Ferguson, Los Angeles, and a 14th Century Sultan

Ibn Battuta, a fourteenth century North African world traveler, spent some time in the employ of Mohammed ibn Tughluq, the fabulously wealthy sultan of Delhi. The Rehla, Ibn Battuta's account of his travels, contains a section on bad things about the Sultan and a section on good things about the Sultan. One of the good things he describes is an incident where Mohammed struck a young man with no legal justification for doing so. The young man took the case to court, the Sultan made no attempt to block it, and the verdict was that the victim was entitled to either monetary compensation or retaliation. He chose the latter, struck the Sultan, and, ibn Battuta tells us, he saw the Sultan's turban fall to the ground. Reading the passage, it is clear that the author thought that was how rulers ought to behave, holding themselves subject to the same law as everyone else, but usually didn't, hence that ibn Tughluq's willingness to accept a legal judgement against himself was admirable.

I was reminded of the passage by recent news stories about unarmed men shot dead by police under circumstances where, it is alleged, there was no legal justification. Such incidents occasionally lead to the policeman responsible being disciplined. They practically never, so far as I can tell, result in his being charged with homicide, tried, and, if convicted, jailed. 

It would be nice if our legal system could at least come up to the standards of a fourteenth century sultan.

The Third Edition of the Machinery of Freedom is Now Available

As a kindle on Amazon.

It is not currently available in hardcopy. I am interested in comments from people as to whether they would want it to be. The kindle is up at $2.99. If I self-publish a hardcopy with CreateSpace it would be substantially more than that, and if I go with a commercial publisher more still. 

I am also interested in comments by people who read it and spot mistakes. One of the advantages of an eBook is that it's easy to make minor changes.

What We Could Learn From Dan Kahan. And Perhaps Shouldn't

I have commented in earlier posts on Dan Kahan's research about why we believe what we do. The basic conclusion is that, in the case of beliefs linked to group identity, individuals choose what to believe not on the basis of the evidence but on the basis of what beliefs fit their group identity. For most of us, as Dan points out, that is rational behavior. My beliefs about evolution or global warming have  little effect on the world at large but could have a large effect on how well I get along with the people who matter to me.

There is no reason to assume that the pattern I have just described only applies to other people. One possible conclusion is that I ought to look for beliefs that it is very much in my interest to hold and think about how good my reasons are for holding them.

One of the first candidates that occurs to me is my belief that minimum wage laws have bad effects, that they make it harder for unskilled workers to get jobs. That is a belief widely held among economists, especially economists generally in favor of free markets. Academic economists are part of an academic world where most people are politically liberal, hence inclined to support minimum wage laws. That makes the fact that economists are inclined to oppose them an important marker for group identity. And I have evidence of the cost to an economist of rejecting it from an interview with David Card, coauthor of a widely cited study that failed to find the expected effect. By his account, getting what was, from the standpoint of his professional peers, the wrong answer cost him a lot of friends.

That is a reason to think that my view on the subject might be mistaken but I cannot think of any good arguments against it, so I will rapidly pass on from my possible false beliefs to other people's. Dan Kahan's, for example.

Dan is a professor at Yale law school. My guess is that if he pointed out that there is no good reason to expect the distribution of intellectual abilities to be the same for men as for women, hence no good reason to interpret unequal outcomes as evidence of discrimination, he would suffer significant social costs. If he made the same point in the context of racial differences, the costs would be more than merely significant. Perhaps he should think about those questions, examine the arguments and evidence, and revise his beliefs accordingly.

Or perhaps not. His explanation for what he observed, after all, was that it was the result of rational behavior. Believing things merely because the evidence supports them may sound like an admirable policy, but it could prove to be a very expensive one.

Why Improving Things Is Hard

Someone who studies the effects of different diets comes up with evidence that consuming more salt causes high blood pressure and associated medical risks and concludes that people should eat less of it. Another researcher repeats the study looking at mortality from all causes and finds that people who eat more than the average amount of salt are no more likely to die early than people who do not.

