Darwin's Dangerous Idea (49 page)

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are available to her, and adjust his strategy only when evidence begins to mount that she is actually bound not to take what otherwise would be the obviously best move.

Such evidence is not at all easy to gather. If you think your opponent cannot move her queen diagonally, you might test that hypothesis by the risky tactic of offering a free capture to that queen on the diagonal. If the queen declines, that counts in favor of your hypothesis—
unless
there is a deeper reason of strategy (unimagined as yet by you) for declining the capture. (Remember Orgel's Second Rule: Evolution is cleverer than you are.)

Of course, another way of learning the hidden constraints at the chessboard is to peek at the paper, and one might think that what Gould and Lewontin are recommending is that adaptationists simply abandon their game-playing and go for the truth via a more direct examination of the molecular evidence.

Unfortunately, this analogy is mistaken. You are certainly entitled to use whatever data-gathering tricks are available in the game of science, but when you peek at the molecules, all you find there is more machinery, more design (or apparent design) in need of reverse engineering. Nowhere are Mother Nature's hidden constraints
written down
in a way that can be read without the help of the interpretive rules of artifact hermeneutics (Dennett 1990b).

The descent to the deeper level of the DNA, for instance, is indeed a valuable way of vastly improving one's investigative acuity—though usually at the F

intolerable cost of drowning in too much data—but in any case it is not an IGURE 9.4

alternative to adaptationism; it is an extension of it.

The example of playing chess with hidden constraints lets us see a pro-that she will undertake to play under, and hides the paper under the board.

found difference between Mother Nature and human chess-players that does What is the difference between a constraint and a forced move? Reason have implications, I think, for a widespread foible in adaptationist thinking. If dictates a forced move—and will always dictate it, again and again—whereas
you
were playing chess under hidden constraints, you would adjust your some frozen bit of history dictates a constraint, whether or not there was a strategy accordingly. Knowing that you had secretly promised not to move reason for its birth, and whether or not there is a reason for or against it now.

your queen diagonally, you would probably forgo any campaign that put your Here are a few of the possible constraints:

queen at risk of capture thanks to her unusual limitation—although of course you could take a chance, hoping your weak opponent wouldn't notice the Unless I am forced by the rules to do so (because I am in check, and am possibility. But you have knowledge of the hidden constraints, and foresight.

obliged to play whatever legal move escapes check), Mother Nature does not. Mother Nature has no reason to avoid high-risk gambits; she takes them all, and shrugs when most of them lose.

(1)I may never move the same piece on two consecutive turns.

Here is how the idea applies in evolutionary thinking. Suppose we notice (2)I may not castle.

that a particular butterfly has protective coloration on its wings that uncan-

(3)I may capture with pawns only three times in the whole game. (4) nily mimics the pattern of colors on the forest floor where it lives. We chalk My queen must move only in rook fashion, never diagonally.

that up as a fine adaptation, camouflage, which it undoubtedly is. This butterfly does better than its cousins
because
its coloration so perfectly repro-Now imagine the epistemological predicament of the weaker player, who duces the coloration of the forest floor. But there is a temptation, routinely
knows
his opponent is playing with hidden constraints but doesn't know what they are. How should he proceed? The answer is quite obvious: he should play
as if
all the
apparently
possible moves—all the legal moves—

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succumbed to, to add, implicitly or explicitly. "And what's more, if the forest If hidden constraints guarantee that there is a largely invisible set of maze floor had any other color pattern on it, the butterfly would look like
that
walls—or channels or railroad tracks—in the space of apparent possibility, pattern instead!" That is uncalled for. It may well not be true. It could even then "you can't get there from here" is true much more often than we might be, in the limit, that this is the
only
sort of forest floor that this lineage of imagine. Even if this is so, we still can do no better in our exploration of this butterfly could mimic with much success; if the forest floor were much possibility than to play out our reverse-engineering strategies at every op-different, this lineage would just not be here—never forget about the im-portunity, at every level. It is important not to overestimate the actual pos-portance in evolution of bait-and-switch. If the forest floor changes, what will sibilities, but it is even more important not to underestimate them, an equally happen? Will the butterfly automatically adapt? All we can say is that either common foible, though not one that adaptationists typically manifest. Many it will adapt by changing its camouflage or it won't! If it doesn't, then either it adaptationist arguments are. of the if-it's-possible-it-will-happen variety: will find some other adaptation in its limited kit of available moves, or it will cheats will emerge to invade the saints; or an arms race will ensue until such-soon disappear.

