The real source of the evolution debate, part 1

Feb 9 JDN 2460716

The last few posts have been about evolution; but everything I’ve said in them has been very technical and scientific, and I imagine it is not very controversial or offensive to anyone. In fact, I would guess that anyone who believes in Creationism, upon reading my definition of evolution as “change in allele distribution in a population”, was thinking, “Of course we believe in that. But that’s not evolution.” Actually it is; evolution is change in allele distribution in a population. What people are objecting to isn’t really evolution.

There are however several propositions that people do object to, which are conceptually related, but not strictly implied by evolution. They are adaptationism, common descent, animalism, abiogenesis, and atheism respectively. They are all true—and in what follows I will offer a defense of each—but they are not necessarily entailed by evolution or the Modern Synthesis, and so they should be considered separately on their own merits. This post will deal with adaptationism and common descent, and I’ll save the others for a later post.

Adaptationism

Adaptationism is the principle that living organisms have the traits they do because these traits are adaptive, that is, that they are beneficial to fitness. It’s obvious that this isn’t completely true in every case; whales have hipbones despite having no apparent use for them, and the human appendix seems mostly useful for collecting toxins and occasionally exploding. There are also limits to how much an organism can change given its current structure; the emerging field of developmental evolutionary biology, or evo-devo, seeks to characterize these limits more precisely.

But in general, adaptationism is an incredibly powerful principle, one which makes sense of the diversity and complexity of life on Earth in a way no other theory can. Natural selection predicts that organisms will become more and more adapted over time; adaptationism is based on the fact that we have had plenty of time to adapt really, really well. In fact, it can be argued that adaptationism is really what evolutionary theory is about, that all this business about changes in allele distributions is useful but not really the point of the enterprise.

When we look at the world, we see that living things are extremely complex and well-suited to their environments; theologians used to say (in fact some still do) that this was evidence that living things were designed by a perfect God.

The problem with this argument was exposed almost immediately by David Hume: If complex things need designers, aren’t designers even more complex than what they design? But then, the designer needs a designer-designer, and the designer-designer needs a designer-designer-designer, and so on into an infinite regress! Another problem with this sort of Intelligent Design thinking is that it cannot explain the cases when adaptationism fails—in particular, why do so many species go extinct? Recently a theory of “Intelligent Recall” was proposed for this purpose; but this forces us to think of our designer as no more intelligent than a financial analyst or an automobile engineer! What kind of God would make mistakes in design?

And now we know better: The remarkable complexity and fitness of living organisms can be entirely explained by adaptationism. When we ask why dolphins have fins, why birds have wings, why centipedes have so many legs, why snakes are so long, or why humans have such enormous brains, adaptationism gives us the answer: organisms have these traits because having these traits benefited their ancestors. In some cases it’s pretty obvious how this would work (having fins lets dolphins swim faster, swimming faster has obvious benefits in catching fish and escaping sharks, so dolphin ancestors with more fin-like limbs survived better); in others we’re still working on the specifics (there is as yet no consensus on how humans got so incredibly smart compared to other animals); but in general adaptationism has explained a huge body of data that we couldn’t account for any other way.

Common descent

Common descent is the proposition that all living organisms on Earth are descended from a common ancestor. This implies, in particular, that human beings share a common ancestor with other animals. The former is strictly stronger, and not quite as certain; at least in principle it could be that some broad classes of organism do not share a common ancestor, but nonetheless it would still be quite clear that humans share a common ancestor with chimpanzees. In practice nearly all biologists agree with the strongest form of common descent, that all living organisms on Earth share a common ancestor. Recently the biochemist Douglas Theobald mathematically compared this strongest form of common descent (universal common descent) with several other models of phylogenetic history, finding that universal common descent was the most probable result by a factor of at least 102000—a 2001-digit number. That is, scientists are 99.999,999,999,999,999,999… (on with 1,980 more nines!) percent sure that universal common descent is right. This is not hyperbole; it is mathematically precise. At this point any sliver of uncertainty left in universal common descent needs to apply to all of our fundamental knowledge of physics and chemistry; in order to be wrong about this, we’d need to be wrong about everything.

How are we so sure? Nature presents us with a very consistent pattern of observations that simply make no sense any other way. Traits in living things (and, we are increasingly finding, genes) have distinct patterns, structural similarities that exist between species irrespective of their lifestyle; we call these similiarities homologues. (Similarities that are due to lifestyle—e.g., both dolphins and fish have fins—are called analogues.) Dolphin skeletons are more like dog skeletons than they are like fish skeletons, even though dolphins live more like fish. Bat skin is more like human skin than like bird skin, even though bats live more like birds. The most parsimonious explanation is that these traits were passed on from some common ancestor—that dolphins and dogs have similar skeletons because dolphins and dogs are actually genetically related somehow, and they differ from fish because they are more distantly related.

