The Darwin Show

December 25, 2009 • 3:18 pm

Over at the London Review of Books, Steven Shapin, a professor of the history of science at Harvard, analyzes the past year of Darwin festivities, mentioning several books along the way and taking a swipe at adaptationism:

‘Adaptationists’ take it as securely established that organic change proceeds through the natural selection of individual traits, each of which improves the organism’s reproductive chances, that each trait’s evolutionary end-point represents an optimum, and that no other process is needed for an evolutionary lineage to move along through time. But adaptationism has distinguished critics within biology departments – Richard Lewontin, Niles Eldredge and the late Stephen Jay Gould among them – and they have argued that there is a difference between asserting adaptation as a possible means of getting smoothly from evolutionary point A to point B and establishing that this is in fact how organic change has occurred. Maybe there are developmental constraints on how traits change, and change with respect to other traits; maybe some traits are accidental by-products of changes in other traits; maybe evolutionary change is in fact discontinuous; maybe there is a dialectical causal relationship between organisms and the environmental niches to which they ‘adapt’; maybe processes other than adaptation are at work but we just don’t know much about them yet. The adaptationist camp includes Dawkins, Dennett and Pinker – some of the most enthusiastic Darwin Year celebrants. Adaptationists tend to give spectators a misleading picture of the scientific state of play, while at the same time laying claim to a founding father who in fact had reservations about the power and sufficiency of natural selection. There is a struggle among scientists for Darwin’s soul. It is understandable that modern evolutionists should configure history as best suits present purposes, but truth in advertising should be part of the exercise.

This piece is both long and pretty lame, and one gets the idea that Shapin hasn’t really digested the subject — or couldn’t think of  anything new to say about it — and is just phoning in his piece.  But he’s way off the mark in implying that adaptationism is “false advertising.”  Yes, there are constraints on selection and evolution, and yes, some evolutionary psychologists have gone overboard in imputing every human behavior to natural selection on our ancestors.  But perhaps the good Dr. Shapin, head humming with fancy new biology terms like “developmental constraints,” “pleiotropy,” and “niche construction,” would like to suggest something other than natural selection that could explain the wings of birds, the fins of fish, the spines of cacti, and so on.  Prediction: he can’t.

It’s a common ploy to tout the impotence of natural selection by throwing around buzzwords like “modularity,” “genetic assimilation,” and so on.  Philosopher Jerry Fodor did just this in his 2007 attack on natural selection, also published in the LRB.  Look for a book-length sequel in 2010.

17 thoughts on “The Darwin Show

  1. A fairly reputable evolutionary biologist at my institution stunned me recently by asserting that there is no evidence of evolutionary change that is directly attributable to natural selection (NS). His view (as I understand it) is that almost all of the evidence that I find so compelling in support of Darwin’s big Idea (the fossil record, conservation and divergence of DNA sequence data) is merely (or instead only) evidence of common descent and that NS as explication of such data amounts to a ‘just so’ story.

    Perhaps I was stunned because I am naive and, in the most favorable sense of the word, ignorant of this perspective. In any case, I have been stymied in my efforts to refute his assertion. NS is intuitively obvious and, for me, provides the most parsimonious explanation of the many facets of biology that surround us, and yet I am somewhat haunted by the notion that my colleague has a point that I should take seriously.

    Thoughts that might lead me out of these woods would be most welcome.

    1. I agree with your colleague; the evidence he cites is evidence merely for the tree of life.

      But there’s surely other evidence. Consider the observation that the sex ratios in animals are optimal, as mathematically demonstrated by Fischer. Presumably that’s evidence that the processes of reproduction and survival tend towards creating and preserving optimality, at least sometimes, and thus is defeasible evidence for natural selection.

      1. Thanks for the reply, but I apparently miss your point regarding ‘optimality of sex ratios’ as positive evidence for NS as motive force. Perhaps it is because I am not familiar with Fischer’s proof. I will google and learn, or perhaps you could elaborate to make your point more clearly– Thanks!

      2. @Scott

        I was thinking the following. E is (abductive) evidence for a theory T if T implies E (and no better theory T’ implies E). Natural selection, if true, implies that more fit phenotypes survive more often than less ones, and thus proliferate. In the absence of knowledge of what phenotypes are in the ancestral population to be selected for, it is nevertheless sure that optimal phenotypes are more fit than all others (by the definition of ‘optimal’). So ToNS predicts a higher incidence of optimal phenotypes, and thus observation of such phenotypes confirms ToNS. Fischer showed that the optimal sex ratios are 50/50 male/female, and this is what we observe. Similar optimal structures can be observed: photon capture rates for the human retina are close to the limit of what is physically possible. All this, I take it, is good reason to believe ToNS.

  2. Quite aside from the swipe at adaptationism, isn’t his claim that “There is a struggle among scientists for Darwin’s soul” simply wrong? Sure, Darwin thought there might be other factors (and there probably are, as I understand it – genetic drift, for example), and in the absence of knowledge about the means of transmitting information from generation to generation, did not know how adaptive modifications were transmitted, but surely there is no question – is there? – about Darwin’s major achievement, the discovery that the mechanism of evolution is natural selection. I have to say that, even with my slight knowledge of biology, this article seemed completely wrong when I read it the other day. I’m pleased to see that I wasn’t simply wired the wrong way. What other major mechanism is being proposed?