and-such a first-order adaptive stability is achieved, etc. These arguments pre-The limiting case, in which exactly one path was ever open to explore, is suppose that enough of the space of possibilities is "habitable" to ensure that an instance of our old nemesis actualism: only the actual was possible. Such the process approximates the game-theory model used. But are these as-straitjacketed explorations of the space of (apparent) possibility are not ruled sumptions always appropriate? Will these bacteria mutate into a form that is out, I am saying, but they must be the exception, not the rule. If they were the resistant to our new vaccine? Not if we're lucky, but we're better off assuming rule, Darwinism would be defunct, utterly incapable of explaining any of the the worst—namely, that there are, in the space actually accessible to these ( apparent) design in the biosphere. It would be as if you wrote a chess-bacteria, countermoves in the arms race our medical innovation has set in playing computer program that could just play one game by rote (say, motion (Williams and Nesse 1991)

Alekhine's moves in the famous Flamberg-Alekhine match in Mannheim in 1914 ) and,
mirabile dictu,
it regularly won against all competition! This would be a "pre-established harmony" of miraculous proportions, and would CHAPTER 9:
Adaptationism is both ubiquitous and powerful in biology. Like
make a mockery of the Darwinian claim to have an explanation of how the
any other idea, it can be misused, but it is not
a
mistaken idea; it is in fact the

"winning" moves have been found.

irreplaceable core of Darwinian thinking. Gould and Lewontin's fabled
But our dismissal of actualism should not tempt us to err in the other
refutation of adaptationism is an illusion, but they have raised everybody's
direction, supposing that the space of real possibilities is much more densely
consciousness about the risks of incautious thinking. Good adaptationistic
populated than it actually is. The temptation, when we think about pheno-thinking is always on the lookout for hidden constraints, and in fact is the typic variation, is to adopt a sort of Identikit tactic of assuming that all the
best method for uncovering them.

minor variations we can imagine on the themes we find in actuality are truly available. Carried to extremes, this tactic will always vastly—Vastly—over-CHAPTER 10:
The view of Darwinian thinking presented so far in this book
estimate what is actually possible. If the
actual
Tree of Life occupies Van-has been challenged, repeatedly, by Stephen Jay Gould, whose influential ishingly narrow threads through the Library of Mendel, the
actually possible
writings have contributed to a seriously distorted picture of evolutionary
Tree of Life is itself some rather bushier but still far from dense partial filling
biology among both lay people and philosophers and scientists in other
of the
apparently possible.
We have already seen that the Vast space of all
fields. Gould has announced several different "revolutionary" abridgments of
imaginable phenotypes—Identikit Space, we might call it—no doubt includes
orthodox Darwinism, but they all turn out to be false alarms. There is a
huge regions for which there are no recipes in the Library of Mendel. But
pattern to be discerned in these campaigns: Gould, like eminent evolutionary
even along the paths through which the Tree of Life wanders, we are not
thinkers before him, has been searching for skyhooks to limit the power of
guaranteed that the neighboring regions of Identikit Space are actually all
Darwin's dangerous idea.

accessible.17

17. Gould is fond of pointing out the mistake of looking back in time and seeing "lin-continuous) bushes of unactualized possibility where in fact there may be rather sparse eages" where we should be seeing "bushes"—including all the failures that have left no twigs creating paths to relatively isolated outposts in the huge space of apparent descendants. 1 am pointing out a contrary sort of mistake: imagining dense (or even possibilities.

