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2009-04-13
On Fodor on Darwin on Evolution

I would like to invite discussion on my paper, On Fodor on Darwin On Evolution, which is a critique of Jerry Fodor's Hugues Leblanc Lectures at UQAM on "What Darwin Got Wrong" (Fodor, forthcoming; Fodor&Piatelli-Palmarini). Jerry Fodor argues that Darwin was wrong about "natural selection" because (1) it is only a tautology rather than a scientific law that can support counterfactuals ("If X had happened, Y would have happened") and because (2) only minds can select. Hence Darwin's analogy with "artificial selection" by animal breeders was misleading and evolutionary explanation is nothing but post-hoc historical narrative. I argue that Darwin was right on all counts. Until Darwin's "tautology," it had been believed that either (a) God had created all organisms as they are, or (b) organisms had always been as they are. Darwin revealed instead that (c) organisms have heritable traits that evolved across time through random variation, with survival and reproduction in (changing) environments determining (mindlessly) which variants were successfully transmitted to the next generation. This not only provided the (true) alternative (c), but also the methodology for investigating which traits had been adaptive, how and why; it also led to the discovery of the genetic mechanism of the encoding, variation and evolution of heritable traits. Fodor also draws erroneous conclusions from the analogy between Darwinian evolution and Skinnerian reinforcement learning. Fodor’s skepticism about both evolution and learning may be motivated by an overgeneralization of Chomsky’s “poverty of the stimulus argument” -- from the origin of Universal Grammar (UG) to the origin of the “concepts” underlying word meaning, which, Fodor thinks, must be “endogenous,” rather than evolved or learned.


2009-04-18
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
COMMENTS BY MICHAEL RUSE

Michael Ruse has made the following comments, which I post with his permission. (I stand corrected on what the rival theories were before Darwin; it does not change my basic points, with which Michael agrees: that before Darwin, others thought otherwise; that Darwin's theory was both fruitful and right; and that it was not just a tautology -- though I doubt that the random-drift effects make it any less tautological...)

Michael Ruse:

"A couple of points: Pre-Darwin, I don’t think anyone by 1859 believed that organisms had existed forever – the fossil record (worked out by non-evolutionists) negated this. The big question was whether they arrived supernaturally after catastrophes (Adam Sedgwick) or naturally somehow on an ongoing basis (Lyell thought this, but could not specify how it happened and could not reconcile natural creation with the design-like nature of organisms). And then there were the evolutionists like Lamarck, Chambers, and Herbert Spencer: Their problem was that they had either no mechanisms (Chambers) or they were wrong  (Lamarck and Spencer both endorsed the inheritance of acquired characteristics, although mainly Lamarck believed in a kind of vitalistic force upwards). 
"The natural-selection-is-a-tautology critique seems to me to be clearly refuted by the hypothesis of genetic drift. That hypothesis claims that the fitter or fittest do not always succeed!!   How widely genetic drift applies is a debated question but no one thinks it a contradictory claim, which it would have to be if selection were a tautology.
"Fodor’s claims about metaphor being a sign of immaturity have always struck me as... out of tune with science: How can you do any modern science without thinking of the world as a machine?  I have always assumed that he has ideological objections to the idea of any application of science, especially Darwinism, to the mind and so this is why he argues as he does..."




2009-04-19
On Fodor on Darwin on Evolution
Reply to Stevan Harnad

Fodor says, “It is, in short, one thing to wonder whether evolution happens; it’s quite another thing to wonder whether adaptation is the mechanism by which evolution happens.” He continues, “Well, evolution happens; the evidence that it does is overwhelming….”

So Fodor is criticizing the claim that adaptation is the mechanism of evolution, not Darwinian evolution as such, though he also thinks Darwin got some things wrong, and Stevan Harnad rightly takes him to task for not getting right what Darwin got wrong.

Before making some further points about good (weak) and bad (strong) adaptationism, and about the importance of levels of explanation and description, I’d like to correct the impression that before Darwin people were mostly creationists or eternalists about species. The issue is important for the current debate  because it brings out that the way in which Darwin is wrong is like the way in which Newton is wrong. Darwin, like Newton, was a synthesizer, adding order and precision to what people already knew, proposed, or speculated in a way that was profoundly, though not completely right.  Further, the contemporary theory (best represented by Dawkins’s conception of a universe of replicator forces) goes beyond and modifies Darwin in important ways, but Fodor’s accusation that Darwinism is wrong because tautologous is on about the same level as the accusation that Newtonianism is wrong because it posits gravity as an occult quality.    

So what did Darwin synthesize? First, the notion that out of a mechanically generated combinatorial array, certain combinations might be functional and persists is an ancient notion, revived in the 17th century. This tied in with all sorts of interests in combinatorics, including probability theory and the construction of “rational” artificial languages out of root elements. Second, the transmutation of the “species” was posited at least since the early 18th century. Buffon grasped that wolf, fox and dog came from a common stock. Evolution and even “hereditary habit” was assumed. Third, it was appreciated that there was a lot of “waste” in nature—a superfluity of seeds and seedlings that would never grow up to reproduce. Malthus noticed this in connection with the poor; they generated far more children than they could maintain and lost them to starvation and poverty. 

However, nobody put these three ideas—combinatorics, transmutation, and waste together in the right way before Darwin. But he didn’t write a theoretical treatise showing how to connect these concepts up. Rather, he begins the Origin by appealing to the breeder, an analogy that has misled a lot of people, including seemingly Fodor. To get straight on this, forget the “agent” of selection and think of a breeding population as a huge pile of minute colored particles representing all the alleles—alternative versions of genes—of the population. Over time, the color-composition of the pile (and its overall hue) changes because of the ways in which the contents of the pile interact with its environment and the particles with one another. Each temporal stage of the pile is realized as a set of living organisms; their phenotypes change, quickly or slowly, depending.

This is evolution by natural selection: we can model it as I’ve just done without referring to “agents” or “selection” or even “fitness.” The laws of nature apply at this level: the level of individual molecular interactions amongst the particles and the particles of their environment. However, the process, when realized at the phenotypic level does involve the comparative reproductive success of organisms as one of the main explanans of the changing colors in the pile. We say useful, explanatory things at this level, and make some generalizations, but we can’t expect to fit a grid of laws of nature over the process described at this level.   

“Adaptation” is not a “mechanism” contrary to what Fodor calls it. The actual mechanism posited by Darwin is variation-and-elimination. “Adaptation” is an ecological term applying to species, not individuals. An “adapted” organism is one that is doing well in its current environment, i.e. maintaining or increasing its population numbers from generation to generation.  “Fitness,” on the other hand, is a statistical concept that is sub-empirical. A is more fit than B if its future lineage is larger. 

What then is adaptationism? Here is a weak, unproblematic statement of adaptationism. “Certain traits possessed by large numbers of organisms, such as eyes or wings are possessed by them because ancestors that possessed the rudiments of those structures outreproduced creatures without the rudiments. Eyes convert  light energy into information and so are  useful and wings permit creatures to colonize the air.” Probably, those explanations are correct as fat as they go, and whiteness in arctic animals is very likely explained by the usefulness of camouflage for both prey and predators. Does Fodor really mean to dispute this?

An extreme version of adaptationism would be the view that view that every heritable morphological or psychological trait observed in any individual organism is possessed by that organism because it favoured survival and reproduction in its ancestors, and that we can know for sure when we have got the uniquely correct explanation of why it was better to have that trait than not to have it.

I do not think mainstream biologists hold this view. Take deafness in blue-eyed white cats, noted by Darwin. Should we believe that it’s good for cats and was good for their ancestors to be deaf ?  No—being deaf is just a potential of the gene or genes responsible for blue eyes and whiteness. It’s not even good to be white in temperate zones. We preserve these frail creatures who would not fare well in the wild for aesthetic reasons. Many traits (vulnerability to sickle cell anemia) persist because they are correlated with something useful (resistance to malaria) that we can identify—but not always. Some are terrible to have, but do not diminish reproductive success because their effects kick in only mid-life, like the Huntington’s gene, and so are not getting eliminated.

