It's logical. It's reasonable. It's nonsense.

I practice law for a living. Specifically, I'm a business litigator. I help businesses deal with the problems that come up when they have disagreements. Sometimes I can help them avoid lawsuits, other times I help them position themselves so that when the anticipated lawsuit arrives they are in the best possible shape to fight it, other times I help them deal with a lawsuit that has hit them out of left field that they never saw coming. Sometimes it's a combination of these. But what these situations have in common is that ordinarily my analysis proceeds from well-known principles of law, and I try to predict logically what the consequences will be of alternative courses of action. Usually I'm right but not always. And when my prediction doesn't come true, it's not because my analysis necessarily was wrong but because someone else did something that I thought wasn't logical. After all, reason is only as good as the person doing the reasoning.

Over two hundred years ago the French masses rose up in revolt against the ancien regime and endorsed radical republican principles. From that day forward, the people would be sovereign and principles of fairness -- liberty, equality and fraternity -- would govern life in la belle France hence and forevermore. The revolutionaries proclaimed the triumph of reason over tradition -- and instituted, well, a reign of terror. Only a few years later France was ruled by Bonaparte, who proclaimed himself Emperor and proceeded to overrun much of Europe. The reason of the revolutionaries didn't prevent that result.

In the 1850s a scholarly fellow with a beard sat in the library of the British Museum, writing out his theories of economics and social justice. Through reason and study he hoped to expose the inner workings of society and predict the future. You may have heard of him. His name was Karl Marx. His "scientific" work of social studies eventually became Das Kapital. The movement his ideas inspired, Communism, eventually ruled much of the planet and during the twentieth century was responsible for more death than any other system of thought in history. The Soviet apparatchiks who claimed to be implementing his work insisted that the system was perfect and scientifically beyond reproach. Many modern day Marxists still do. But reason didn't rescue Marxism from near-total discredit.

The problem with the French revolutionaries and the communists was their failure to understand that reason itself is not ironclad. What is logical to one person is not logical to another, and moreover, people don't always behave in ways that detached thinkers might regard as logical. In fact, there are whole branches of economics that attempt to explain why people, who presumably should act in economically rational ways, engage in what appears to be irrational behavior. The usual answer is that that the behavior isn't really irrational, it's just responding to different incentives and thus has to be viewed a different way. That's why people don't always choose the best investments for their IRA, why they're willing to pay huge sums to see sporting events and why they don't pay their credit card balances every month but instead pay extortionate rates of interest. What they're doing is purchasing convenience, leisure or the ability to focus, and sacrificing some return in order to get it. But if you can't predict that sort of different rationality, then your system of reasoning isn't as good as you thought, right?

Why is this important? Primarily because people usually try to invoke logical and reason-based arguments to justify their opinions. Go out on the internet and read some political websites. The more respectable ones (meaning the ones with low vitriol-to-substance ratios) advance calm, structured, logical arguments to support their points of view. It's interesting to look at the names of some of the ones I read fairly regularly. "The Reality-Based Community" is a leftish blog from a bunch of professors, maintained primarily by Mark Kleiman of UCLA. The URL is www.samefacts.com, which I take it is a reference to Daniel Patrick Moynihan's famous aphorism that everyone is entitled to his own opinion but not his own facts. The idea, of course, is that if you look at the facts, the conclusions you logically draw are the ones the blog authors draw. On the other hand, Stubborn Facts is a rightish group blog authored by a collection of lawyers [correction: Pat from Stubborn Facts notes below that only one of the bloggers there is a lawyer]. At the top of their home page is a picture of Mark Twain and the his quote "Get your facts first, and then you can distort them as much as you please" -- clearly a wry implication that the discussion in the blog, which yields mainly right-of-center conclusions, is based on the facts.

Of course, they can't both be right, because they disagree far more than they agree. I could talk about confirmation bias and all the studies that discuss how people seek out facts that support their conclusions, how people seek out others who agree with them, and how group dynamics of those with similar opinions tend to pull the group members to the extremes. But for this purpose I have a different observation: facts and reasoning alone won't get you the truth. They are only as good as the person who is using them.

