MARCH/APRIL 2010
Misunderstanding Darwin
Natural selection’s secular critics get it wrongWhat Darwin Got Wrong
Jerry Fodor and Massimo Piattelli-Palmarini
Farrar, Straus and Giroux, $26 (cloth)
In On the Origin of Species, published in 1859, Charles Darwin made two remarkable scientific contributions. First, he presented an overwhelming case for the relatedness of all living things. Biological diversity, he argued, results from a process of “transmutation” of species—via “descent with modification.” Second, he recognized that the basic mechanism of such change is natural selection: a combination of variations in traits and a selective retention of the variations that contribute to reproductive success.
Descent with modification was accepted quickly. As early as 1872, Thomas Henry Huxley described Darwin as having achieved a revolution comparable to that brought about by Newton’s Principia. Natural selection, by contrast, remained controversial until the 1930s, when Darwin’s ideas were integrated with the genetics of Gregor Mendel and Thomas Hunt Morgan, creating the “Modern Synthesis.” More than 70 years later, thanks to a proliferation of evolutionary explanations and significant new theoretical contributions, the fundamentals of evolutionary biology are reasonably well settled.
To be sure, religiously inspired opposition to evolution persists. Although religious opponents seem to have accepted—at least officially—the relatedness of organisms, proponents of “intelligent design” continue to insist that natural selection is unable to explain some prominent instances of evolutionary change. Their skepticism is based on alleged examples of “irreducible complexity”—an intricate interdependence in the features of organisms that supposedly cannot be explained by Darwinian mechanisms of step-by-step improvement.
Other critics—more sophisticated and scientifically informed—wonder whether natural selection explains as much about evolution as biologists commonly assert. They urge, for example, that causes other than natural selection (such as genetic drift) are important in explaining evolution. Or they argue—overemphasizing something all evolutionary biologists agree with—that natural selection operates against a background of constraints, perhaps stemming from features of genomes. Darwin himself was aware of these complexities about the role of natural selection, and throughout the Origin laments his own ignorance about the extent of that role and what alternative causes of evolutionary change there are. His awareness of how much he did not know led him to cautious formulations: for example, he writes, “Natural Selection has been the main but not exclusive means of modification.”
As in other areas of science, then, lively debate continues, and an interest in deeper and more comprehensive understanding moves the field forward. But even as some scientists suggest that natural selection may be limited in ways Darwin could not envisage, they accept his basic insights and work to improve our biological understanding within the framework he set forth.
In their controversial new book, What Darwin Got Wrong, Jerry Fodor and Massimo Piattelli-Palmarini set out to dismantle that framework. They argue that standard evolutionary thinking—what they call Darwinism—is guilty of a basic logical error, not a mistake in biology but an “intensional fallacy.” That fallacy, they say, undermines the entire enterprise. To be clear, the authors preface their demolition with a disclaimer: in attacking Darwin, they are not supporting any religious view of “origins”; thoroughgoing materialists, they do not think that biological patterns require an intelligent designer. But their criticisms are intended to knock evolutionary theory from its scientific pedestal by demolishing the scientific credentials of natural selection.
Fodor and Piattelli-Palmarini are not biologists. Fodor is a leading philosopher of mind and cognitive scientist, best known for his ideas about the modularity of mind and language of thought; Piattelli-Palmarini is a cognitive scientist. They do not have new data, new theory, close acquaintance with the everyday practice of evolutionary investigations, or any interest in supplying alternative explanations of evolutionary phenomena. Instead, they wield philosophical tools to locate a “conceptual fault line” in contemporary Darwinism. Apparently unshaken by withering criticism of Fodor’s earlier writings about evolutionary theory, they write with complete assurance, confident that their limited understanding of biology suffices for their critical purpose. The resulting argument is doubly flawed: it is biologically irrelevant and philosophically confused. We start with the biology.
• • •
In 1979 evolutionary biologists Stephen Jay Gould and Richard Lewontin published an influential article, criticizing what they called the “adaptationist programme” in evolutionary theory. Some of their contemporaries, they lamented, were much too quick to accept stories about the adaptive advantage of every trait of an organism. According to Gould and Lewontin, adaptationists suppose that every trait contributes to an organism’s reproductive success (its fitness), and exists because of that contribution.
Gould and Lewontin’s critique of adaptationism begins with the observation that the characteristics of organisms are often correlated with one another. Because of those correlations, they argued, evolutionary biologists need to explore the possibility that an allegedly favorable characteristic might be a side effect of something else (a “correlation of growth,” Darwin said). Entering the basilica of San Marco, you might marvel at the wonderful use of spandrels—the tapering triangular spaces filled with mosaics where the dome adjoins the columns. (Too much ink has already been spilled about whether the term “spandrels,” usually confined to two-dimensional spaces, should be used to cover the three-dimensional pendentives in San Marco. We will spill no more.) Struck by the spandrels, you might conclude that the architect designed those spaces so that they could contain mosaics showing the four evangelists.
The basic problem, according to Fodor and Piattelli-Palmarini, is that the distinction between free-riders and what they ride on is ‘invisible to natural selection.’
As Gould and Lewontin observed, however, spandrels are not the result of a design: if you have arches supporting a dome, you also have spandrels. Spandrels are hitchhikers on arches-plus-dome. Or, to take one of Gould and Lewontin’s biological examples, consider the diminutive front legs of the tyrannosaurus. Instead of inventing an adaptive story (“the legs promoted the skill of tyrannosaurus males in sexual foreplay”), the reduction of size may simply be a byproduct of increased growth rates elsewhere. The problem for adaptationism is that it can be hard to know which trait was selected for and which was the free-rider: maybe architects wanted spandrels in order to display mosaics, and built arches-plus-dome as a solution; maybe the tiny legs are for mating, and produce huge hind limbs and an impressive tail as byproducts.
In the architectural case, we can be fairly sure of the intentions of the builders, and so conclude that the use of the spandrels for mosaics was an afterthought. But in a natural case we would need to know how differences in reproductive success were brought about before we could distinguish the selected-for traits from the free-riders. Gould and Lewontin think that we can sometimes figure out the answer, and urged evolutionary biologists to do so by remaining mindful of all the tools provided by Darwin and his successors rather than falling back on an easy adaptationism.
Fodor and Piattelli-Palmarini believe that the spandrels problem is much deeper. While Gould and Lewontin had a nice insight about “correlations of growth,” they ultimately affirmed a “very sophisticated kind of adaptationism” because they took for granted that there can be a genuine fact about which of two correlated properties—say, large hind-quarters and tiny forelimbs—is selected for and which is a free-rider.
The basic problem, according to Fodor and Piattelli-Palmarini, is that the distinction between free-riders and what they ride on is “invisible to natural selection.” Thus stated, their objection is obscure because it relies on an unfortunate metaphor, introduced by Darwin. In explaining natural selection, the Origin frequently resorts to personification: “natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest” (emphasis added). When they talk of distinctions that are “invisible” to selection, they continue this personification, treating selection as if it were an observer able to choose among finely graded possibilities. Central to their case is the thesis that Darwinian evolutionary theory must suppose that natural selection can make the same finely graded discriminations available to a human (or divine?) observer.
Neither Darwin, nor any of his successors, believes in the literal scrutiny of variations. Natural selection, soberly presented, is about differential success in leaving descendants. If a variant trait (say, a long neck or reduced forelimbs) causes its bearer to have a greater number of offspring, and if the variant is heritable, then the proportion of organisms with the variant trait will increase in subsequent generations. To say that there is “selection for” a trait is thus to make a causal claim: having the trait causes greater reproductive success.
Causal claims are of course familiar in all sorts of fields. Doctors discover that obesity causes increased risk of cardiac disease; atmospheric scientists find out that various types of pollutants cause higher rates of global warming; political scientists argue that party identification is an important cause of voting behavior. In each of these fields, the causes have correlates: that is why causation is so hard to pin down. If Fodor and Piattelli-Palmarini believe that this sort of causal talk is “conceptually flawed” or “incoherent,” then they have a much larger opponent then Darwinism: their critique will sweep away much empirical inquiry.
We can clarify their criticism of what natural selection can see by translating it into causal language that avoids personification. Their specific charge is that, with respect to correlated traits in organisms—traits that come packaged together—there is no fact of the matter about which of the correlated traits causes increased reproductive success. In other words they appear to be making the very ambitious claim that whenever there are correlated traits there is no fact of the matter about which of the traits causes any effect.
Consider the famous case of industrially induced melanism in the peppered moth. Supposedly, in landscapes where pollution has destroyed the lichens on the trunks of trees, melanic (black) variants of the moth are better camouflaged when they rest on tree trunks than their lighter, speckled relatives. With improved camouflage, birds and other predators are less likely to pick the moths off the tree trunks. In polluted environments, then, melanic moths are more likely to survive, and hence to leave descendants in later generations. So far, so familiar.
Enter Gould and Lewontin. Maybe moth coloration is a spandrel, and some other property of the moths is both relevant to their proliferation and correlated with their color. For example, evolutionary biologists have observed that moths usually rest by day on the undersides of branches rather than on the trunks of trees. So is the familiar black-as-camouflage story really true? Perhaps a characteristic of the larvae of melanic moths makes them more likely to survive. Or perhaps melanic moths have a tendency to move around less at night, which makes them less vulnerable to being eaten by bats (who care nothing for color). These are interesting alternatives to the familiar story, and the causal hypotheses they introduce can be tested in obvious ways: by examining the rates of larvae survival or by investigating nocturnal motions of moths. And this is what biologists have done. Concerned that an apparent adaptation (a camouflaging color) may be a side effect, they have looked for correlated traits that might figure in some alternative process that would culminate in greater representation of the melanic moths. Despite some controversy in the 1990s, the traditional story seems to be standing up well.
If Fodor and Piattelli-Palmarini acknowledge the evidence that favors the camouflaging-color hypothesis over the moth-larvae and moth-mobility hypotheses, they will have to say that the biologists have not been imaginative enough—that they have overlooked some other correlated trait for which there could be no fact of the matter about whether it, or the black coloration, caused the reproductive success.
What exactly could this trait be? One possibility, suggested by remarks in some of Fodor’s previous writings, would be that there are two different properties: being black, on the one hand, and matching the environment on the other. Is there a fact of the matter as to which of these causes the reproductive success?
There are two ways to interpret the question, and each one has a good answer. The first focuses on the specific environments in which melanic moths are selected: the woods that have suffered from industrial pollution. In these environments, being-well-camouflaged and being-black come to more or less the same thing. In a polluted environment, a black moth matches the surroundings better than a lightly speckled moth. The result is less predation and hence increased survival and procreation. Biology focuses on the process, and biologists are quite willing to identify how selection is acting by picking out any feature of the organisms that is central to the process. So if you are focused on this specific environment, then it is a matter of indifference whether you talk of selection for black color or for camouflage or for decreased predation. Among these options, you can talk as you like. Any of them will distinguish the selection process of the traditional industrial-pollution story from the potential rivals, such as larval resilience, or lower nocturnal mobility.
A second interpretation would consider all the woody settings in which the moths can be found. Speckled moths will be at a disadvantage if they rest on polluted trees (they will be picked off more easily), and melanic moths will be similarly vulnerable in unpolluted surroundings. Biologists can test and confirm these causal facts, and can report their conclusions by finding that, across the whole spectrum of environments, matching the color of the trees causes increased reproductive success. Of course, saying that accords perfectly with, and generalizes in a particular direction, the thought that, in the polluted woods, being black causes a moth to match its environment better. There are no great mysteries, no inscrutable distinctions between spandrels and properties selected, no general troubles about distinguishing between the causal powers of correlates.
Why then do Fodor and Piattelli-Palmarini think that problems about selection-for are omnipresent? Because they envisage a vast space of properties and expect proponents of natural selection to discriminate among all the rivals. Not only is there a property of being-a-melanic-moth, there is also a property of being-a-melanic-moth-and-smaller-than-Manhattan. These properties are not only correlated in the world’s actual moth populations, they are correlated universally. Maybe it is impossible, even with the most rarefied genomic technology, to build a moth bigger than Manhattan. If so, the correlation between these properties could not be broken. How then could there be a sense in which one of the properties—being-a-melanic-moth—rather than the other—being-a-melanic-moth-and-smaller-than-Manhattan—caused the increased reproductive success?