Fodor also criticizes teleosemantics. It’s right to point out that to say that frogs evolved to snap at flies is imprecise. The frog is a snapping machine whose action is triggered by black spots. In the historical and actual environment of frogs, black spots are usually flies, and this explains why there is a black-spot-snapping mechanism. Spot means “fly” to a frog in a particular context, and the context has supported this meaning for millions of years in the case of frogs, but it doesn’t mean it timelessly or in all possible environments.

Such meanings can be very hard to decode. There is a lot of debate right now about the interpretation of reliable and deceptive signals from animals to other animals. Since it is metabolically costly to build and maintain certain meaningful structures, we assume they have been selected for. But does the peacock’s tail “mean” “I am so fast, strong, and smart I can scoff at predators, choose me!” (handicap) Or do female peacocks just “like” fancy tails and therefore “want” their sons to have them, even if the possessors are and are in fact more vulnerable than shorter-tailed males? (aesthetics) Does a big bust on a woman mean “I’m a top-notch  female, come hither?” (superstimulus) or does it mean “I’m pregnant/lactating, go away so I can get some work done?” (deterrent, but men detect the deception).  Or does it have no meaning but a use—either in courtship behaviour, or just for energy reserves? We don’t know and may never know.

Dawkins pointed out that “adaptationism” is vitiated by the observation that traits in their present environment may be obsolete and actually being selected against. As well, organisms can produce in other organisms responses that are not conducive to the reproductive success of the organism that possesses them.

Conclusion: there are various reasons to think that that a strong adaptationist program of explanation is ontologically and explanatorily ill-grounded. Biologists already know this. Meanwhile, Fodor’s arguments do not show that weaker versions of adaptationism that imply only that frequently observed morphological and behavioural traits are conducive to the reproductive success of some organism (not necessarily the one possessing them) and that we can sometimes correctly explain their usefulness are illegitimate. 


2009-04-19
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
SUMMARY FROM JERRY FODOR (posted with permission):

Look guys, there's an argument. Replying to my views would mean replying to the argument. So far, nobody (I mean, NOBODY) has even mentioned the existence of this argument in replying to (what they have taken to be) my views.

Here's the argument: It is short and easy. (Notice that it applies equally to both `strong' and `weak' adaptation ism, so I'm at a loss to understand what Catharine Wilson thinks that distinction has to do with the present issues.)

A theory of adaptation is supposed to be a theory of the fixation of phenotypic traits.

The Darwinian principle is that phenotypic traits are selected for their (presumably causal) connection with fitness.

Prima facie, this principle is falsified by phenotypic traits that go to fixation but are not connected to fitness (drift and the like)

Some such cases can be handled by `friendly amendments' to the Darwinian principle.

But there is a serious problem about `free riding': cases where a trait that is NOT connected to fitness goes to fixation because it is (locally or otherwise) linked to a trait that IS connected to fitness. (This is the arch/spandrel situation).

The usual way to understand cases where a process distinguishes between coextensive traits is to claim that the process is INTENSIONAL.

This is what Darwin does; he introduces the intensional context `select for...'. By stipulation, one but not the other of two coextensive traits can be selected for in an evolutionary process.

In practice, this comes down to claiming either that there are laws of selection, or that selection involves intervention by a mind (an agent).

Both these possibilities appear to be ruled out as explications of `select for...'. The first because there are no laws of selection, the second because there is no Tooth Fairy.

This appears to be a dilemma; one from which, as far as I can tell. Darwin has no exit.

Historical addendum: I suspect that Darwin got into this mess because he assumed that natural selection can be modeled by artificial selection: Start with breeding, take the breeder away, and you have natural selection. If so, then he was the victim of a fallacy of subtraction. That could happen to anybody.

I don't mind people ignoring this argument; that's gone on for some 150 years. Nor do I mind being preached to about strong adaptation, weak adaption, and so on. (One very distinguished Darwinist has suggested to me that the Theory of Evolution isn't a theory at all; it is, he said, a `tool box'.) But enough is enough. Would some body very kindly reply to the argument? Or would everybody very kindly leave me alone?

jf

PS: All this, along with a lot of other stuff, is expounded at length in a forthcoming book with Massimo Piatelli Do buy lots of copies..



2009-04-20
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
As far as I can tell, Fodor's thesis complements one advanced by Denis Walsh, Andre Ariew, and myself (and originally Tim Lewens, though some say he has defected to the causal side).  (References to my published work on this subject are available on this site.)

THESIS: Natural selection is predictive because there are STATISTICAL correlations between initial conditions and the increase of "selected-for" traits, and not because selection CAUSES the increase of these traits. 

INTENSIONALITY ANALOGUES: (1) Walsh in particular has shown how subdividing a population in different ways will result in different distributions of variance-in-fitness, demonstrating the intensionality that Fodor talks about.  (2) And in an unpublished paper, "Drift and 'Merely Statistical Explanation'" (available at http://web.mac.com/mohanmatthen/Site/Mohan_Matthen.html), I argue that since drift is supposed to be inversely proportionate to population size, it will be STRONGER in sub-populations than it is in a whole population.  This creates a weird situation: the sum of strong drift in sub-populations is weak drift in whole populations.  These sort of puzzles go away on a statistical interpretation.

QUERY: I am not at all sure, however, what is at stake in Fodor's attack on Darwin.  Clearly, Darwin did not anticipate the statistical interpretation: statistics was (at best) in its infancy when he wrote.  (In my view, Fisher was the first to develop the statistical interpretation, in The Genetical Theory of Natural Selection, 1928.)  However, I think Darwin was well aware of the aggregative nature of selection -- he knew that it is the summary consequence of individual births, deaths, and matings. 

Whether I am right about this or not, Darwin was clearly aware of the parallels between selection and various "invisible hand" effects such as those treated in Adam Smith's economics. The Law of Supply and Demand, for instance, is intensional in exactly the same way as natural selection. 

BOTTOM LINE: the theory of natural selection is based on statistics -- the mathematical treatment of aggregations of individual events -- and in this it is more similar to economics than to (say) physics. 

SCHOLIUM to the bottom line: the statistical interpretation has been furiously attacked by philosophers of biology, but nobody has accused Walsh, Ariew or me of being anti-Darwin.  I am not sure why Darwin/anti-Darwin is an issue in the Fodor argument. 

2009-04-20
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
I am happy to see that JF appears to have dropped his tautology objection to Darwinism, is no longer (I think) denying that the whiteness of arctic animals can reasonably be considered an adaptation, and urges us to focus on his poverty of the stimulus argument. This is progress. It is still  essential to separate the level of the mechanics of selection (lawful molecular interactions resulting in changes in gene frequencies in a selected population) from the surface level where we are observing limbs, organs, behaviour and other features of the phenotype, and can find explanations but probably not laws. My colored particles example is Fisherian in spirit and is intended to bring this out. Once this distinction is clear (Mohan Matthen and his co-authors have nicely distinguished between statistical and vernacular fitness), many confusions can be eradicated.  

2009-04-20
On Fodor on Darwin on Evolution
Reply to Stevan Harnad

ON FODOR ON DARWINIAN EVOLUTION

Jerry Fodor (JF):  "A theory of adaptation is supposed to be a theory of the fixation of phenotypic traits." 

Actually, it is a theory of the redistribution of genotypes (not phenotypes) as a consequence of the effect of the environment on the survival/reproduction of the phenotypes of the organisms bearing them.

So it is not phenotype fixation, but just genotype proportion change (following random mutation, recombination, and reproductive success).

JF: "The Darwinian principle is that phenotypic traits are selected for their (presumably causal) connection with fitness."

"Fitness" is also a secondary and somewhat misleading property. The right property is just the distribution of genotypes from generation to generation, and it couldn't be simpler:

The distribution of genotypes from generation N to generation N+1 will tend to change in favor of the genotypes that generate the phenotypes that are more successful in surviving and reproducing (if there is any systematic difference in success).

No need to mention "fitness." No need to mention "fixation." Just a fairly mechanical (and quasi-tautological, once we realize that there are heritable traits at all) regularity relating genotype distribution and reproductive success across generations.

JF: "Prima facie, this principle is falsified by phenotypic traits that go to fixation but are not connected to fitness (drift and the like)"

Why is it falsified, rather than just extended? Some traits are inherited because they have systematically enhanced reproductive success; other traits are inherited because of random variation and because they have not systematically diminished reproductive success.  