There is an infinite number of facts in the world. If you want to figure something out, you have to select the facts you think are important as the basis for your reasoning. By doing that, you have already shaped your result even before you started doing analysis. Here is a very simple way to think about it. If you want to learn about butterflies you can go out and collect lots of butterflies. But you will never know where the butterflies came from if all you do is study the butterflies you collected. By choosing only large-winged insects to look at, you have screened out caterpillars from your study -- yet studying caterpillars will tell you a lot about butterflies. So choosing the facts you think are important will almost assuredly skew your conclusions.

That isn't necessarily a criticism of people who claim that the facts back them up. After all, the number of facts is infinite. It's impossible to use and reason from an infinite number of facts. The only way anyone can deal with the world is by selecting out what realms are relevant.

The selection problem goes deeper than that, though. It's not just that people can't know what facts are relevant unless they already are knowledgeable enough about the subject matter they are looking at to know how to discern what is relevant. A further, and more serious, problem is that the people doing the reasoning are prisoners of their own experience. By definition they can't step outside themselves, so they have no idea whether what they find logical is also what someone else will find logical. People who are involved in thinking about how to solve social problems tend to be the educated and middle class, or upper middle class - call them bourgeois. Being bourgeois means having certain habits of mind, including, to one extent or another, rationality, industriousness and ability to defer gratification. That means what is logical to a bourgeois person - someone like, say, me - will make a totally different impression on someone who isn't from that slice of society.

One of my favorite bloggers, Megan McArdle, who posts as Jane Galt, once put up a post that included a discussion of this point. Here's what she said:

To sketch a brief history of welfare, it emerged in the nineteenth century as "Widows and orphans pensions", which were paid by the state to destitute families whose breadwinner had passed away. They were often not available to blacks; they were never available to unwed mothers. Though public services expanded in the first half of the twentieth century, that mentality was very much the same: public services were about supporting unfortunate families, not unwed mothers. Unwed mothers could not, in most cases, obtain welfare; they were not allowed in public housing (which was supposed to be--and was--a way station for young, struggling families on the way to homeownership, not a permanent abode); they were otherwise discriminated against by social services. The help you could expect from society was a home for wayward girls, in which you would give birth and then put the baby up for adoption.

The description of public housing in the fifties is shocking to anyone who's spent any time in modern public housing. Big item on the agenda at the tenant's meeting: housewives, don't shake your dustcloths out of the windows--other wives don't want your dirt in their apartment! Men, if you wear heavy work boots, please don't walk on the lawns until you can change into lighter shoes, as it damages the grass! (Descriptions taken from the invaluable book, The Inheritance, about the transition of the white working class from Democrat to Republican.) Needless to say, if those same housing projects could today find a majority of tenants who reliably dusted, or worked, they would be thrilled.

Public housing was, in short, a place full of functioning families.

Now, in the late fifties, a debate began over whether to extend benefits to the unmarried. It was unfair to stigmatise unwed mothers. Why shouldn't they be able to avail themselves of the benefits available to other citizens? The brutal societal prejudice against illegitimacy was old fashioned, bigoted, irrational.

But if you give unmarried mothers money, said the critics, you will get more unmarried mothers.

Ridiculous, said the proponents of the change. Being an unmarried mother is a brutal, thankless task. What kind of idiot would have a baby out of wedlock just because the state was willing to give her paltry welfare benefits?

People do all sorts of idiotic things, said the critics. If you pay for something, you usually get more of it.

C'mon said the activists. That's just silly. I just can't imagine anyone deciding to get pregnant out of wedlock simply because there are welfare benefits available.

Oooops.

Of course, change didn't happen overnight. But the marginal cases did have children out of wedlock, which made it more acceptable for the next marginal case to do so. Meanwhile, women who wanted to get married essentially found themselves in competition for young men with women who were willing to have sex, and bear children, without forcing the men to take any responsibility. This is a pretty attractive proposition for most young men. So despite the fact that the sixties brought us the biggest advance in birth control ever, illegitimacy exploded. In the early 1960s, a black illegitimacy rate of roughly 25 percent caused Daniel Patrick Moynihan to write a tract warning of a crisis in "the negro family" (a tract for which he was eviscerated by many of those selfsame activists.)