Arguably you not only should not be surprised at the result, you should expect it. We have, after all, been "as if designed" by evolution for reproductive success. Dying, whether from high blood pressure or some other cause, makes it difficult to either help rear your existing children or produce more. Our bodies have built into them a sophisticated chemical factory for converting what we eat into what our body requires; reducing the amount of salt absorbed and excreting the excess should not be beyond its capabilities. If the body instead  absorbs all the salt consumed, that suggests that the disadvantages of higher blood pressure are on average balanced by other advantages.

That is one example of a more general point, suggested by my rather vague memories of what I have read about the effects of salt consumption and a comment someone made on an earlier post. For another, and this time entirely imaginary, example of the same point, suppose you discover that increasing the size of your car's tires improves its gas mileage. Before concluding that bigger tires are a good idea, it would be prudent to look at other consequences of the change—because you will probably discover that some of them are negative.

The logic is the same as in my previous example, although this time the design is by engineers rather than by evolution. People who design automobiles would like them to use less gas. If bigger wheels achieved that objective and had no disadvantages, someone in the past century would have discovered the fact. The current size of wheels is not an accident. It is the best solution engineers could come up with to the problem of optimal design.

The argument does not apply to everything; there is no reason to assume that either the climate or the population of the earth is optimal. But it does apply to anything that has already been optimized for some purpose, whether by human design or some natural mechanism. Any change from the present design that produces a benefit probably also produces a cost. That is why it is not already in the design.

Of course, even if something has been optimized, it may have been optimized for a purpose other than yours. Evolution designs organisms, including me, to do the best possible job of passing their genes down to later generations. That is its objective but not mine. Birth control is one of the ways in which humans subvert the objectives of the genes in order to better achieve their own objectives. 

For another example, consider trade barriers such as tariffs. There are good economic arguments to show that we would be better off if we went to complete free trade. That seems puzzling—if we would be, why don't we?

The answer is provided by public choice theory, the branch of economics that deals with the workings of the political market. A tariff makes the inhabitants of the country that imposes it worse off but the politicians who pass the tariff better off, since it benefits a concentrated interest group at the cost of dispersed interest groups. More concentrated interest groups are better able to pay politicians to do things for them.Trade policy is optimized, but for the wrong objective.

Another exception to the general rule occurs where optimization is slow and constraints have recently changed. Through most of the history of our species it made sense to get fat if you could in order to increase your odds of surviving the next famine. Now that famines are vanishingly rare, the same hardwired tastes produce less optimal behavior. Similarly, if gas prices have recently gone up a lot, existing car designs may weight fuel efficiency less heavily than  they now should.

Improving things is not always impossible. But it is often harder than it seems.

Another Good Article by Dan Kahan

The source of the public conflict over climate change is not too little rationality but in a sense too much. Ordinary members of the public are too good at extracting from information the significance it has in their everyday lives. What an ordinary person does—as consumer, voter, or participant in public discussions—is too inconsequential to affect either the climate or climate-change policymaking. Accordingly, if her actions in one of those capacities reflects a misunderstanding of the basic facts on global warming, neither she nor anyone she cares about will face any greater risk. But because positions on climate change have become such a readily identifiable indicator of ones’ cultural commitments, adopting a stance toward climate change that deviates from the one that prevails among her closest associates could have devastating consequences, psychic and material. Thus, it is perfectly rational—perfectly in line with using information appropriately to achieve an important personal end—for that individual to attend to information on in a manner that more reliably connects her beliefs about climate change to the ones that predominate among her peers than to the best available scientific evidence.

His empirical claim is that disbelief in global warming, or in evolution, is not evidence of scientific ignorance. If you separate groups on roughly a left/right basis, belief in warming increases with increasing scientific intelligence (measured in other ways) in the group predisposed to believe in it (left), decreases with increasing scientific intelligence in the group predisposed not to believe in it (right). Similarly with evolution if you divide the groups into more or less religious. His explanation ...:

If that person happens to enjoy greater proficiency in the skills and dispositions necessary to make sense of such evidence, then she can simply use those capacities to do an even better job at forming identity-protective beliefs.

The article is too long and starts with an irrelevant analogy to observer effects in quantum mechanics, but it has lots of interesting stuff in it. Among other things, if you test people to see how much they understand about the theory of evolution, those who believe in it do no better than those who don't. Similarly for global warming.