Once we began to understand DNA, we became able to detect even more compelling homologues. Many kinds of mutation are completely ineffectual; some involve a change to DNA that doesn’t do anything, others swap out two amino acids that are essentially the same; in fact because of the way genes code for amino acids, it’s possible to have a change in a gene that isn’t reflected in the resulting protein at all. All of these changes have no effect on the organism, but they are still passed on to offspring. When you find two organisms that have the same trait (e.g. bats and birds both have wings), if that trait does something important (lets you fly), then maybe it’s just a similarity in lifestyle; if that happens we call it convergent evolution. But when we’re looking at a DNA sequence that doesn’t do anything, lifestyle can’t be the reason—it must be either common ancestry or pure coincidence. Statistical analysis can rule out pure coincidence, and then we are left with only one possibility: common descent. A third option often proposed by Creationists simply doesn’t work: A common designer of sharks and dolphins would not give one a cartilaginous skeleton and gills and the other a bony mammalian skeleton and lungs. There is no reason for dolphin skeletons to be more like dog skeletons than shark skeletons—except that dogs and dolphins share closer common ancestry to each other than they do to sharks.

There are thousands of traits and genes that we can use to assess these relationships. When we do this, we find a remarkably consistent organizational structure, a pattern of a few common ancestors diversifying into a wide variety of descendants—it looks a bit like a tree, so we call it a phylogenetic tree. In some cases there is ambiguity about which species are more closely related, and we need to gather more evidence. This is a normal part of evolutionary biology research.

One thing is not disputed: Humans share a common ancestor with apes. This is simply too obvious from the morphological and genetic homologues. Human and chimp DNA coincides 95-98\%, depending on how you count insertions and deletions.

A standard measure of genetic distance is the Nei distance; a larger Nei distance implies more genetic differences, which in turn suggests that the common ancestor was further in the past. (Exactly how it’s calculated is a bit too technical for this post.)

Humans and chimps have a Nei distance of 0.45. This similarity between humans and chimps represents a closer similarity than that between dogs and foxes, who differ by a Nei distance of 1.1. Almost anyone can see that dogs and foxes are related animals; so why is it so hard to believe that humans and chimps are related too?

Creationists often claim that we never find the transitional forms predicted by evolutionary theory, but this is simply not true. We do in fact see many transitional forms; feathered dinosaurs mark the transition from reptiles to birds, ambulocetids mark the transition from land mammals to cetaceans, therapsids mark the transition from reptiles to mammals, and a huge variety of hominids marks the transition from apes to humans. It’s important to understand what this means: transitional forms are not bizarre combinations of their descendant organisms, but fully-functional lifeforms in their own right that have descendants very different from one another. Just as your grandparents are not a combination of half of you and half of your first cousin, common ancestors are not simply half-and-half combinations of their descendant organisms. Ambulocetids are not half-deer/half-dolphin, they are somewhat deer-like yet somewhat dolphin-like mammals whose ancestors were on average slightly more deer-like and whose descendants were on average slightly more dolphin-like. Different traits changed at different times, generations apart: Ambulocetids began to swim before they lost their legs, and even modern dolphins haven’t lost their lungs or hipbones.


This is such a deep, marvelous truth that Creationists are missing out on: All life on Earth is part of one family. We are kin with the dogs and the cats and the elephants, with the snakes and the lizards and the birds, with the beetles and the flies and the bees, even with the flowers and the bushes and the trees.

The irrationality of racism

JDN 2457039 EST 12:07.

I thought about making today’s post about the crazy currency crisis in Switzerland, but currency exchange rates aren’t really my area of expertise; this is much more in Krugman’s bailiwick, so you should probably read what Krugman says about the situation. There is one thing I’d like to say, however: I think there is a really easy way to create credible inflation and boost aggregate demand, but for some reason nobody is ever willing to do it: Give people money. Emphasis here on the people—not banks. Don’t adjust interest rates or currency pegs, don’t engage in quantitative easing. Give people money. Actually write a bunch of checks, presumably in the form of refundable tax rebates.

