Sunday, February 20, 2011

Quotations from Richard Lewontin


Darwin's theory of evolution by natural selection in particular is hopelessly metaphysical, according to the rules of etiquette laid down in the Logic of Scientific Inquiry and widely believed in by practicing scientists who bother to think about the problem. The first rule for any scientific hypothesis ought to be that it is at least possible to conceive of an observation that would contradict the theory. For what good is a theory that is guaranteed by its internal logical structure to agree with all conceivable observations, irrespective of the real structure of the world? If scientists are going to use logically unbeatable theories about the world, they might as well give up natural science and take up religion. Yet is that not exactly the situation with regard to Darwinism? The theory of evolution by natural selection states that changes in the inherited characters of species occur, giving rise to differentiation in space and time, because different genetical types leave different numbers of offspring in different environments... Such a theory can never be falsified, for it asserts that some environmental difference created the conditions for natural selection of a new character. It is existentially quantified so that the failure to find the environmental factor proves nothing, except that one has not looked hard enough. Can one really imagine observations about nature that would disprove natural selection as a cause of the difference in bill size? The theory of natural selection is then revealed as metaphysical rather than scientific. Natural selection explains nothing because it explains everything.

“Testing the Theory of Natural Selection” Nature March 24, 1972 p.181


It is the great irony of modern evolutionary genetics that the spirit of explanation has moved more and more towards optimal adaptation, while the technical developments of population genetics of the past 30 years have been increasingly to show the efficacy of non adaptive forces in evolution.

"A natural selection" Nature May 11,1989 p.107



Theodosius Dobzhansky, the leading empirical evolutionary geneticist of the twentieth century, who spent most of his life staring down a microscope at chromosomes, vacillated between deism, gnosticism, and membership in the Russian Orthodox Church. He could not understand how anyone on his or her deathbed could remain an unrepentant materialist. I, his student and scientific epigone, ingested my unwavering atheism and a priori materialism along with the spinach at the parental dinner table.

"The Wars Over Evolution" New York Review of Books October 20, 2005


As to assertions without adequate evidence, the literature of science is filled with them, especially the literature of popular science writing. Carl Sagan's list of the "best contemporary science-popularizers" includes E.O. Wilson, Lewis Thomas, and Richard Dawkins, each of whom has put unsubstantiated assertions or counterfactual claims at the very center of the stories they have retailed in the market. Wilson's Sociobiology and On Human Nature5 rest on the surface of a quaking marsh of unsupported claims about the genetic determination of everything from altruism to xenophobia. Dawkins's vulgarizations of Darwinism speak of nothing in evolution but an inexorable ascendancy of genes that are selectively superior, while the entire body of technical advance in experimental and theoretical evolutionary genetics of the last fifty years has moved in the direction of emphasizing non-selective forces in evolution. Thomas, in various essays, propagandized for the success of modern scientific medicine in eliminating death from disease, while the unchallenged statistical compilations on mortality show that in Europe and North America infectious diseases, including tuberculosis and diphtheria, had ceased to be major causes of mortality by the first decades of the twentieth century, and that at age seventy the expected further lifetime for a white male has gone up only two years since 1950. Even The Demon-Haunted World itself sometimes takes suspect claims as true when they serve a rhetorical purpose as, for example, statistics on child abuse, or a story about the evolution of a child's fear of the dark.

"Billions and Billions of Demons" a review of Carl Sagan's
The Demon-Haunted World: Science as a Candle in the Dark
, New York Review of Books, Jan. 9, 1997



Third, it is said that there is no place for an argument from authority in science. The community of science is constantly self-critical, as evidenced by the experience of university colloquia "in which the speaker has hardly gotten 30 seconds into the talk before there are devastating questions and comments from the audience." If Sagan really wants to hear serious disputation about the nature of the universe, he should leave the academic precincts in Ithaca and spend a few minutes in an Orthodox study house in Brooklyn. It is certainly true that within each narrowly defined scientific field there is a constant challenge to new technical claims and to old wisdom. In what my wife calls the Gunfight at the O.K. Corral Syndrome, young scientists on the make will challenge a graybeard, and this adversarial atmosphere for the most part serves the truth. But when scientists transgress the bounds of their own specialty they have no choice but to accept the claims of authority, even though they do not know how solid the grounds of those claims may be. Who am I to believe about quantum physics if not Steven Weinberg, or about the solar system if not Carl Sagan? What worries me is that they may believe what Dawkins and Wilson tell them about evolution.