Interesting Post About the Climate Argument

I came across a recent piece discussing evidence about beliefs on climate issues. It finds  that Democrats mostly believe temperatures are warming due to human action and something must be done about it, Republicans mostly don't, but that the difference is not due to differing perceptions about what climate scientists believe. If the question is not what is true but what most climate scientists believe, Republicans and Democrats give roughly similar answers—correct in some cases, incorrect in others.

The author's conclusion is that the debate has become a status conflict, with each side taking the position that it is wise and good, the other side the opposite. One implication he draws is that the campaign to persuade people that 97% of climate scientists agree is based on the mistaken assumption that the reason people are not persuaded is that they don't know what climate scientists believe.

It struck me that his description fits my observations of the online debate. Most participants appear confident that their side is right, the other side stupid or evil. Most of the posts and comments are attempts by one side to put down the other. Substantive arguments occasionally appear, but they are largely cut and paste from popular web sites on the side of whoever is posting them.

I should add that I do not think it is clear what climate scientists believe. As best I can tell by my involvement in the argument, most such scientists think global temperature has been trending up and humans are at least partly responsible, many, perhaps a majority, think humans are mainly responsible. I have seen no evidence of what percentage take the next two steps, the conclusion that if nothing is done the results will be terrible and the further conclusion that there is something that can be done that is worth doing. But those steps are essential for the policy argument that one side of the dispute is pushing and the other side opposing.

As of 5:50 EST 6/23/14 the piece described in this post appears to have vanished. I have not yet figured out why or where, if anywhere, I can find it again.

After an exchange of emails with the author, who turned out to be someone I knew from my time at U of C Law school, the link is now fixed.

The Purpose of Commencement Addresses

I don't usually make posts that are links to webcomics, but this one is both good economics and good commentary.

I deduce from further research that the strip in question is aimed at readers with a background in physics and economics and side interests in philosophy and probability theory. Funny that.

Is the Ocean Still Warming?

The latest data seem to show a very considerable slowdown in ocean warming, starting a few years after the slowdown in atmospheric warming.

That raises an obvious puzzle. As I understand the situation—readers are welcome to correct me if I am wrong—there are satellite measurements of incoming and outgoing radiant energy, and they show a substantial net inflow. If atmosphere, surface, and ocean are all warming much more slowly than they were twenty years ago, where is that energy going?

The two obvious alternatives are that we are missing something, that warming is happening somewhere we cannot readily measure it such as the deep ocean, or that there is something wrong with the measurements that show a net inflow. I do not know enough to offer an educated guess as to which is the case and no other alternatives occur to me.

Heat Content, Temperature, Oceans, and the Pause

Surface and atmospheric temperature appears to have been roughly constant for about the past twelve years, perhaps a little longer, a pattern not predicted by the IPCC models. One response has been that the "missing heat" is going into the ocean. This raises a number of questions, but I want to start with one that only occurred to me recently. Data on the surface and atmosphere is routinely reported in the form of average temperature. Data on the ocean is routinely reported in the form of total heat content. Why?

What is measured, in both cases, is temperature. Presumably the heat content numbers are produced either by multiplying average temperature  by the heat capacity of the ocean or perhaps by doing it for different parts of the oceans and adding. To reverse the process, one divides the increase in heat content of the ocean by the heat capacity of the ocean. The result should be the increase in average ocean temperature. I have not been able to find any exact statement of what the heat capacity of the oceans, so calculated it, using the following figures found online:

Heat capacity of ocean water:   3993J/Kg/K

Volume of the oceans: 1.3 billion cubic kilometers

A cubic kilometer is 10^9 cubic meters and a cubic meter of water is 10^3 kg. Multiplying it out, I get a heat capacity of the ocean of about 5x10^24 Joules/°K. Readers are invited to check the calculation.

Consider the following graph:

It shows an increase in ocean heat content from 1960 to the present of a little less than 2x10^23 Joules. Dividing that by the heat capacity of the ocean gives us an increase in average ocean temperature over fifty years of .04°C. That looks a lot less scary than the graph of heat content, which may explain why it is not the form in which the data is usually presented.