The only reason I can think of that economists don’t do this is they are afraid of helping poor people. They wouldn’t put it that way; maybe they’d say they want to avoid “moral hazard” or “perverse incentives”. But those fears didn’t stop them from loaning $2 trillion to banks or adding $4 trillion to the monetary base; they didn’t stop them from fighting for continued financial deregulation when what the world economy most desperately needs is stronger financial regulation. Our whole derivatives market practically oozes moral hazard and perverse incentives, but they aren’t willing to shut down that quadrillion-dollar con game. So that can’t be the actual fear. No, it has to be a fear of helping poor people instead of rich people, as though “capitalism” meant a system in which we squeeze the poor as tight as we can and heap all possible advantages upon those who are already wealthy. No, that’s called feudalism. Capitalism is supposed to be a system where markets are structured to provide free and fair competition, with everyone on a level playing field.

A basic income is a fundamentally capitalist policy, which maintains equal opportunity with a minimum of government intervention and allows the market to flourish. I suppose if you want to say that all taxation and government spending is “socialist”, fine; then every nation that has ever maintained stability for more than a decade has been in this sense “socialist”. Every soldier, firefighter and police officer paid by a government payroll is now part of a “socialist” system. Okay, as long as we’re consistent about that; but now you really can’t say that socialism is harmful; on the contrary, on this definition socialism is necessary for capitalism. In order to maintain security of property, enforcement of contracts, and equality of opportunity, you need government. Maybe we should just give up on the words entirely, and speak more clearly about what specific policies we want. If I don’t get to say that a basic income is “capitalist”, you don’t get to say financial deregulation is “capitalist”. Better yet, how about you can’t even call it “deregulation”? You have to actually argue in front of a crowd of people that it should be legal for banks to lie to them, and there should be no serious repercussions for any bank that cheats, steals, colludes, or even launders money for terrorists. That is, after all, what financial deregulation actually does in the real world.

Okay, that’s enough about that.

My birthday is coming up this Monday; thus completes my 27th revolution around the Sun. With birthdays come thoughts of ancestry: Though I appear White, I am legally one-quarter Native American, and my total ethnic mix includes English, German, Irish, Mohawk, and Chippewa.

Biologically, what exactly does that mean? Next to nothing.

Human genetic diversity is a real thing, and there are genetic links to not only dozens of genetic diseases and propensity toward certain types of cancer, but also personality and intelligence. There are also of course genes for skin pigmentation.

The human population does exhibit some genetic clustering, but the categories are not what you’re probably used to: Good examples of relatively well-defined genetic clusters include Ashkenazi, Papuan, and Mbuti. There are also many different haplogroups, such as mitochondrial haplogroups L3 and CZ.

Maybe you could even make a case for the “races” East Asian, South Asian, Pacific Islander, and Native American, since the indigenous populations of these geographic areas largely do come from the same genetic clusters. Or you could make a bigger category and call them all “Asian”—but if you include Papuan and Aborigine in “Asian” you’d pretty much have to include Chippewa and Najavo as well.

But I think it tells you a lot about what “race” really means when you realize that the two “race” categories which are most salient to Americans are in fact the categories that are genetically most meaningless. “White” and “Black” are totally nonsensical genetic categorizations.

Let’s start with “Black”; defining a “Black” race is like defining a category of animals by the fact that they are all tinted red—foxes yes, dogs no; robins yes, swallows no; ladybirds yes, cockroaches no. There is more genetic diversity within Africa than there is outside of it. There are African populations that are more closely related to European populations than they are to other African populations. The only thing “Black” people have in common is that their skin is dark, which is due to convergent evolution: It’s not due to common ancestry, but a common environment. Dark skin has a direct survival benefit in climates with intense sunlight.  The similarity is literally skin deep.

What about “White”? Well, there are some fairly well-defined European genetic populations, so if we clustered those together we might be able to get something worth calling “White”. The problem is, that’s not how it happened. “White” is a club. The definition of who gets to be “White” has expanded over time, and even occasionally contracted. Originally Hebrew, Celtic, Hispanic, and Italian were not included (and Hebrew, for once, is actually a fairly sensible genetic category, as long as you restrict it to Ashkenazi), but then later they were. But now that we’ve got a lot of poor people coming in from Mexico, we don’t quite think of Hispanics as “White” anymore. We actually watched Arabs lose their “White” card in real-time in 2001; before 9/11, they were “White”; now, “Arab” is a separate thing. And “Muslim” is even treated like a race now, which is like making a racial category of “Keynesians”—never forget that Islam is above all a belief system.

Actually, “White privilege” is almost a tautology—the privilege isn’t given to people who were already defined as “White”, the privilege is to be called “White”. The privilege is to have your ancestors counted in the “White” category so that they can be given rights, while people who are not in the category are denied those rights. There does seem to be a certain degree of restriction by appearance—to my knowledge, no population with skin as dark as Kenyans has ever been considered “White”, and Anglo-Saxons and Nordics have always been included—but the category is flexible to political and social changes.