JF: "Some such cases can be handled by `friendly amendments' to the Darwinian principle. But there is a serious problem about `free riding': cases where a trait that is NOT connected to fitness goes to fixation because it is (locally or otherwise) linked to a trait that IS connected to fitness. (This is the arch/spandrel situation)."

Neutral correlated traits are not at all a problem for the simple heritability process just described (heritable traits that enhance survival and reproduction are more likely to be transmitted than traits that diminish survival and reproduction; and linked, neutral fellow-travelers can hang in there until and unless they happen to diminish survival and reproduction).  

JF: "The usual way to understand cases where a process distinguishes between coextensive traits is to claim that the process is INTENSIONAL."

In experimental genetics, the way to find out which genetically inherited traits do and don't make a causal contribution to reproductive success and which ones are merely linked fellow-travelers (when it's not obvious) is to try to unlink them and test the effects on reproductive success.

(I am using "reproductive success" as shorthand for "adaptive success," because it is more transparent that we are talking about the success of heritable traits in managing to get inherited!)

The experimental test is much the same as it is with Skinner's pigeons, if they are trained to respond to a green triangle and not to a non-green, non-triangle: Just test to see whether they respond to a green non-triangle or a non-green triangle. (Fellow-travelers are no problem for either a Skinnerian or a Darwinian -- though Skinnerians have plenty of other problems!)

JF: "This is what Darwin does; he introduces the intensional context `select for...'. By stipulation, one but not the other of two coextensive traits can be selected for in an evolutionary process."

I think Darwin doesn't mean anything nearly so complicated with "select for": He just means whatever enhances reproductive success (in a given environment).

Heritable traits can be coupled. A breeder can select deliberately for one of them (and ignore the fellow-traveler). Reproductive success can also crown one of them (and not handicap the fellow-traveler).

JF: "In practice, this comes down to claiming either that there are laws of selection, or that selection involves intervention by a mind (an agent)."

There's no need to speak of anything as fancy as a "law." It is enough to point out the simple (but true, and richly predictive and productive) regularity (eventually discovered to be embodied in the genome) that there is variance in heritable traits and that those (heritable) traits that enhance reproductive success tend to increase their frequency in the next generation, relative to (heritable) traits that diminish it. That's really all there is to it.

And there is no need at all to speak of (or to worry about somehow being committed to) mental intervention; the point of the breeder analogy was precisely to show that mental intervention is not necessary to explain how heritable traits evolve across the generations.

JF: "Both these possibilities appear to be ruled out as explications of `select for...'. The first because there are no laws of selection, the second because there is no Tooth Fairy."

The simple, true regularity, the only one at issue, stands firm: There are heritable traits. (Their mechanism has even been discovered, since Darwin [via Mendel to Watson/Crick]: genes, mutations, and recombinatory DNA.) There is variation (both random mutation and recombination.) And reproductive success in a given environment does influence the relative frequency of genotypes in succeeding generations.

What more can one ask? And what is missing?

JF: "This appears to be a dilemma; one from which, as far as I can tell. Darwin has no exit."

I don't think it's any sort of dilemma at all. It seems to be a consequence of taking a few of Darwin's metaphors ("selection") too literally.

JF: "Historical addendum: I suspect that Darwin got into this mess because he assumed that natural selection can be modeled by artificial selection: Start with breeding, take the breeder away, and you have natural selection. If so, then he was the victim of a fallacy of subtraction. That could happen to anybody."

There may be a general fallacy of subtraction, but certainly Darwin did not fall into it. What he said was perfectly correct: With animal breeding, the breeder decides consciously what traits will have "reproductive success." With evolution, no conscious decision is needed: reproductive success in a given environment determines the genotypic distribution across generations.

(In my critique -- On Fodor on Darwin on Evolution -- I added something that I suspect Jerry found especially wrong-headed: That in fact mindful selection by human breeders is merely a special case of ordinary Darwinian evolution, in which it is human breeders' tastes that determine (say) dogs' survival/reproductive success, rather than, say, predators' tastes...)

JF: "I don't mind people ignoring this argument; that's gone on for some 150 years. Nor do I mind being preached to about strong adaptation, weak adaption, and so on. (One very distinguished Darwinist has suggested to me that the Theory of Evolution isn't a theory at all; it is, he said, a `tool box'.) But enough is enough. Would some body very kindly reply to the argument? Or would everybody very kindly leave me alone?"

One reply above. Please don't leave it alone!

-- SH



2009-04-22
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
As I understand it, the answer to the "arch/spandrel" situation is as follows:  The distinction between an arch and a spandrel is external to the process whereby arches and spandrels are constructed.  Similarly, the distinction between coextensive traits is made externally to the process of natural selection.  The fact that one can distinguish between coextensive traits does not imply that any laws or processes make the same distinction when speciation occurs.  So I do not see a problem with Darwin here.

2009-04-27
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Why exactly is coextensiveness issue a problem for Darwinism in particular?  Why is it a problem at all?  Take an ontology like that of atomic physics as it was in 1930. There are only: negatively charged light particles (electrons), positively charged heavy particles (protons), and neutral heavy particles (neutrons).  Now, all and only electrons swerve towards protons.  Does this mean that we can't tell whether charge or mass was the cause of the attraction? -- since negative charge is coextensive with low mass??

2009-04-27
On Fodor on Darwin on Evolution
Reply to Mohan Matthen
COEXTENSIVENESS IS A PSEUDOPROBLEM
MM: "Why exactly is coextensiveness issue a problem for Darwinism in particular?"
Ask Jerry Fodor! I think it's either a pseudoproblem or simply the usual empirical task of reducing underdetermination by sorting out, refining and testing rival hypotheses and causal factors with further experiments. (Philosophers for some reason prefer to talk of this instead in terms of "counterfactuals"...)


2009-04-27
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Well, actually, I would like Fodor to answer, but he doesn't seem to be picking up! 

Responding to you, though Stevan: counterfactuals are relevant here, aren't they?  In my example (above) negatively charged sub-atomic particles are coextensive with low-mass sub-atomic particles.  But one can nevertheless say (counterfactually) that were there a heavy negatively charged sub-atomic particle, it would swerve towards a proton.  And (as you point out, Stevan) one could try to test this counterfactual claim against others with further experiments.  The counterfactual claim implies, though, that the swerve is caused by negative charge, not by low mass.

2009-04-27
On Fodor on Darwin on Evolution
Reply to Mohan Matthen
COUNTERFACTUAL CONDITIONALS VS. FUTURE CONDITIONALS
-- -- SH: "(Philosophers for some reason prefer to talk of this instead in terms of "counterfactuals"...)"
-- MM: "counterfactuals are relevant here, aren't they?  In my example (above) N are coextensive with L.  But one can nevertheless say (counterfactually) that if non-LNs, then X.  And (as you point out, Stevan) one could try to test this counterfactual claim against others with further experiments.  The counterfactual claim implies, though, that the X is caused by N, not by L"

I really do think the difference is just in the way philosophers and scientists, respectively, prefer to talk. 

Scientists prefer to say "If A is true, then if I do this, that will happen, and if A is not true, then if I do this, that will not happen." 

Philosophers for some reason prefer "A is a natural law iff, had this happened, then that would have happened"...




2009-05-03
On Fodor on Darwin on Evolution
Reply to Stevan Harnad

Jerry Fodor complains that the criticisms of the objections he makes to the theory of natural selection in his paper Against Darwinism don't address his argument. If he is wrong then someone should say exactly where he has gone wrong. Fair enough - I will address his argument directly and show where I think that he has made a mistake. In summary, my disagreement with Fodor is that he only takes seriously two ways of making the distinction between being selected and being selected for and that, despite his claims to the contrary, there is a third and satisfactory way of making the required distinction.

The crucial question for Fodor is how we can distinguish between selection of and selection for. Darwin claimed that giraffes have long necks so that in times of drought they can feed on leaves that other, less fortunate, giraffes cannot reach. This increased their chances of surviving to breed, and so on. As necks grow longer, so the overall weight of giraffes increases. Both weight and neck length have been selected, but if we accept the Darwin's explanation (about which more later), then only length of neck has been selected for, and the concomitant increase in weight, although selected, is simply a side effect.