We suggest that the question deserves a shrug. Serious evolutionary biology is concerned with comparative causal claims among interestingly different alternatives. Is it the black coloration rather than the larval resilience or the nighttime lethargy? Good question. Is it the coloration rather than coloration-and-being-smaller-than-Manhattan? Silly question. Fodor and Piattelli-Palmarini create the idea that natural selection is a fine-grained discriminatory enterprise that distinguishes among all the properties philosophers can discover (or invent?) precisely so they can demolish it. The authors’ error is to note correctly that there is some indeterminacy and then to conclude that indeterminacy is total: that there can be no matter of fact with respect to causal efficacy as between any of a set of correlated properties. Evolutionary theory, Fodor and Piattelli-Palmarini say, contains, at its core, a causal notion—selection-for—that picks out the properties that cause increased reproductive success. They then declare that there is no fact of the matter about what causes increase reproductive success when the candidate properties are correlated with others. But correlation is omnipresent, so evolutionary biology totters.
This critique makes no contact with the practice of evolutionary biology, where the focus is on the causal processes (for example, camouflage) that lead to reproductive success, the salient properties (say, melanism) that play a role in them, and whether other causal processes (say, stillness at night) might have been at work.
• • •
A different example (due to the philosopher Elliott Sober) can offer further clues to the ways in which the authors inflate the position they attack. Sieves are very simple selection devices. Imagine a sieve with a mesh that will allow balls with radii of one inch to fall through, but that will retain those that are even a tiny bit larger. Suppose that balls with several different radii—one inch, two inches, three inches, and four inches—are placed in the sieve. The one inch balls are blue, while the larger ones have different colors. The blue balls fall through, and the others remain. In one sense the sieve has “selected” the blue balls, although it has not “selected for” being blue. That is because size not color is what matters to the transmission. Using the language Fodor and Piattelli-Palmarini employ, we might say that the property of having a particular color (blue) is a spandrel or free-rider.
Yet we might divide the properties up more finely. The balls with radius one inch have a diameter of two inches, a circumference of 2π inches, a cross-sectional area at the equator of π square-inches, a volume of 4π/3 cubic inches, etc., etc. Lots of geometrical properties are correlated—indeed perfectly so. Which of these properties caused the balls to fall through? The question is idle. A person could select for radius rather than diameter, but the sieve cannot. Yet that makes absolutely no difference to the judgment originally made: the sieve selects for size, rather than for color. To recur to the language of indeterminacy, there is a determinate matter of fact as between color and size but not as between radius and diameter.
If Fodor and Piattelli-Palmarini’s criticism is taken seriously, then there are no facts of the matter about causal claims in any field of inquiry.
Just as ordinary people recognize that sieves select for size and not color, evolutionary biologists work hard to discover the mechanisms at work in producing increased frequency of types of organisms. They are happy if they can trace the prevalence of melanic moths to coloration, camouflage, and decreased predation rather than to superior survival of larvae. They remain unperturbed when asked if it is coloration rather than camouflage, or rather than lowered predation, or rather than being-melanic-and-smaller-than-Manhattan.
We can know the fact that the sieve selects for size rather than color without the presence of any actual environments in which size and color are not correlated because we understand the causal mechanisms: we know what would have happened if size and color were de-correlated in this device, namely, there would still be selection for size rather than color. A real causal difference is a feature of the world that can be investigated in different ways, for example, by looking at mechanisms; by considering real cases of de-correlation; or by looking at cases where the selection pressures are slightly different, such as unpolluted environments in which light moths are at a disadvantage. The way evolutionary biologists think about causation allows for the discussion of causal process in any of a number of ways—even those strange ways that invent peculiar properties. Fodor and Piattelli-Palmarini almost grasp this point where they discuss the “prima facie” plausibility that polar bear color is a result of selection for matching the environment rather than selection for whiteness, a difference that, as we saw in the analogous case of the moths, can be real and can be investigated.
Have we dismissed the questions the authors would foist on evolutionary biology too quickly? We think not. As already noted, if their concerns are taken seriously, correlated properties pose a general problem. For example, since human beings are smaller than Manhattan, the properties being-obese and being-obese-and-smaller-than-Manhattan are perfectly correlated in the human population. So there are no facts of the matter about causal claims in epidemiology. And the same goes for atmospheric science, geology, engineering . . . and, indeed, everything else.
• • •
Despite the powerful claims of evolutionary biologists and all other scientific investigators, suspicion might linger that these insightful outsiders have identified commitments the practitioners have missed, that they have exposed presuppositions that have gone unrecognized because of the fuzziness of everyday reflections. To address such suspicions, we need to treat Fodor and Piattelli-Palmarini’s critique in its own terms. Setting the scientific practice to one side, let’s see if they have the philosophy straight.
They allege that Darwinism is guilty of an “intensional fallacy.” To explain what they have in mind, we need to introduce two ideas: intensionality and coextensive properties.
The authors introduce intensionality by considering the substitution of terms for one another in sentences. There are some sentences in which, if you substitute one name for another, and both are names for the same thing or person, you always go from a true sentence to a true sentence, or from a false sentence to a false sentence. “Madonna” and “Louise Ciccone” name the same person. The sentence “Madonna is a woman” is true. If you substitute “Louise Ciccone” for “Madonna,” you obtain the sentence “Louise Ciccone is a woman,” which is also true. Not all sentences work this way. Our world is full of people who do not know that Madonna is Louise Ciccone. If Bert is one of these people, then the sentence “Bert believes that Madonna is a star” may well be true, even though “Bert believes that Louise Ciccone is a star” is false.
This phenomenon is not a trivial linguistic matter but actually reveals something deep about something real. Thinking that someone is a star always works via some specific way of thinking of the person; you may think of the person under another guise as well, and under that guise you may not think the person is a star. An important feature of our thought—that we can think about the very same things under very different guises—is expressed by the linguistic facts. There are some contexts, such as “ is a woman,” in which substitution of names that name the same entity preserves truth (or falsehood); these contexts are said to be extensional. Other contexts, such as “Bert thinks that is a star,” allow for changes from truth to falsehood under similar substitutions; these are intensional.
The authors’ entire argument depends on their claim about the intensionality of selection-for. Are they right about this?
Now for the second piece of terminology: two properties are said to be coextensive if and only if they apply to exactly the same objects. Such properties are (in the more familiar terminology we used earlier) correlated. Being-a-melanic-moth-and-smaller-than-Manhattan is coextensive with being-a-melanic-moth; being a sphere whose radius is less than one inch is coextensive with being a sphere whose diameter is less than two inches.
Turning from terminology to substance, Fodor and Piattelli-Palmarini’s central thesis is that selection-for is intensional:
There can be coextensive but distinct phenotypic properties, one (but not the other) of which is conducive to fitness, but which natural selection cannot distinguish. In such cases, natural selection cannot, as it were, tell the arches from the spandrels. That being so, adaptationist theories of evolution are unable, as a matter of principle, to do what they purport to do: explain the distribution of phenotypic traits in a population as a function of its history of selection for fitness.
The idea is that natural selection will favor individual organisms which carry both of two coextensive properties: having large hind-quarters and having diminutive front legs. Since all individuals who have one of the two coextensive properties must have the other as well, their reproductive success will not distinguish the two properties. But selection-for requires distinguishing such coextensive properties: the large hind legs and tail are selected-for, the tiny front legs are not. That is what the authors mean when they say that selection-for is an intensional context.
Here, then, is the problem restated: the causal processes at work in evolution cannot distinguish between coextensive properties, but selection-for requires that they be distinguished. In cases of selective breeding (or church architecture), the breeder (or architect) knows what he is selecting for, and that distinguishes the two coextensive properties. In natural selection, however, there are no intentions of a breeder to appeal to, no intelligent designer, no architect who is aiming to build a dome and happily creating spandrels as necessary byproducts. We cannot appeal to the intentions of Mother Nature, so the intensionality must come from something else: Fodor and Piattelli-Palmarini suggest that the only possibilities are to suppose that there are laws of nature or facts about how things would have been under somewhat different circumstances that determine that one, but not the other, of the coextensive properties is the property selected for.
Fodor and Piattelli-Palmarini take this intensionality of selection-for to be central to Darwinian theorizing:
Not just selection-for but a whole galaxy of other concepts that adaptationist explanations routinely employ suffer from the same disease. These include, notably, such notions as ‘ecological niche’, ‘problem of adaptation’ and ‘biological function’, all of which are interdefined with ‘selection-for’ and thus inherit the problems that intensionality occasions.
The upshot is that intensionality sinks the whole apparatus of evolutionary theorizing: “Darwinists have a crux about free-riding because they haven’t noticed the intensionality of selection-for and the like; and when it is brought to their attention, they haven’t the slightest idea what to do about it.”
Describing the issues this way simply restates in technical philosophical terms the basic charge: in the face of spandrels, evolutionary theory requires that there be a process that makes discriminations that natural selection cannot make. So the entire argument depends on the authors’ claim about the intensionality of selection-for. Are they right about this?
In a word, no. In the only way that matters for evolutionary biology, selection-for is extensional rather than intensional—and this suffices for making sense of the use made in evolutionary thinking of the notion of selection-for and correlative notions such as adaptation and biological function.
To see why, consider the notion of causation. If decreasing temperature causes freezing and decreasing temperature is the same property as decreasing mean molecular kinetic energy, then decreasing mean molecular kinetic energy causes freezing. The causal powers of a property—temperature, say—do not depend on how we refer to it or think about it. In that respect, causation is extensional.
But if causation is extensional, then so is selection-for, since selection-for is a causal idea. Consider, once again, the sieve and the balls. The balls that are blue and small fall through, leaving the larger (and differently colored) spheres in the sieve. What is causally responsible for the blue balls passing through the sieve is that they are small, not that they are blue; what is selected for is smallness, not blueness. In sum: being small is the cause, just as being black is the cause of the moths’ reproductive success rather than (say) correlated nighttime lethargy.
Why, then, do Fodor and Piattelli-Palmarini think selection-for is intensional? Perhaps because they are drawing the line between intensional and extensional in a way different from ours, and on their way of drawing the distinction both causation and selection-for come out as intensional. Suppose having-a-heart is coextensive with having-a-kidney: every animal with a heart is also an animal with a kidney and vice versa. Consider “Ernie has a heart, and that caused the blood to flow through his veins. Substituting “has a kidney” for “has a heart” in that context would yield a falsehood: Ernie’s blood does not flow through his veins because he has a kidney. Because of this failure of substitution, we might describe causation as intensional (in a different sense from the one we originally explained). But this kind of failure of substitution is of no significance for evolutionary theory, as we will now see.
When we introduced the notions of intensionality and extensionality, we did so by talking about substitutions of terms that name the same entity. If the substitution of a term leads from truth to falsehood (or from falsehood to truth), even though the term substituted names the very same thing as the term it replaces (as with Bert’s musings on Madonna), that fact is significant because it reveals something important about our thought: that we think about things under guises. It is a quite different matter to consider contexts in which you cannot always replace one term associated with a property with another term associated with a different property that applies to exactly the same things, with preservation of truth and falsity. Different properties—having-a-heart, having-a-kidney—can apply to exactly the same objects. When you are interested in causation, however, you are not concerned about guises. What is of concern is the identity of the causing property. Having a heart but not having a kidney is causally efficacious in pumping blood, no matter how you describe having a heart. What we have are not two guises for the same thing, thus not intensionality in our sense, but two distinct properties that apply to the same things.
If the authors want to mind their neighbors’ business, they should spend a little time discovering just what those neighbors do.
The authors are entitled to pick how they want to use the term “intensional.” Maybe they will suppose (as we do) that intensionality is marked by the failure to preserve truth (or falsehood) when terms are replaced by other terms that name the same thing—when one guise is substituted for another. Or perhaps they will prefer a different notion, signaled by failure to preserve truth (or falsehood) when terms that are associated with distinct but coextensive properties are substituted. The essential point is that however they choose, causation and selection-for always travel together. If they take the first approach, both will be extensional; if they opt for the second, both will be intensional. Their argument turns on mixing criteria, taking one version in one place and a different one elsewhere.
We can explain the notion of selection-for in evolutionary reasoning so that both selection-for and causation are extensional. Further, on this way of reconstructing both notions, there can be a fact about which of two correlated properties is selected for and which is a free-rider. Fodor and Piattelli-Palmarini’s argument collapses.
As mentioned earlier, they think that because of the extensionality of causation and the intensionality of selection-for, causation alone cannot be the basis of selection-for, so appeal must be made to something else—the intentions of a breeder or claims about what might have been or laws of nature. As a result, their book is filled with discussions of philosophical issues about contrary-to-fact claims and scientific laws. But all of these discussions—lengthy and obscure—explore ways out of a false impasse. They are needed only because of the authors’ misunderstandings of the basic issue: that selection-for is a causal notion, and, since causation is extensional, so is selection-for.
