Darwin's Dangerous Idea (23 page)

"from here to there" because of restrictions on the genome-reading process?

about die past. There is a single, unified Design Space in which the processes
As we have already noted, we should be impressed by the severe restrictions
of both biological and human creativity make their tracks, using similar
encountered by this process, but we should not be carried away. Those
methods.

restrictions may not be a
universal
feature, but a temporally and spatially local feature, analogous to what Seymour Papert has dubbed the QWERTY

phenomenon in the culture of computers and keyboards.

The top row of alphabetic keys of the standard typewriter reads QWERTY.

12. Others have exploited the QWERTY phenomenon to make similar points: David For me this symbolizes the way in which technology can all too often serve 1985, Gould 1991a.

not as a force for progress but for keeping things stuck. The QWERTY

13. George Williams (1985, p. 20) puts it this way: "1 once insisted that'... the laws of arrangement has no rational explanation, only a historical one. It was Physical science plus natural selection can furnish a complete explanation for any bio-introduced in response to a problem in the early days of the typewriter: logical phenomenon' [Williams 1966, pp. 6-7]. I wish now I had taken a less extreme The keys used to jam. The idea was to minimize the collision problem by view and merely identified natural selection as the only theory that a biologist needs in addition to those of the physical scientist. Both the biologist and the physical scientist separating those keys that followed one another frequently.... Once need to reckon with historical legacies to explain any real-world phenomenon."

Drifting and Lifting Through Design Space
125

tirely in limericks. So it goes. The number of
actual
books about Charles Darwin is a huge number, but not a Vast number, and we won't get down to that set (that set as of today, or as of the year 3000 A.D. ) by just piling on the CHAPTER SIX

restricting adjectives in this fashion. To get to the actual books, we have to
Threads of Actuality in

turn to the historical process that created them, in all its grubby particularity.

The same is true of the actual organisms, or their actual genomes.

We don't need laws of biology to "prevent" most of the physical possi-Design Space

bilities from becoming actualities; sheer absence of opportunity will account for most of them. The only "reason"
all
your nonactual aunts and uncles never came into existence is that your grandparents didn't have time or energy (to say nothing of the inclination) to create more than a few of the nearby genomes. Among the many nonactual possibles, some are—or were—

"more possible" than others: that is, their appearance was more
probable
than the appearance of others, simply because they were
neighbors
of actual genomes, only a few choices away in the random zipping-up process that puts together the new DNA volume from the parent drafts, or only one or a few random typos away in the great copying process. Why didn't the near-1. DRIFTING AND LIFTING THROUGH DESIGN SPACE

misses happen? No reason; they just didn't happen to happen. And then, as the actual genomes that
did
happen to happen began to move away from the
The actual animals that have ever lived on Earth are a tiny subset of the
locations in Design Space of the near-misses, their probability of ever
theoretical animals that
could
exist. These real animals are the products
happening grew smaller. They were so close to becoming actual, and then
of a very small number of evolutionary trajectories dvough genetic
their moment passed! Will they get another chance? It is possible, but Vastly
space. The vast majority of theoretical trajectories through animal space
improbable, given the Vast size of the space in which they reside.

give rise to impossible monsters. Real animals are dotted around here
But what forces, if any, bend the paths of actuality farther and farther away
and there among the hypothetical monsters, each perched in its own
from their locations? The motion that occurs if there are no forces at all is
unique place in genetic hyperspace. Each real animal is surrounded by
called random genetic drift. You might think that drift, being random, would
a little cluster of neighbours, most of whom have never existed, but a
tend always to cancel itself out, bringing the path back to the same genomes
few of whom are its ancestors, its descendants and its cousins.

again and again in the absence of any selective forces, but the very fact that

—RICHARD DAWKINS 1986a, p. 73

there is only limited sampling in the huge space (which has a million dimensions, remember!) leads inevitably to the accumulation of "distance"

The actual genomes that have ever existed are a Vanishingly small subset between actual genomes (the upshot of "Dollo's Law").

of the combinatorially possible genomes, just as the actual books in the Darwin's central claim is that when the force of natural selection is im-world's libraries are a Vanishingly small subset of the books in the imaginary posed on this random meandering, in addition to drifting there is lifting. Any Library of Babel. As we survey the Library of Babel, we may be struck by motion in Design Space can be measured, but the motion of random drift is, how hard it is to specify a
category
of books that isn't Vast in membership, intuitively, merely sideways; it doesn't get us anywhere important. Consid-however Vanishingly small it is in relation to the whole. The set of books ered as R-and-D work, it is idle, leading to the accumulation of mere
typo-composed entirely of grammatical English sentences is a Vast but Vanishing
graphical change,
but not to the accumulation of
design.
In fact, it is worse subset, and the set of readable, sense-making books is a Vast but Vanishing than that, for most mutations—typos—will be neutral, and most of the typos subset of it. Vanishingly hidden in that subset is the Vast set of books about that aren't neutral will be deleterious. In the absence of natural selection, the people named Charles, and within that set (though Vanishingly hard to find) drift is inexorably
downward
in Design Space. The situation in the Library of is the Vast set of books purporting to tell the truth about Charles Darwin, and Mendel is thus precisely like the situation in the Library of Babel. Most a Vast but Vanishing subset of these consists of books composed en-typographical changes to
Moby Dick
can be supposed to be practically 126 THREADS OF ACTUALITY IN DESIGN SPACE

Drifting and Lifting Through Design Space
127

neutral—as good as invisible to most readers; of the few that make a differ-No analysis of the genomes in isolation of the organisms they create could ence, most will
do damage
to the text, making it a worse, less coherent, less yield the dimension we are looking for. It would be like trying to define the comprehensible tale. Consider as an exercise, however, the version of Peter difference between a good novel and a great novel in terms of the relative De Vries' game in which the object is to
improve
a text by a single typo-frequencies of the alphabetical characters in them. We have to look at the graphical change. It is not impossible, but far from easy!