By 1990, that rate was over 70 percent. This, despite the fact that the inner city, where the illegitimacy problem was biggest, only accounts for a fraction of the black population.

But in that inner city, marriage had been destroyed. It had literally ceased to exist in any meaningful way.

* * *

How did people go so badly wrong? Well, to start with, they fell into the basic fallacy that economists are so well acquainted with: they thought about themselves instead of the marginal case. For another, they completely failed to realise that each additional illegitimate birth would, in effect, slightly destigmatise the next one. They assigned men very little agency, failing to predict that women willing to forgo marriage would essentially become unwelcome competition for women who weren't, and that as the numbers changed, that competition might push the marriage market towards unwelcome outcomes. They failed to forsee the confounding effect that the birth control pill would have on sexual mores.

But I think the core problems are two. The first is that they looked only at individuals, and took instititutions as a given. That is, they looked at all the cultural pressure to marry, and assumed that that would be a countervailing force powerful enough to overcome the new financial incentives for out-of-wedlock births. They failed to see the institution as dynamic. It wasn't a simple matter of two forces: cultural pressure to marry, financial freedom not to, arrayed against eachother; those forces had a complex interplay, and when you changed one, you changed the other.

The second is that they didn't assign any cultural reason for, or value to, the stigma on illegitimacy. They saw it as an outmoded vestige of a repressive Victorial values system, based on an unnatural fear of sexuality. But the stigma attached to unwed motherhood has quite logical, and important, foundations: having a child without a husband is bad for children, and bad for mothers, and thus bad for the rest of us. So our culture made it very costly for the mother to do. Lower the cost, and you raise the incidence. As an economist would say, incentives matter.

(Now, I am not arguing in favor of stigmatising unwed mothers the way the Victorians did. I'm just pointing out that the stigma did not exist merely, as many mid-century reformers seem to have believed, because of some dark Freudian excesses on the part of our ancestors.)

But all the reformers saw was the terrible pain--and it was terrible--inflicted on unwed mothers. They saw the terrible unfairness--and it was terribly unfair--of punishing the mother, and not the father. They saw the inherent injustice--and need I add, it was indeed unjust--of treating American citizens differently because of their marital status.

But as G.K. Chesterton points out, people who don't see the use of a social institution are the last people who should be allowed to reform it:

In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle; a principle which will probably be called a paradox. There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, "I don't see the use of this; let us clear it away." To which the more intelligent type of reformer will do well to answer: "If you don't see the use of it, I certainly won't let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it."

Note the key words in that discussion: "I just can't imagine anyone deciding to get pregnant out of wedlock simply because there are welfare benefits available." The people who thought they were doing good just couldn't imagine it, therefore it couldn't be.

But sometimes it is. We are necessarily bounded by our own imaginations. The public safety authorities in the US were not able to protect us from the 9/11 attacks because no one ever expected that fanatics would crash fully fueled airplanes into buildings - people simply didn't do things like that. But they did.

So does that mean we can never improve our community, that anything we might propose is likely to have unintended negative consequences? Not necessarily, but we would do well to maintain our humility about how much we can reshape the world around us. Our ability to understand and predict is limited.

I started this post by talking about how I use logic in my legal work. If you read a judicial opinion you'll typically notice a fair amount of emphasis on logical reasoning, as the judge tries to explain how he or she arrived at the conclusion. But there's a fair amount of truth to the aphorism articulated by Oliver Wendell Holmes about a century ago: ""[t]he life of the law has not been logic, but experience." Logic alone isn't all that informative. It has to be leavened with the real world, how people actually react to situations, how problems get solved by people who are presented with them in their day to day lies. What works is much more effective than what's logical. After all, what seems logical may or may not work -- but if something works, we can usually see what the logic is as to why it does.

There are things we don't understand. Refusing to recognize that when we tinker with the world and with society we are opening up areas we might not understand is a recipe for potential trouble. Doing homework, testing and experiments is the only way we can gain some comfort about what the consequences of our pet programs might be. And if we can't accumulate data first, we need to be very very careful.