September 26, 2002
A HERO OF OUR TIMES:
THE DESCENT OF GOULD: How a paleontologist sought to revolutionize evolution. (H. ALLEN ORR, 2002-09-23, The New Yorker)[G]ould was perhaps at his best when on the attack. He warred relentlessly against what he viewed as bad science. His chief enemy was genetic determinism, the view that it's all in the genes. He battled this cant on two fronts. The first was sociobiology and its stepchild evolutionary psychology, and their often soaring speculations on the evolutionary basis of human culture. Gould charged the champions of these creeds with both a vulgar hereditarianism (they were given to saying things like "Consider a gene for gathering behavior in women"—even when no such gene has ever been found) and an addiction to untestable Just So stories ("Gathering behavior is favorable because . . ."). He went on to argue that all such "adaptationist" tales ignore the possibility that some features of animals and plants are simply by-products of how organisms are built, not the direct, designed products of natural selection. Such features, as Gould and his Harvard colleague Richard Lewontin famously put it, are like spandrels in church architecture—the triangular spaces that appear automatically between arches. Speculation about the "purpose" of these unplanned spaces is both futile and foolish. Likewise for speculation about the purpose of, say, the color of blood: as Lewontin and others have pointed out, blood looks red when it carries oxygen, but surely it's the oxygen that natural selection cares about, not the red.The other front in Gould's war was the I.Q. industry. A large and apparently sophisticated literature claimed that I.Q. measured a single real thing called intelligence, and that this thing showed profound genetic differences across races. Over the years, these conclusions were invoked to justify a number of racist policies, including the Johnson-Reed Actof 1924, which ultimately barred entry to millions of Jews attempting to flee prewar Europe. In work that culminated in "The Mismeasure of Man," Gould levelled city blocks of this literature, exposing its appalling intellectual shoddiness. His book enjoyed enormous popular success and earned him a National Book Critics Circle Award. This was terrific stuff, and it's too bad we won't have more of it. [...]
The biggest of Gould's theories—and the one on which his scientific legacy will surely ride—is known as "punctuated equilibrium." Gould introduced punctuated equilibrium with Niles Eldredge, of the American Museum of Natural History, in 1972. Their starting point was simple: trust the fossils. The fossil record, they said, shows something surprising. Species look unchanged for vast stretches of time and then—suddenly—they morph. Certain species of African snail, for instance, look the same for millions of years and then abruptly change shell shape. The question was why. The traditional answer among evolutionary biologists was that species change gradually, by natural selection, and if the fossil record says different, so much the worse for the fossil record. This attitude isn't quite as cavalier as it sounds. Evolutionary biologists have always believed that the fossil record is abysmally bad. (Imagine trying to reconstruct Western history from two snapshots, one of Pontius Pilate and the other of Evel Knievel.) Moreover, biologists can see gradual adaptive change happening around them. (Think of antibiotic resistance.) So, the argument went, we're better off extrapolating from what we can see clearly now than trusting a fragmentary record of what allegedly happened then.
Gould and Eldredge believed otherwise. They said that the pattern of long stasis punctuated by sudden change is real. It doesn't reflect gaps in the data; it is the data. [...]
Echoing arguments made by the naturalist Ernst Mayr, [Gould and Eldredge] claimed that speciation involves "genetic revolutions," episodes of extensive genetic change that shake up much of an organism's genome. Going even further, Gould and Eldredge argued that only speciation—only passage through a genetic revolution—is sufficiently violent to break the binds of developmental constraints. The result is that all evolutionary change is restricted to rare moments of species-splitting. Lizards can't just go changing tail length; they can do so only when splitting into different species. So much for Darwinism. [...]
Gould's second defense is far more important. Early in the debate, he began to reassess just what was revolutionary about punctuated equilibrium. He came to think that the truly outrŽ aspect of the theory was something called species selection. In Darwin's account, natural selection acts at the level of organisms, not at the level of species. Some organisms are better adapted to their environments than others, and so have more progeny. Imagine, for instance, two kinds of moths belonging to the same species. One is white and easily seen by bird predators; the other is brown and often mistaken by birds for a dead leaf. The result is that the brown moths typically have more offspring: brown moths have a higher "fitness" than white ones. The percentage of brown moths will, consequently, increase with each generation. This is normal "organismal selection"—it yields organisms that neatly fit their environments.
