Darwin's Dangerous Idea - Evolution and the Meaning of Life

126 THREADS OF ACTUALITY IN DESIGN SPACE
neutral—as good as invisible to most readers; of the few that make a difference,
most will do damage to the text, making it a worse, less coherent, less
comprehensible tale. Consider as an exercise, however, the version of Peter
De Vries' game in which the object is to improve a text by a single typographical
change. It is not impossible, but far from easy!
These intuitions about getting somewhere important, about design improvement,
about rising in Design Space, are powerful and familiar, but are
they reliable? Are they perhaps just a confusing legacy of the pre-Darwinian
vision of Design coming down from a Handicrafter God? What is the relationship
between the ideas of Design and Progress? There is no fixed agreement
among evolutionary theorists about this. Some biologists are fastidious,
going to great lengths to avoid allusions to design or function in their own
work, while others build their whole careers around the functional analysis of
this or that (an organ, patterns of food-gathering, reproductive "strategies,"
etc.). Some biologists think you can speak of design or function without
committing yourself to any dubious doctrine about progress. Others are not
so sure. Did Darwin deal a "death blow to Teleology," as Marx exclaimed, or
did he show how "the rational meaning" of the natural sciences was to be
empirically explained (as Marx went right on to exclaim), thereby making a
safe home in science for functional or teleological discussion?
Is Design something that can be measured, even indirectly and imperfectly?
Curiously enough, skepticism about this prospect actually undercuts
the most potent source of skepticism about Darwinism. As I pointed out in
chapter 3, the most powerful challenges to Darwinism have always taken this
form: are Darwinian mechanisms powerful enough, or efficient enough, to
have done all that work in the time available? All what work? If the question
concerned mere sideways drifting in the typographical space of possible
genomes, the answer would be obvious and uncontroversial: Yes, there has
been much more than enough time. The speed at which random drift should
accumulate mere typographical distance can be calculated, giving us a sort of
posted speed limit, and both theory and observation agree that actual
evolution happens much slower than that. 1 The "products" that are impressive
to the skeptics are not the diverse DNA strings in themselves, but the
amazingly intricate, complex, and well-designed organisms whose genomes
those strings are.
1. See, for instance, the discussion in Dawkins 1986a, pp. 124-25, which concludes:
"Conversely, strong 'selection pressure', we could be forgiven for thinking, might be
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
natural selection, is the maximum possible rate. That is synonymous with the mutation
rate."
Drifting and Lifting Through Design Space 127
No analysis of the genomes in isolation of the organisms they create could
yield the dimension we are looking for. It would be like trying to define the
difference between a good novel and a great novel in terms of the relative
frequencies of the alphabetical characters in them. We have to look at the
whole organism, in its environment, to get any purchase on the issue. As
William Paley saw, what is truly impressive is the bounty of astonishingly
ingenious and smoothly functioning arrangements of matter that go to compose
living things. And when we turn to examining the organism, we find
again that no mere tabulation of the items composing it is going to give us
what we want.
What could be the relationship between amounts of complexity and
amounts of design? "Less is more," said the architect Ludwig Mies van der
Rohe. Consider the famous British Seagull outboard motor, a triumph of
simplicity, a design that honors the principle that what isn't there can't break.
We want to be able to acknowledge—and even measure, if possible— the
design excellence manifest in the right sort of simplicity. But what is the
right sort? Or what is the right sort of occasion for simplicity? Not every
occasion. Sometimes more is more, and of course what makes the British
Seagull so wonderful is that it is such an elegant marriage of complexity and
simplicity; nobody has quite such high regard, nor should they, for a paddle.
We can begin to get a clear view of this if we think about convergent
evolution and the occasions on which it occurs. And, as is so often the case,
choosing extreme—and imaginary—examples is a good way of focusing on
what counts. In this instance, a favorite extreme case to consider is extraterrestrial
life, and of course it may someday soon be turned from fantasy
into fact, if SETI, the ongoing Search for Extra-Terrestrial Intelligence, finds
anything. If life on Earth is massively contingent—if its mere occurrence in
any form at all is a happy accident—then what can we say, if anything, about
life on other planets in the universe? We can lay down some conditions with
confidence approaching certainty. These at first appear to fall into two
contrasting groups: necessities and what we might call "obvious" optimalities.
Let's consider a necessity first. Life anywhere would consist of entities
with autonomous metabolisms. Some people would say this is "true by
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
gnawing effects of the Second Law of Thermodynamics. All complex macromolecular
structures tend to break down over time, so, unless a system is
an open system, capable of taking in fresh materials and replenishing itself, it
will tend to have a short career. The question "What does it live on?"