"Billions and Billions of Demons" a review of Carl Sagan's
The Demon-Haunted World: Science as a Candle in the Dark
, New York Review of Books, Jan. 9, 1997



If Darwin's revolution was not in proclaiming evolution as a fact, then it must have been in his theory of its mechanism. And what was that theory? Why, "natural selection," of course, which then makes the theory of natural selection the very essence of Darwinism and any doubt about the universal efficacy of natural selection anti-Darwinian. There is a form of vulgar Darwinism, characteristic of the late nineteenth century and rejuvenated in the last ten years, which sees all aspects of shape, function, and behavior of all organisms as having been molded in exquisite detail by natural selection—the greater survival and reproduction of those organisms whose traits make them "adapted" for the struggle for existence. This Panglossian view is held largely by functional anatomists and comparative physiologists who, after all, make a living by explaining what everything is good for, and by sociologists who are self-consciously trying to win immortality by making their own small revolution. Evolutionary geneticists, on the other hand, who have spent the last sixty years in detailed experimental and theoretical analysis of the actual process of evolutionary change, and most epistemologists take a more pluralistic view of the forces driving evolution.

An occasional philosopher has allied himself or herself with the "adaptationists," who give exclusive emphasis to natural selection., and one such, Michael Ruse, makes a characteristic presentation in Darwinism Defended. Darwinism, the representative of objective modern science, is under ideologically motivated attack. Professor Ruse is alarmed: "'Darwinism,' as I shall refer to Darwin-inspired evolutionary thought, is threatened from almost every quarter." Well, not from every quarter, just the right and left flanks, it seems. First, the fundamentalists, supported by Ronald Regan, make a know-nothing assault from the right. No sooner have real evolutionists wheeled to face this attack than they are fallen upon by subversive elements from the left, "biologists with Marxist sympathies" and their "fellow travelers" among philosophers who argue "that any evolutionary theory based on Darwinian principles—particularly any theory that sees natural selection as the key to evolutionary change—is misleadingly incomplete."

Onto the field, mounted upon his charger perfectly adapted for the purpose, with weapons carefully shaped by selection to spread maximum confusion among the enemy, not to mention innocent civilians, comes Professor Ruse, "trying to rescue ... from the morass into which so many seem determined to drag them," "Darwin's life and achievements." In all fairness to Professor Ruse, he did not invent this version of events. The theory that evolutionary science is being brutally beaten and cut with crosses, hammers, and sickles made its first appearance in E.O. Wilson's On Human Nature as the only plausible explanation he could imagine for the failure of sociobiology to achieve instant, universal, and lasting adherence. The situation of evolutionary theory, however, is rather more complex and more interesting than Professor Ruse's Manichaean analysis suggests....

What vulgar Darwinists fail to understand, however, is that there is an asymmetry in Darwin's scheme. When adaptation is observed, it can be explained by the differential survival and reproduction of variant types being guided and biased by their differential efficiency or resistance to environmental stresses and dangers. But any cause of differential survival and reproduction, even when it has nothing to do with the struggle for existence, will result in some evolution, just not adaptive evolution.

The Panglossians have confused Darwin's discovery that all adaptation is a consequence of variational evolution with the claim that all variation evolution leads to adaptation. Even if biologists cannot, philosophers are supposed to distinguish between the assertion that "all x is y" and the assertion that "all y is x," and most have. This is not simply a logical question but an empirical one. What evolutionary geneticists and developmental biologists have been doing for the last sixty years is to accumulate a knowledge of a variety of forces that cause the frequency of variant types to change, and that do not fall under the rubric of adaptation by natural selection. These include, to name a few: random fixation of nonadaptive or even maladaptive traits because of limitations of population size and the colonization of new areas by small numbers of founders; the acquisition of traits because the genes influencing them are dragged along on the same chromosome as some totally unrelated gene that is being selected; and developmental side effects of genes that have been selected for some quite different reason.


from a review of Darwinism Defended: A Guide to the Evolution Controversies by Michael Ruse. It was first published in The New York Review of Books on June 16, 1983 and reprinted in It Ain't Necessarily So: The Dream of the Human Genome and Other Illusions.


It is time for students of the evolutionary process, especially those who have been misquoted and used by the creationists, to state clearly that evolution is a FACT, not theory, and that what is at issue within biology are questions of details of the process and the relative importance of different mechanisms of evolution. It is a FACT that the earth with liquid water, is more than 3.6 billion years old. It is a FACT that cellular life has been around for at least half of that period and that organized multicellular life is at least 800 million years old. It is a FACT that major life forms now on earth were not at all represented in the past. There were no birds or mammals 250 million years ago. It is a FACT that major life forms of the past are no longer living. There used to be dinosaurs and Pithecanthropus, and there are none now. It is a FACT that all living forms come from previous living forms. Therefore, all present forms of life arose from ancestral forms that were different. Birds arose from nonbirds and humans from nonhumans. No person who pretends to any understanding of the natural world can deny these facts any more than she or he can deny that the earth is round, rotates on its axis, and revolves around the sun.

