Darwin's Dangerous Idea (47 page)

drives out its rivals by normal channels, just as second-rate reverse But you will already have noticed that in each case these rules of thumb engineering betrays itself sooner or later.

can be overridden by a more ambitious inquiry. Suppose someone marveling at the brilliant autumn foliage in New England asks
why
the maple leaves are The eskimo face, once depicted as 'cold engineered' (Coon
et al.,
1950) so vividly colored in October. Isn't this adaptationism run amok? Shades of becomes an adaptation to generate and withstand large masticatory forces Dr. Pangloss! The leaves are the colors they are simply because once the (Shea, 1977). We do not attack these newer interpretations; they may all summer energy-harvest season is over, the chlorophyll vanishes from the be right. We do wonder, though, whether the failure of one adaptive leaves, and the residual molecules have reflective properties that happen to explanation should always simply inspire a search for another of the same determine the bright colors—an explanation at the level of chemistry or general form, rather than a consideration of alternatives to the proposition physics, not biological purpose. But wait. Although this may have been the that each part is 'for' some specific purpose. [Gould and Lewontin 1979, p.

only explanation that was true up until now, today it is true that human beings 152.)

so prize the autumn foliage (it brings millions of tourist dollars to northern New England each year) that they protect the trees that are brightest in Is the rise and fall of successive adaptive explanations of various things a autumn. You can be sure that if you are a tree competing for life in New sign of healthy science constantly improving its vision, or is it like the England, there is now a selective advantage to having bright autumn foliage.

pathological story-shifting of the compulsive fibber? If Gould and Lewontin It may be tiny, and in the long run it may never amount to much (in the long had a serious alternative to adaptationism to offer, their case for the latter run, there may be no trees at all in New England, for one reason or another), verdict would be more persuasive, but although they and others have hunted but this is how all adaptations get their start, after all, as fortuitous effects that around energetically, and promoted their alternatives boldly, none has yet get opportunistically picked up by selective forces in the environment. And of taken root.

course there is also an adaptationist explanation for why right angles predominate in manufactured goods, and why symmetry predominates in Adaptationism, the paradigm that views organisms as complex adaptive organic limb-manufacturing. These may become utterly fixed traditions, machines whose parts have adaptive functions subsidiary to the fitness-which would be almost impossible to dislodge by innovation, but the reasons promoting function of the whole, is today about as basic to biology as the why
these
are the traditions are not hard to find, or controversial.

atomic theory is to chemistry. And about as controversial. Explicitly ad-Adaptationist research always leaves unanswered questions open for the aptationist approaches are ascendant in the sciences of ecology, ethology, next round. Consider the leatherback sea turtle and her eggs: and evolution because they have proven essential to discovery; if you doubt this claim, look at the journals. Gould and Lewontin's call for an Near the end of egg laying, a variable number of small, sometimes mis-alternative paradigm has failed to impress practicing biologists both be-shapen eggs, containing neither embryo nor yolk (just albumin) are de-cause adaptationism is successful and well-founded, and because its critics posited. Their purpose is not well understood, but they become desiccated have no alternative research program to offer. Each year sees the estab-over the course of incubation and may moderate humidity or air volume lishment of such new journals as
Functional Biology and Behavioral Ecol-in the incubation chamber. (It is also possible that they have no function
ogy.
Sufficient research to fill a first issue of
Dialectical Biology
has yet to or are a vestige of some past mechanisms not apparent to us today.) materialize. [Daly 1991, p. 219.]