whole organism, in its environment, to get any purchase on the issue. As These intuitions about getting somewhere important, about design
im-William Paley saw, what is truly impressive is the bounty of astonishingly
provement,
about
rising
in Design Space, are powerful and familiar, but are ingenious and smoothly functioning arrangements of matter that go to com-they reliable? Are they perhaps just a confusing legacy of the pre-Darwinian pose living things. And when we turn to examining the organism, we find vision of Design coming down from a Handicrafter God? What is the rela-again that no mere tabulation of the items composing it is going to give us tionship between the ideas of Design and Progress? There is no fixed agree-what we want.

ment among evolutionary theorists about this. Some biologists are fastidious, What could be the relationship between amounts of complexity and going to great lengths to avoid allusions to design or function in their own amounts of design? "Less is more," said the architect Ludwig Mies van der work, while others build their whole careers around the functional analysis of Rohe. Consider the famous British Seagull outboard motor, a triumph of this or that (an organ, patterns of food-gathering, reproductive "strategies,"

simplicity, a design that honors the principle that what isn't there can't break.

etc.). Some biologists think you can speak of design or function without We want to be able to acknowledge—and even measure, if possible— the committing yourself to any dubious doctrine about progress. Others are not design excellence manifest in the right sort of simplicity. But what is the so sure. Did Darwin deal a "death blow to Teleology," as Marx exclaimed, or right sort? Or what is the right sort of
occasion
for simplicity? Not every did he show how "the rational meaning" of the natural sciences was to be occasion. Sometimes more
is
more, and of course what makes the British empirically explained (as Marx went right on to exclaim), thereby making a Seagull so wonderful is that it is such an elegant marriage of complexity and safe home in science for functional or teleological discussion?

simplicity; nobody has quite such high regard, nor should they, for a paddle.

Is Design something that can be measured, even indirectly and imper-We can begin to get a clear view of this if we think about convergent fectly? Curiously enough, skepticism about this prospect actually undercuts evolution and the occasions on which it occurs. And, as is so often the case, the most potent source of skepticism about Darwinism. As I pointed out in choosing extreme—and imaginary—examples is a good way of focusing on chapter 3, the most powerful challenges to Darwinism have always taken this what counts. In this instance, a favorite extreme case to consider is extra-form: are Darwinian mechanisms powerful enough, or efficient enough, to terrestrial life, and of course it may someday soon be turned from fantasy have
done all that work
in the time available? All what work? If the question into fact, if SETI, the ongoing Search for Extra-Terrestrial Intelligence, finds concerned mere sideways drifting in the typographical space of possible anything. If life on Earth is massively contingent—if its mere occurrence in genomes, the answer would be obvious and uncontroversial: Yes, there has any form at all is a happy accident—then what can we say, if anything, about been
much
more than enough time. The speed at which random drift should life on other planets in the universe? We can lay down
some
conditions with accumulate mere typographical distance can be calculated, giving us a sort of confidence approaching certainty. These at first appear to fall into two posted speed limit, and both theory and observation agree that actual contrasting groups: necessities and what we might call "obvious" optimal-evolution happens much slower than that.1 The "products" that are impressive ities.

to the skeptics are not the diverse DNA strings in themselves, but the Let's consider a necessity first. Life anywhere would consist of entities amazingly intricate, complex, and
well-designed
organisms whose genomes with autonomous metabolisms. Some people would say this is "true by those strings are.

definition." By defining life in this way, they can exclude the viruses as living forms, while keeping the bacteria in the charmed circle. There may be good reasons for such a definitional fiat, but I think we see more clearly the importance of autonomous metabolism if we see it as a deep if not utterly necessary condition for the sort of complexity that is needed to fend off the 1. See, for instance, the discussion in Dawkins 1986a, pp. 124-25, which concludes: gnawing effects of the Second Law of Thermodynamics. All complex mac-

"Conversely, strong 'selection pressure', we could be forgiven for thinking, might be romolecular structures tend to break down over time, so, unless a system is expected to lead to rapid evolution. Instead, what we find is that natural selection exerts a braking effect on evolution. The baseline rate of evolution, in the absence of an
open
system, capable of taking in fresh materials and replenishing itself, it natural selection, is the maximum possible rate. That is synonymous with the mutation will tend to have a short career. The question "What does it live on?"

rate."

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Forced Moves in the Game of Design
129

might get wildly different answers on different planets, but it does not betray So at least some "biological necessities" may be recast as obvious solu-a "geocentric"—let alone "anthropocentric"—assumption.

tions to most general problems, as
forced moves in Design Space.
These are What about vision? We know that eyes have evolved independently many cases in which, for one reason or another, there is only one way things can be times, but vision is certainly not a necessity on Earth, since plants get along done. But reasons can be deep or shallow. The deep reasons are the fine without it. A strong case can be made, however, that
if
an organism is constraints of the laws of physics—such as the Second Law of Thermody-going to further its metabolic projects by locomoting, and if the medium in namics, or the laws of mathematics or logic.2 The shallow reasons are just which the locomoting takes place is transparent or translucent and amply historical. There
used to be
two or more ways this problem might be solved, supplied by ambient light, then
since
locomoting
works much better
(at but now that some ancient historical accident has set us off down one furthering self-protective, metabolic, and reproductive aims) if the mover is particular path, only one way is remotely available; it has become a "virtual guided by information about distal objects, and
since
such information can be necessity," a necessity for all practical purposes, given the cards that have garnered in a high-fidelity, low-cost fashion by vision, vision is a very good been dealt. The other options are no longer really options at all.