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Wednesday, July 27, 2005

genes

Jerry Fodor strings together some nice crochets against evolutionary psychology in the TLS this week. His argument, which in itself is pretty hard to beat, is that if psychology relies on motivations, it can’t, uncontroversially, reduce those to the “motivations” of the gene. Fodor uses one of those analytic uninteresting examples – Davidson liked buttering toast and lighting the furnace, and Fodor likes Mr. Jones carrying an umbrella. Fodor says that the fact that Mr. Jones is carrying an umbrella doesn’t tell us Mr. Jones’ motives for carrying an umbrella. He could think it is going to rain; he could want to give the umbrella back to its owner; he could be making a style statement. And then he writes: “It’s more of a problem – and Buller is quite clear on this – that an Adaptationist account of Jones’s behaviour may need to appeal to a motive that explains his action but that Jones didn’t actually have; not consciously, not unconsciously, not at all. It’s a main tenet of psychological Darwinism that the “ultimate” motivation for an adaptive behaviour is to maximize one’s relative contribution to the genetic endowment of one’s breeding group. So (still assuming it’s an adaptation) what Buller calls the “proximal” cause of Jones’s behaviour is that he wants (maybe consciously, maybe not) not to catch his death of cold and he believes (maybe consciously, maybe not) that he won’t catch his death of cold if he doesn’t get wet. But the “ultimate” cause of his behaviour is his wanting to maximize his contribution to the gene pool of his breeding group, which requires, inter alia, that he not be dead. That, to repeat, is what Jones really wants, assuming that his umbrella-carrying behaviour is an adaptation; and it’s what his ancestors were selected for wanting in the old days back on the savannah.

The trouble is, of course, that Jones wants no such thing – not consciously or unconsciously either. Jones may never have so much as heard about breeding groups; his ancestors certainly never did.So, really, what are we to make of motives that explain one’s actions even though one doesn’t have them? And who is it that is motivated by Jones’s genotypic ambitions if it isn’t Jones? Notice, once again, that this is a kind of puzzle that is proprietary to Psychological Adaptationism; it doesn’t arise for evolutionary explanations of the opposed thumb, or of bipedal gait, or of the anatomy of the retina; that’s because neither your motivations, nor your ancestors’, nor anybody else’s, come into the story about why thumbs work the way they do. It’s Psychological Adaptationism, not Adaptationism per se, that is raising this spectre of unattached motives.”

What Fodor is getting at is what Stephen Jay Gould called the bookkeeping fallacy. According to Gould, there is a difference between finding out that there is a mathematical spread of genes through a population and taking it to be the case that genes are riding organisms as vehicles to spread themselves through a population. The one could well be the effect of various causes in the population due to organisms – selection pressure could well be working at that level. The other view, however, has something that makes genes transcend selection. Or at least makes them agents of a mysterious kind. One could say that a successful toymaker has made toys that make him money, but the money hasn’t caused the success of the toys – that success came out of the things money bought, the advertising, the assembly line, the designers, the parents and kids who for their various reasons bought the toys, etc. It isn’t that there isn’t a selection level for money – one could invest in toys or armaments – but that the money itself is not a cause on the toy level (I could spend more money and make a suck toy, that gets nowhere, for instance).

It is odd that Fodor doesn’t mention Gould’s argument. There’s a letter to the Human Nature from Val Dusek that attributes the bookkeeping metaphor to William Wimsatt. Dusek sums up the idea nicely, commenting that it was employed, after Wimsatt, in an article by Lewontin and Sober: “Using Reichenbach's notion of "screening off" causes they [Lewontin and Sober] claim individual genes rarely if ever function as causes in selection processes. Dan Dennett lamely replies in Darwin's Dangerous Idea that counters can be important. Gould and Lewontin do not deny this. They simply say they are results not causes of selection. The situation is similar to that in economics. Labor can be a numeraire of profits, but that hardly justifies the labor theory of value, because many things can be numeraires. Stock predictors who use "technical" approaches do a kind of astrology on share price fluctuations and numbers of shares sold, but do not claim to be following causes of this within corporate structure and production that "fundamentalists" claim to be analyzing.”

I have doubts about this takedown of labor theory, but the analogy to technical analysis is pretty good. Except for one thing – technical analysis really does just use patterns in the past, whereas the theory of gene propagation is dealing with creatures that actually can endow or not, in various ways, their descendents with kinds of chromosomes. Hamilton’s work with ants was not only descriptive, but it has predicted patterns among ant societies having to do with descent. In a sense, the problem here is thinking that “bookkeeping” and the next “level” of selection are completely separate.

Dawkins and Smith and Williams have a different take. This is from Mark Ridley on the units of selection. He is considering lion hunting, which naturally involves selection. But is the important selection done by the organism “lion” or the genes?

“We must discuss one other matter before considering the significance of the genic unit of selection. Critics, such as Gould, have objected that gene frequencies change between generations only in a passive, "bookkeeping" sense. The frequency changes provide a record of evolution, but are not its fundamental cause. True natural selection, the critics would say, happens at the level of organismic survival and reproduction. For instance, the actual selection in the lion example happens when a lion catches, or fails to catch, its prey. The differential hunting success drives the gene frequency changes, and it is a mistake to identify the gene frequency changes as causal. Williams and Dawkins, however, do not deny that the ecological processes causing differential organismic survival produce gene frequency changes within a generation. What they deny is that this ecological interaction of organisms means that natural selection directly adjusts the frequencies of organisms over the evolutionary time scale of many generations.

An easy philosophical method has been developed for deciding whether natural selection works on genes, or larger phenotypic units. We can consider a phenotypic change such as a new hunting skill, and ask whether natural selection can work on it if it is produced genically and if it is produced non-genically. In the lion's case, the skill is produced genically--the advantageous new hunting behavior was caused by a genetic mutation. Now suppose that the same advantageous phenotypic change was caused by a non-heritable phenotypic change, such as individual learning or some developmental accident in the lion's nervous system. The thought-based experiment provides a test case between the organismic, phenotypic, and genic accounts of evolution. In the genic case, we know that natural selection favors the improved hunting type and the gene for it increases in frequency. But what happens in the phenotypic case? The individual lion with improved hunting ability will survive and produce more offspring than an average lion, but no evolution, or natural selection in any interesting sense, will occur. The trait will not be passed on to the next generation. Natural selection cannot work directly on organisms.”

That gives us, of course, a weird dualism in which the genes are something other than the organism. What are they? In the English school, they are ultimately bearers of information. Information longs to be free, and works through the mere lion. But of course one wonders what kind of improved hunting type we are talking about. If the organism doesn’t survive its childhood, or starves to death in a drought, it is not about to pass on those genes. It does seem like the “information” centric idea that has created a distinction between the gene and the vehicle to such a degree that natural selection only works on the information is not an entirely convincing model.

“What matters, in the process of natural selection, is that some of the lion's offspring inherit the mutation. These offspring, in turn, produce more offspring, and the gene increases in frequency. The gene can increase in frequency because it is not fragmented by meiosis (like the genome) or returned to dust by death (like the phenotype). The gene, in the form of copies of itself, is potentially immortal, and is at least Permanent enough to allow its frequency to be altered in successive generations.”

What matters, one feels like replying, is that the lion mates with a lioness. That permanence is so severely constrained that the horniest lion can’t mate with the most agreeable of mice.

In other words, the genocentric view defended by Ridley has the unintended consequence of virtually liquidating the notion of the species, which was where Darwin began. This isn’t good.

Perhaps I should say something about Hull’s interactor model. Or perhaps I’ll leave it for now.

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