort as reading pornography that does only subjective harm (unlike Bork, it isn't clear that he is thinks his argument is right, only that he thinks it interesting), that it is not legitimate to ban the reading of pornography hence not legitimate to ban that particular sort of rape. 
I agree with both Bork and Landsburg that there is a real puzzle in our response to the legal (and moral) issues they raise. Hence I disagree with the various commenters whose response to the Landsburg piece was that it showed he was crazy, evil, or both.

My interest in the global warming controversy centers mostly on the question, largely although not entirely economic, of what the net effect for humans would be of global warming on the scale suggested by past IPCC projections; for details see my previous posts on the subject. I have, however, also been an observer, mostly from a safe distance, of the ongoing war between proponents of the conventional view of global warming and critics. For anyone else interested in observing it, I suggest the RealClimate blog for the former side and Anthony Watt's What's Up With That for the latter. They represent the more reasonable range of their respective factions. For the less reasonable range, a sample of both sides can be found on the Usenet group alt.global-warming.
One not surprising feature of the argument is that each side tends to demonize everyone on the other side. That is a mistake. Some people hold a position for good reasons, some for bad. Some supporters of a position are honest, some are not. And that is true both of correct positions and of incorrect ones, given that most such disputes are over questions complicated enough so that there are good arguments for both sides.
I was reminded of this point by a recent link on WUWT to a paper coauthored by James Hansen, who has been a prominent supporter of the idea that global warming is a very serious problem and strong measures should be taken to deal with it. The paper is a defense of nuclear energy, both on the grounds that it results in many fewer deaths than conventional energy sources and on the grounds that it does not produce CO2, hence shifting to nuclear energy would reduce global warming.
That is interesting because, while the second point is clearly true and the first may well be, it is not a position popular with environmentalists. I pointed that out in an old post on this blog, and ended with:

I am sure there are people who are both seriously worried about global warming and in favor of nuclear power. But how many of them are there? How many high profile spokesmen or organizations have taken that position?

 I now have at least one example.
This is the second time I have noticed Hansen getting something right. The first was a video of a talk he gave on how to control global warming. It was in favor of what economists call a pigouvian tax, in this case a tax on putting CO2 in the air, as a superior alternative to more direct forms of regulation. Given his underlying assumption—that global warming produces large net negative externalities—he had the economics right. In that case as well, although not as clearly, he was going against the consensus of "his side," most of whose members, in my experience, support a range of more direct regulations and many of whom disapprove of the idea of allowing firms to "buy the right to pollute."
I offer, as a contrast to Hansen, another prominent figure on the same side of the dispute, Michael Mann, most famous for his role in the hockey stick controversy, the argument over whether features of a graph of global temperature in an article he co-authored were real or were artifacts of an error in the statistical procedure he used to produce it. That particular controversy is complicated enough so that I have no strong opinion on it, although I do have the opinion of one statistician I know that there was a real problem with the analysis. 
But I also observed, mostly via arguments on the Usenet group, a less important controversy over a simpler issue, the claim by Mann, his university, and his supporters, that he was a "Nobel winning scientist."
That claim was bogus twice over. To begin with, the Nobel prize in question was the Peace Prize, so even if Mann had won it, the description, although literally true, would be misleading. But in fact, the prize did not go to him, it went to the IPCC. His claim was based on a certificate from the IPCC, sent to a substantial number of people, crediting them with work that helped the organization win the prize. 
Doing work, along with others, that helps an organization win the Peace Prize does not make you a Nobel prize winning scientist, as should have been obvious to anyone not blindly partisan—but wasn't to a considerable number of people who were. Mann's university, many of his supporters, and (I think) Mann himself, finally abandoned the claim after someone got in touch with the Nobel committee and got the response that the prize had been given to the IPCC, not to Mann et. al., and he was thus not a Nobel winner. That does not tell me whether the hockey stick is or isn't bogus, but it does tell me something about Mann that makes me very reluctant to trust anything he writes.
I could, I suppose, make longer lists of good guys and bad guys on both sides of this and other controversies—Pachauri, the head of the IPCC, would be on the same list as Mann, for his role in the Himalayan glacier controversy. So would some people on my side of other issues. But I think two examples are sufficient to make the point.