The controversies about evolution lie in the realm of the relative importance of various forces in molding evolution.


"Evolution/Creation Debate: A Time for Truth" Bioscience 31, 559 (1981) reprinted in Evolution versus Creationism J. Peter Zetterberg ed., ORYX Press, Phoenix AZ 1983



To say that genetic differences are relevant to hetero- and homosexuality is not, however, to say that there are "genes for homosexuality" or even that there is a "genetic tendency to homosexuality." This critical point can be illustrated by an example I owe to the philosopher of science, Elliott Sober. If we look at the chromosomes of people who knit and those who do not, we will find that with few exceptions, knitters have two X chromosomes [women], while people with one X and one Y chromosome [men] almost never knit. Yet it would be absurd to say that we had discovered genes for knitting. ... [I]n our culture, women are taught to knit and men are not. The beauty of this example is its historical (and geographical) contingency. Had we made our observations before the end of the eighteenth century (or even now in a few Irish, Scottish and Newfoundland communities), the results would have been reversed. Hand knitting was men's works before the introduction of knitting machines around 1790, and was turned into a female domestic occupation only when mechanization made it economically marginal.

Letter to the editor, New York Review of Books, Nov. 2, 1995


13 comments :

  1. Yes, there are a lot of false assertions in Lewontin's ramblings. The first quotation is flat out wrong. There are tess designed and executed that have confirmed the theory.

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  2. I have to say I always find descriptions of adaptationism very hard to comprehend. I never know how to interpret it - is it a serious suggestion that eg Dawkins doesn't know about genetic drift? That E.O . Wilson is oblivious to developmental constraints? Or is it more of a stylistic complaint, that these things aren't emphasised enough and that natural selection should never be mentioned without also mentioning lots of other things at the same time?

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  3. I'm also confused about the essence of the disagreement. This seems to be one of Lewontin's key paragraphs.

    The Panglossians have confused Darwin's discovery that all adaptation is a consequence of variational evolution with the claim that all variation evolution leads to adaptation. Even if biologists cannot, philosophers are supposed to distinguish between the assertion that "all x is y" and the assertion that "all y is x," and most have. This is not simply a logical question but an empirical one. What evolutionary geneticists and developmental biologists have been doing for the last sixty years is to accumulate a knowledge of a variety of forces that cause the frequency of variant types to change, and that do not fall under the rubric of adaptation by natural selection. These include, to name a few: random fixation of nonadaptive or even maladaptive traits because of limitations of population size and the colonization of new areas by small numbers of founders; the acquisition of traits because the genes influencing them are dragged along on the same chromosome as some totally unrelated gene that is being selected; and developmental side effects of genes that have been selected for some quite different reason.

    Is the claim that Dennett disagrees with this? Does he say he disagrees?

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  4. rjw says,

    I have to say I always find descriptions of adaptationism very hard to comprehend.

    Here's a good rule of thumb. If you have trouble understanding what people mean by adaptationism then you are an adaptationist.

    It's sorta like being a right-wing conservative. If you can't understand why people are upset about right-wing conservatives then you probably are one. :-)

    I've never met a pluralist who didn't understand the problem.

    Or a socialist.

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  5. Well, thats one way to say "fuck off" to an honest enquirer.. reductio ad tea party?

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  6. @rjw,

    How hard have you tried to really understand the issue? Did you read the Spandrels paper?

    It's not that hard. It has to do with how you go about doing science.

    When faced with a new observation how do you go about forming hypotheses? Do you just leap to the assumption that a character has to be adaptive and start looking for explanations that support your assumption or do first try and figure out whether a character actually confers a beneficial effect?

    The adaptationist program skips right over the possibility that a character may be non-adaptive—or not even heritable— and jumps right into making up just-so stories. Evolutionary psychology is an excellent example of this way of approaching a problem.

    The pluralist approach demands that you assume as your default hypothesis that the character is neutral. You then need to actually show that it's adaptive before you eliminate all non-adaptive explanations.

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  7. The theory of natural selection is then revealed as metaphysical rather than scientific. Natural selection explains nothing because it explains everything.

    A bit extreme, which is of course why you quoted it. I'm sure you would not deny either that natural selection is one of the drivers of evolution; or that if one is careful (like Darwin), it can be used as a scientific principle that explains some but not all aspects of evolution.

