Michael Ruse Defends Adaptationism

Jerry Fodor and Massimo Piattelli-Palmarini have just published a book called What Darwin Got Wrong. I haven't read the book but from the reviews I've seen, it's not something that I'm looking forward to. However, their main thesis is that natural selection has been oversold as an explanation for evolution and I have a great deal of sympathy for that point of view. Furthermore, I think that adaptationism—the assumption that adaption is the default explanation for everything that evolves—is a scientifically bankrupt position. I'm a pluralist.

Michale Ruse has reviewed the book for boston.com and I'd like to analyze his review in order to reveal where he goes wrong.

Origin of the specious
This new critique intends to rebut Darwin’s ideas but seems largely to misunderstand evolutionary theory.

“What Darwin Got Wrong’’ is an intensely irritating book. Jerry Fodor, a well-known philosopher, with coauthor Massimo Piattelli-Palmarini, a cognitive scientist, has written a whole book trashing Darwinian evolutionary theory - the theory that makes natural selection the main force of change in organisms through the ages.

Like I said, I haven't read the book so I can't really comment on the specifics. But I can comment on what Micahel Ruse says about the book.

He begins by claiming that the authors misunderstand evolutionary theory. That may be true but it will become painfully obvious that Michael Ruse is not enough of an authority to make such a claim.

Let's begin by seeing how Ruse describes evolution. He says that "Darwinian evolutionary theory" is the theory proposing that natural selection is the main force of evolution. Strictly speaking, that's correct. What we're interested in debating is whether "Darwinian evolutionary theory" is correct as defined.

The answer is clearly "no." Random genetic drift is the most common mechanism of evolution as long as you define evolution properly. Thus, as a explanation of evolution, Darwinism is not as good as a pluralistic evolutionary theory. Although Ruse isn't clear on this, it's well known from his previous writings that he thinks of Darwinism as the preferred explanation of evolution and not just of adaptation. In fact, he rarely distinguishes between the two.

I conclude, right from the beginning of the review, that Michael Ruse has a poor understanding of evolutionary theory.

You would think that somewhere in the pages there would be one - just one - discussion of the work that evolutionists are doing today to give a sense of how the field itself has evolved. Peter and Rosemary Grant on Darwin’s finches for example; Edward O. Wilson and Bert Hölldobler on ant social structures perhaps; David Reznick on Trinidadian guppies perchance? But no such luck. A whole book putting in the boot and absolutely no serious understanding of where the boot is aimed.

Aren't those interesting examples? Just what you'd expect from a myopic adaptationist. What about studies of molecular evolution which are almost entirely based on neutral changes and random genetic drift. You'd think that someone who claims to be on top of modern evolutionary theory would recognize the growing evidence of non-adaptive change, wouldn't you?

Why write such a book? The authors would respond in two ways. First, in a section that would be better described as “What Darwin Didn’t Know,” rather than “What Darwin Got Wrong,” they tell us that today’s cutting-edge biology has all sorts of explanations of organic origins that make Darwinism otiose. We learn that life is constrained by the laws of physics and chemistry, and that something like natural selection, which supposedly molds organic life into sophisticated bundles of adaptations, simply cannot get off the ground. To the contrary, evolution is all a matter of molecular development, guided by the self-organizing laws of the physical sciences.

To which Darwinians can only respond, wearily again, that they have known about constraints since “The Origin of Species.’’ Because body weight cubes as length increases, you cannot build a cat the size of an elephant. The elegant feline legs needed for jumping must be replaced by tree trunks able to carry many pounds. And examples of plausible self organization have been fitted into the Darwinian picture for many years. A favorite example is the way that many flowers and fruits (like pine cones) exhibit patterns following the Fibonacci series, made famous by “The Da Vinci Code.’’ Chauncey Wright, a 19th century pragmatist, discussed these patterns in detail, showing how formal rules of mathematics can nevertheless yield organisms that are highly adapted and that natural selection is the vital causal element. The rules give the skeleton, and then selection fills in the details. The order of a plant’s leaves may be fixed, but how those leaves stand up or lie down is selection-driven all of the way.

In their various published articles Fodor and Piattelli-Palmarini have over-emphasized "constraints" and they come off sounding like some new-agers who have just discovered molecular biology.

But the fundamental point about constraints is interesting and it's true that adaptationists have been forced to recognize it every since Gould and Lewontin published the Spandrels paper back in 1977. Most adaptationist still don't get it and Ruse is no exception, although in this case he probably gets it better than Fodor and Piattelli-Palmarini. Ruse admits that there are certain physical constraints on the way plant leaves evolve, for example, but he then goes on to say that everything else is an adaptation. How does he know this? How does he know for sure that the differences in the leaves of red maples, silver maples, and sugar maples are all due to natural selection?

The second half of the book is a frontal attack on natural selection itself. The main argument is very odd. It is allowed that there is differential reproduction. Some organisms have many offspring, and some have just a few. It is even allowed that the reason why some succeed and others don’t might have to do with the superior features possessed by the winners and not the losers. At which point you might think: Darwinism wins, because what else is there to natural selection?