Fodor points out that the distinction between selection for and selection of is intensional: had neck length not been accompanied by weight gain (by decreasing bone density, say) neck length would still have been selected. If, though, weight increase was selected for and not neck length, then had weight gain not been accompanied by increase in neck length the heavier giraffes would still have been selected. The distinction between selection for and selection of is a modal distinction; to say that there has been selection for a property P is to say that the counterfactual 'those entities not having P would not have been selected' is true and to say that there has been selection of but not for P is to say that such counterfactuals are false.

The task then is to find a way of making the distinction between selection of and selection for that respects the intensional, modal nature of the distinction. Here is an example, deliberately non-biological, but non-intentional, that will show how the distinction can be made. Suppose that you are walking along the beach with a friend on a volcanic island the day after a violent storm. You come across a cave and you notice that there are unusually many small pieces of volcanic rock on the cave floor. You ask yourself: why are there so many small rocks on the cave floor? You look up and you see a crack in the ceiling of the cave, sufficiently large to let small rocks fall through. You therefore form the hypothesis that the reason why there are so many small rocks is because over a period of time they fell through the gap. Your friend, when told of your hypothesis, responds by saying that although that is a possible explanation, there are others. For example, during the storm the wind may have been blowing in from the sea, and the small pieces of rock were light enough to have been blown through the mouth of the cave. These hypotheses don't exhaust the options, nor are they mutually exclusive. Children might have been playing in the area the previous day and they might have collected small rocks and dumped them in the cave at the end of the day. Some of the stones could have been blown there, and some might have fallen through the crack in the ceiling. If we were really keen, we could test the hypotheses. We could ask the children whether they put any rocks in the cave, we could build a model of the environment and see whether either the blown-in-the-wind or fall-through-the-gap hypothesis is plausible.

But regardless of how we might determine which, if either, of the two initial hypotheses are correct, each provides a different explanation of why there are small rocks on the cave floor. If after having examined in detail all the various alternatives we decided in favour of one hypothesis over another, we would not feel that the explanation was in some sense incomplete - we might think that we have explained what really happened.

This kind of explanation could reasonably be called a sieve explanation. To sieve flour there are two things that we need to do: first, we need a sieve, and second we need to pour the flour through the sieve. Once we have done so, we have separated the sieved from the lumpy flour and we can then explain why there is no lumpy flour in the bowl - it has been sieved. In general, when giving a sieve explanation we claim (i) that there exists a condition that objects must satisfy that separates those objects in a larger set that satisfy the condition from those that don't and (ii) that the conditions must have been applied to the objects in the larger set. We can now say that those objects that have been sieved have been selected for the condition. The point of the earlier example was simply to illustrate that not all sieves are artefacts.

Sieve explanations are intensional (but not necessarily intentional) and they support the relevant counterfactuals. In the cave example, the blown-in-the-wind hypothesis it is true that had there been other objects suitably placed in the environment that were too big to fall through the gap in the cave but light enough to be blown around then some of these would have been blown into the cave; on the fall-through-the-gap hypothesis, it is true that had there been other heavier rocks around that were small enough to fall through the hole, then they would have dropped onto the floor of the cave. But as volcanic islands tend to be geologically pretty dreary, with lots of similar rocks around and not much else, examination of the rocks on the cave floor would not help in deciding amongst the two hypotheses.

The two explanations support different counterfactuals and select for different properties (weight against shape). However, although counterfactuals are supported, they do not directly invoke laws of nature - being sievable is not a causal property we would normally ascribe to flour. But in itself this is not a problem. Laws of nature support counterfactuals, but not all counterfactuals support laws of nature, and the original requirement was to find a form of explanation that supports counterfactuals.

Fodor is not unaware of this kind of argument, which he ascribes to Sober (Dawkins also talks of filters and sieves), but he only discusses this proposal in a footnote and gives it pretty short shrift. He writes (about Sober's pebble sorting machine):

...what grounds the counterfactuals in Sober's example is the structure of the mechanism; given how it works, it lets the round pebbles through but no others; one's intuitions about which trait is  selected for follow not from what laws of selection per from mechanics. Notice, for example, that whereas competition plays a central role in the explanation of every bona fide Darwinian selection, it plays no role at all in explaining how Sober's machine sorts for round marbles.

Note first that, as I pointed out earlier, selection for traits does not have to follow from laws of selection; they just have to support the appropriate counterfactuals. Second, although Fodor is right in claiming that competition plays a crucial role in Darwinian selection, this does not mean that it has to play a crucial role in the explication of the distinction between selection for and selection of. Sieve explanations are not local to the theory of natural selection or any other theory that involves competition.

Although sieve explanations have a temporal aspect, they are ahistorical. But it is easy to see, in outline anyway, the role that sieves play in the theory of natural selection. Assuming once again Darwin's explanation of why giraffes have long necks, there is a sieve for neck length in giraffes that filters out those giraffes that cannot reach the leaves at the top of the trees. Without competition for resources amongst giraffes the existence of such a sieve is irrelevant to natural selection, for in such a case how well-fed a giraffe is would have no differential impact on the number of offspring produced. But if there is such competition, and if further the sieve is in operation over a number of generations, and neck length is heritable, then there would be upward pressure on neck length leading to the fixation of the phenotype that the theory of natural selection is supposed to explain.

Adaptationist explanations are historical explanations that do not depend on laws of selection in Fodor's sense, but do depend on sieve explanations that support counterfactuals and are thus able to make the distinction between selection simpliciter and selection for. They are also highly context-dependent and post hoc, but as far as I can tell no-one is disputing this - for example, the familiar claim that if we were to rewind natural history then we would get a different story, is an expression of a general recognition of the contingency of the actual historical account. The context-dependency and post hoc nature of adaptationist explanations are only problematic if they have to be based on laws of selection construed as causal laws connecting traits to fitness, and laws of selection in this sense are unnecessary - sieve explanations provide an alternative.

The discovery of suitable sieves is a complex matter - possible explanations are not necessarily true explanations..Darwin's theory of giraffe neck length could well be wrong. Craig Holdrege ('The Giraffe's Short Neck' , http://www.natureinstitute.org/pub/ic/ic10/giraffe.htm) writes: "The giraffe's neck carries out a variety of functions - it allows feeding from high branches, serves as a weapon in males, brings the head to elevated heights that give the giraffe a large field of view, is used as a pendulum while galloping, and so on". On Holdrege's view, Darwin got the explanation wrong, but the difficulty of finding the right explanation does not mean that there is no explanation to be had, and indeed Holdrege's alternatives are themselves based on empirical observation.

Those of us who share Fodor's dislike of evolutionary psychology might share my concern that if evolutionary psychology is to stand or fall with the theory of natural selection in general, then it will stand.




2009-05-04
On Fodor on Darwin on Evolution

FODOR REPLY TO GALFAVY

Jerry Fodor
"Galfalvi seems actually to have understood the argument I offered. In this respect, what he writes is to the point in ways that the other replies I've seen  distinctly are not. What I don't understand, however, is why he is happy about it, or what he thinks is wrong with the morals I drew from the argument.
"As far as I can tell, Galfavi agrees with me that if a phenotypic property is pervasive in a population in an ecology, there must be a mechanism in virtue of which it is pervasive in that population in that ecology. This is, as I've elsewhere remarked, not an application of Darwinism but of the principle of sufficient reason. We also agree that, to explain why the property is pervasive, we'd need an account of the relevant mechanism. Galfalvi calls this a `sieve explanation'; which is OK with me. The relevant points, however, are (1) that the theory of Natural Selection does NOT provide the required sieve explanations; and (2) that Darwin offers no theory of the properties of  sieves that holds across the various cases in which traits become pervasive in populations in ecologies. Put in Gavalvi's terms, a THEORY OF SELECTION would be a THEORY OF SIEVES. Darwin hasn't got one; Galfalvi  (I suppose) hasn't got one; and, it seems to me, there very likely  can't be one. That's because the mechanisms of trait fixation vary, pretty much arbitrarily, from case to case. If that's so, then finding sieve explanations is the domain of natural history, not of evolutionary theory. Since it appears that Galfalvi thinks all that too, it's unclear to me what his  residual objection is supposed to be.
"A theory of sieves would be a theory of selection and vice versa. Since, however, this is a truism it can be of no comfort to Darwin."