[Eckert 1992, p. 30]

What particularly infuriates Gould and Lewontin, as the passage about the But where does it all end? Such open-endedness of adaptationist curiosity Eskimo face suggests, is the blithe confidence with which adaptationists go is unnerving to many theorists, apparently, who wish there could be stricter about their reverse engineering, always sure that sooner or later they will find codes of conduct for this part of science. Many who have hoped to contribute
the reason
why things are as they are, even if it so far eludes them. Here is an to clearing up the controversy over adaptationism and its backlash have instance, drawn from Richard Dawkins' discussion of the curious case of the despaired of finding such codes, after much energy has been expended flatfish (flounders and soles, for instance ) who when they are born are vertical fish, like herring or sunfish, but whose skulls undergo a weird twist-250 SEARCHING FOR QUALITY

Playing with Constraints
251

ing transformation, moving one eye to the other side, which then becomes Dawkins' adaptive scenarios make no mention of the costs of allegedly the top of the bottom-dwelling fish. Why didn't they evolve like those other adaptive changes. Mimicry might deceive potential mates as well as po-bottom-dwellers, skates, which are not on their side but on their belly, "like tential predators.... Still, I do think this objection is something of a quibble sharks that have passed under a steam roller" (Dawkins 1986a, p. 91)?

because essentially I agree that natural selection is the only possible Dawkins
imagines
a scenario (pp. 92-93):

explanation of complex adaptation. So something like Dawkins' stories have got to be right. [Sterelny 1988, p. 424.]11

... even though the skate way of being a flat fish might
ultimately
have been the best design for bony fish too, the would-be intermediates that set out along this evolutionary pathway apparently did less well in the short 3. PLAYING WITH CONSTRAINTS

term than their rivals lying on their side. The rivals lying on their side were so much better, in the short term, at hugging the bottom. In genetic
It is just as foolish to complain that people are selfish and treacherous
hyperspace, there is a smooth trajectory connecting free-swimming ances-as it is to complain that the magnetic field does not increase unless the tral bony fish to flatfish lying on their side with twisted skulls. There is not a smooth trajectory connecting these bony fish ancestors to flatfish lying
electric field hasa curl.

on their belly. There is such a trajectory in theory, but it passes through

—JOHN VON NEUMANN, quoted in William

intermediates that would have been—in the short term, which is all that Poundstone 1992, p. 235

matters—unsuccessful if they had ever been called into existence.

As a general rule today a biologist seeing one animal doing something
to benefit another assumes either
that it
is manipulated by the other
Does Dawkins
know
this? Does he know that the postulated intermediates
individual or drat it is being subtly selfish.

were less fit? Not because he has seen any data drawn from the fossil record.

This is a purely theory-driven explanation, argued
a priori
from the

—GEORGE WILLIAMS 1988, p. 391

assumption that natural selection tells us the true story—some true story or One may nevertheless be reasonably nervous about the size of the role of other—about every curious feature of the biosphere. Is that objectionable? It sheer, unfettered imagination in adaptationist thinking. What about butterflies does "beg the question"—but what a question it begs! It assumes that with tiny machine guns for self-protection? This fantastic example is often Darwinism is basically on the right track. (Is it objectionable when mete-cited as the sort of option that can be dismissed without detailed analysis by orologists say, begging the question against supernatural forces, that there adaptationists seeking to describe the ensemble of possible butterfly must be a purely physical explanation for the birth of hurricanes, even if adaptations from which Mother Nature has chosen the best, all things many of the details so far elude them?) Notice that in this instance, Dawkins'

considered. It is just too distant a possibility in design space to be taken explanation is almost certainly right—there is nothing especially daring about seriously. But as Richard Lewontin (1987, p. 156) aptly notes, "My guess is that particular speculation. Moreover, it is, of course, exactly the sort of that if fungus-gardening ants had never been seen, the suggestion that this thinking a good reverse engineer should do. "It seems so obvious that this was a reasonable possibility for ant evolution would have been regarded as General Electric widget casing ought to be made of two pieces, not three, but silly." Adaptationists are masters of the retrospective rationale, like the it's made of three pieces, which is wasteful and more apt to leak, so we can be damn sure that three pieces was seen as better than two in somebody's eyes, shortsighted though they may have been. Keep looking!" The philosopher of biology Kim Sterelny, in a review of
The Blind Watchmaker,
made the point 11. Dawkins is not content to rest with Sterelny's dismissal of his own objections as this way:

"quibbles" since, he points out (personal communication), they raise an important point often misunderstood: "It is not up to individual humans like Sterelny to express their own Dawkins is admittedly giving only scenarios: showing that it's
conceivable
commonsense scepticism of the proposition that 5% like a stick is significantly better than
4%.
It is an easy rhetorical point to make: 'Come on, are you really trying to tell me that ( e.g.) wings could evolve gradually under natural selection. Even so, that 5% like a stick really matters when compared to 4%?' This rhetoric will often one could quibble. Is it really true that natural selection is so fine-grained convince laymen, but the population genetic calculations (e.g. by Haldane) belie com-that, for a protostick insect, looking 5% like a stick is better than looking mon sense in a fascinating and illuminating way: because natural selection works on
4%
like one? (pp. 82-83). A worry like this is especially pressing because genes distributed over many individuals and over many millions of years, human actuarial intuitions are over-ruled."

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Playing with Constraints
253

chess-player who only notices
after
he's made the move that it forces check-scribe his own actions but not those of the others. Nevertheless those mate in two moves. "How brilliant—and I almost thought of it!" But before alien' variables cannot, from his point of view, be described by statistical we decide that this is
zflaw
in adaptationist character or method, we should assumptions. This is because the others are guided, just as he himself, by remind ourselves that this retrospective endorsement of brilliance is the way rational principles—whatever that may mean—and no
modus procedendi
Mother Nature herself always operates. Adaptationists should hardly be can be correct which does not attempt to understand those principles and faulted for being unable to predict the brilliant moves that Mother Nature the interactions of the conflicting interests of all participants. [Von Neu-herself was oblivious of until she'd stumbled upon them.

mann and Morgenstern 1944, p. 11.]

The perspective of game-playing is ubiquitous in adaptationism, where mathematical
game theory
has played a growing role ever since its intro-The fundamental insight that unites game theory and evolutionary theory is duction into evolutionary theory by John Maynard Smith (1972, 1974 ).12

that the "rational principles—whatever that may mean" that "guide" agents in Game theory is yet one more fundamental contribution to twentieth-century competition can exert their influence even on such unconscious, unreflective thinking from John von Neumann.13 Von Neumann created game theory in semi-agents as viruses, trees, and insects, because the stakes and payoff collaboration with the economist Oskar Morgenstern, and it grew out of their possibilities of competition determine which lines of play cannot help realization that
agents
make a fundamental difference to the complexity of winning or losing if adopted, however mindlessly they are adopted. The best-the world.14 Whereas a lone "Robinson Crusoe" agent can view all problems known example in game theory is the Prisoner's Dilemma, a simple two-as seeking stable maxima—hill-climbing on Mount Fuji, if you like—as soon person "game" which casts shadows, both obvious and surprising, into many as other (maxima-seeking) agents are included in the environment, strikingly different circumstances in our world. Here it is in basic outline (excellent different methods of analysis are required:

detailed discussions of it are found in Poundstone 1992 and Dawkins 1989a).

You and another person have been imprisoned pending trial (on a trumped-up A guiding principle cannot be formulated by the requirement of maximiz charge, let's say), and the prosecutor offers each of you, separately, the same ing two ( or more) functions at once ___One wouid be mistaken to believe deal: if you both hang tough, neither confessing nor implicating the other, you that it can be obviated ... by a mere recourse to the devices of the theory of will each get a short sentence (the state's evidence is not that strong); if you probability. Every participant can determine the variables which de-confess and implicate the other and he hangs tough, you go scot free and he gets life in prison; if you both confess-and implicate, you both get medium-length sentences. Of course, if you hang tough and the other person confesses, he goes free and you get life. What should you do?

12. Maynard Smith built his game-theory applications to evolution on the foundations already laid by R. A. Fisher ( 1930). One of Maynard Smith's many more recent contri-If you both could hang tough, defying the prosecutor, this would be much butions was showing Stuart Kauffman that he was, after all, a Darwinian, not an anti-better for the two of you than if you both confess, so couldn't you just Darwinian (see Lewin 1992, pp. 42-43).