And it matters. Assuming the IPCC calculations of net heat content increase are correct, the effect of heat going into places other than the ocean is significant. The effect of heat going into the ocean is not.

The Tangled Web of Foreign Policy

Has anyone commented on the fact that the recent events in Iraq make the U.S. and Iran de facto allies, both opposing a Sunni uprising? Or that the U.S. and the militants we oppose in Iraq are de facto allies against Assad's regime in Syria, a semi sort of maybe Shia regime supported by Iran?

When the militants steal military equipment the U.S. provided to the Iraqis to use it against the Iraqi government, that's just terrible. If, on the other hand, they steal it to use against Assad, ...  .

A Hockey Stick Question

There is an interesting argument I have seen with regard to Mann's hockey stick reconstruction of past temperatures. I am not sure if it is correct. The hockey stick has been the subject of a lot of heated controversy pro and con and I am not in a mood at the moment to try to wade through it, so I thought I would sketch the argument and see if anyone here can give me a good reason to believe that it is either true or false. 

It goes as follows:

Most of the reconstruction is based on proxies for temperature such as tree rings, since nobody was producing reliable instrumental data in 1500 A.D. The recent part, on the other hand, is based on instrumental data. The claim I have seen is that Mann's graph shows proxies up to one date, proxies and instrumental up to another date, instrumental only starting sometime around 1960-80. That fits what sense I can make of the graph in his paper, the exact date at which the proxies disappear being hard to make out. The further claim, and the critical part, is that if you run the proxies up all the way to the present they do not show as sharp a rise as the instrumental data.

The instrumental data is a more reliable source of information than the proxies for the period when we have it, so if the only objective is reconstructing what has happened to global temperatures over the past six hundred years or so it makes sense to use it where available. But part of the point of Mann's paper is that the recent temperature rise is unprecedented. To show that he needs an apples to apples comparison, a comparison between the proxy record for the past and the proxy record for the recent period of rising temperature or a comparison between the instrumental record for the past and the instrumental record for the recent period. The latter is impossible, since there is no instrumental record for most of the period he is looking at, but the former is not. 

If the proxy record for the past century fails to show the rapid temperature rise in the instrumental record, that is evidence that the proxy record is an unreliable source of information, in particular unreliable as a way of detecting rapid rises. And it is probably more unreliable the farther back we go, since the farther back we go the less relevant data is available. If so, the fact that the proxy record shows no rapid rises in the past may not mean that they did not happen.

Can anyone tell me if this argument is correct? Does the proxy record for the second half of the 20th century show a substantially milder rise in global temperature than the instrumental record?

Global Warming and Wishful Thinking

Political beliefs affect what one wants to be true. People are pretty good at persuading themselves that what they want to be true is true.

That works in both directions in the context of arguments about climate change. People who share my political views are suspicious of government regulation, CAGW (Catastrophic Anthropogenic Global Warming) provides an argument in favor of more government regulation and is used as such an argument at present, so we naturally want to look for arguments against CAGW.

On the other side, it's my experience that people who think global warming is a terrible problem that must be dealt with are also, by some odd coincidence, people who think the things that need to be done to deal with it are things most of which ought to be done anyway, that the real cost is low or negative. They are likely to put that point in terms of creating a cleaner, more sustainable world. From their standpoint, CAGW provides arguments to persuade people to do things they want done, so they naturally want to look for arguments in favor of CAGW.

There is no logical reason why there could not be people out there who believe that a forced shift away from fossil fuels has very large human costs, that by raising the cost of energy it will slow or stop the process by which several billion people are finally escaping from poverty, but think the cost of not doing it is even worse. But despite participating in quite a lot of online climate arguments, I do not think I have encountered a single person  who takes that position.

[I specify CAGW rather than AGW because the argument for action to hold down CO2 emissions requires not only that the globe is warming because of human action but that the net effect of that warming will be negative and large. Also because my own view is that global temperatures have trended up over the past century, that at least part of the reason is probably CO2 produced  by human action, but that there is no good reason to expect the consequences to be negative and large—for details see my old post on the subject and related posts. Hence I believe in AGW but not in CAGW.]

