Thoughts, Ideas, Observations


Richard Lewontin, It Ain't Necessarily So:  the Dream of the Human Genome and Other Illusions.  New York Review Books, 2000; and The Triple Helix:  Gene, Organism, and Environment.  Harvard University Press, 2000.

Reviewed by John Bedell

Our species suffers from a widespread condition that one might call neomania, the absurd fascination with new things and the belief that every innovation will completely transform the world. I remember hearing a self-proclaimed philosopher saying on the radio that the introduction of computer chips using fuzzy logic would overturn our whole way of thinking about ethical questions, leading us to replace black/white characterizations with shades of gray. Yes, I thought, it's true; nobody ever considered that statements might be be partly true and partly false until 1985.

These days the field of neomaniacs is dominated by the molecular geneticists and their hangers on, who think the deciphering of the human genome is the most important event in human history. From Walter Gilbert's famous statement that the sequencing of the genome will explain "what it means to be human" to the steady barrage of news bulletins announcing the discovery of genes for cancer, schizophrenia, obesity, homosexuality, and what-all, we are constantly assured that genetics is the key to the future. The human genome, it has been said again and again, is the "Holy Grail" of biology. Medicine will be revolutionized, but not just medicine; the editors of Science have expressed the faith that genes will soon be found for alcoholism, drug addiction, unemployment, and violence, so that our oldest and most dispiriting social problems are on the verge of being solved by biological science.

Fortunately for our sanity, neomania is not universal. There are always people unimpressed by the latest craze, and some of them fill the role of the debunkers, calling our attention to the flaws in the new vision. When it comes to molecular genetics, the best debunker working today is biologist and statistician Richard Lewontin. The essays collected in these two volumes show him at his best, as a wise skeptic dissecting trendy baloney, and at his worse, as a close minded curmudgeon unwilling to even consider that ideas he finds repugnant might nonetheless be true.

I first learned of Lewontin when I read his magnificent New York Review essay on the National Bioethics Advisory Commission's report on human cloning. Lewontin worked point by point through the report's confusions, evasions, and obfuscations, and then offered a lucid explanation of what the commission was really up to:

...the possibility of human cloning has produced a nearly universal anxiety over the consequences of hubris. The testimony before the bioethics commission speaks over and over of the consequences of "playing God".... It is impossible to understand the incoherent and unpersuasive document produced by the National Bioethics Advisory Commission except as an attempt to rationalize a deep cultural prejudice.
I was deeply impressed by Lewontin's level-headed approach to this emotion-laden subject, and I grabbed up both of these books as soon as they appeared on the shelf at my public library. It Ain't Necessarily So is a collection of nine of Lewontin's essays, including the piece on cloning, along with some debates from the New York Review's letter columns and brief epilogues that bring the science of the older pieces up to date. The Triple Helix is a little book, originally published in Italian (?), that examines the complexity of interactions among genes, organisms, and their environments. Anyone interested in the possibilities and perils of the new biology, and of its intersections with philosophy and politics, would probably enjoy and benefit from both.

Consider just one of the claims coming from the molecular geneticists these days, that genes make organisms. In the most obvious sense, this is simply false. DNA is a storage bank for information on how to make proteins, and it makes nothing; the actual construction of proteins is done by other parts of the cell. Nor is this a trivial objection. There is no obvious translation of base pair sequences into birds or reptiles, any more than there is an obvious translation of the 0s and 1s on a computer disk into pictures of Tonya Harding's wedding night. The translation has to be made by some operating system. In the case of the cell, the translation system is extraordinarily complex, and we are only beginning to understand how it works. The notion that merely sequencing the genome will tell us how an organism is made is not true, because only when we also understand how the instructions coded in DNA are read and put into operation by the cell will we have information we can actually use. Sorry for all you Jurassic Park fans, but dinosaur DNA would be useless for making a dinosaur in the absence of an egg cell containing the operating system that could read and act on that DNA's instructions.

Nor can one exclude the organism's environment from the process. In many organisms, the genes specify quite different forms in different environments. Ordinary English ivy has two different leaf forms, one for tendrils that are climbing up and another for those that are falling downward; other species add further complexities. In the course of explaining these interactions (in The Triple Helix) Lewontin mentions an important discovery about how different individuals of the same species respond to different environments. He reproduces an imaginary graph, created by IQ theorist A.R. Jensen, purporting to show how individuals with different heredities might respond to different home environments. On this imaginary graph, the vertical axis represents hereditary intelligence, while the horizontal represents the quality of the environment, from "impoverished" to "enriched." The lines on the graph all trace out neatly rising curves, showing that an increasingly enriched environment always produces greater intelligence, but that at any level of enrichment, the people with the best genes are always the smartest. Research on how real organisms respond to environmental variation shows nothing of the kind. Take multiple cuttings from four yarrow plants and grow them at several different elevations, and you find that no particular elevation is best for all of them, and that no plant does better than the others at all elevations. The real graph of their responses is a crisscrossing mess strikingly different from our Dr. Jensen's fantasies. So why does anyone think there is one sort of enriched environment that is better for every child?