    The heart of Fodor’s position always seemed to me a simple misunderstanding. He says that selection can be read in two ways: either environments select traits for fitness, or selection acts on individuals which struggle and survive or die. But what is being selected when individuals surive are the traits that individuals have and pass on. So there is no fault line here along which the theory comes unstuck in the way he suggests. I have never understood what Fodor was really trying to say. Is it as simple a mistake as I think it is?

      1. Didn’t help me, I have to say, and my first reaction was “right, this is why we ignore philosophers who aren’t named Daniel Dennett.”

        In the comments, MJ links to this posting by one of the commenters, which makes the point that if you follow Fodor’s thinking to its natural conclusion, all of science is impugned. I think he makes a strong case for it, too. In the comments of that post, MJ says that Fodor believes that while biology is reducible to physics, there are scientific theories that are not and gives economics is an example. I can’t see any basis to that argument. If biology is reducible to physics, then economics must be as well, because economics is reducible to psychology, which is reducible to neurology, which is reducible to biology, which puts us back on the path down to quantum mechanics. His argument is that if you create a twin earth and replace the dollars with sea shells, supply and demand will continue to work just as they did before. Well, of course they would, because it’s the psychological concept of money that is important, not its physical form. I and probably everyone else reading this comment uses multiple “forms” of money every day, such as notes and coins, debit and credit cards, or electronic money transfers. It’s the psychology involved that makes giving a cashier a pile of specially marked paper and/or metal an equal exchange for a six-pack of Strongbow, and it’s the same psychology that allows a system like debit cards to replace that pile of physical objects with nothing more substantial than bits on a drive somewhere. By the way, virtual money is nothing new. It’s there pretty much from the beginning, at least from the beginning of banking. A first century BC Roman needing to move money from one end of Rome’s dominions to another just had to send a bank draft and accounts would be credited and debited in pretty much the same fashion they are today. No need to haul around cart loads upon cart loads of silver coins, just tuck a slip of paper into the sinus of your toga and you’re set.

      2. @CarlosT

        The reason Fodor takes economics to be non-reducible to physics is that economic properties are multiply realizable– two things can be as physically different as you like, but possess the same economic properties, so economic properties are not physical properties. You deny this by saying that two things cannot be as psychologically different as you like, but possess the same economic properties– and further psychological properties are physical properties. I won’t argue with the first step (though it’s contentious), but the second definitely seems off. Psychological properties are also multiply realizable– radically different species, robots, or aliens may be physically different from us but nevertheless psychologically identical (e.g. both I and an AI may believe the same things and desire the same things). So psychology isn’t neuroscience, or so say the cognitivists who live here at Rutgers (e.g. Feldman, Gallistel, Pylyshyn, Gleitman, etc.)

      3. RE: Fodor could be right!?

        @MJ: I thought your conclusion in your “Darwin was wrong?” piece was good and clear; so I made a response therein under with a similar title as referenced above.

        Best wishes, Mong 12/30/9usct4:12p; practical science-philosophy critic; author “Decoding Scientism” and “Consciousness & the Subconscious” (works in progress since July 2007), Gods, Genes, Conscience (iUniverse; 2006) and Gods, Genes, Conscience: Global Dialogues Now (blogging avidly since 2006).

  3. I have struggled as well to understand what Fodor is on about. As I did with the quoted paragraph from Steven Shapin, especially the claim that “adaptationists” claim inter alia “… that each trait’s evolutionary end-point represents an optimum…”. Some math modellers may do so, perhaps, for convenience, but I suspect most so-called adaptationists subscribe more to the idea that selected traits, in Herbert Simon’s terms, satisfice rather than optimize (which is why, for example, most of them also point to the apparently ridiculous mechanisms as the best evidence for natural selection), and that the concept of “end-point” is meaningless, except, at best, in retrospect. Worse is the equation of these muddled ideas with the more sophisticated and nuanced viewpoints of, say, Dick Lewontin.

  4. Emmm…excuse me, didn’t Darwin say that if his theory needed supranatural interventions or miracles or whatever you may choose to call them, he would be the first to discard it?
    So what exactly was Shapin trying to say?

  5. I guess the most galling thing about Shapin’s writing is the implication that “Richard Lewontin, Niles Eldredge and the late Stephen Jay Gould” are/were not adaptationists. Of course they are/were. To say otherwise is just silly. They are not adaptationists in the caricatured sense of Shapin (or Fodor), but who is? But, what has that to do with natural selection as the principle mechanism? Has any of this brief pantheon *ever* repudiated natural selection as that? They have, necessarily and obviously questioned it as THE universal and only mechanism, but then so has Dawkins, Dennett, and others of the supposed “adaptationist” brigade. This is just silly science journalism and history: to be ignored.

  6. He pulls a sneaky sleight of hand too.

    He cites Dobzhansky’s famous quote about nothing in biology making sense except in the light of evolution, then later renders it so:

    “To say that nothing in biology makes sense except in light of Darwinism….”

    Oh well, I guess it’s understandable that he should configure history as best suits present purposes, but truth in advertising should be part of the exercise.

  7. I was most dazzled by Shapin’s, “maybe there is a dialectical causal relationship between organisms and the environmental niches to which they ‘adapt’. Is this a political sop to Lewontin? Coming back to it several times, I simply cannot figure out what it might mean. Do organisms post a thesis, then the environment an antithesis, followed by a source other than natural selection and adaptation (drift?, dispersal?) performing the synthesis? Epigenetic effects probably. Yes, that is what he is getting at. Brilliant.

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