That said, however, one final detail bears notice: although contexts of causation and selection-for are extensional in the respect mentioned, contexts of explanation are notoriously intensional. Does that mean that there can’t be evolutionary explanations? Not at all. Nature determines which properties are causally efficacious, and hence what is selected for. Then we theorists can find out about this and give explanations based on what is selected for. Thus if nature tells us that it is melanic color rather than larval resilience or nightime lethargy that was selected for, then we thinking beings can give (intensional) explanations in terms of melanic color rather than the other properties. In giving the explanation, we (thinking beings) describe the property in our preferred way.
• • •
Fodor and Piattelli-Palmarini take the role of philosophy to consist in part in minding other people’s business. We agree with the spirit behind this self-conception. Philosophy can sometimes help other areas of inquiry. Yet those who wish to help their neighbors are well advised to spend a little time discovering just what it is that those neighbors do, and those who wish to illuminate should be sensitive to charges that they are kicking up dust and spreading confusion. What Darwin Got Wrong shows no detailed engagement with the practice of evolutionary biology, nor does it respond to the many criticisms that have been leveled against earlier versions of its central ideas. In this latter respect, the authors resemble the creationist debaters who assert that evolution is incompatible with the second law of thermodynamics, hear detailed refutations of their charge, and repeat their patter in the next forum.
We admire the work that both Jerry Fodor and Massimo Piattelli-Palmarini have produced over many decades. We regret that two such distinguished authors have decided to publish a book so cavalier in its treatment of a serious science, so full of apparently scholarly discussions that rest on mistakes and confusions—and so predictably ripe for making mischief.
Fodor and Piattelli-Palmarini respond to Block and Kitcher in a Web-only exchange.
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About the Author
Ned Block, Silver Professor of Philosophy, Psychology, and Neural Science at New York University, is author of Consciousness, Function, and Representation.
Philip Kitcher, John Dewey Professor of Philosophy at Columbia University, received a Lannan Foundation Distinguished Book Award for Living With Darwin.
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thanks to block and kitcher for the excellent review.
All we can really learn from F & PP is that even really smart people can look extremely stupid when they arrogantly traipse into a field they haven't even attempted to understand and start pontificating. The Dunning-Kruger effect strikes again!
I don't know whether Fodor's critique of Darwinism is ultimately correct or not, but I'm disheartened by its not-very-thoughtful dismissal, both in this review and in the community at large.
http://www.evolutionnews.org/2010/02/id_the_future_kicks_off_academ.html
Now, I don't want to surrender the terms of discussion to creationists. However, when such incompetent thinking is enshrined with tenure, we can expect problems ahead.
"'But if causation is extensional, then so is selection-for, since selection-for is a causal idea.' It is not at all difficult to see that this step is invalid."
Sure, but Block and Kitcher say more than this. They give a causal definition of selection-for. They write:
"To say that there is 'selection for' a trait is thus to make a causal claim: having the trait causes greater reproductive success."
I think it's pretty clear that this definition doesn't introduce any intensionality.
If that's meant as a stipulation, it's a highly contentious one, and leaves the central issue behind.
Remember that Fodor accepts evolutionary history; what he denies is that there is a theory or a science. So he accepts that some traits caused greater reproductive success, and even that there is a sense in which this fact explained why those traits became prevalent. What Fodor disputes is the mechanism: Darwinism, Fodor claims, has it that traits that would cause greater success are selected for -- this is meant to explain why they became prevalent. And he has some pretty compelling arguments against this idea.
Now maybe Block and Kitcher are dancing around the claim that this is a mischaracterization of the commitments of Darwinism. I suspect that that critique might be right. But the way to evaluate it is to look at the details of how claims about selection are used in evolutionary biology. And anyway, they don't say that that's what they're doing. They say that Fodor is committing to denying natural causation. And this just strikes me as way off.
Jeremy Goodman,
Surely that sentence you quote names only a necessary condition. A necessary and sufficient condition would need to rule out *deviant* causal chains.
So one question is whether any (true) necessary and sufficient condition would remain extensional.
Block and Kitcher acknowledge that Fodor disputes only the mechanism. And they show why Fodor's arguments are actually not very compelling—at least to my satisfaction. Which are these compelling arguments that remain?
Furthermore, Block and Kitcher do look at how claims about selection are used in evolutionary biology. That is what the whole first half of this article is about. It is possible, using controlled experiments, to isolate causal factors and thereby ascertain which stories about selection make sense and which don't.
And you have misunderstood if you believe they are saying that Fodor is committed to denying natural causation. They are arguing that that is the logical conclusion to be drawn from the book. They know that Fodor would not deny the possibility of causation in every context, so they are hoisting him by his own petard, showing how his theory is only coherent if causation is never discernible.
I think you could make a nominalist case against Block and Kitcher—that what they call causation in nature is actually just a matter of how human beings describe things. But we're not on quite such rarified epistemic terrain. Certainly Fodor and Piatelli-Palmarini wouldn't defend themselves on those grounds.
To the best of my knowledge, Fodor has a view of causation where a causes b just in case there is a covering law: A -> B, such that a has A and b has B. So whenever a causes b, there'll be a fact of the matter which property or properties of a are such that in virtue of them, a caused b, namely all those properties X such that there is a law X -> B, where a has X and b has B (for some B). So according to Fodor, there are lots of facts of the matter about what causes what, and in virtue of what.
But when there's no covering law, there's no real causation. Fodor's example is that of history. Suppose Frenchman tend to lose battles and all and only Frenchman are short. Is it because they're short or because they're French that they lose? Or because of some other property correlated with Frenchness and shortness? Well, none of the above. There's no fact of the matter because there are no laws of the form: French -> lose or short -> lose. There just aren't any laws of history, not even ceteris paribus laws.
This is also Fodor's view regarding natural history (evolution). White polar bears proliferate. Is it because they're white or because they're snow-colored? No fact of the matter *because* there's no law of the form snow-colored -> proliferate, and no law of the form white -> proliferate. There aren't even ceteris paribus laws of this form.
Furthermore, as I read Fodor, this is what the "seeing" metaphor is doing. Natural selection can't "see" the counterfactuals like 'had the bears been white but not snow-colored, they'd've not proliferated' because they aren't entailed by biological laws, because there aren't any such things. These counterfactuals are true, but not sufficient to ground causal claims involving phenotypic properties-- because they're true in virtue of the laws of fundamental physics, and the physical state of the world, not laws of biology involving phenotypes.
I'm not saying Fodor's right. I just think that on at least this point, Block & Kitcher have his view wrong.
Intensional constructions resist substitution for co-extensive terms. Intentional constructions resist substitution for co-referential terms. "Necessarily" is intensional but not (as Kripke showed us) intentional. "Believes" is notoriously intentional (as Frege discovered). Intentional constructions are intensional but not vice versa.
Fodor is not confused about this. He always means intensionality by "intensionality". The reviewers don't and
the conflation renders the reviewers criticisms gibberish.
These reviewers really ought to know better-- and I rather fear they really do.
Anyway, the gist of the F&PP criticism seems to me to be a (almost Humean) form of general scientific skepticism: whenever there are no factual laws regulating some phenomenon (what in one of the comments above was referred to as ‘covering laws’), there can be no science of this phenomenon, and retorting to statistical methods is a feeble cover-up. But then, in which contexts exactly are there covering laws? Quantum mechanics looks like a tricky case, for example; history is a plausible case for the absence of covering laws, but what about, say, sociology? Block and Kitcher draw the implication that F&PP’s criticism would affect all sciences based on causal explanation-phenomena; the comments here suggest that this is not really the case because Fodor does hold a robust notion of ‘covering laws’ in some contexts. But what are these contexts exactly? Physics? Chemistry? Presumably, the criticism will hold in all other contexts; in that case, nothing so special about evolutionary biology, and the point being made really pertains to general philosophy of science, it would seem.
A phenotype is the set of all properties of an organism. These properties may be identifiable and measurable by an observer (what we call traits), or unobservable and unmeasurable. Selection is a population-level phenomenon and so we assume some number of individuals in a particular population in some environmental context. Let us first say that this population consists of individuals with the exact same phenotypes. Any differential reproductive success between individuals in the same environmental context is by chance and will not change the makeup of the next generation, and so we would say that there is no selection and there is no evolution.
Next, we change the population so that it includes several different phenotypes. If individuals in the population have differential reproductive success, but this success is not due to a difference between phenotypes, and if the phenotypes of the offspring are positively correlated with their parents (what we call heritable), then the frequencies of the different phenotypes may change by chance from one generation to the next. In this case, we do not have selection, but we do have evolution by random processes (i.e. genetic drift).
Finally, we take our population with several phenotypes, and in a particular environmental context, the individuals with phenotype A are reproductively more successful than the other phenotypes in the population, B, C, etc. If all the phenotypes of the offspring are positively correlated with their parents, then it is easy to see that the frequency of A will increase in the population with respect to the other phenotypes. In this case, we have selection and we have evolution.
Now, the question becomes, can we identify a particular property of A that causes it to have greater reproductive success than the other phenotypes for a given environmental context? F&PP argue for no, and B&K argue that, to the satisfaction of evolutionary biologists, we can, at least in principle. The comments in this thread criticizing B&Ks critique do not seem to take issue with how evolutionary biologists do biology, and so the debate centers around coming up with an answer that satisfies philosophers.
I am not competent to discuss intensions, intentions, causal requisites, etc., and so I hope others will breakdown the theory I have laid out above into these philosophical terms. I believe I can offer a covering law to meet Michael Johnson's logic. I may be mistaken about the construction of a covering law, and if I am, I hope someone will set me straight. Suppose that there is a single property, a, of A that is different from every property of B, and that when A and B are found in the same environmental context, A will have greater success than B in reproducing than is expected by chance. The frequency of A will increase in the next generation, and we say this change in frequency is d(A). If this relation holds in every environmental context, then we can say a -> d(a) is the covering law of selection. F&PP argue, I believe, that there might exist a and d(a), but we cannot say d(a) occurs in the next generation because of a in the previous generation, because there are other properties coextensive with a, such as a', in which we could also say a' -> d(a).
Is this the proper translation of F&PPs argument to theoretical evolution terms? Does this help in determining the validity of F&PPs argument or B&Ks critique?
What caused the bears with thick white fur to be more successful? Was it the thickness of their fur, or the whiteness? Is there a determinate answer?
Yes, there is. It was the thickness. Thickness and whiteness are different physical properties of fur. Thickness protects against cold, whereas whiteness does not.
I see nothing conceptually problematic about this. I therefore see nothing conceptually problematic about distinguishing advantageous traits from free-riders. I therefore have no idea what F&PP were thinking, even after reading their book.
One of Fodor's arguments is that selection for requires the truth of certain counterfactuals (involving the same properties as the those involved in the selection for claim) and these counterfactuals require the existence of certain laws (involving the same properties) and- Fodor argues- it is doubtful that there are such laws. Another argument is that knowledge of claims about what traits are selected for requires knowledge of certain counterfactuals and if the the counterfactuals involve situations that can't be manipulated by us (say because they are historical) then that requires knowledge of certain certain laws but it is doubtful that we can have such knowledge (especially if there are such laws.). My own view is that Fodor is wrong to think that biological counterfactuals need to be grounded in biological laws and he may be wrong that there are no or few biological laws of the sort he thinks are needed to ground "selection for" counterfactuals; though he is certainly right that, cases of moths aside, we usually cannot obtain much evidence that is relevant to historical biological counterfactuals and where we can it is not the theory of natural selection that provides the backing for the counterfactuals (in fact I think most biologists and B&K will agree with this last point and correctly point out that contra Fodor this does not show that there is anything wrong with natural selection as a general account of one of the mechanisms that underlies evolution... but F&Ps point concerns whether claims about "selection for" are true and can be known). Block and Kitcher are wrong to think that Fodor's account generalizes to an attack on all causation or all counterfactuals. Fodor thinks that there may well be laws (and we may know such laws) of meteorology, sociology etc. but that there are not laws connecting e.g. the coloration of polar bears to their reproductive success. Although a number of issues may be together by F&P they have a point that when there are no laws in the same vocabulary as historical counterfactuals it is very difficult to obtain evidence for them as opposed to others... e.g. "if Gore had been president in 2001 then ....", "if the mutation for lighter fur had not appeared in ......".
Let's go back to Block and Kitcher's example of the sieve, and let's imagine some changes that will bring the analogy closer to how nature works: 1) imagine that the sieve is very large and it contains not just big and small balls, but objects of all different shapes and sizes (sand, marbles, models of the Statue of Liberty, pieces of string, slips of paper, etc.); plus, 2) those objects are slowly but constantly changing through time; and 3) the holes in the sieve are also slowly but constantly changing in size and shape, sometimes closing off altogether.
Now let's shake the sieve and see what happens. Obviously, some objects will fall through (i.e. reproduce) and some will not. But here's the problem. If we then ask what property of a given object "caused" it to fall through, there is no good answer. We can only say that it was lucky: it was in the right place at the right time with the right size and right shape with respect to the hole that it (by chance) encountered.