But really I hate that word “privilege”, because it gets the whole situation backwards. When you talk about “White privilege”, you make it sound as though the problem with racism is that it gives unfair advantages to White people (or to people arbitrarily defined as “White”). No, the problem is that people who are not White are denied rights. It isn’t what White people have that’s wrong; it’s what Black people don’t have. Equating those two things creates a vision of the world as zero-sum, in which each gain for me is a loss for you.

Here’s the thing about zero-sum games: All outcomes are Pareto-efficient. Remember when I talked about Pareto-efficiency? As a quick refresher, an outcome is Pareto-efficient if there is no way for one person to be made better off without making someone else worse off. In general, it’s pretty hard to disagree that, other things equal, Pareto-efficiency is a good thing, and Pareto-inefficiency is a bad thing. But if racism were about “White privilege” and the game were zero-sum, racism would have to be Pareto-efficient.

In fact, racism is Pareto-inefficient, and that is part of why it is so obviously bad. It harms literally billions of people, and benefits basically no one. Maybe there are a few individuals who are actually, all things considered, better off than they would have been if racism had not existed. But there are certainly not very many such people, and in fact I’m not sure there are any at all. If there are any, it would mean that technically racism is not Pareto-inefficient—but it is definitely very close. At the very least, the damage caused by racism is several orders of magnitude larger than any benefits incurred.

That’s why the “privilege” language, while well-intentioned, is so insidious; it tells White people that racism means taking things away from them. Many of these people are already in dire straits—broke, unemployed, or even homeless—so taking away what they have sounds particularly awful. Of course they’d be hostile to or at least dubious of attempts to reduce racism. You just told them that racism is the only thing keeping them afloat! In fact, quite the opposite is the case: Poor White people are, second only to poor Black people, those who stand the most to gain from a more just society. David Koch and Donald Trump should be worried; we will probably have to take most of their money away in order to achieve social justice. (Bill Gates knows we’ll have to take most of his money away, but he’s okay with that; in fact he may end up giving it away before we get around to taking it.) But the average White person will almost certainly be better off than they were.

Why does it seem like there are benefits to racism? Again, because people are accustomed to thinking of the world as zero-sum. One person is denied a benefit, so that benefit must go somewhere else right? Nope—it can just disappear entirely, and in this case typically does.

When a Black person is denied a job in favor of a White person who is less qualified, doesn’t that White person benefit? Uh, no, actually, not really. They have been hired for a job that isn’t an optimal fit for them; they aren’t working to their comparative advantage, and that Black person isn’t either and may not be working at all. The total output of the economy will be thereby reduced slightly. When this happens millions of times, the total reduction in output can be quite substantial, and as a result that White person was hired at $30,000 for an unsuitable job when in a racism-free world they’d have been hired at $40,000 for a suitable one. A similar argument holds for sexism; men don’t benefit from getting jobs women are denied if one of those women would have invented a cure for prostate cancer.

Indeed, the empowerment of women and minorities is kind of the secret cheat code for creating a First World economy. The great successes of economic development—Korea, Japan, China, the US in WW2—had their successes precisely at a time when they suddenly started including women in manufacturing, effectively doubling their total labor capacity. Moreover, it’s pretty clear that the causation ran in this direction. Periods of economic growth are associated with increases in solidarity with other groups—and downturns with decreased solidarity—but the increase in women in the workforce was sudden and early while the increase in growth and total output was prolonged.

Racism is irrational. Indeed it is so obviously irrational that for decades now neoclassical economists have been insisting that there is no need for civil rights policy, affirmative action, etc. because the market will automatically eliminate racism by the rational profit motive. A more recent literature has attempted to show that, contrary to all appearances, racism actually is rational in some cases. Inevitably it relies upon either the background of a racist society (maybe Black people are, on average, genuinely less qualified, but it would only be because they’ve been given poorer opportunities), or an assumption of “discriminatory tastes”, which is basically giving up and redefining the utility function so that people simply get direct pleasure from being racists. Of course, on that sort of definition, you can basically justify any behavior as “rational”: Maybe he just enjoys banging his head against the wall! (A similar slipperiness is used by egoists to argue that caring for your children is actually “selfish”; well, it makes you happy, doesn’t it? Yes, but that’s not why we do it.)

There’s a much simpler way to understand this situation: Racism is irrational, and so is human behavior.

That isn’t a complete explanation, of course; and I think one major misunderstanding neoclassical economists have of cognitive economists is that they think this is what we do—we point out that something is irrational, and then high-five and go home. No, that’s not what we do. Finding the irrationality is just the start; next comes explaining the irrationality, understanding the irrationality, and finally—we haven’t reached this point in most cases—fixing the irrationality.