The Boy Who Cried Wolf?
263

has proven to be more than a mild corrective to orthodoxy at best, their rhetorical impact on the outside world has been immense and distorting. This presents me with a problem that I cannot ignore or postpone. In my own CHAPTER TEN

work over the years, I have often appealed to evolutionary considerations, and have almost as often run into a curious current of resistance: my appeals to Darwinian reasoning have been bluntly rejected as discredited, out-of-date
Bully for Brontosaurus

science by philosophers, psychologists, linguists, anthropologists, and others who have blithely informed me that I have got my biology all wrong—I haven't been doing my homework, because Steve Gould has shown that Darwinism isn't in such good shape after all. Indeed, it is close to extinction.

That is a myth, but a very influential myth, even in the halls of science. I have tried in this book to present an accurate account of evolutionary thinking, deflecting the reader from common misunderstandings, and defending the theory against ill-grounded objections. I have had a lot of expert 1. THE BOY WHO CRIED WOLF?

help and advice, and so I am confident that I have succeeded. But the view of Darwinian thinking I have presented is quite at odds with the view made
Scientists have power by virtue of the respect commanded by the
familiar to many by Gould. Surely, then, my view must be mistaken? After all,
discipline. We may therefore be sorely tempted to misuse that power in
who knows better about Darwin and Darwinism than Gould?

furthering a personal prejudice or social goal
—
why not provide that
Americans are notoriously ill-informed about evolution. A recent Gallup
extra oomph by extending the umbrella of science over a personal
poll (June 1993 ) discovered that 47 percent of adult Americans believe that
preference in ethics or politics? But we cannot, lest we lose the very
Homo sapiens
is a species created by God less than ten thousand years ago.

respect that tempted us in the first place.

But insofar as they know anything at all about the subject, it is probably due

—STEPHEN JAY GOULD 1991b, pp. 429-30

more to Gould than to anyone else. In the battle over the teaching of "creation science'' in the schools, he has been a key witness for the defense of evolution Many years ago, I saw a program on British television in which young chil-in the court cases that continue to plague American education. For twenty dren were interviewed about Queen Elizabeth II. Their confident answers years, his monthly column, "This View of Life," in
Natural History,
has were charming: the Queen, it seems, spends a large part of the day vacuum-provided professional and amateur biologists with a steady stream of cleaning Buckingham Palace—while wearing her crown, of course. She pulls arresting insights, fascinating facts, and well-needed correctives to their the throne up to the telly when she is not occupied with affairs of state, and thinking. In addition to his collections of these essays, in such volumes as wears an apron over her ermine robes when she does the washing up. I re-Ever Since Darwin (1977a),
The Panda's Thumb
( 1980a),
Hen's Teeth and
alized then that the largely imaginary Queen Elizabeth II of these young
Horse's Toes
( 1983b),
The Flamingo's Smile
(1985 ),
Bully for Brontosaurus
children (what philosophers would call their
intentional object)
was in some ( 1991b), and
Eight Little Piggies
( 1993d), and his technical publications on regards a more potent and interesting object in the world than the actual snails and paleontology, he has written a major theoretical book,
Ontogeny
woman. Intentional objects are the creatures of beliefs, and hence they play a
and Phytogeny
( 1977b); an attack on IQ testing,
The Mis-measure of Man
(

more direct role in guiding (or misguiding) people's behavior than do the real 1981); a book on the reinterpretation of the fauna of the Burgess Shale, objects they purport to be identical to. The gold in Fort Knox, for example, is
Wonderful Life
(1989a); and numerous other articles on topics ranging from less important than what is believed about it, and the Albert Einstein of myth Bach to baseball, from the nature of time to the compromises of
Jurassic
is, like Santa Claus, much better known than the relatively dimly remembered
Park.
Most of this is simply wonderful: astonishingly erudite, the very model historical fellow who was the primary source for the myth.