Of course, we might be able to identify in that particular case the particular path that the object took through the sieve. We could even identify traits that tend to keep other objects stuck inside the sieve. But we definitely cannot say that any of the traits of the first object were "selected for"; we can say (at most) that none of its traits were massively selected against.
From this perspective, the controversial issue is not the fact of evolution but rather the explanatory power of adaptive (i.e. "selected for") explanations. From what I have understood so far, Fodor and Piatelli-Palmarini make a good case that adaptationist explanations do not work. I would be very eager for someone to tell me if I've misunderstood the issue (either the biology or the philosophy, or both!).
That is to say, "spandrels" can be seen absolutely as adaptions: are Gould and Lewontin's evolutionary arguments as wrong as their art historical?
"Of course, we might be able to identify in that particular case the particular path that the object took through the sieve. We could even identify traits that tend to keep other objects stuck inside the sieve. But we definitely cannot say that any of the traits of the first object were "selected for"; we can say (at most) that none of its traits were massively selected against."
Here's the problem with philosophy: the words you choose to describe a particular causal scenario can never have any causal power over that scenario. You can find all the necessary and sufficient conditions you like to prove that EbNS is impossible, but supposing it is true, the ink philosophers spill over whether or not it is doesn't make the slightest difference. It DOESN'T MATTER whether there is selection for trait X or simply no selection against traits W,Y, and Z. Those are simply ways of describing a concrete causal scenario and that scenario will not spontaneously reconfigure itself because Fodor can't find a Boolean calculus to describe it.
The main problem is that Fodor etc. seem to have higher ambitions for scientific theories than any scientists ever did. Take the phenomenon of gravitational lensing: there are many phenomena in the night sky that seem to be distorted or duplicated images, and from these we infer the position and mass of black holes.
We've never directly observed a black hole, mind you. We can't quite be sure they exist, and these incidences of gravitational lensing could have some completely different cause. But we infer that they are black holes because our best gravitational theory predicted their existence, because there are several phenomena besides lensing that are most easily explained with reference to black holes, and because there are no more parsimonious explanations for why we should see such strange feature duplication in the night sky.
That is to say, we infer the existence and causal implication of black holes by inference from best explanation.
Now explain to me how certain flowers come to look like the insects that pollinate them with using any sort of selection arguments. Would you suggest that there is an intrinsic genetic or epigenetic tendency for such plants to examine the bees? Is it genetic drift, i.e. do the flowers actually get bee genes mixed in? You don't even have to find a mechanism that would work better than selection; find ANY mechanism that isn't prima facie absurd. Until Fodor's evolutionary theories can account for orchid morphology, I'll stick with EbNS.
1. Explaining the distribution of a phenotypic trait in a natural population
requires a notion of ‘selection for’ a trait.
2. If T1 and T2 are coextensive traits, the distinction between selection for
T1 and selection for T2 depends on counterfactuals about which would be selected in a possible world where the actual coextension doesn’t hold.
3. The truthmakers for such counterfactuals must be laws about the relative fitness of having the traits.
4. Since any trait may be advantageous in one phenotypic context but disadvantageous in another, there are no laws of relative fitness.
5. For the ‘theory of natural selection’ to explain anything, there must be laws of relative fitness.
6. Therefore, the theory of natural selection can’t explain the distribution of
phenotypic traits in natural populations.
In my view at least 3 and 5 are false. Unfortunately, this review doesn't diagnose what is wrong with Fodor's claim that they are true.
If that's a fair characterization of Fodor etc.'s argument, then I'd like to point out that the review attacks (2) and (4) quite effectively:
(2) If T1 and T2 are coextensive, then selection for one is de facto selection for the other and vice versa. We can simply define T3: T1+T2 and then talk about the fitness implications of T3. In reality, any phenotype we talk about with regard to selection is likely the product of many genes working together, and so to speak coherently of selection of traits, we need to allow recursive or at least hierarchical definitions of "trait." For example, the notion of polar bears being "selected for camouflage" and "being selected for being white" are hierarchical -- "selected for being white" is interpreted as a more concrete implementation of "selected for camouflage." If Fodor's definition of "trait" doesn't allow "selection for being white" to mean the same thing as "selection for matching the environment," then there's something wrong with his definition of "trait."
(4) This argument, if it has any teeth, takes a bite out of the entire scientific edifice -- which the authors point out. Let's make the argument abstract:
"Since any X behaves differently in different contexts, there are no laws governing the behavior of X."
Does this strike you as absurd yet? How about after this:
"Since any cloud of hydrogen gas behaves differently in different contexts (e.g. a vacuum versus an oxygen atmosphere), there are no laws governing the behavior of hydrogen clouds."
It's simply a faulty inference, possibly based on a misunderstanding of what scientific laws are in the first place -- (5) fails for similar reasons.
(3) is so silly only a philosopher could have dreamt it. What is counterfactual by definition has never happened. What has never happened cannot be causally implicated in what does happen. If natural selection happens -- if EbNS is true -- it is not by virtue of things happening, not things not happening. Again, only a philosopher could believe otherwise.
What I learned from this review and the comment thread is that philosophers appear to spend their time developing beautifully embroidered academic b*llsh*t.
Organisms that are better adapted to their environment have greater reproductive success. The trait, or combination of traits, that make them better adapted spread within the population. This process is real and observable. It takes a rare person to spend their days debating whether it is extensional or intensional.
I'm confused. Block and Kitcher contend that, so far as biologists are concerned, a trait's being selected for =df the trait's causing greater reproductive success. So, if you're right that Fodor "accepts that some traits caused greater reproductive success, and even that there is a sense in which this fact explained why those traits became prevalent" then, if Block and Kitcher are right, then this simply amounts to his accepting that some traits are selected for, and that this explains their prevalence. But you write that "What Fodor disputes is the mechanism: Darwinism, Fodor claims, has it that traits that would cause greater success are selected for -- this is meant to explain why they became prevalent."
I'm not qualified to say whether Block and Kitcher are right that causing reproductive success is the only notion of selection-for that biologists should and do care about. But, if they're right about this, their criticism seems sound to me.
John Turri: Block and Kitcher don't *seem* to be offering a mere necessary condition. Also, what kind of deviant causal chain do you have in mind?
Brad Weslake: I suspect Block and Kitcher would deny premise 2. They take themselves to have provided an explanation of why, in moths, being black, rather than being black-and-smaller-than-Manhatten, was selected-for. They do so by invoking a mechanism, not by appealing to counterfactuals. We can, of course, argue about whether their explanation is any good.
p.s. In physics we have laws of great power and generality. We have none yet that we are completely confident will apply under all conditions, e.g. on the Planck scale or during collisions between infinite 3-branes, etc. Therefore I suppose the Fodor would conclude we can make no causal claims.
Given two competing causal claims the one accepted has to make more "independent sense", given other accepted theories and knowledge. So one would be justified in dismissing claims about the efficacy of having the trait of being X-and-smaller-than-Manhattan, for instance.
Scientific holism to the rescue, in other words.
I agree. I am also a biologist, and what I got from the article was that philosophers expect reality (nature, the physical world) to behave in accordance with their weird classifications and terminology. That somehow the world must conform to their baloney.
Scientists learned something long ago that these philosophers seem to have failed to grasp. If the data doesn't fit your theory, discard your theory.
A lot of this is just mind games over what is causation and how is our understanding of something different from the thing itself. From these games they reach silly conclusions through convoluted chains of thought, in which the standard for truth becomes "I defined it so" rather than "this is what I observe in nature". It doesn't surprise me when their conclusions fail to match the observations, or when they are unhappy with the conclusions drawn by scientists, because scientists didn't bother to explore their silly chains of thought.
In reality, if you are puzzling over whether it was the whiteness of a polar bear's hair that helps his survival or the camouflage benefit of white in a snowy environment, you need your head examined. Being white in the snow IS what camouflage is all about. Whiteness and camouflage are just words to express a basic idea, that if the seal can't see the polar bear very well, it will get caught more often, the polar bear will eat more often, and will probably reproduce more successfully, all else being equal. Adding words like "intension" and "extension" adds nothing valuable to this idea, though they may be job security for someone.
In practice, we know that many traits are linked - inheritance of one is often accompanied by inheritance of the other. Not all cases are clear cut, and in many instances we don't KNOW which of these (if any) was selected. We don't pretend to. We just say "more information needed", because unlike philosophers, we don't need to draw conclusions from and about everything.
However, in other cases, you CAN make an argument that makes sense in a biological/evolutionary context, where you can differentiate between the selected trait and the free rider. If a set of genes which confer some resistance to malaria in an area where malaria is endemic happen to be "coextensive" with the trait of having a somewhat pointy chin, you can be pretty sure that it was the malarial resistance that got selected. You may be wrong, but it's a good working hypothesis. If you're a scientist, you'll try to find a way to figure out which. Over time, more data may accumulate which allows you to be more confident about your hypothesis. Or it may not. That's how science grows.
Pretending like everything needs to fit in with your pet terminology or else "Darwinism is junk" is stupid ego-gratification. What's worse is setting up strawmen, criticizing an oversimplified idea of evolution without taking the trouble to observe how evolutionary biologists actually work in the field.
This is probably why science has progressed from burning twigs for warmth to lighting up nuclear reactors for power, while philosophy continues to wrangle about basic stuff while never seeming to get anywhere.
I am not criticizing all philosophers or all philosophy, I know there are some good ones. But I fear that they are weighed down by such a volume of trash in their field that they cannot pull philosophy out from the self-referential self-satisfied circle jerk it has become.
I think we know what's going on. It's right there in the title you chose.
If you want a more detailed view, well, money is what's going on. These two guys write a popular book that they know is going to be quoted by Creationists, ID'ers and other assorted idiots (it already is). This will generate controversy and drive sales. Also, it will keep their names in the public view, through interviews for popular magazines, who knows, maybe TV.
In other words, this academic b*llsh*t is all about money and fame.
Because the natural world is so complex, the contexts in which natural selection works on every population are unique enough that it's hard to find robust generalizable "covering laws" that predict which traits we expect to see favored for particular populations. This is indeed similar to the example of history.
Instead, biologists have to come up with ad-hoc explanations for why the traits actually observed are adaptive ("we know they're the fittest because they survive"): often referred to as "just-so" stories.
If we boil it down to that, it seems like a valid but not fatal criticism of evolutionary arguments. It is true that adaptive traits are whatever the environment happens to select for; biologists are just trying to provide a simplified model of this process that accounts for the causal relationship and matches, to a good approximation actual historical trends, so we can actually understand it.
"What this discussion seems to circle back to is the old argument that the theory of evolution by natural selection proposes the survival of the fittest, in other words that adaptive traits are selected for, and then defines adaptive traits as those that are selected for, making the whole thing a tautology devoid of meaning."
That's all of science. You always look to nature to make up your definitions, so it's no wonder that you refer back to nature to make sure you got it right.
It would be tautological if that's all there were to it. But it isn't. Unlike philosophy, science isn't a closed cycle.
Explanations in science must make sense in the context of all of science. Even in fields that are far apart. Your biological or evolutionary explanation mustn't contradict physics, or else there's a problem
Further, explanations in science must have predictive power. That is often considered a criterion of the quality of the explanation - how much predictive power it has.
The tests for explanations are experiments. Experiments generate more data. This data must also fit into the explanation; otherwise the explanation gets tossed into the trash.
Take a concrete example from evolution. Human skin becomes whiter the farther north you go. Is this an example of selection for white skin? Well, an evolutionary biologist can look at it two ways. First, as you move away from the equator, you get less UV radiation, so the need for black skin in order to survive decreases.
This is not empty theory, it's backed by an understanding of how UV light promotes skin cancer, and how pigments in the skin can have a protective effect against that.
Secondly, decreased pigmentation makes your skin more effective at converting Vitamin D. If you are living in an area with lower sunlight (northern latitudes), then being able to use that diminished sunlight more efficiently is a net plus.
Again, this is not empty theory. We can measure how much Vitamin D is produced with how much sunlight. We can measure how that varies with skin pigmentation. We know Vitamin D is essential, we know the biochemical pathways through which it works, we know the deficiency states its lack can create.
So if an evolutionary biologist concludes that lightened skin with higher latitudes is an example of selection, he's not making a tautology. The circularity is that he is deriving his observations from the natural world, but then also referring back to the natural world to provide explanations. This is good. In science, the natural or physical world is the arbiter of what's a good theory and what's junk.