2009-06-29
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Natural selection is a pattern of a certain form, related to processes of a certain form. First you see the pattern (a statistical distribution of traits), then you look for a process that can instantiate the pattern along the lines of differential success in reproduction due to the trait's (differential) function. Since there are usually many different ways to instantiate the observed pattern, and since there are many traits, the disjunction / coextension problem pops out everywhere.

Fodor thinks that the only way to address the coextension problem (apart from asking Mother Nature) is to look at possible worlds where a certain coextension does not occur. This mimics what can be done in actual-world experimental settings, but Fodor finds this hopeless and stops there. There may be, however, a further way to address the problem.

Integrative biology draws from a lot of literature in order to check testable adaptive hypotheses: "if T were selected for function F, then we would expect T, or the organism O, to possess certain other traits improving, or not impeding, its function; if T were selected for other function F' instead..." you got the idea. Then, you check the available datasets, and if you are lucky enough to rule out all competing hypotheses (except one) you would be justified in saying that "selection for" does indeed happen, as Darwin also thought.

(whether you succeed or not sounds to me like an epistemological problem)

The main difference is that you don't figure out a nomologically possible world where the coextension does not occur: you look at coextensive traits for useful insights. After all, "coextensive biological trait" is not a natural kind and there are many ways (genetic, developmental, functional-morphological) for an organism to instantiate coextensive traits. Also note that genetics, development, and functional morphology are domains where you can find mechanisms, nomicity, quantifiers and covering laws. Their generalizations are pretty robust, and a simple just-so story would be ruled out quite soon.

Salvaging "selection-for" arguments (and Darwin) may thus turn out to be a matter of pushing the intensional problem back where it belongs (intentional states) treating prima facie coextensive characters in terms of the concepts and generalizations provided by the relevant disciplines.

Granted, this won't give you any "laws of selection" in Fodor's sense. What I don't understand, however, is why Fodor wants them. I used to think that what you usually do in special sciences is to adopt a two-prong strategy: you build a theory that says that some entities and processes exists, and work out which patterns, on the basis of your theory, are possible or impossible; on the other hand, you build your datasets and check them against the impossible patterns -- if any impossible pattern is instantiated your theory is wrong. Why should natural selection be more special than that?


2009-06-29
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Speciation is merely a (relatively fancy) example of the much larger phenomenon of the ongoing emergence of organized dynamic structures/systems in nature.  The metaphysical issue is nothing that is specific to biology.  Darwin was reading Adam Smith: the law of effect.  There is no "mind" that is "selecting" which jokes are funny.  Jerry Fodor has turned into Alvin Plantinga.

2009-06-29
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
I actually don't think that Fodor's argument in his UQAM lecture, "What Darwin Got Wrong", cited by Stevan Harnad, turns on anything technical in the theory of evolution (as Marcello Pucciarelli seems to suggest). 

The argument is this: Selection is an extensional notion ("If you select a mechanism that catches Xs, and if the Xs are Ys, then you thereby, select a mechanism that catches Ys.")  It cannot therefore be equivalent to selection-for, which is intensional.  ("If you are selecting for Bs and Bs are Cs, it doesn’t follow (and it needn’t be true) that you are selecting for Cs.")  Because it is extensional, selection does not distinguish between fitness-producing traits and co-extensive neutral traits.  But the theory of natural selection requires this distinction.  Therefore, the theory of natural selection is on logically shaky ground. 

Fodor grants that the intensionality of selection-for would make sense if a mind were choosing between co-extensive traits, but "natural selection doesn’t have a mind".  More importantly, he also concedes that if there were a law that required selected-for traits to increase in frequency, but no law that required co-extensive neutral traits to do so, then the intensionality of selection-for would, again, be vindicated.  But he doesn't think that there is any such law: "historical explanations offer not covering laws but plausible narratives."

Now, intensionality is ubiquitous in social-science explanation -- as Anderson Brown rightly implies -- and Fodor implicitly recognizes this.  His real beef seems to be with people who think that selection-for is law-governed: such people assimilate historical narratives to covering law explanations.  But he does not object to historical explanations as such:

"many paradigm scientific theories are, I think, best understood as historical narratives;
Consider, inter alia: theories about lunar geography, theories about why the dinosaur became extinct,
theories about the origin of the Grand Canyon, or of the Solar System or, come to think of it, of the
universe. All these projects (and, surely many others) are post hoc searches for chains of sufficient causal
conditions whose satisfaction would explain the occurrence of the event in question.  If I’m right, theories
about how heritable traits evolve are also of this kind.
  (p. 25, emphasis added)

It is unclear to me how this supports the rhetorical force of Fodor's conclusion: "It is, in short, one thing to wonder whether evolution happens; it’s quite another thing to wonder whether adaptation is the mechanism by which evolution happens" (26)  I agree that theories about "how heritable traits evolve" are indeed best understood as historical narratives, but as we just saw, Fodor thinks that historical narratives are scientifically legitimate.  How then does the historicity of evolutionary explanations support "doubts about the whole adaptationist enterprise" (1)?

One last point: Fodor insists that "None of this should, however, lighten the heart of anybody in Kansas; not even a little . . . evolution happens; the evidence that it does is overwhelming."  His target is the theory of natural selection, which is a proper part of Darwin's theory of evolution.  "I’ve provided not the slightest reason to doubt the central Darwinist theses of the common origin and mutability of species. Nor have I offered the slightest reason to doubt that we and chimpanzees had (relatively) recent common ancestors." (25-26)  He's not in the same boat as Alvin Plantinga.

2009-07-02
On Fodor on Darwin on Evolution
Reply to Mohan Matthen
Well, I didn't mean to enter into technicalities, just wanted to add a third option to those presented by Fodor (intensional process and laws of selection), because the idea that "selection for" may be intensional worries me, and I think everyone should be worried, while the non-existence of laws of selection is not a source of concern.

Fodor's "option b" for addressing the issue of coextensive traits is "disentangle them". He does this in some possible worlds, others do that in the laboratory. Either way, I agree with Fodor that it's unlikely that this procedure will solve all the problems. I'm even ready to accept that some coextensions may be nomic (e.g., governed by the laws of developmental biology), barring any possible-world disentanglement.

The option I offered is to double check the coextensive traits themselves. Did they get the attention of genetics, developmental biology, functional morphology, physiology, something else? If so, we may expect that these disciplines will tell us more about other things we could not know by mere reflection. Some of these things may be related to function and suggest an adaptive hypothesis. Another interesting possibility would be discovering that a trait is a developmental correlate of some other trait. Either way, we would be in a better position in order to evaluate whether an adaptive hypothesis would provide the right kind of explanation.

(An incidental point of some importance: this is how we might proceed if we are after a historical explanation of real-life traits. A perfectly legitimate but different endeavor is to assign fitness values to "disentangled traits" when modeling the patterns of natural selection.)

How could this option affect the "selection for" issue? Roughly, by replacing "coextension" with two (and, very likely, more) biological phenomena: developmental correlation and functional interaction. Taken together, the theories that biologists have built around these phenomena provide plausible grounds for justifying the distinction between traits that are "selected" and traits that are "selected for". Very roughly, to show how this can be, I'd like to provide yet another resume of Darwin's theory. 

In order not to be carried away by mentalistic intuitions, I suggest a temporary change of name: let's call the core of our theory "survival of the fittest". The theory says that in a certain kind of process of trait fixation the following happen: (1) the fittest in each generation possess one or more differential traits; (2) there is a process connecting the possession of those differential traits to improved chances of leaving offspring. To me it sounds extensional enough: although we get to know the details only post hoc, the only condition for being the fittest is the possession of a certain set (possibly a singleton) of differential traits. The traits and their interactions with organism and environment do the rest. Let's call these traits adaptations.

The theory does not require that every differential trait observed in the fittest is also an adaptation -- leaving ample room for the developmental biologist's generalizations. It requires, however, that all adaptations are involved in improving the chances of leaving offspring through their interactions with other parts of the organism -- ask the functional morphologist. Thus, a principled distinction between traits that undergo fixation (selected) and traits that undergo fixation and are also adaptations (selected for) seems tenable.