The evolution skeptic reading this essay feels like a kid in a candy store--he hardly knows which sweet treat to grab off the shelf first. Surely one's eye is caught by the umpteenzillionth recourse to that specious case of the peppered moths. But on the other hand, how can one pass up the way Gould sought to save evolution from the damning testimony of the lack of a fossil record by simply proposing that the fossils actually reflected how things evolve--one day we were australopithecus the next homo sapiens (or however that famous wall chart went) with no messy need for gradual change. Truly, were he right, Darwin would have been dead. But as Mr. Orr points out, this theory was refuted as easily as pointing at the dog at your feet, which has obviously changed gradually from the ur-wolf he began as many moons ago.
Posted by Orrin Judd at September 26, 2002 11:22 PM
Everybody thinks he understand Darwinism
because it can be stated so simply. Well, so
can Einstein's energy equation, but not
everybody thinks he can pontificate on that
without study.
Gould was a superb publicist, of himself
especially. Nothing in his and Eldredge's
"punctuated equilibrium" was not already
in Mayr's "modern synthesis," as anybody
who reads Mayr can easily determine.
Gould's career problem was that the modern
synthesis was pretty complete, like, say,
the theory of heat. You can investigate
particular cases, but nobody's going to give
you any prizes for a "big idea" (in Wittfogel's
sense of the term) in Darwinism. It's been
done.
And Gould did not say, in "Mismeasure of
Man," that there are no differences in
intelligence among men, only among groups.
This may or may not be so. Nobody knows
how to measure "it" or even, as Gould
argued, that "it" exists. Gardner has since
made cogent arguments that there should
be five (or maybe seven) "it"s.
What Gould said was that the distribution --
the bell-shaped curve -- is indistinguishable
in whatever group you test it. This would
certainly be unremarkable if said about, say,
the ability to play tennis, which is obviously
as evenly distributed among Australians as
Swedes.
But we know how to measure the ability to
play tennis. We don't know how to measure
intelligence, so staking out a bold position
about it is -- well, unintelligent.
Harry:
Yet physical apptitudes are not evenly distributed, are they?
The dog breeding comparison, re human groups and intelligence, is specious, because in the case of dogs we
bred them for different characteristics of intelligence, loyalty, fetching etc. So dogs prove that some sort of selection can
wreak huge changes in morphology, temperment and intelligence, but for species that evolved in the wild, there is nothing so obvious as a human master selecting who can breed with whom. So there is no evidence that, e.g., different races evolved under such different selective conditions that intelligence would be favored in one race over another.
That isn't to say that some racial differences aren't attributable to natural selection -- e.g. increased sickle cell anemia in blacks, which is directly correlated with resistance to malaria and is distributed, in Africa, in precise accord with malarial hotspots. Matt Ridley goes into other such examples in his amazing Genome
(grade: A+
). (BTW, this example is the sort of thing that makes people question the so-called "biological basis of race," because even in Africa, not all "blacks" carry the sickle-cell allele.) There is simply no similar evidence for intelligence selection difference between races.
Charles:
So we are asked to believe that a distinct ethnic grouping can develop a unique resistance to malaria (a different type of hair, different skin color, different eye color, different bone structure, etc., etc., etc.), yet no group's intelligence can possibly differ from another's? This is charmingly PC but risible as a scientific theory.
Selection pressure has to be intense to get results. The facial characteristics of Mongols (flat nose, structure of fat etc.) are very distinct from other groups, including even other groups that have also experienced extremely cold environments.
This implies a severe pruning event -- sometimes called a bottleneck -- or, more likely, a founder event followed by radiation.
Either way, the selection came down to either/or.
But it is impossible to imagine such a severe selection for intelligence. Since humans can transfer knowledge, and even the dullest can flip a light switch and take advantage of the combined intelligences of Faraday, Maxwell and Edison, there can hardly be selection for intelligence.
Besides, if you think you can measure intelligence, to follow Orrin's line of thought, your proof would have to be to find a human group, measure its intelligence and find that its range did not overlap with the range of some other group. No one has ever done this, no one has any idea how you could do this, and there is plenty of evidence that, in fact, the ranges of mental capacities among human groups are identical.