I am profoundly impressed by the intellectual achievement embodied in our new understanding of cellular biology, and I love to read about the latest elucidations of our molecular machinery. I have to agree with Lewontin, though, that so far the practical results have been unimpressive. None of the new drugs for heart disease work as well as regular exercise and a moderate diet, the treatment recommended by Hippocrates. Compared to sanitation, the health effects of which were perfectly understood by the Romans, or the early antibiotics, which were developed without any idea of how they worked, the new biochemistry has done very little to extend or improve human life. It is not certain yet that biotechnology can, even in principle, have such effects. We have more or less doubled the average human life span in the modern era, and a further doubling would require a profound rewiring of the mechanisms that control our progress from life to death. How this might done, and what price might have to be paid for it, are unknown.

Lewontin has a skeptical approach to science, and he often dwells on the inadequacies of our knowledge. His most amusing essay covers a major American survey on sexual behavior, puncturing the authors' scientific pose and demolishing point for point the conclusions they base on what people willing to respond to such a survey say about their own sexual behavior. Lewontin's real purpose in most of these essays, though, is almost always not debunking for its own sake, but debunking in the service of his own ideological predilections. He is waging a one-man war against what he calls "genetic determinism," the belief that the behavior of organisms is determined by their genes. He opposes genetic determinism because he believes that it legitimizes conservative politics; indeed, he sometimes implies that no one could be interested in genetic determinism except as part of a conservative ideology. Lewontin has no trouble producing examples of this intersection, from Oliver Twist to The Bell Curve. The general thesis that modern social distinctions are only expressions of biological differences was blandly stated by Harvard psychologist Richard Herrnstein in 1973:

The privileged classes of the past were probably not much superior biologically to the downtrodden, which is why revolution had a fair chance of success. By removing artificial barriers between classes, society has encouraged the creation of biological barriers. When people can take their natural level in society, the upper classes, by definition, have greater capacity than the lower.
No need for stock speculators to feel guilty that they earn so much more money than school teachers or farmers--it's all just a reflection of their different biologies.

Lewontin is having none of this. To him, all such arguments are merely the latest rationalizations brought forward by the ruling class to justify their dominant position.  Lewontin's political views are clearest in his review of Gould's The Mismeasure of Man, where he attacks at length not just the inheritibility of IQ but the whole notion that "intelligence" is a real thing that can be measured even in principle. I am somewhat sympathetic to this view. I have already noted somewhere on this site that although I am pretty good at IQ tests I couldn't sell food to the starving, and we all know people who seem to excel at one sort of mental activity while failing miserably at others. And  yet, can the notion of "intelligence", so widespread and deeply entrenched, really correspond to nothing at all? Have Lewontin and Gould never noticed how much easier it is to explain a new idea or procedure to some people than to others? I notice that on the back of my copy of It Ain't Necessarily So is a little blurb from Stephen Jay Gould that says, "Lewontin is simply the smartest man I have ever met." So, Dr. Gould, if intelligence is not a real thing but a creation of IQ mavens, what exactly did you have in mind?

What do we actually know about the inheritance of mental characteristics? Rather little, it seems to me, despite the immense sound and fury of the debate. Modern twin studies and comparisons of biological with step siblings suggest that for measurable characteristics, genetic differences account for at least half of the observed variation within western societies.  I've seen this number in enough places, with enough reputable names attached, to think that it has some research basis, but for the life of me I can't figure out what it actually means. IQ tests are by far the most highly standardized and well studied method of quantifying human mental variation, but even they have a rather dubious relationship to the world outside the testing room. How, exactly, does one quantify the spectrum of human violence, or of artistic skill? Can one assert that artistic ability is 50% hereditary without some means of measuring how much better Beethoven is than Barry Manilow, or Tolstoy than Clive Cussler?

The whole notion of quantifying the inheritance of such qualities seems to me absurd. Yet, despite the problems with all these questions, I cannot follow Lewontin in dismissing the whole notion of inherited mental characteristics. People do not look exactly like their parents, but, on average, they look quite a lot like them, and I can think of no reason why this general resemblance should not extend to every other aspect of the organism, from spleen function to musical talent. This is also the general impression most people derive from everyday observation, and it seems to be supported by such science as we have on the subject. Nowhere in either of these books does Lewontin come out and say that we inherit nothing but skin color, but that certainly seems to be the thrust of some of his statements. Like those he criticizes, Lewontin lets his judgment slip a little when dealing with the subjects he cares most about.

The occasional extremism of Lewontin's anti-gene stance raises the whole question of why people invest their thinking about human nature with so much ideological intensity. Sometimes it seems to me that a whole range of questions simply cannot be intelligently discussed in America because ideological conflict crowds out the desire to know the truth. Genetic determinism is one. Like most Americans of my generation, I am much impressed with the influence of heredity and very curious about genes. But instead of turning me into a libertarian, this only makes me more certain that the government must take strong measures to protect equality. I cannot see how the morality or immorality of earning huge profits from stock speculation while factory workers go hungry is affected in the tiniest degree by the presence or absence of genetic differences among people. Nor--and this is a point I would like to shout again and again from the rooftops of the academy-- do the possible political uses of an idea have any bearing on whether it is true. Lewontin brilliantly exposes the exaggeration and distortions of the genetic extremists, but it is always a mistake to reject any idea just because it is admired by fools and hucksters. There is something to inheritance, and much potential for good in the new molecular genetics; I only hope we can keep our heads about us to work out what those things are.

March 24, 2001

From the 
Commonplace Book

"Medical scientists speak of 'preventing' deaths by curing disease, but the evidence is that death
cannot be prevented, only postponed at best."

--Richard Lewontin


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