Circularity in logic is bad. Logic is something in man's mind, and if you have circular logic, you've proven nothing, just restated one thing in two different ways. But this is something different. This is looking at the natural world and asking "what kinds of organisms are alive today? and what kind died out?" Then you ask why, why did X survive but not Y? Obviously, in order to survive, X must have had more reproductive success. This is a corollary of "survive", biologically speaking. Some lay people equate this with "fitness" (a much overused word).
Then you ask "why did X have more reproductive success". The answer is not in your mind, it's out there in nature, if you can find it. This is why we refer back to nature, to investigate the life style of the organism X, compare it to organism Y, try to find biologically sound explanations (that fit in with observations and fit in with the vast amount of prior knowledge we have accumulated).
Then we test these explanations. In evolution, testing is often by making predictions - if my theory about the reproductive success of X is correct, it should also follow that we should observe facts A, B and C in nature. Now go observe nature, and see if you can find A, B and C. If you can, you have strengthened your theory. If not, you need to go back to the drawing board.
The circularity isn't in the logic, it's in the observations. We have only one source that is acceptable for data, and that's the real world. That's where our observations have to come from, that's what are theories and definitions are based on, and that's the measure of how successful our theories prove to be.
To a scientist, this is good. It keeps science from descending into a parlor game or an endless discussion of semantics, and ensures that knowledge continues to grow.
The argument some have made is that if we are unable to come up with generalizable laws in evolutionary theory from which we can derive predictions that explain actually observed adaptations, e.g. that polar bears are white, then we're simply making up plausible-sounding stories for why things are the way they are. And with enough creativity, you can come up with a convincing explanation for pretty much any state of affairs (if you're out of ideas, just call it a spandrel). Human skin pigmentation can be accounted for by referring to D vitamins and cancer, but if humans were various shades of green we could talk about camouflage and predators in different terrains.
I think this is where Fodor's insistence on grounding evolutionary explanations in covering laws becomes relevant. A covering law ensures that we're not just accounting for each adaptation on a case-by-case basis, but are actually able to anticipate and predict adaptations before they are observed.
As others have mentioned, if we look at another example, history is fickle and has not proved particularly amenable to general laws--at least not formal ones--though many have tried. That doesn't mean we're not able to convincingly account for why various events had the outcomes they did, just that the factors we identify aren't robust enough to reliably predict the outcomes of other events. (We are of course able to see certain general trends.) Those who study history are doomed to draw the wrong lessons and repeat some other event they weren't even thinking of, to put it glibly.
In natural history we may be in a similar, though perhaps somewhat better, situation. Nature is brutal, and therefore not quite as fickle as history, and averaged over longer timescales and more individual events, anomalies (e.g. instances where an in general maladaptive trait happened to provide a reproductive advantage just that once) fade further into the background noise. Our plausible accounts can only appeal to biological processes and natural phenomena, not to all the vagaries of human psychology (e.g. the genius of a great general) or society (e.g. "the protestant work ethic"), which makes them less ambiguous. And some degree of experimentation and falsification is in fact possible.
Perhaps for those reasons, I believe evolutionary theory has come a bit further than history in proposing generalized (within constraints) laws of adaptive traits.
That's why I'm saying the criticism is valid but not fatal. Evolutionary explanations have historically had a tendency towards plausible-sounding "just-so" stories, e.g. Thayer's explanation for why flamingoes are pink (to camouflage them against the sunset). Similar charges have been leveled more recently against evolutionary biology. We need to make sure that evolutionary explanations do not slip into more sophisticated versions of "just-so" stories.
"Similar charges have been leveled more recently against evolutionary biology."
It should read "evolutionary psychology," of course.
However, none of this need mean that natural selection doesn't exist (and mind that this is far from being the only possible explanation of evolution: see the beginning of this very review!). It just means that its scientific status is only somewhat more robust that would be that of a kind of history that involved "smoking gun" predictions about data as yet unstudied. (This is not the way most historians currently practice, but it could be.)
Furthermore, there is an obvious logical flaw in this review: the authors state that "two properties are said to be coextensive if and only if they apply to exactly the same objects. Such properties are (in the more familiar terminology we used earlier) correlated. Being-a-melanic-moth-and-smaller-than-Manhattan is coextensive with being-a-melanic-moth; being a sphere whose radius is less than one inch is coextensive with being a sphere whose diameter is less than two inches."
Here they have clearly confused "necessary and sufficient" (IFF) with "necessary" (if). But these are logically distinct. In other words, it is easy to think of a sphere whose diameter is less than two inches that is NOT a sphere whose diameter is less than one inch.
There are some other slippery bits, too, but this is the most obvious one.
Finally, to all the evolutionary biologists who invoke "testing by going back to nature," I would like to know whether you have tested all of your interpretations by making falsifiable predictions about data that would prove your theory invalid if it were to turn out that way, and then actually carried out the experiments or empirical studies to test whether your predictions were true. In theory, this is how it SHOULD work, but I very much doubt that any polar bear biologist has come up with a falsifiable statement of the polar-bear example you keep repeating and tested it. Doing experiments on polar bears is not very common. I highly doubt that this particular claim is anything other than a convincing-sounding but unproven and unprovable hypothesis--which is far from being the same as a scientific finding.
Until you have actually done such experiments/observations, you really are merely telling just so stories. Not everyone in the field deserves this much deference, if any.
Perhaps the most common variety of natural selection is that involved with dealing with parasitic organisms like parasites and bacteria. For example, having genes for sickle cells makes you more resistant to malaria; the biochemistry of the sickle cell disrupts the malaria's ability to reproduce. The causative process seems very clear here. Malaria has killed more people than anything else in human history, and being resistant to it is a clear and obvious survival advantage (ignoring the sickle cell anemia you get with having two copies of the gene). That sickle cells make you more resistant to malaria is not simply statistical and correlational in the way that F&PP allege; we know, to the letter, what change to DNA caused the genetic mutation that results in sickle cells, we know how this DNA alteration affects the manufacture of blood cells, and we know exactly what biochemical mechanism causes sickle cells to cause trouble for malaria.
I fail to see how F&PP can argue that the evolution of the sickle cell gene is not natural selection, given such a clear and demonstrated causal mechanism.
Additionally, I'd like to propose a test of how serious F&PP are. Several modern medical treatments are based on the assumption that replicating the effects of certain genes in people resistant to a particular virus can be useful to treating people. If F&PP are actually serious, they would believe that these treatments are based on a flawed premise. If they truly believed that there was *only* a correlation between having these genes and survival, they would decline such treatments as pointless. If they would not decline such treatments, their argument is essentially trivial, the kind of thing that pragmatic biologists can safely ignore.
Fodor MUST been doing this for the money.
Clearly, this is untrue and silly (I don't mean that you are silly--almost everyone assumes this, both historians and natural scientists alike, simply because they have not paused to consider what they are actually saying). The timescale of historical change is extremely short. Human institutions, social practices, and other historical phenomena--certainly, anything that can legitimately be defined as a historical "event"--change on the scale of a single human lifetime, if not more rapidly, in many cases. That there are "historical fossils" such as monarchy only serves to make this observation more clear: human society of any kind evidently has a much shorter timescale than the history of, say, the coelacanth, or the horsetail. Thus, whatever we can usefully say about human history must appeal to mechanisms that operate at least on the shorter evolutionary timescales--change over years, decades, or centuries, rather than millenia or longer.
It is especially ironic that so many commenters invoke example that are, in fact, historical: in particular, the evolution of resistance to malaria, something that has taken place over historical timescales and as a result of historical phenomena, i.e. the growth and concentration of human populations as reservoirs for the evolution of the malaria organism that could only take place in the context of the invention of pastoralism and agriculture.
If historical "selection" (or whatever causal explanations best account for historical change) is harder to describe than natural selection, it is merely because natural selection is one underlying element of historical selection--and one which is subject to complex feedback with other causal factors, those which social science and psychology, as well as the humanities, attempt to account for. This is not a claim that history will never be understood: quite the opposite. Rather, it is a claim that history is composite, and that it includes biological, social, and humanistic elements, and that we have yet to place these elements in any coherent deterministic hierarchy or to account for the sum total of their interaction in any one case.
As for the idea that these philosophers are to be compared to people who refuse medical treatment: no, they are the equivalent of Jerome Groopman, who argues that "evidence-based medicine" makes sense in some cases but not in others--in the case of how to place a central line, but not in the case of whether to tightly control blood sugar levels in diabetics. This is not a trivial argument. Some evolutionary cases ARE well-defined mechanistically, but to argue that because we can explain SOME cases in clear mechanistic terms, therefore no evolutionary biologist should ever be challenged for telling just-so stories, is dangerous. (Thank you for the evolutionary-psychology example, Gunn H!)
Every emerald we've encountered has turned out to be green, so being green is a property of emeralds. However, we could wake up tommorow emeralds could be blue. That would mean they weren't green like other things, but rather "grue" - green yesterday, and blue tommorow.
This is irrefutable, and not a useless insight, but as other posts have noted , misrepresents what science tries to do. Science does not make claims to universal laws. The laws are very solid theories,w hich might be falsified by new observations.
Of course, all evolutionary theory is inductive - we cannot be certain that the causal properties we describe as adaptive were not really the crucial ones- there is no "ultimate law" that enables us to discriminate. We can only look at all the observations we currently have, and see which ones are perfectly consistent.
They may turn out to not be consistent in light of other unknown observations, but we don't have those observations, so we can't know for certain.
However, we don't have much else. Some philosophy won't even allow that this is a "best explanation, pending further information" - it could be the worst.
If I'm right in understanding, this isn't new, and it doesn't apply only to evolution.
A totally hypothetical, and from a biological standpoint, extremely silly--but perhaps familiar--example of a "humanistic causal factor" is the black slab that falls from heaven in the first 20 minutes of "2001". This is a cultural artifact, whose effect is in the first instance culturally mediated--even though the longer-term effects are represented in (loony) evolutionary terms. Similarly, the (derivative) Coke bottle in the Kalahari.
Again, better examples readily forthcoming. But I wanted to make crystal clear that this was not a crypto-theological attack.
"The argument some have made is that if we are unable to come up with generalizable laws in evolutionary theory from which we can derive predictions that explain actually observed adaptations, e.g. that polar bears are white, then we're simply making up plausible-sounding stories for why things are the way they are. And with enough creativity, you can come up with a convincing explanation for pretty much any state of affairs (if you're out of ideas, just call it a spandrel). Human skin pigmentation can be accounted for by referring to D vitamins and cancer, but if humans were various shades of green we could talk about camouflage and predators in different terrains."
You can indeed make up stories about anything. The worth of those stories, however, depends on the quality of work that backs them up, as I explained.
Indeed, if humans were shades of green we could talk about camouflage. Why not? Evolution doesn't lead singularly to white or green, these things are accidents which were either selected or not, depending upon any reproductive advantage they conferred to the organisms. If they were green, we would be explaining why they were green, and if you could make an argument based on camouflage, that would be fine. It would explain the green-ness, which is a different matter than explaining the white-ness.
It seems you are looking for a single overarching principle or "covering law" that guides it all, and there is none other than "if you produce lots of healthy babies, you have a greater chance of leaving progeny behind in the distant future".
You say:
"I think this is where Fodor's insistence on grounding evolutionary explanations in covering laws becomes relevant. A covering law ensures that we're not just accounting for each adaptation on a case-by-case basis, but are actually able to anticipate and predict adaptations before they are observed."
This is silly. You can't have a general law to anticipate and predict adaptations - evolution is too random for that. What you are in effect asking is that we create some sort of scale on which we can balance the reproductive advantages of mutation X versus mutation Y, and show which one will ultimately triumph. X and Y might be totally different things. To use an example offered in the article, short fore limbs versus large hind limbs on a tyrannosaur. The effects of these 2 things on the life of a tyrannosaur is completely different. One is about locomotion, the other isn't. Locomotion directly affects how it catches prey. Short arms may or may not have to do with something totally different, such as mating. There is just no comparison, and no single scale that can weigh both and assign a number to each for "reproductive advantage".
This can't be done on any fine scale because the random chaotic fluctuations of nature can't be predicted. It's like trying to predict the climate of a region 10,000 years from now (that's the evolutionary time scale). Only it's even more complicated, because climate is only one of many factors that will affect selection. In the tyrannosaur example above, climate will affect the vegetation of the region, which will affect the distribution of herbivores, which are the tyrannosaur's food supply. There are thousands more such factors. And even then, how could you be SURE that you included ALL the relevant factors? In order to establish this scale, we would need to be gods, i.e, we'd need to be omniscient. This is not a human goal, and certainly not the goal of science.
I say "fine scale" because you can obviously make predictions on a coarser scale. If you take a plant and insert a gene which provides protection against a common disease of that plant, obviously the progeny of such a plant will have a huge survival advantage. We've actually done experiments like that, and the predictions match the observations.