2009-07-19
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
I would like to make a few comments on Stevan Harnad's paper, On Fodor on Darwin on Evolution, as per original invitation. 
In my opinion, one of the issues raised by Fodor is: "did Darwin discover, in Michael Ruse's words, a 'mechanism' for the fixation of new traits?" (quite clearly, he did not discover a mechanism for their generation or transmission). While Harnad (like Ruse) believes that this is the case, Fodor's doesn't. But Fodor is in the good company of many present-day evodevoists who hold that 'mechanism' is a term better suited to developmental processes (my impression is that the consensus about what counts as 'mechanism' is shifting in the same direction, from selection to development -- which is not to say that natural selection does not occur, or that it explains nothing). What makes Fodor's stance anti-Darwinian are the peculiar reasons he offers, i.e., the argument of intensionality and the metaphysical implications he draws from it.

I think Harnad's critique would have been much more effective, had he taken a stance less committed to neo-Darwinism. For example, many respectable biologists today talk about phenotypic (or morphological) evolution. Harnad's insistence on the genotype as the appropriate level of selection looks like an arbitrary (and unnecessary, since not much seems to depend on it) imposition of terms. 

Fodor's argument mirrors the concerns of some biologists (including some adaptationists) about distinguishing adaptations, exaptations, 'spandrels', and perhaps a few more special cases. But he turns this scientifically legitimate concern into a metaphysical issue: "how can a natural process (other than intentional) distinguish between 'coextensive traits'?" It can't, so in Fodor's view natural selection is just the occurrence of selection but has no explanatory power (except for whatever explanatory power we might want to assign to statistical correlations). 

The core of Harnad's reply is (or, could have been) stated in his reformulation of the principle of natural selection (PNS):
There is natural variation of (heritable) traits, and, from that (heritable) variation, it is the relative success of the creatures that inherit the traits, in surviving and reproducing in a particular environment, that determines which traits are passed on to the next generation (in much the same way that, in Artificial Selection, the animal breeder selects for the traits he prefers).
Having rewritten the PNS with no mention of 'natural selection' or 'fitness', Harnad could easily deal with the issue of intensionality. Unfortunately, he forgot here to mention the (roughly causal) relation between the trait(s) and their bearers' reproductive success. As stated, this formulation of the PNS does not distinguish between traits that just happen to be there (for some reason) from traits that are there for the precise reason that they provided a certain advantage to their bearers. Fodor still wins. When, later on, Harnad supplies the missing element, he produces a fairly extreme selectionist statement, which only undermines his case: 
The distribution of heritable traits is always determined by how successful they make their bearers in surviving and reproducing.
One final weakness in Harnad's reformulation of the PNS is his defense in the same statement of the breeder's analogy. In so doing, he seems to suggest that the causal interactions among traits, organisms and environment are comparable to the purposeful actions of an (external) agent -- what Fodor also says, for opposite reasons. Here, however, Darwin's original analogy seems overstretched. What Darwin wanted to achieve with the breeder's analogy, was to give his readers a rough idea of the power -- the potential effects -- of natural selection. He also used artificial selection as a sort of laboratory for the study of variation. But on the issue of how natural selection works Darwin did not use the breeder's analogy, the name of the game being "struggle for life".




2009-07-19
On Fodor on Darwin on Evolution

ON DARWIN'S PRESCIENCE


MP: "[O]ne of the issues raised by Fodor is: "did Darwin discover, in Michael Ruse's words, a 'mechanism' for the fixation of new traits?" (quite clearly, he did not discover a mechanism for their generation or transmission)."

Fodor did not ask about a "mechanism" but a "natural law."

Yes, it was later Mendel, and still later, Watson&Crick, who discovered the mechanism for inheriting traits. Darwin merely presupposed it. But his presupposition was right.

MP: "Fodor is in the good company of many present-day evodevoists who hold that 'mechanism' is a term better suited to developmental processes"

Evo/Devo is a bit of a cult, but it does not replace genetic transmission, it just elaborates it.

MP: "What makes Fodor's stance anti-Darwinian are the peculiar reasons he offers, i.e., the argument of intensionality and the metaphysical implications he draws from it."

And I have pointed out why and how both the intensionality argument and the metaphysical implications are red herrings.

MP: "[M]any respectable biologists today talk about phenotypic (or morphological) evolution. Harnad's insistence on the genotype as the appropriate level of selection looks like an arbitrary (and unnecessary, since not much seems to depend on it) imposition of terms." 

The phenotype is the phenotype of a genotype. You cannot bootstrap to phenotypes without genes; nor are phenotypes hanging by a developmental skyhook. It is genes that also make development possible.

MP: "'[H]ow can a natural process (other than intentional) distinguish between 'coextensive traits'?' It can't..."

"It" needn't.

MP: "...so in Fodor's view natural selection is just the occurrence of selection but has no explanatory power (except for whatever explanatory power we might want to assign to statistical correlations)."

Genetics provides the mechanism of selection just as gravity (etc.) provides the mechanism for galaxy formation. But there is no "natural law" for the formation of any particular galaxy, just boundary conditions and statistical regularities.

MP: "Having rewritten the PNS with no mention of 'natural selection' or 'fitness', Harnad could easily deal with the issue of intensionality. Unfortunately, he forgot here to mention the (roughly causal) relation between the trait(s) and their bearers' reproductive success. As stated, this formulation of the PNS does not distinguish between traits that just happen to be there (for some reason) from traits that are there for the precise reason that they provided a certain advantage to their bearers. Fodor still wins." 

No particular need to make that distinction. You just need to note that (most of) the heavy work is being done by generation to generation changes in the proportions of genetically coded traits, as determined by their reproductive success. That's all there is to it. The fellow-traveller traits (whether genetic or nongenetic) are simply an (intentionalist) red herring.

MP: "What Darwin wanted to achieve with the breeder's analogy, was to give his readers a rough idea of the power -- the potential effects -- of natural selection. He also used artificial selection as a sort of laboratory for the study of variation. But on the issue of how natural selection works Darwin did not use the breeder's analogy, the name of the game being 'struggle for life'."

As I said, the genetic mechanism underlies both; indeed deliberate animal-breeding by human breeders is merely a special case of natural selection.

-- SH



2009-07-19
On Fodor on Darwin on Evolution
It's not clear to me how Fodor's argument distinguishes between "neo-Darwinism" (by which, I take it, Marcello Pucciarelli means to include any version of theories that give any weight to adaptation) and "evo-devo". 

In the first place, almost every evo-devoist gives some weight to adaptation -- even say Brian Goodwin.  And by that token, they fall afoul of the intensionality argument.

Secondly, the evo-devo argument falls equally afoul of intensionity.  In general, evo-devoists hold that a process might emerge because it satisfies condition C.  Condition C might be coextensive with C'.  They may deny that the process emerged because it satisfies C'.  Here, C may well not be "adaptive". 

The intensionality argument is a very blunt instrument.  It does not restrict itself to selection or fitness.

Kripke has some harsh words in Theoria 2008 concerning "Quine's longstanding remarks against 'frankly inequalitarian' attitudes towards differnet ways of designating the same object".  He notes that though some seem to hold that these "inequalitarian" attitudes have no place in "serious science", they cut even against mathematical disciplines, such as recursion theory.  Kripke notes that if anti-intensionalism were to be taken seriously, we would be forced to hold that every function is computable -- which would obviously be rather silly.  The anti-Darwinian consequences drawn by Fodor are no less silly.
  

2009-07-20
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Here's the part of Fodor's argument that I think is flawed: "A process that distinguishes between coextensive traits is claimed to be intensional."  Since no one is ever going to accuse Jerry Fodor of being a bad writer (eccentric maybe but bad definitely not), I'll take this literally.  Processes aren't the kind of things that "distinguish" (it looks like Fodor actually takes this to be a key point - on that we agree).  There are people who have explanations that distinguish.  The explanations of those people are law-governed.  The process itself is not law-governed at all.  There is a much too literal treatment of the word "selection" here.  Nature "selects" nothing.  Darwin simply applied a homely fact of life that (as I mentioned before) he got from reading Adam Smith, the "law of effect": negative outcomes tend to extinguish, positive outcomes tend to replicate.  Groucho Marx, when asked how he developed his routines, explained that over thirty years in vaudeville, when the crowd laughed, he did what he was doing some more, when they didn't he didn't. 