This is evident even taking into account Sahlins' warning (in "How Natives Think") that there are real differences, culturally, in how different groups interpret the world. There are cultures that do not count beyond two, but you can take any individual out of that culture and easily teach him to count to 10.
Harry:
Why wouldn't superior intelligence be selected for by such survival pressures too? In a region where food was not abundant wouldn't the intelligence to figure out how to secure what there is or to produce more be a favored characteristic?
Jeez, I promised myself that I wouldn't weigh in on this anymore -
OJ, selection has to work with what's there. It's not that hard to select for things that are controlled by a single gene, because you have the allele or you don't. Things that are controlled by many genes are far more resistant to selection. I find it highly unlikely that "intelligence" is controlled by one or even a few genes. The fast/slow twich muscle differences or height differences are controlled by a relative small number of genes and so are easier to select for.
OTOH there's the sigma and environment problems. It may well be that there are genetic based differences in intelligence among human demes, but that the differences in inter-demic averages is smaller than the intra-demic sigma. And we know that intelligence, more than many other genotype expressions, is affected by environment. This makes objective measurement of genetic influence difficult.
Finally, this isn't a problem peculiar to evolutionists. If you agree that there are other genetic differences in racial traits, you have the same problem with genetic determinism. The origin of those differences (evolution or God) is irrelevant.
AOG:
I agree with much of that. There must be many types of "intelligence" and many genes that influence them. How then is it possible that selection has made it possible to differentiate a Masai from a Korean from a Swede at a glance, but we are to believe that their brains are identical?
Note I'm not saying that anyone is more intelligent than anyone else. I'd assume that each group is intelligent in its own way. At the end of the day how do you fifferentiate between the genius of Albert Einstein and Wynton Marsalis?
But the idea that natural selection can raise us up from amoeba to human but can never have differentiated our brains in the slightest seems to be a triumph of PC hope over coherent scientific theory.
Sigh. Intelligence is fungible. Having a propensity to sickle-cell anemia is not.
I, who never invented anything in my life, can benefit from the use of internal combustion engines, recombinent-origin insulin or woven cotton every day.
No matter how much I want it, though, I cannot get sickle-cell anemia.
That's enough. But there is the further point that in a condition of society, lack of intelligence is only occasionally selected against. Orrin, you who freely predict the demise of the Germans before the birthrate of the expat Turks, ought to see that.
The elementary principle of Darwinism is that selection works on individuals to alter populations. But every selective event does not alter a population. When a streetcar ran over Pierre Curie, the overall intelligence of the next generation of Frenchman was not affected.
Why can't we just assume that the Turks are more intelligent than the Germans?
Posted by: oj at September 27, 2002 8:03 PMHarry:
You've also confused knowledge and intelligence. That I can teach you to weave cotton no more makes you intelligent than a tanning lamp makes you a person of color.
No I haven't. If I use somebody's else's
intelligence, then I have got all the benefits
there are to being intelligent, in an evolutionary
sense.
If I learn from some more intelligent person
to lay by grain for the winter, then I am just
as well prepared for the winter as he is. Under
the pressure of selection, we are equal, and
thus there is no selection.
As for Turks and Germans, if one group is
enjoying better reproductive success than the
other -- your claim! -- then that group is
being selected for. We have then to identify
the selective pressure being exerted.
Not, in this case, intelligence, I bet.
In Darwinism, this kind of selection would not,
by itself, result in speciation and would not
result in a different range of functional
characters between the two groups,
though there could end up being
non-functional differences -- skin color comes
to mind. To get speciation, there would
have to be a founder event -- most likely
a behavioral differentiation. (Gould never
talked about such things. He peddled a
simplified and incomplete kind of evolution;
he was a popular teacher but like many
popular teachers, he couldn't really deliver
the goods.)
Mayr's term for this is "population thinking,"
and you find many professional biologists
who never quite understood it, though, like
all the other parts of the modern synthesis,
it is not particularly recondite.
Harry:
As I said of Gould, I find it heartening that folks would rather deny science than accept its implications. The argument that the genes that produce our brains have remained entirely and uniquely stable and unchanged across all races and ethnicities for tens of thousands of years is so obviously impossible under evolutionary theory as to amount to mere faith.
That's a theoretical stance, but where are
your observations? What differences? Among
whom?
There are millions of well-observed characters
that have changed little over hundreds of
millions of years -- the structures of myoglobin
would be a good example.