The real world is much more complex than any lab. There are completely random things like genetic drift, the founder effect on small populations, random natural disasters like sudden climate changes, volcanoes, earthquakes. Some of these can't be modeled at all, others will take us hundreds of years to reach such a level of sophistication to attempt.
It's fine for a philosopher who looks at this from the outside to say "well, that's the standard I want, that's the sort of covering law I will accept". Biologists know that he's talking out his rear end, he has no idea of what his expectations require. Science proceeds with what we have, not what we would like to have.
To a biologist, a causal connection is one which makes sense scientifically (that is, you can say why X ought to cause Y in mechanistic terms), one which can make successful predictions, and one which is easily falsifiable. Not all causal connections carry equal weight, some are better established than others. But none ever reach the philosopher's desired level of certainty. And guess what, biologists don't care. They don't need that level of certainty, a good working theory is fine, with the understanding that more or better data might change it in the future.
So when you say:
"Evolutionary explanations have historically had a tendency towards plausible-sounding "just-so" stories, e.g. Thayer's explanation for why flamingoes are pink (to camouflage them against the sunset). Similar charges have been leveled more recently against evolutionary biology. We need to make sure that evolutionary explanations do not slip into more sophisticated versions of "just-so" stories."
- then my understanding is that you're saying some explanations are weaker than others, some are more researched and others are less, some make more biological sense, have more data to support them than others. This I can agree with. Of course they're not all the same.
If, however, you are saying that they are so because we lack a "covering law", then I have to say, dream on. We won't get such a covering law. Not tomorrow, probably not in a thousand years. Meanwhile, biology will grind on as always, collecting and integrating more data.
That said, there were several earlier posters who reiterated or tried to reformulate some of the book's central claims from what seemed to me a more favorable approach, so that I had some sense of at least certain core arguments of the book from the posts I had read. Not that if I were then to go and write about the book, I wouldn't need to read it--but I was more responding to the responses, from a different point of view.
Now, I do have the vague (and obviously ill-informed) impression that, as Gunn H. puts in in #39 above,
"I think this is where Fodor's insistence on grounding evolutionary explanations in covering laws becomes relevant. A covering law ensures that we're not just accounting for each adaptation on a case-by-case basis, but are actually able to anticipate and predict adaptations before they are observed,"
that while F&PP themselves may have other motives, and may not primarily be driven by the desire to make evolutionary biology a more powerful explanatory field, nevertheless the critique they mount does have some real lessons for biologists, just as a similar critique could be mounted for any field aimed at explaining how and why populations change over time.
I.e.: it's not enough to put forward a plausible story that doesn't violate other levels of science and accounts for all the evidence you already have. You also need to propose experimental or observational data that would (a) support your hypothesis and (b) disconfirm your hpothesis, or at worst fail to confirm it. Then, ya gotta go test! Presumably this is how actual evolutionary biologists--whether studying E. coli or orchids--actually operate. But when there is the attempt to extend the results of observations and experiments in these well-characterized systems to larger, more natural situations--real species, real disease epidemiology, etc.--speculation and laziness some times come in.
That said, the authors of the book in question do seem to have oversold their case, in the typical controversialist tactic...
"In regards to Megan's response to me, I agree that evolutionary biologists shouldn't be exempt from criticism! Thanks.
But challenging the occasional (or frequent) dodgy just-so story does not seem to be F&PP's intention. If it was, there wouldn't be much to the book beyond "Gould and Lewontin were right!" They, instead, seem to be arguing that *all* explanations involving natural selection are philosophically problematic and therefore must be incorrect (if they are not, in fact, arguing this, then B&K are misrepresenting them).
I think at this point I'm going to have to go and read, if not the book, something by its authors or about them, to see if they're being somewhat strawmanned here. But certainly the view you suggest is not unprecedented even within the philosophy of biology, to my limited knowledge.
So the medical treatment test stands; they are not like Groopman, but more like Deepak Chopra, who argues that modern medicine completely misses the point (at an essentially philosophical rather than evidential level)."
This may be true. I guess I was performing a strong misreading, appropriating their critique of adaptationist explanation as merely "just-so-story" to create a distinction between adaptationist explanations that actually do give rise to further empirical work, and do make falsifiable predictions about its outcomes, and do test them. Polar-bear theories are cute, but not very easy to study. (Do we have the polar bear genome? Anybody know how to make DNA from a polar bear?)
I think that on the level of teasing out the epistemological differences between (1) interpretations for which the only support could be inherent plausibility and failure to contradict the rules of other branches of science and (2) interpretation for which smoking-gun predictions can be made--"If my reconstruction of how this evolved is correct, you will find an intermediate fossil with x specific feature"--and better yet for which falsifying conditions can be imagined--"If you detect evidence of -x trait in a growing population on the same side of the next mountain, then the interpretation I proposed for why my population is mostly x phenotype cannot be valid"--then adaptationist intepretations take on more scientific, and perhaps also philosophical traction. I read a good article on the philosophy of paleontology a couple of years ago that touched on these issues.
Of course, evolutionary psychology is perhaps most prominently the field where untested and untestable just-so stories, sailing free of their original context to land on op-ed pages, cause great problems.
"A covering law ensures that we're not just accounting for each adaptation on a case-by-case basis, but are actually able to anticipate and predict adaptations before they are observed."
@Gabble, I don't think Fodor and PP are looking for the kind of covering law that would solve the meta-problem of induction. Rather, the kind of law that could "anticipate and predict adaptations before they are observed" as Gunn H said.
@David M, when you say
"... dream on. We won't get such a covering law. Not tomorrow, probably not in a thousand years"
you mean that it's OK that natural selection is the primary mechanism of evolution, but that the absence of a covering law of the kind hoped for by Gunn H is not a problem?
Fodor and PP are committed materialists that believe evolution happened. What they are disputing is the view that the primary mechanism for evolution is natural selection. So in other words, they challenge the prevailing view. Of course the prevailing view does not deny the (secondary) role of other mechanisms, but it asserts natural selection as the primary mechanism.
So in order to defeat the prevailing view, Fodor and PP do not have to assert that natural selection exerts no influence. As a matter of fact, they aren't even burdened with showing how another kinds of mechanisms could be more powerful (though this would help). Rather, Fodor and PP are only burdened with showing that the proposition "natural selection is the primary mechanism for evolution" is unwarranted (according to standards of what makes a proposition scientific).
If no covering law can be found, then what is the warrant for the proposition that natural selection is the primary mechanism for evolution? Case by case reflections are fine, and the rationalist's imagination (as opposed to the empiricist's laboratory) is taken with natural selection. As for me, I'm not so down on "just-so" theories, many of them are probably true, it's just that presumably they aren't scientific. I mean, maybe the case by case statements are true, but don't we need a law to generalize, or to predict? And since the mechanism of natural selection is so context sensitive, how are we going to get such a law?
Please correct me where I've missed something/misunderstood.
Let me choose one particularly awful example, and analyze it from an empirical viewpoint. @ #22 "Fodor's argument": The philosophical "argument" is so besides the testable (and tested, I would like to point out) selection theory that it doesn't connect with it except on this point:
"4. Since any trait may be advantageous in one phenomenal context but disadvantageous in another, there are no laws of relative fitness." It is unclear what is meant by "one phenotypic context", but as phenotypes are the environment of genes we can back up to the later. (As Dawkins points out.) Observationally environments differ. In other words the claim would look from the theory's (of selection) viewpoint: Since relative fitness exist, there are no laws of relative fitness.
Clearly this is a (rather dumb) non-starter. As Dan L points out, this is actually a non-starter for all science, yet we know it works. Further, relative fitness (differential reproduction) is predicted and tested: brood sizes vary with environment, say seasonal access to food or good parenting behavior (remember, we are ultimately looking at the gene's environment).
Point 1 is a declaration that selection is necessary to have traits. This is outside a testable theory here, but in fact outside of science as general rule because we can have several factors resulting in one effect. (And it is observationally wrong too here, for example we have genetic drift.)
As a nitpick I have to agree with Dan L., the only point that touches biology in some small way in "Fodor's argument", point 4, is already dealt with in the article.
As always I see that the confusion comes from believing that cryptoinductionism ("inference from best explanation" et cetera) can be used in science. That isn't so, testing observably works and can further be rigorously and consistently tested by going meta on its ass and predict that is the underlying theory of science. While inductionism fails miserably in test. Why that is so is explained in an easy accessible manner in Deutsch "The Fabric of Reality".
The main reason why inductionism is entertained is likely because it allows for "gaps" where religious believers can stuff their beliefs in. Never mind that by their own description those gaps observationally decreases, so "best inference" would be that "best inference" is inconsistent by observation and by its own method (and so doesn't work, either way). Well, duh!
So if "natural selection doesn't cause most evolution" is F&PP's argument, they're not even disagreeing with Richard Dawkins. The only difference between Dawkins and F&PP would be Dawkins' insistence that the mutations that people tend to care about (the eye, for example) are not neutral, but evolved by natural selection.
If the summary of Fodor's argument in @22 is accurate, Fodor is not simply arguing that natural selection is not usually the causal mechanism behind evolution. He is arguing that natural selection cannot logically be the causal mechanism. In the face of very well understood causal mechanisms like that with sickle cells and malaria (see @42), the issue is likely to be with the structure of Fodor's argument, rather than with the evidence.
In regard to your question, "And since the mechanism of natural selection is so context sensitive, how are we going to get such a law?", the effect of context seems well studied to me. Animals are necessarily constrained by the relationship between the amount of energy they can find in their particular ecological niche and the amount of energy required to inhabit that particular ecological niche (e.g., how much energy it takes to successfully evade predators, how much energy it takes to find food, to nurture infants, etc). For example, part of the reason that panda bears are endangered is because, for an animal that eats bamboo, they are terrible at turning bamboo into energy. In contrast, because we humans can eat almost anything, and have been very successful in evading predators, and in building and maintaining energy resources etc, we have reached plague proportions.
With this in mind, it's fairly easy to make 'covering laws' that make predictions about an animal's phenotype. Take Kokko et al. (2002), who argue that there is a strong relationship between the amount of female parental investment required to raise a child, and the survival usefulness of the indicator trait that is sexually selected. A peacock tail being so useless thus predicts that peafowl spend less investment on their young than equivalent birds. And this in turn suggests that peafowl are in a particular ecological niche that doesn't require much parental investment comparatively, and in which there are relatively plentiful energy supplies (peacocks do in fact live in such a context).
*So when I read Dawkins statement "some mutations really do change the body, but in such a way as to have no effect on survival, one way or the other" I'm correct that that he's not pointing to an evolutionary mechanism here, correct? Fodor and PP are saying that we have reason to disbelieve the view that natural selection is the primary mechanism of evolution, not just that other mutations happen to, to no effect (they've offered examples of other possible mechanisms, but I'm not as much interested in the details of their alternatives).
*My understanding is that the concern over covering law is not that the general idea of natural selection can't guide us in forming covering laws on a case by case basis, but that the law must be more generalizable aside from case by case contexts. Now if this concern is misguided because we allow perfectly good broad ideas in the other sciences (physics, chemistry) to guide us in making covering *laws* (plural) on a case by case basis, then fine, perhaps it would be helpful to point those example out (I'm not being coy, just trying to grapple with whether natural selection is special or not).
So which feature predominates in the selection of hollow white hairs? Is it that being white (like other Arctic animals from foxes to whales) has camouflage properties? or that hollow air trapping hairs allow lower energy expenditure on thermogenesis?
Or is the question not interesting? or instead can we measure (theoretically) the relative contributions of the two features and conclude that in the context of bear evolutionary history the question did not arise because (and we could test this genetically) that one and the same mutation caused both features at a stroke?
This therefore brings up the whole phenotype point introduced above. We humans are great classifiers and as such we are prone to make a category error: that the lines we draw on nature exist in nature in a causal sense.
This is why Dawkins attempted to short circuit adaptationist arguments by focussing on genes and gene survival. If you take a population geneticist level view of any of these situations they all dissolve. This is why F & PP's example of linked genes in their New Scientist article was a hostage to fortune since we know all linked genes are unlinkable given enough recombination.
If it turns out that hollowness and whiteness are not unlinkable (in the bear genomic history) then questions we might ask at the level of individual adaptations are not even wrong.
So F & PP's criticism is only relevant wrt paleontology (if it is relevant at all) since only there can we not determine the genetic truth of the matter.
Yes, I see: Philosophers never base their observations upon experience, and scientists never expect nature or the external world to conform to their their own prejudices.
Take your Manichean nonsense somewhere else, please. Scientists are not infallible saints, and they are as subject to human frailty, even to acts of stupidity, as anyone else--including their blinkered worshipers and apologists.