A note on the "Tooth Fairy" reference: The pernicious Chomskian influence here is the notion that humans are unique.  They're not.  Just some more chunks of nature.  There are no "minds."  Including in my and JF's heads.  Bad metaphysics.    

2009-08-18
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
I also find Fodor's 'coextensionality' argument puzzling, or rather obviously wrong.

Suppose all and only the brown organisms in a population are over 6ft tall, so 'browness' and 'tallness' are coextensive.
Suppose these brown and tall organisms enjoy a survival advantage over their red and small rivals.
Suppose both colour and height are heritable traits.
Then, browness and tallness will both spread in the population, vis-a-vis their allelic traits.

Fodor's worry seems to be this. How can we say that there was 'selection for' tallness, as opposed to be browness, without invoking a conscious selecting agent?
But the answer's obvious.
To say that there was 'selection for' tallness, but not browness, means just that the tall-and-brown organisms enjoyed a survival advantage because they were tall, not because they were brown.
Equivalently: the survival differences in the population were caused by the height differences, not by the colour differences.

So the 'selection for' locution can be translated into simple causal talk.

The intensionality of 'there was selection for trait X' thus derives from the intensionality of the locution: 'trait X caused differences in survival/reproduction'.
(Note that the intensionality of the latter locution is perfectly compatible with the extensionality of singular causal relations, i.e. of the locution 'event a caused event b'.)

That's all there is to it, so far as I can see.












2009-08-18
On Fodor on Darwin on Evolution
Reply to Samir Okasha
Samir is actually making the same point I have made a couple of times in this thread (e.g. on 27/04).  (Good to find that he agrees with me about at least one thing.)  Intensionality is rife in all of the social sciences, including psychology.

Fodor does sort of recognize the point, as I pointed out on 29/06.  I wrote:

"Fodor grants that the intensionality of selection-for would make sense if a mind were choosing between co-extensive traits, but "natural selection doesn’t have a mind".  More importantly, he also concedes that if there were a law that required selected-for traits to increase in frequency, but no law that required co-extensive neutral traits to do so, then the intensionality of selection-for would, again, be vindicated.  But he doesn't think that there is any such law: "historical explanations offer not covering laws but plausible narratives.""

To me, all of this is very odd.  why would intensionality be ontologically more excusable if there were a law.  Suppose there's a law that red rabbits are small, and brown ones large.  Couldn't there still be selection-for largeness?  Secondly, is historical causation supposed to be ontologically suspect?

Maybe what is needed here is a thorough-going examination of intensionality in causation.  Surely there is something prima facie wrong with it.  But equally surely there ought to be a framework for understanding exactly why, or rather when, it is ontologically innocuous.

Mohan Matthen



2009-08-19
On Fodor on Darwin on Evolution
Reply to Samir Okasha
Samir, I think you're missing his point about the need for causal laws to back causal and counterfactual claims.  He argues that evolutionary biology doesn't have any such laws to appeal to.  
You can reject the premise that causal and counterfactual claims need to be backed by laws, or you can reject the premise that there are no relevant laws in this domain.  But you certainly *cannot* simply ignore that crucial aspect of his argument.

2009-08-19
On Fodor on Darwin on Evolution
Two questions for David. 

1.  Why would intensionality suddenly become acceptable if there were a law to support the causal connection?  The original fuss about intensionality (in Quine) was that intensionality was the mark of unreality -- no exceptions made for the mental or for the law-like.  Fodor seems to be using the original criterion, but introducing exceptions without saying why they are OK.

2.  Are there laws in, say, economics, where similar intensional phenomena exist?



2009-08-19
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
David, I don't see I'm ignoring anything crucial. I'm simply setting the issue up a bit differently from Fodor (and in a way that I think is clearer.)

I was merely making the mundane and obvious point that 'selection for' talk can be translated without loss into causal talk.

So in the scenario I describe, if Fodor wants to maintain that there must be selection for both browness and tallness, on the grounds that they're coextensional, he is committed to saying that the two causal statements I provide can't differ in truth value. But since they patently can differ in truth value, Fodor must be wrong.

This argument doesn't require me to take any stand on the relation between causation, laws, and counterfactuals, nor other metaphysical minutae. (Just as well as I have no opinion on these matters!) It appeals just to what I regard as the obviously true fact that the two causal statements in question can differ in truth value.






2009-08-22
On Fodor on Darwin on Evolution
Reply to Mohan Matthen
Mohan,
I wasn't out to defend Fodor's position, and my views on laws and intensionality are not nearly settled enough to make any serious pronouncements on the issues you raise.  I was merely objecting to the very last line of Samir's post: "That's all there is to it, so far as I can see."  He seemed to be gliding past a crucial bit of Fodor's argument--a point to which I felt I should draw attention.  Perhaps Fodor's position is, in the end, wrongheaded.  But I don't think it can be as easily dismissed as Samir seemed to suggest.


As regards laws in economics:  I wonder if you could provide a concrete example for the purposes of the discussion.  I suspect that the cases you have in mind have to do with psychological ascriptions rather than anything to do with prices, wages, employment rates, etc.--all of which might fit comfortably into a purely extensional framework.  Perhaps it's laws of social psychology that you have in mind.


Now, when it comes to psychology, it's clear that Fodor holds that the way to go is to formulate psychological laws, despite his insistence on the irreducibly intensional character of psychological predicates.  I've asked him whether he sees this as a tension in his overall position.  His reply was that he doesn't see the same problems cropping up for psychology as the ones he claims to have identified in the case of evolutionary biology.  However, he did go on to say that if psychology was, in fact, subject to the same criticisms, then he would stop treating it as a attempt to formulate genuine laws and treat it instead as trafficking in what he calls "historical narratives."  I see this as a rather large problem for his overall position, because I think that the two cases are parallel in the relevant ways.
.
As regards Quine on intensionality:  It's not so clear to me that Quine was hostile toward "natural necessities" and the attendant modal linguistic constructions.  What passages in his work do you have in mind?


2009-08-22
On Fodor on Darwin on Evolution
Reply to Samir Okasha
Fodor would ask you about the grounds on which you believe that the relevant causal claims can "patently ... differ in truth value."  Unless you're willing to invoke brute intuition here, your reply will embroil you in issues concerning laws, counterfactuals, and what you call "metaphysical minutiae."

2009-08-22
On Fodor on Darwin on Evolution
Reply to Samir Okasha
Although my proposal of resurrecting the "survival of the fittest" did not succeed, it was meant to show that Darwin himself addressed the problem of the intentionality of selection (similar to the present issue about intensionality) by giving a different formulation of the principle of natural selection along the lines of a sort-of-causal account: the possession of a certain trait increases the reproductive success of its bearer, which in turn makes the trait itself more pervasive. We all know, however, and Fodor knows, that Darwin's concept of fitness was rather imprecise by modern standards. It does not translate well into the concepts and models of population genetics (a paper by Ariew and Lewontin, The Confusions of Fitness (2004), provides lots of convincing arguments about that). The problem for a causal account of natural selection is that population genetics cannot make a distinction between, say, height and color, unless they form different distribution patterns in a population (but then, tallness and browness wouldn't be 'coextensive'). Fodor would still accept a causal account of natural selection (one that could discriminate among coextensive properties) if it were a law that, say, tallness is more fitness-enhancing than browness. Then, one could tell which one is the 'true' fitness-enhancing property and assert sonething about its being selected-for. But there are no such laws. The conclusion (and I think Fodor is not alone in drawing this particular conclusion) is that one can tell a causal story based on natural selection only for those special cases (not very many, I believe) where population genetics agrees with, say, functional morphology or physiology about the increased prevalence of a trait that has a fitness-enhancing role..

2009-08-24
On Fodor on Darwin on Evolution
David: Sorry for the delay in responding.

1.  When I said that economics was subject to intensionality, this was what I meant:

Suppose all and only diamonds are shiny crystals.
Suppose that there is a reduction of the supply of diamonds.
Does the price of diamonds go up because the supply of diamonds was reduced, or because of supply of shiny crystals was reduced?

This has the same form as the example given by Samir Okasha.  Differentiating between reducing-supply-of-diamonds and reducing-the-supply-of-shiny-crystals involves differentiating co-extensive sets within the context of a causal 'because'.