What Would/Does Modern Polygamy Look Like?

The most common human mating pattern is monogamy, the next most common polygyny (one husband, two or more wives), then polyandry (one wife, two or more husbands). Tibet had both polyandry and polygyny. I know of no society where group marriages (two or more of each) were common, but examples have existed, such as the Oneida commune in 19th century New York and various smaller groups in the 1960's and thereafter.

Under current U.S. law, although monogamy (including same sex monogamy) is the only form of marriage legally recognized, there do not seem to be any serious legal bars in most states to de facto polygamy. All three forms, although uncommon, exist. It is interesting to speculate on what forms polygamy might take in the future in modern developed societies, given  a technological and economic environment different from the environment of past polygamous societies.

On the technological side, two big changes are reliable contraception and paternity testing. The latter solves the most obvious problem with polyandry. Men want to know whether a child is theirs. In the past, the only reliable way of doing so was for the man to have had exclusive sexual access to the child's mother; now all it takes is a reliable lab. So we could have several husbands sharing a wife who bears children by all of them, with each taking a special interest in his own children. The selective use of contraception would even make it possible to decide in advance which men would father children and how many. 

One function of marriage is to produce and rear children, another is sexual pleasure. One woman is physically capable of satisfying several men and some women might enjoy doing so. Reliable contraception makes it more practical than in the past to delink sex from marriage, and to a considerable extent it has happened. But keeping sex within a small group has an obvious advantage for reducing the risk of sexually transmitted diseases and may also make better use of the emotional concomitants of intercourse.

Why polyandry instead of monogamy? Modern technology provides ways in which parents can choose to raise the odds of producing a son, and the result in some societies is a substantial m/f imbalance in the population. Polyandry would make it possible in such a society for the excess men to have wives and families.

What about polygyny, the historically more common form of polygamy? It provides a solution to a different problem. Back when legalized abortion and readily available contraception first became hot political issues, a major argument in favor of both was preventing the birth of unwanted children, meaning children born to unmarried mothers. Both legalized abortion and readily available contraception now exist in most developed societies—and have been accompanied by the precise opposite of the predicted effect, a sharp increase in the number of children born to single mothers.

One possible explanation is that, in a world where intercourse was likely to lead to pregnancy, most women were unwilling to sleep with a man unless he was prepared to offer support to any resulting offspring, typically by being engaged or married to her. Breaking that link meant that women who did not want children and did enjoy sex were willing to engage in it without such a guarantee, which sharply worsened the bargaining position of women who wanted sex, children, and support. Some of those who could not find husbands chose to produce children without them. Polygyny would offer some of them the more attractive alternative of being one of two or more wives of men who wanted children and had sufficient resources to support them. And for such men, it provides more sexual variety than monogamy, more emotional security and less medical risk than promiscuity. Also more children.

So far I have been looking at marriage primarily from the standpoint of sex and children. It is also an institution for the production of household services and the sharing of income. In one traditional form of monogamy there was a fairly sharp division of labor, with the wife running the household and the husband working outside it to bring in income. The combination of low rates of infant mortality, meaning that a family that wants to end up with two children need only produce two, and modern technology—washers and dryers, dishwashers, microwave ovens, food bought already prepared—has converted household production from a full time to a part time job. The usual modern response is for both partners to earn income outside of the household, possibly with one of them, usually the wife, taking some years off for child rearing. An alternative, possibly a superior alternative, would be a family of three or more, with one member specializing in running the household and caring for the children.

One additional feature of modern society might affect how practical various forms of marriage would be. We are used to taking it for granted that most income earning is done outside of the household. That has not always been the case in the past—a common pattern has been for family members to be self employed running a shop or a farm. Telecommuting may make something similar again common. The problem of having someone home to keep an eye on the children is substantially reduced if parents who work do their work at home.

All of this is mostly speculation. Over the years I have occasionally encountered people who were part of polygamous families of one sort or another, but have never done much research into how or why they were organized. There is a literature, largely online, on polyamory, but it seems to deal more with structuring the emotional relationships than with organizing production, child rearing, and associated activities.

Comments welcome, especially from those with first hand experience.