So what explains racism? In short, the tribal paradigm. Human beings evolved in an environment in which the most important factor in our survival and that of our offspring was not food supply or temperature or predators, it was tribal cohesion. With a cohesive tribe, we could find food, make clothes, fight off lions. Without one, we were helpless. Millions of years in this condition shaped our brains, programming them to treat threats to tribal cohesion as the greatest possible concern. We even reached the point where solidarity for the tribe actually began to dominate basic survival instincts: For a suicide bomber the unity of the tribe—be it Marxism for the Tamil Tigers or Islam for Al-Qaeda—is more important than his own life. We will do literally anything if we believe it is necessary to defend the identities we believe in.

And no, we rationalists are no exception here. We are indeed different from other groups; the beliefs that define us, unlike the beliefs of literally every other group that has ever existed, are actually rationally founded. The scientific method really isn’t just another religion, for unlike religion it actually works. But still, if push came to shove and we were forced to kill and die in order to defend rationality, we would; and maybe we’d even be right to do so. Maybe the French Revolution was, all things considered, a good thing—but it sure as hell wasn’t nonviolent.

This is the background we need to understand racism. It actually isn’t enough to show people that racism is harmful and irrational, because they are programmed not to care. As long as racial identification is the salient identity, the tribe by which we define ourselves, we will do anything to defend the cohesion of that tribe. It is not enough to show that racism is bad; we must in fact show that race doesn’t matter. Fortunately, this is easy, for as I explained above, race does not actually exist.

That makes racism in some sense easier to deal with than sexism, because the very categories of races upon which it is based are fundamentally faulty. Sexes, on the other hand, are definitely a real thing. Males and females actually are genetically different in important ways. Exactly how different in what ways is an open question, and what we do know is that for most of the really important traits like intelligence and personality the overlap outstrips the difference. (The really big, categorical differences all appear to be physical: Anatomy, size, testosterone.) But conquering sexism may always be a difficult balance, for there are certain differences we won’t be able to eliminate without altering DNA. That no more justifies sexism than the fact that height is partly genetic would justify denying rights to short people (which, actually, is something we do); but it does make matters complicated, because it’s difficult to know whether an observed difference (for instance, most pediatricians are female, while most neurosurgeons are male) is due to discrimination or innate differences.

Racism, on the other hand, is actually quite simple: Almost any statistically significant difference in behavior or outcome between races must be due to some form of discrimination somewhere down the line. Maybe it’s not discrimination right here, right now; maybe it’s discrimination years ago that denied opportunities, or discrimination against their ancestors that led them to inherit less generations later; but it almost has to be discrimination against someone somewhere, because it is only by social construction that races exist in the first place. I do say “almost” because I can think of a few exceptions: Black people are genuinely less likely to use tanning salons and genuinely more likely to need vitamin D supplements, but both of those things are directly due to skin pigmentation. They are also more likely to suffer from sickle-cell anemia, which is another convergent trait that evolved in tropical climates as a response to malaria. But unless you can think of a reason why employment outcomes would depend upon vitamin D, the huge difference in employment between Whites and Blacks really can’t be due to anything but discrimination.

I imagine most of my readers are more sophisticated than this, but just in case you’re wondering about the difference in IQ scores between Whites and Blacks, that is indeed a real observation, but IQ isn’t entirely genetic. The reason IQ scores are rising worldwide (the Flynn Effect) is due to improvements in environmental conditions: Fewer environmental pollutants—particularly lead and mercury, the removal of which is responsible for most of the reduction in crime in America over the last 20 yearsbetter nutrition, better education, less stress. Being stupid does not make you poor (or how would we explain Donald Trump?), but being poor absolutely does make you stupid. Combine that with the challenges and inconsistencies in cross-national IQ comparisons, and it’s pretty clear that the higher IQ scores in rich nations are an effect, not a cause, of their affluence. Likewise, the lower IQ scores of Black people in the US are entirely explained by their poorer living conditions, with no need for any genetic hypothesis—which would also be very difficult in the first place precisely because “Black” is such a weird genetic category.

Unfortunately, I don’t yet know exactly what it takes to change people’s concept of group identification. Obviously it can be done, for group identities change all the time, sometimes quite rapidly; but we simply don’t have good research on what causes those changes or how they might be affected by policy. That’s actually a major part of the experiment I’ve been trying to get funding to run since 2009, which I hope can now become my PhD thesis. All I can say is this: I’m working on it.