I am currently working on a book on legal systems very different from ours; interested readers can find the draft webbed for comments on my site. This post is a first cut at something I intend to include in it.
One of the things that has struck me, looking at a wide variety of legal systems past and present, is the important role of feud—often but I think misleadingly referred to as blood feud—as a form of law enforcement. The essential logic of feud is simple: If you wrong me, I threaten to hurt you unless you compensate me for the wrong. It is a decentralized form of law enforcement. In order for it to work, it requires some mechanism that makes my threat of hurting you substantially more believable when you actually have wronged me than when you have not, in order to prevent the enforcement mechanism from being used instead for extortion. To put it differently, you need some mechanism such that right makes might.
For a simple example, consider the feud system of the Rominchal gypsies, the largest gypsy population in England, as described in Chapter 3 of Gypsy Law. If you wrong me, I threaten to beat you up. Both of us know that if you have wronged me, as judged by the norms of our community, my friends will back me and your friends won't back you, making it in your interest to either compensate me or leave town.
Feud systems (not, incidentally, the same thing as feudal systems—the words sound similar but are unconnected in both meaning and origin) are very common among human societies. In addition to the Rominchal, well recorded examples include saga period Iceland and traditional Somali. In the Icelandic case, the mechanism for converting right into might was an explicit law code and a court system. You sued the person who wronged you. If you won, the verdict was a damage payment he owed you. If he failed to pay, he had two weeks to leave Iceland, after which he was an outlaw, meaning that it was legal for you to kill him and tortious for anyone to defend him. The system functioned for about a third of a millenium—for details see the relevant chapter in my draft. The Somali version was somewhere between the Icelandic and the Rominchal, with customary law and customary mechanisms for setting up courts to arbitrate disputes—along with a fascinating system of prefabricated coalitions to deal with both paying damages and enforcing their members' claims.
Perhaps more interesting, there is good evidence that many, perhaps most, legal systems were built on top of preexisting feud systems. That includes Jewish law and Muslim law, both of which contain what I would described as fossilized evidence of a feud system, along with Anglo-American common law and Roman law.
Feud systems are not only a matter of historical interest—de facto, if not de jure, they still exist. One current example is patent litigation among modern high-tech companies such as Apple and Samsung.
Suppose Apple sues Samsung, claiming that Samsung's phones infringe some of Apples' patents.  Doing so costs Apple something, since lawyers have to be paid, but it also produces two benefits. There is some chance that Apple will win, be awarded damages, and be able to some degree to cripple Samsung's product line by refusing to license the relevant patents. And even if it loses, the uncertainty generated by the litigation will to some degree reduce Samsung's ability to compete with the iPhone.
If the legal system worked perfectly, Apple would always lose when its patents were not infringed and would be liable for the costs that its unsuccessful suit imposed on Samsung. But it does not work perfectly. The rights established by patent law are sufficiently fuzzy so that Apple has some chance of winning even when it is in the wrong. And, under most circumstances, if Apple loses it will not be found liable for costs, direct or indirect, that the suit imposed on Samsung.
Part of Samsung's response is to try to win the case in the courts. But the other part is to have or acquire a patent portfolio large enough so that it can plausibly claim that Apple infringes some of its patents, sue, and so impose costs on Apple to retaliate for the costs Apple imposes on it. As best I can tell, this is currently standard practice in the high tech world. Firms acquire portfolios of patents not primarily for their own use but as weapons with which to attack, or threaten to attack, other firms.
What I have just described is a feud system, with litigation taking the place of direct violence. Like other feud systems, its functioning depends on some mechanism making it easier to win when you are in the right, some way of converting right into might. Without that, the threat of suit can be used not to enforce rights but to extort money.
In theory, the court system provides that mechanism by making it easier to win an infringement case when your patents have actually been infringed. Absent the feud mechanism, the courts would have to work well enough so that suing innocent people on average lost money. With the feud mechanism, it is sufficient that suing innocent people and then having them counter sue you on average loses money, while suing guilty people on average makes money, even if they counter sue you—provided you have not really infringed their patents.
Whether this particular feud system works or is broken is a matter people  disagree about. Those who think it is broken describe the people they think are using it for extortion as patent trolls.

Comments welcome.