2.  I don't think it's particularly controversial that Quine thought that modal logic was on shaky philosophical ground (because of intensionality).  It's true, however, that his position became more refined as time went on.  Here are some pretty good notes on the topic: http://seis.bris.ac.uk/~plxol/Courses/PHIL30081/Handout3.pdf.  A very sophisticated version of his position is to be found in "Three Grades of Modal Involvement" -- which is in From a Logical Point of View, I believe.  (Harman's syllabus on http://www.wvquine.org/wvq-phil-516.pdf should be useful.)

2009-08-29
On Fodor on Darwin on Evolution
Reply to Mohan Matthen

On 'mechanism' in development and evolution


Sorry for the late reply to Mohan Matthen's comment of July 19. I have been tempted to start a new thread without the baggage of the intensionality argument and I was slow to take a decision. 

The issue is: against a rather common view, I subscribe to William Provine's assertion that "natural selection is not a mechanism" (in the Afterword to The Origins of Theoretical Population Genetics). Compared to development, where one can find genotypes that turn into phenotypes through precise interactions between cells and molecules, NS is the result of contingent relations, that may remain stable for a long time but are never tightly integrated.

Apparently, calling NS 'a mechanism' is a metaphorical way to imply that NS occurs reliably, follows a definite sequence of steps, and/or that it is deterministic. This metaphorical usage, however, can be confusing (the more confusing, since its metaphorical character is seldom acknowledged). A more satisfactory notion of 'mechanism' is advanced by at least some evolutionary developmental biologist (e.g., Gerd Muller, Stuart Newman) who locate it in the physico-chemical interactions that determine development and constrain (or facilitate) its evolution. To be sure, I don't know what the 'proper' meaning of 'mechanism' should be, and I think it would deserve a thread of its own: my view is that a mechanism is an arrangement of parts that interact according to physico-chemical principles involving some transfer of energy (movement, signaling, protein-binding...). Besides, since a biological mechanism is highly context-sensitive, and there are many of them and they often interact, the precise output of a mechanism depends on its interactions. Finally, all interactions taken together may produce a process that can be robust, buffering the variations occurring at the level of the individual mechanisms. 

Back to the issue, leaving aside the selection/selection-for distinction, I have no qualms about the occurrence of natural selection and of adaptations. If one takes the 'NS as the mechanism of evolution' metaphor seriously, however, the obvious implication is that the main route to understanding evolution is the study of 'the mechanism'. Thus, if NS is not a mechanism after all, one may end up taking the wrong route. Part of the difficulty in abandoning the 'mechanism' metaphor seems to be due to the difficulty of conceptualizing NS in generic terms: not a mechanism, not a process, probably not a cause... My view is that it is a pattern of distribution, captured by the models of population genetics (and I would think that I'm following Mohan Matthen's views on this point). Additionally (and maybe inconsistently), I reserve a place for NS in the 'original' Darwinian sense of 'selection-for', which is the only available when studying major transitions of the distant past (origins of tetrapods, of birds, ...). A bit surprisingly, this also applies to some present-day 'bizarre' structures such as the giraffe's neck, where population genetics is of little help. 

Thus, I wonder whether the common view of NS as the mechanism of evolution (even when supplemented by genetic drift) can be defended, or should rather be abandoned. My further conclusion is that when an adaptive hypothesis is based on a 'Darwinian' concept of NS, and not supported by population genetics, it might well be explanatory (depending on how many competing hypotheses it rules out) but there is little ground for asserting a priori its superiority in relation to other, non-selectionist kinds of explanation.


2009-08-30
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
Your points are well taken, Steven.  What else to say, other than best wishes.
John Fentress
john.fentress@gmail.com
etholife.net

2010-04-05
On Fodor on Darwin on Evolution
Reply to Stevan Harnad
SAMIR OKASHA ON FODOR&PIATELLI-PALMARINI ON EVOLUTION
Samir Okasha has written a restrained but decisive critique of F & P-P in TLS

One could almost have said a-priori that any stance according to which the causal status of correlated traits such as white fur and blue eyes in polar bears is "problematic" in principle is an armchair absurdity. To compound it by adding that even if the causality is sorted out it is just ad-hoc historifying is even further away from the actual exigencies and pragmatics of the causal explanation and prediction that is "science" (rather than the stodgy and sterile "covering-legalism" some have imagined it to be). Your review makes these points clearly and convincingly.

Okasha is of course also right about the generalizations that certain kinds of modeling make possible in evolutionary biology, allowing conclusions to be drawn and generalizations to be made that go beyond specific adaptations, but I'm not sure one even needs to invoke these in order to show how empty is Fodor's criticism.

Some of the same points  -- and a few additional ones -- were made in this PhilPapers discussion thread and the paper cited in it: Harnad, S (2009) On Fodor on Darwin on Evolution .

One of the additional points was a link between Fodor's odd oppositionism toward Darwinian evolution and his (equally odd) nativism about "concepts." His nativism is inspired by Chomsky's universal grammar (UK) and the poverty of the stimulus (which makes UG both unlearnable and unevolvable), but none of the empirical details in the special case of UG are present in the case of concepts and concept learning, since concepts, unlike syntax, do not suffer from the poverty of the stimulus but are perfectly well instantiated, so one can learn them from positive and negative examples in the usual unproblematic way. Yet there, too, Fodor is inventing supposedly insurmountable complications and obstacles (such as the problem of "vanishing intersections") where in reality it is evident to common sense that there is no problem at all about learning concepts (nor about evolving the means to do so).

I think it may have been the special pleading and epicycles that were necessitated by the defense of the innateness (and non-evolvability!) of "concepts" that led to this extremely odd position on evolution in general.

Stevan Harnad



2010-04-05
On Fodor on Darwin on Evolution
Reply to Stevan Harnad

Whist Fodor &PP's point that you indicate might be subject to some revision, these are not key to the argument they are making. What is more important is...
There has been a long-standing, subtle confusion, elegantly expressed by Fodor&Piattelli-Palmarini between “(1) The claim that evolution is a process in which creatures with adaptive traits are selected and (2) the claim that evolution is a process in which creatures are selected for their adaptive traits.”[1] This subtle difference is at the heart of the diverse uses and abuses of Darwinism.
This intentionality at the heart of Darwinism is an artefact of using the model of sexual and domestic selection, whilst this does not invalidate natural selection per se, it does point to a far more serious complaint, not with natural selection but with how it has been conceived.  In the last 150 years Darwinism has always been dragged by the nose to form normative interpretations for the employment of political policy, and a host of scientific spin-offs as diverse as Social Darwinism, Eugenics, Evolutionary psychology, memetics and temetics. Thes have all relied on the assertion that point 2 is implied by point 1. In simple language, natural selection has been mobilised to support  theory that is anything but NATURAL, but is teleological. The language of 'selected for'; 'evolutionary pressure'; 'adapting TO the environment'; 'evolution as a cause' all imply claim 2. where in fact natural selection ought to be about the fact that individual organisms that have viable progeny FOR WHAT EVER REASON, urges 'adapting from the environment', 'evolution as a effect', and so on. When we get to the 'selfish gene' fiction, and Susan Blackwood's memes 'wanting to be selected' , it is easy enough to see how natural selection is being employed to ridiculous ends - it is clear that humans are doing the 'selection' by arbitrarily identifying traits and behaviours in the fossil record that they personally deem to have been selective. The tautology is ALSO with the process of biological research that has preserved and maintained the teleological fiction, which as shown a distinct lack of humility and a callous disregard for the subtle , but highly important distinction, of the 2 statements above.
This fallacy of purpose infects most of biological research. Next time you ask what is the purpose of a kidney, you should react with humility by stating that only its function can be known.







[1] Fodor, J., & Piattelli-Palmarini, M. (2010). What Darwin Got Wrong. London: Profile Books., p xvii





2010-04-06
On Fodor on Darwin on Evolution
The teleological misinterpretations you mention are just that -- misinterpretations. No serious biologist makes those silly mistakes; it's invariably nonbiologists, getting it wrong, and attributing their own confusions to biology. (Nor does any of that vindicate the nonproblems that F&PP are claiming to be problems. It's not Darwin that got it wrong: It's F&PP that keep getting it wrong -- and not just wrong, but trivially, superficially wrong.)