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  8. Larry, thanks for the response. I agree with everythng you've said there, I have read the paper, I have read some books by Gould. I completely agree about a lot of evolutionary psychology. I remain unconvinced that "the adaptationist program" as you describe it is subscribed to by many of the people it seems to be assigned to. Thats my issue - the whole thing sometimes sounds like "if you don't continually bang on about how useless natural selection is in the face of these constraints, I will assign you this set of indefensible views and condemn them". Maybe this impression is unfair because its formed decades after the main debate was had. Anyway thanks for making clear what the accusation is - it is just what I had always thought and understood.

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  9. @rjw,

    Okay, I got confused when you said, "I always find descriptions of adaptationism very hard to comprehend."

    What you meant, apparently, was that you understand the definition but you just don't think the adatationist program is actually practiced by anyone. My snarky comment from earlier referred to that fact that this point is often made by adaptationists who all claim that they know about drift, punctuated equilibria, and mass extinctions, so what's the problem?

    Yet you agree with me that most evolutionary psychologists are guilty of adaptationism so that makes at least some scientists who haven't gotten the message.

    They are not alone. One of the recurrent debates on Sandwalk is about the existence of junk DNA. Opponents of junk DNA tend to practice adaptationist thinking.

    You see the same conflict when we start talking about "design." There are some biologist who claim that life has the strong appearance of design and that design is due to natural selection (not God). There are others—I am one—who just don't see such a strong appearance of design. Instead, we see mostly the results of tinkering and accident with selection acting whenever it can.

    We argue against the Intelligent Design Creationists by pointing out that things don't look at all like design. Dennett and Dawkins, on the other hand, emphasize selection as the mechanism behind the strong appearance of design. Neither of them ever talk about random genetic drift as an alternative mechanism of evolution and they rarely place any emphasis at all on the things that don't look designed.

    It's a debate about worldview not just about how to do science correctly. What's the best way to view the history of life on Earth? What's the best way to communicate this view to the general public?

    Should we be emphasizing the insights of Charles Darwin in 1859 and promoting natural selection as a synonym for evolution or should we be promoting the random, accidental, nature of that history and emphasizing the modern discoveries in evolution?

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  10. Opponents of junk DNA tend to practice adaptationist thinking.

    Really? Who are these people? The only kind of opponents of junk DNA that I know are creationists. Who are the others?

    Should we be emphasizing the insights of Charles Darwin in 1859 and promoting natural selection as a synonym for evolution or should we be promoting the random, accidental, nature of that history and emphasizing the modern discoveries in evolution?

    That's a very (mis)leading question, Larry. Who but a fool would say no to emphasizing the modern discoveries? And yet, only a fool would juxtapose "the insights of Charles Darwin in 1859" with "promoting natural selection as a synonym for evolution". Then, you very much make it sound like the modern discoveries in evolution do not at all confirm that natural selection is indeed very important at all levels of organization (while, yeah yeah, drift occurs and other mechanisms exist to shape variation).

    Lastly, I find it odd that you would just paste these rather extreme quotes of Lewontin without comment. Are we to assume that you are a blind fan of everything the man stands for? That you agree with every single word quotes here? That you even agree with his and Gould's politically induced attacks on E. O. Wilson?

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  11. Really? Who are these people? The only kind of opponents of junk DNA that I know are creationists. Who are the others?

    This is one of them.

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  12. @larry, right. My confusion has always stemmed from working out who is being criticised. I think the main difficulty comes with identifying ( imo ) outright crazy evolutionary psychology people with eg Dawkins and Dennett.

    Here I've made the mistake of thinking that because I've excluded the evo psych lot from my idea of people seriously talking about evolution, that everyone else has too. To me it seems akin to taking Chopra seriously ib medicine or quantum mechanics - use of a pop version of science to justify whatever crap is come up with.

    I would say it would be advisable to seperate the two kinds of criticisms: one about actual crazy adaptationism, and one about lack of emphasis on non selective mechanisms in popular science books and even university programs. Treating the second as if its the same as the first - eg making people wonder if you really think Dawkins doesn't know about genetic drift - just leads non experts like myself to get very confused about the nature of the debate. It also makes all the arguments seem like strawman bashing because the set of views being criticised clearly aren't really identifiable with the supposed targets .

    (Please don't take any of this to mean I don't have issues with eg Dennetts way of explaining things)

    Cheers

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  13. Here is a good example of adaptationist thinking in modern biology. The abstract and the Science News story.

    It is amusing that the author is a geneticist from University of Chicago.

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