Not so fast, however. Our authors take as gospel the argument of the late Stephen Jay Gould and the geneticist Richard Lewontin that although some features may be adaptive others may not. This argument is then used to say that if an organism succeeds in life’s struggles, you can never conclude that a particular feature was essential for this success, because there may be other features linked to it. Perhaps it was the latter features that were essential. Natural selection fails therefore as a mechanism of change.

I take it as "gospel" that random genetic drift is an important mechanism of evolutionary change. Why do I get the impression that Michael Ruse has doubts about this? Why does he use the word "gospel" to refer to the ideas of Gould and Lewontin but not Dawkins and E.O. Wilson? Isn't that strange?

Hundreds of evolutionary biologists have written about random genetic drift and other possible mechanisms of evolution (e.g., molecular drive, species sorting). They do not claim, as Ruse implies, that non-adaptive traits become fixed because they are "linked" to adaptive ones. Is this how Ruse dismisses random genetic drift—by treating it as a by-product of natural selection?

In fairness, Fodor and Piattelli-Palmarini do go on about linkage in their published articles so Ruse is right to mock those silly claims. However, I wish he didn't make things worse by implying that hitchhiking is the explanation for drift.

The existence of random genetic drift does not mean that natural selection "fails. " It just means that natural selection by itself is not a sufficient explanation for evolutionary change. Perhaps Fodor and Piattelli-Palmarini are confused about this—other reviews suggest that this is the case—but Michael Ruse seems to be trashing the very idea that something other than natural selection could be at play.

I read all of this stuff a couple of times. I am just not used to people giving the opposition everything for which they have asked and then plowing on regardless. But, even if you ignore the apparently shared belief that selection is at work - we may not know which features were crucial, but that hardly stops us saying that there was selection at work - the other points hardly crush the Darwinian. It has long been known that features get linked. And in any case, we can ferret out which features are most useful and which are just along for the ride. Suppose eyes, which are surely necessary, are linked to tufts of hair, which may not be. Well, experiment and see how the organisms get along without eyes and then without hair.

Non-adaptive features can arise even if they are completely unlinked to adaptive feature. Ruse doesn't seem to understand this basic concept of population genetics. And Ruse needs to take his own advice. Rather that just assume that a feature is an adaptation, you need to do the experiments. This applies to the leaves on a tree and the beaks of the finch.

Fodor and Piattelli-Palmarini will not allow this, because apparently we are now ascribing conscious intentionality to the nonconscious world. We are saying the eyes were designed for seeing in a way that the tufts were not. And they stress that the whole point of a naturalistic explanation, to which the Darwinian is supposedly committed, is that the world was not designed.

In response, one can only say that this is a misunderstanding of the nature of science. The Darwinian does not want to say that the world is designed. That is what the Intelligent Design crew argues. The Darwinian is using a metaphor to understand the material nonthinking world. We treat that world as if it were an object of design, because doing so is tremendously valuable heuristically. And the use of metaphor is a commonplace in science.

Darwinist are always saying that the world has the appearance of design. Of course it's a metaphor but it's a metaphor based on the idea that natural selection, and not God, is the designer.

Ruse and his fellow adaptationists treat the world as if it were an object of design because they are psychologically committed to the idea that natural selection is responsible for almost everything. They cannot adjust to the fact that much of what we see in living things could be due to accident, or even the fixation of deleterious mutations. That's one of the reasons they have so much trouble with junk DNA and it's why they can't account for so much diversity in populations.

Here's a clue. Life doesn't actually look terribly designed. Get over it. Abandon the metaphor—it just feeds into a false notion of evolution and, incidentally, lends support to the IDiots.

Why then do we have these arguments? The clue is given at the end, when the authors start to quote - as examples of dreadful Darwinism - claims that human nature might have been fashioned by natural selection. At the beginning of their book, they proudly claim to be atheists. Perhaps so. But my suspicion is that, like those scorned Christians, Fodor and Piattelli-Palmarini just cannot stomach the idea that humans might just be organisms, no better than the rest of the living world. We have to be special, superior to other denizens of Planet Earth. Christians are open in their beliefs that humans are special and explaining them lies beyond the scope of science. I just wish that our authors were a little more open that this is their view too.

This is despicable. Evolutionary psychology is a broken discipline. And it's not because there is no genetic components to behavior—of course there is. It's because the field is dominated by adaptationist explanations and crazy "just-so" stories that would make Rudyard Kipling proud.

If you accept, as I do, that humans do all kinds of silly things just because of their culture and superstitions, and not necessarily because they are adaptive, then that makes us more like the other animals and not more special. If you accept that we are products of evolution by accident and not "design" (metaphorically) then that makes us farther removed from a potential designer and not closer to God as Ruse would have you believe.

Ruse and the adaptationists are the ones who skate close to the edge when it comes to supporting Christian concepts of life. They do this by conceding that we look designed when that's simply not the full story.

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[Image Credit: The photo is from Paul Nelson on the Intelligent Design website. It refers to Ruse's idea that evolution is a form of religion. There's something to be said for this idea, especially when it's applied to confirmed Darwinists.]