There's no mention by Block and Kitcher of epigenetics and the conceivable role of "noncoding" (a.k.a. "junk") DNA. Hyperadaptationists (cf PZ Myers) reject a role for it for reasons that can only be called ideological. This statement by B & K is either disingenuous or dishonest:
"Other critics ... —overemphasizing something all evolutionary biologists agree with—that natural selection operates against a background of constraints, perhaps stemming from features of genomes." This from a pair of authors who slam another pair for their lack of biological expertise and scientific expertise.
K and PP are saying something that is already obvious in science: All knowledge is proximate and provisional. Nothing is certain or final. Present knowledge allows us to say a causes b. Yet this is not certainty, only a probability. So are K and PP simply stating the obvious, from the philosophy of science, and trying to beat it to death by giving it a different treatment. I say a causes b, but K & PP reply with the equivalent of, “Not so fast. How can you really be sure there is nothing else going on? You need a 'Covering Law' to be really sure. Otherwise, you can not conclude anything.”
Catarina Dutilh Novaes:
The purpose of this comment is to discuss the notion of resorting to statistical methods as a feeble cover-up for an absence of 'covering laws.' I am not a biologist, but a research psychologist. Statistical methods abound in the social sciences, in other sciences, and areas of engineering. There is some truth to this, but it has to be stated very carefully.
It could be a feeble cover-up if the user views inferential statistics and familiar distribution curves, like the Normal Curve, as laws of nature themselves. Too many scientists who use statistical methods for mathematical argument, make several fundamental mistakes.
1. Francis Galton, for example, believed the Normal Curve was a law of nature. The Normal Curve is a purely mathematical construction that does not represent nature, is not derived from nature, and is not based upon anything in nature. It is a tool, and a model, that is judged appropriate only on the basis of utility. In other words, it seems to work and helps in making decisions.
2. An assumption about a population value, in parametric inferential statistics, is a variation on Plato's Ideal Forms. According to Plato (and many scientists using statistical methods – de facto, if not explicit,) these parameters and their values have a real existence in the World of Ideas. Assumptions about these parameters and their values are the foundations of parametric statistics. What escapes most users of statistical methods is that such parameters and their values have no real, independent existence. Statistical methods must be viewed as tools, and, as such, can only be judged in terms of utility. Inferential statistical analysis is not a royal road to truth, nor an example of laws of nature.
Fodor would have a point – statistical methods and distributions are a feeble cover-up – if researchers grant them law of nature status. There's nothing wrong with using them, as long as we acknowledge they are models and tools with great utility. If we do acknowledge this, then his criticism becomes a straw man argument.
As an outsider to biology, I might argue about how some bias has pushed research in a certain direction or how some metaphor has driven the work that biologists do. I wouldn't argue that all their ideas are, like, wrong. Cause I'm not, like, a biologist.
Anyway, thanks for a detailed explanation of this. I can skip the book now.
I stumbled onto this whole thing through a horrid interview in Salon. My first thought was. . . "wait. . . even I've read that Spandrels thing. . . I read it in a Freshman composition class ten years ago and it was old then. . .what are they on about here. . . "
As for my reconstruction of laws as "objective patterns" - this is somewhat contentious, but so is thinking in terms of the "covering law" format. Mario Bunge (in 1967, to boot) lists a dozen or so categories of laws, some of which do not fit in that sort of "universal conditional" form when stated (except in so far as anything whatever can be put in that form). The law statement/law distinction itself is also vital here.
Dawkins argues, however, (and I completely agree) that these mutations are too weak and too random to account for, say, the intricacy and precision of the eyes you're reading your computer screen with.
So if F&PP were only arguing that natural selection is not the "primary means of evolution", it would largely come down to an argument about the meaning of "primary" - perhaps most evolution, especially at the level of individual genes, is not caused by natural selection. But natural selection almost certainly plays some causal role in most of the biological questions that the average person would care about - how our eyes became so precise, how we became so intelligent, why polar bears are white, why fish left the sea, why orchids are so pretty, etc. So which is primary?
This therefore brings up the whole phenotype point introduced above. We humans are great classifiers and as such we are prone to make a category error: that the lines we draw on nature exist in nature in a causal sense.
Yes. It's clear that while this book itself, and the work of the scholars associated with it, may represent an extreme and exaggerated view, some of their underlying points deserve considerably more weight than scientists who (falsely) believe that Hume's skepticism has been refuted in some straightforward sense, rather than simply rejected because modern science succeeded in accounting for certain domains of reality so effectively, would be willing to grant them.
"I just want to jump in to note how embarrassing it is when someone calling himself a philosopher shows up and makes a stupid claim about science."
Why don't you find it equally embarrassing when scientists "show up" and make stupid claims about philosophy, like the authors of this review, or like our own David M? Got to love the double standard!
This double-standard, however, is very typical of science-worshippers. Such comments make plain that science is indeed the new (relatively speaking) religion substitute. Its advocates are as fanatical and emotionally vehement as Savanorola (witness some of Dawkins's rhetoric, for instance).
Indeed, science, and especially Darwinism, has replaced religion as the new bringer of soothing certainty and absolute truth (pace one commentator, above, the value of science for most lies not in its asymptotic approach to truth, but because it supplies firmness and an illusory sense of absolute truth). Just as science has supplanted religion in this role, one wonders what, a few thousand years hence, will have replaced science?
Thanks, by the way, to Gunn H and to Megan for their contributions, which are far and away the most intelligent and illuminating to appear in this comments thread.
I think nothing will replace science, just as nothing will replace uncertainty. In the physical world, as opposed to the world of ideas, there are no absolutes. Or rather: the odds are that we will never know absolutely what is or isn't. But I assume we're descended from apes in the same sense that I assume that when I put a pot of water over a high flame, the water will boil.
The authors of this review are philosophers: Ned Block is in the Philosophy Dept. at NYU and Philip Kitcher is at Columbia.
2) Megan at post #41 writes: "Furthermore, there is an obvious logical flaw in this review: the authors state that "two properties are said to be coextensive if and only if they apply to exactly the same objects. Such properties are (in the more familiar terminology we used earlier) correlated. Being-a-melanic-moth-and-smaller-than-Manhattan is coextensive with being-a-melanic-moth; being a sphere whose radius is less than one inch is coextensive with being a sphere whose diameter is less than two inches."
Here they have clearly confused "necessary and sufficient" (IFF) with "necessary" (if). But these are logically distinct. In other words, it is easy to think of a sphere whose diameter is less than two inches that is NOT a sphere whose diameter is less than one inch."
It is indeed easy to think of a sphere whose diameter is less than two inches but greater than one inch, but that is not what B&K said: they said that any sphere with a diameter of less than two inches is coextensive with any sphere with *radius* of less than one inch. Even if there are many different sized spheres with a diameter of less than two inches and a radius of less than one inch, they still form a coextensive set of objects less than two inches in diameter - just as all melanic moths are of different sizes but are also all smaller than Manhattan - so I fail to see the flaw in this reasoning.
3) Finally, isn't the mechanism of natural selection itself a covering law that incorporates myriad subordinate instantiations? We might phrase this law recursively* as "The most reproductively successful organisms will be those best suited to their environment". There don't seem to many (any?) exceptions to this law. A subordinate law might be something like "those organisms subject to predation will be most reproductively successful who are able to blend into their environment". We can of course make these subordinate laws more and specific, e.g. "Those organisms subject to predation and who live in the arctic will be most reproductively successful if they are white." And so on, forming thousands upon thousands of laws, down the chain of specificity.
Now, I'm not married to this idea - which is admittedly more of a theoretical rather than scientifically practicable solution to the problem - but it did occur to me while reading the comments and I wanted to get some other people's perspectives.
* The recursive circularity of this law is, I think, more a virtuous circle than a vicious one because it allows us to think of trait selection as a consequence of reproductive success at the same time as it allows us to think of reproductive success as a consequence of trait selection.
"The authors of this review are philosophers: Ned Block is in the Philosophy Dept. at NYU and Philip Kitcher is at Columbia. "
Mea culpa, with respect to Block and Kitcher; I meant to edit that bit before I posted, but got so caught up in the rest of what I wrote that I forgot. My apologies as well to JamieMc if I misunderstood his point. here, indeed, we do have a pair of philosophy professors (not necessarily "philosophers") saying stupid things about science, as well as, in the comments, scientists saying stupid things about philosophy.
Of course, the reviewers defend Darwin so rabidly that it would be easy to confuse them for scientists of a certain type. Once upon a time, we had "Darwin's bulldog". Nowadays, we have "Darwin's pismires".
I take the proposition "natural selection is the primary mechanism of evolution" to mean not only something similar to "those characteristics that confer fitness to a particular environment will confer a survival advantage on those organisms that posses said characteristics" but also entailing something like, "the characteristics that lead to varying population differences in generations of organisms are the characteristics relevant to considering what the primary causal mechanism of evolution is."
My understanding is that Fodor and PP are denying that we are warranted in believing that natural selection is the primary *mechanism* of evolution (I take the word "mechanism" to refer to the differences that make a difference to survival); I don't think their interesting claim is that natural selection is not responsible for the majority of the characteristics organisms have.
@Dustin,
In regard to your point #3, I think now we're getting to brass tacks. Your most broad formulation of natural selection, while a nice rule of thumb for practice, doesn't seem to have much content. Moving a step down the latter of specificity, I think we're getting somewhere. My fear is that Fodor and PP would also question whether those kinds of statements are representative of the kinds of statements most responsible for evolution. I hope that's not all they have to offer. I understand the most broad statement of natural selection, and I see how your more specific statements refer back to the most general statement. Now, I may be behind the times here (it's hard not to be in the Philosophy of Science) but supposedly theories are supposed to be testable. And if they have nothing but conceptual content, they aren't. So maybe it would be helpful to me if I could be reminded of or taught about other scientific theories in good standing (in Biology or otherwise) that are as purely conceptual, that also lead to specific predictions, so that I can then see that natural selection isn't special.
BTW, I think your last thought is very insightful, but I'm reminded of what the philosopher Chandran Kukathus said... it was something to the effect of "Theory leads to reductios, which are very unsatisfying." He was referring to political philosophy, but I think it applies here. The problem is that in the hope of excluding mumbo-jumbo, we come up with abstract standards of what counts as science and what doesn't, but we always are on the verge of being over or under inclusive with those standards, so we tinker with them. The point Chandran Kukathus was making, I think, was that a real and sustained commitment to an abstract theory (a philosophical one) will eventually lead to a practical result you don't like. So, a commitment to theory means you have to bite a bullet eventually. Our choice of bullets here seem to be discarding a paradigm that has been very useful (Fodor and PP don't deny that natural selection does work, but if everyone decided that it wasn't the main worker, seemingly that would be a paradigm shift) on the one hand, or accepting a paradigm that has at its core a purely conceptual statement. Now, my own concerns here may be different from those of Fodor and PP, but I suspect they overlap at least a bit.
Ghiselin's solution likely wracks professional philosophers and others, including certain scientists, with some pain (see Metaphysics and the Origin of Species 1997. SUNY Press, NY). This treats metaphysics as the most basic science, which means we study the basic organization of the world scientifically....use real evidence to decipher the make up of the world...
It also raises the need to remedy that frequent criticism of biology, and those other sciences. This is that we cannot test the material reality of historically derived systems (such as why polar bears have think white fur). The late Steve Gould did ample justice to this apparent riddle. A useful entree is Chapter 2 in his Magnum opus "Structure of Evolutionary Theory". Darwin's various works demonstrates how to interpret the different categories of historical evidence, whose taphonomy rank from the abundantly preserved (that one just has to join the dots) to the diffuse and singular cases.
Ironically, Darwin put to work the message resplendent in the prodigious work of William Whewell, who in studying the history of science, worked with real historical evidence: real discoveries made by real scientists; and reconstructing their paths to enlightenment came up with the notion of Consilience. Therefore, there can be no coincidence why Darwin presents an exhaustive argument in consilience to demonstrate, beyond reasonable doubt, that domestic pigeon evolved from its nearest relative the Rock pigeon (see the Origin). This brings us back to this reviewed book that apparently pecks all manner of holes in the credibility of Darwinism...well there are very good reasons why natural selection is such a powerful law in biology. It works. Ask someone diagnosed positive with HIV, and also read the evidence for origins of HIV (namely Nature article in 2008 455: 661-665) as to how we know that AIDS evolved from our closest living relatives.
Too many practising scientists rely on smattering of philosophy to argue how science works. It is high time we moved beyond Popperian; it is instructive to understand that biology and other historical sciences rely on the palaetiological methodology of science. Falsificationism using controlled experiments might work in studied microcosms, but so much of evolutionary biology studies much much more. We all need to be very grateful to Whewell, who laid the groundwork for this historical methodology of science, back in 1940 (read Gould for enlightenment, and Darwin for inaugural applications with real data).
I haven't read much about consilience, and I haven't read the whole review I'm linking to, but considering the author of the book review that started this thread, and what you've said in reply, I couldn't resist:
http://www.lrb.co.uk/v20/n21/jerry-fodor/look
I think there fruitful areas of discussion at the juncture of science and philosophy but his debate isn't one of them. What about questions about the nature of will, morality and law in the light of what science has to tell us about behaviour?
An interesting point and I recently heard of an instance where a prediction in the manner you refer to was made and observed.
I heard a radio interview with a biologist who studied wing length in songbirds. He observed that the composition of forests in eastern Canada has changed to include more conifers (pine and spruce) and less deciduous trees (maple, oak, etc) as humans had harvested the deciduous trees. Since songbirds with shorter wings do better in a conifer forest he expected to observe shorter wingspans in today's songbirds than in historic records. And this is precisely what he found. He also looked at forests in the North eastern US which were harvested earlier and where the deciduous trees have been increasing again due to forest management changes. In these forests he expected to find songbirds with longer wingspans than in the historic record.
And he did.
So we have a prediction based on adaptation that was testable. There are other examples. In an environment where antibiotics are heavily used you have a selection pressure for antibiotic resistance. And lo and behold our hospitals now have multiple resistant staphylococcus aureus (MRSA). This is not a case of science developing a just-so story to explain MRSA. The appearance of antibiotic resistant bacteria was predicted before MRSA showed up.
Biologists and evolutionary scientists don't only look back, they make these types of predictions and test them.
Predicting the particular traits an environmental change will generate is difficult since it requires a very thorough knowledge of the organism in order to predict the traits that will arise. It also requires an organism with rapid generations to allow observation within a reasonable time frame.
"Everything is physical perhaps, but surely there are many different kinds of physical things. Some are protons; some are constellations; some are trees or cats; and some are butchers, bakers or candlesticks"
So how many candlesticks does it take to make a proton?
The problem with Wilson's physicalism is that of the "logic" of his preference for ants. Even if humans have no more free will than plant life it still makes no sense to extend that [in the interests of clarity?] to say we're all the equivalent of ivy. Let a billion flowers bloom. In fact it seems they do already; and one can be interested both in people and in persons. It just takes a little more effort.
I'll give this to Fodor, he makes reference to his own neuroses. I thought mention to conditioned response were verboten in cognitive science. Now if he'd only begin to think about what their existence might imply about his own behavior.
"Now if he'd only begin to think about what their existence might imply about his own behavior."
Given the obvious pure reactivity of your comment, perhaps you should consider taking your own advice.
Why are flamingoes pink?
It’s for survival in the sunset..don’t you think?
Why is Apocalystick red?
It’s flash for flesh
for ‘going rogue’ is so in vogue
like the predator distinction
the fittest fling is not a fiction
Select for class
drive by wire for the stash
stuff and flash
flesh and flash
lesser lemmings don’t do the dash
for it’s stuff that makes your class
Pretty in pink?
It’s all relative don’t you think?
There are plenty of instances of scientists rigorously identifying selective pressures, and plenty of instances of scientists making rigorous and correct predictions of evolved traits and/or of specific DNA sequences, which should be impossible under their formulation of the uncertainty of biological knowledge.
Their argument boils down to "it's too complicated to figure out", which is only true in if you're a somewhat dumb pedant.
Or an intelligent realist.
I associate pedantry with arrogant certainty, myself--with the majority of Darwinists, for instance. Better go back to the thesaurus.
A selection-against model fits better, in my opinion. Those that do not fit the environment well DIE or DO NOT REPRODUCE AS WELL. Those genes decrease in frequency, and (as a byproduct)the others increase in frequency. No intensionality is needed. The strong aren't chosen, the weak are killed.
Think of what we do with statistics. We keep significances when they are above threshold (p
My guess is that by the time the philosopher has proven beyond any doubt that adaptation to the environment is not a causal factor to survival he is probably quite dead.
Do Fodor and Piattelli-Palmarini's 'thoughts' make any valid contribution to biology as a science?
Or is it as it appears, without having read the stuff, just empty sophistry?
My 'problem' is that anything lauded by the Disco Institute automatically is suspect in that it overwhelmingly is propaganda rather than science.
Time for a spoof eh?
Most of the contemporary philosophy of science is intimately connected to actual scientific practices and present theoretical and methodological problems, and those philosophers know how the science works. They ususally know as much about the science they talk about as they know about philosophy. The same cannot be said about all scientists. Quite often, when a practicing scientist starts philosophising about science (making assertions about the aims, methodological principles and ontological assumptions), the result is extremely naive.
Just look at the issue at hand. There are two scientists, Fodor and Piattelli-Palmarini, who are cognitive scientists. (Fodor is, sure, a philosopher too, but a philosopher of mind, not of science, so he is a diletant in philosophy of science and he is not a representative about what philosophical understanding of these things are. He gets it all wrong.) They totally miss the point of how scientific explanations work, and two philosophers, Kitcher and Block, set them straight.
The difference between contemporary philosophy and science comes in degrees. Some researchers are closer to the actual empirical research and some are more theoretical, even concentrating entirely on conceptual and formal issues. (The latter would be philosophers.) There isn't (sensible) abstract philosophy unrelated to empirical research and there is no empirical research that would be indifferent about methodological and ontological assumptions. And taking a stance in a methodological question needs to be argued for. "I am a scientist, you are a philosopher" is not an argument.
On the other hand, pure philosophical arguments without close connection to empirical knowledge about what the issue is in the first place and how the scientific theories about it work, is just like speculating about angels. Philosophy used to be like that, you know, a long time ago. *So did science*. Some of us have moved on. Fodor hasn't.
According to Kitcher and Block, "Philosophy can sometimes help other areas of inquiry. Yet those who wish to help their neighbors are well advised to spend a little time discovering just what it is that those neighbors do, and those who wish to illuminate should be sensitive to charges that they are kicking up dust and spreading confusion." Most philosophers would agree. And the same applies for scientists: when you are making judgements about philosophy, learn first what you are talking about.
"In theory, this is how it SHOULD work, but I very much doubt that any polar bear biologist has come up with a falsifiable statement of the polar-bear example you keep repeating and tested it. Doing experiments on polar bears is not very common."
One thing I'd like to point out is that it has been demonstrated that Polar Bears and certain groups of Brown Bears (aka Grizzlies) are so closely related genetically that they are by some definitions of the term the same species, and that they have been known to interbreed and produce viable offspring.
These hybrids have occurred in Zoo's and even occasionally been encountered (and killed by hunters) in the wild. From this we know that it *is* possible to have a "polar" bear with a mixture of features from both sides - including a range of coloration from brown to white.
Given this it is unclear to me what experiments would be required to back up the claim that bears that stand out are at a disadvantage compared to those that don't.
Now if we had never ever seen a brown polar bear then I might understand the need for an experiment to determine why this might be. But given that we have, and the fact they are so rare, seems to me make the experiment redundant. Surely in this case nature *is* the experiment?
http://bostonreview.net/BR35.2/darwin_exchange.php
"Here they have clearly confused 'necessary and sufficient' (IFF) with 'necessary" (if). But these are logically distinct. In other words, it is easy to think of a sphere whose diameter is less than two inches that is NOT a sphere whose diameter is less than one inch.'"
You misquote B&K here. They write of a diameter less than two inches and a radius less than one inch. There is, in fact, a necessary and sufficient relationship between these two properties, as every radius is exactly one half its coextensive diameter....
For instance, Fodor’s logic proves that Newtonian gravity “doesn’t work”. Gravity (supposedly) exerts an attractive force between two masses, proportional to each mass and inversely proportional to the squared distance between them. But gravity cannot tell the difference between (1) things with mass and (2) things lacking mass but physically coupled to things with mass. It will pull on them both just the same. As neo-Newtonians understand it, gravity is not able to distinguish the causes of acceleration from their local confounds.
As one way to see this (not by any means the only way) — the gluons within atomic nuclei are massless, yet they get accelerated by gravity by consequence of the protons and neutrons they are correlated with. Thus the free-rider problem — massless gluons literally ride free with protons. Prima facie, free riding is a counterexample to gravity. As far as I can see this objection to gravity is decisive.
...seems to me make the experiment redundant. Surely in this case nature *is* the experiment?
That's the problem with evolutionary biology. It almost always is.
Consider B & K's sieve.
Imagine a sieve with a mesh that will allow balls with radii of one inch to fall through, but that will retain those that are even a tiny bit larger. Suppose that balls with several different radii—one inch, two inches, three inches, and four inches—are placed in the sieve. The one inch balls are blue, while the larger ones have different colors. The blue balls fall through, and the others remain. In one sense the sieve has “selected” the blue balls, although it has not “selected for” being blue. That is because size not color is what matters to the transmission.
How do you know? Unless you are previously aware of how a sieve works, simply by observing the blue balls falling through, you don't.
An experimental scientist introduces into the system some blue balls of different sizes, and some balls the same size as the original blue ones, but of different colours. It then becomes clearer how the sieve is operating. But in a biological set-up, particularly one needing a long time scale to produce the effects observed, such interventionist experiments are very difficult to perform.
Without such active experimental intervention, it can be harder to distinguish between rival theories.[Which may be why Richard Dawkins used the sieve as a 'simple' example of a random process producing an ordered result. The sieve produces order (blue balls on one side, not on the other) not just by having holes of a given size but needing the directional force of gravity. Now there's a thought for natural rather than plant breeder's selection.]
Attributes can appear together (be correlated), but since natural selection is unthinking it can't tell these apart, therefore it can't "select-for" a particular one.
Am I correct in thinking that? If I am, surely natural selection doesn't need to know which one causes increased reproductive success?
NB: I'd be much obliged if any replies are as jargon-free as possible ;)
and indeed game theory is not a "scientific theory" like that of gravitation since most GTal phenomenology depends crucially on the arbitrary (or non-unifiable natural-historical) details relevant in each case.
natural selection (NS) narratives fall between these two extremes: to explain short-term events they mobilize a firework of crucial circumstantial natural-historical details that are GTally relevant (in ceteris-paribus or dynamically positive way), but abstractly speaking the winners are always "the result" of the Bauplan's potential to be altered (due to mutation, etc, and accidents) and modified "units" to show up that deal with the specific selective agent/regime better than existing units do.
this Bauplan's potential is part of the "gravity-like" force driving evolution by natural selection (EBNS) and GT has nothing "ontologically" comparable to offer (i.e., GT has no obligate links to natural entities and quantities).
but these Bauplan potentials are not the central element of this "gravity-like" force. the deepest driver of EBNS must be something along the lines of what van valen's "3rd law of natural selection" (1976) was meant to describe (van valen meant EBNS when he wrote "natural selection").
no need to say that the "gravity-like" force driving NS (as opposed to that driving EBNS) cannot be studied in the same way and time scales as the "gravity-like" force driving of EBNS...
all in all, B&K's trailer-park-level understanding of what a scientific theory should be (like that of most of the phil.of biol and evol.biol establishment frauds who have commented on the F&PP "idiot-savant" book) rivals with that of the peddler of puerilo-retarded animistico-suggestive anthropomorphizations, r.dawkins; and their arguments are barely better informed and more heuristically beneficial that the latter's pernicious syllogistic imbecility about "DNA with intentionality".
F&PPs missed much if not most of the petty details they included about NS and EBNS as well as about what students of NS and EBNS can and cannot disentangle; but they got the most important thing right:
the unifying "gravity-like" forces driving NS and EBNS remain unknown and available stories "different for each case" (let's celebrate diversity!) are ontologically truncated. (in his tired recent nyrb piece on this affair, r.lewontin mentions that F&PP have stated that they are not asking for such a force, but the real question if they would have anything to criticize if the force was already a central focus of research in evol.bio).
truly, it's shocking to see --among "professional" philosophers of science-- such ignorance of the deep epistemological canons that distinguish sounder scientific theories, and of evolutionary biology among "professional" evolutionary biologists.
this whole debate shows one more time what kind of charade the american system of promotion of self-complacent paper churners has generated...
I have the utmost respect for the natural sciences and I think that the natural and social sciences are inevitably intertwined. I just think it is quite closed minded to unequivocally dismiss philosophy based on one, foolish argument.
In fact this book presents a version of evolution that does not eliminate natural selection, but instead downplays to create space for and account for other factors such as the internal structural factors genetic constraints. So you can keep your explanations for white bears, black moths, and flowers that look like insects... what this book is challenging is the extension that you can use the same reasoning to explain all or even most of the variation in species.
lolcats