Darwin's Dangerous Idea (28 page)

As Dawkins goes on to say (p. 316), "The one thing that makes evolution such a neat theory is that it explains how organized complexity can arise out of primeval simplicity." This is one of the key strengths of Darwin's idea, and the key weakness of the alternatives. In fact, I once argued, it is unlikely that any other theory could have this strength:

Darwin explains a world of final causes and teleological laws with a prin-F

ciple that is, to be sure, mechanistic but—more fundamentally—utterly IGURE 7.1

independent of "meaning" or "purpose". It assumes a world that is
absurd
in the existentialist's sense of the term: not ludicrous but pointless, and this But how could this process get started? Denton (p. 323) goes to some assumption is a necessary condition of any non-question-begging account lengths to calculate the improbability of such a start-up, and arrives at a
of purpose.
Whether we can imagine a non-mechanistic but also non-suitably mind-numbing number.

question-begging principle for explaining design in the biological world is doubtful; it is tempting to see the commitment to non-question-begging To get a cell by chance would require at least one hundred functional accounts here as tantamount to a commitment to mechanistic materialism, proteins to appear simultaneously in one place. That is one hundred si-but the priority of these commitments is clear ___ One argues: Darwin's multaneous events each of an independent probability which could hardly materialistic theory may not be the only non-question-begging theory of be more than 10-20 giving a maximum combined probability of 102000

these matters, but it is one such theory, and the only one we have found, which is quite a good reason for espousing materialism. [Dennett 1975, pp.

This probability is Vanishing indeed—next to impossible. And it looks at 171-72.]

first as if the standard Darwinian response to such a challenge could not
as a
matter of logic
avail us, since the very preconditions for its success—a Is that a fair or even an appropriate criticism of the religious alternatives?

system of replication with variation—are precisely what only its success One reader of an early draft of this chapter complained at this point, saying would permit us to explain. Evolutionary theory appears to have dug itself that by treating the hypothesis of God as just one more scientific hypothesis, into a deep pit, from which it cannot escape. Surely the only thing that could to be evaluated by the standards of science in particular and rational thought save it would be a skyhook! This was Asa Gray's fond hope, and the more we in general, Dawkins and I are ignoring the very widespread claim by behave learned about the intricacies of DNA replication, the more enticing this lievers in God that their faith is quite beyond reason, not a matter to which idea has become to those who are searching for a place to bail out science such mundane methods of testing applies. It is not just unsympathetic, he with some help from religion. One might say that it has appeared to many to claimed, but strictly unwarranted for me simply to assume that the scientific be a godsend. Forget it, says Richard Dawkins:

method continues to apply with full force in this domain of faith.

154 PRIMING DARWIN'S PUMP

Molecular Evolution
15 5

Very well, let's consider the objection. I doubt that the defender of religion come up with a good defense of this) or you are kidding yourself. (The ball will find it attractive, once we explore it carefully. The philosopher Ronald is now in your court.)

de Sousa once memorably described philosophical theology as "intellectual Dawkins' retort to the theorist who would call on God to jump-start die tennis without a net," and I readily allow that I have indeed been assuming evolution process is an unrebuttable refutation, as devastating today as when without comment or question up to now that the net of rational judgment was Philo used it to trounce Cleanthes in Hume's
Dialogues
two centuries earlier.

up. But we can lower it if you really want to. It's your serve. Whatever you A skyhook would at best simply postpone the solution to the problem, but serve, suppose I return service rudely as follows: "What you say implies that Hume couldn't think of any cranes, so he caved in. Darwin came up with God is a ham sandwich wrapped in tinfoil. That's not much of a God to some magnificent cranes to do
middle-level
lifting, but can the principles that worship!" If you then volley back, demanding to know how I can logically worked so well once be applied again to do the lifting required to get the justify my claim that your serve has such a preposterous implication, I will booms of Darwin's cranes off the ground in the first place? Yes. Just when it reply: "Oh, do you want the net up for my returns, but not for your serves?

might appear that the Darwinian idea has come to the end of its resources, it Either the net stays up, or it stays down. If the net is down, there are no rules jumps niftily
down
a level and keeps right on going, not just one idea but and anybody can say anything, a mug's game if there ever was one. I have many, multiplying like the brooms of the sorcerer's apprentice.

been giving you the benefit of the assumption that you would not waste your If you want to understand this trick, which at first glance seems unimag-own time or mine by playing with the net down."

inable, you have to wrestle with some difficult ideas and a raft of details, both Now if you want to
reason
about faith, and offer a reasoned (and reason-mathematical and molecular. This is not the book, and I am not the author, responsive) defense of faith as an extra category of belief worthy of special you should consult for those details, and nothing less could really secure your consideration, I'm eager to play. I certainly grant the existence of the phe-understanding, so what follows comes with a warning: although I will try to nomenon of faith; what I want to see is a reasoned ground for taking faith
acquaint
you with these ideas, you won't really know them unless you study seriously as a
way of getting to the truth,
and not, say, just as a way people them in the primary literature. (My own grasp on them is that of an amateur.) comfort themselves and each other (a worthy function that I do take seri-Imaginative theoretical and experimental explorations of the possibilities are ously). But you must not expect me to go along with your defense of faith as now being conducted by so many different researchers that it practically a path to truth if at any point you appeal to the very dispensation you are constitutes a subdiscipline at the boundary between biology and physics.

supposedly trying to justify. Before you appeal to faith when reason has you Since I cannot hope to demonstrate to you the validity of these ideas—and backed into a corner, think about whether you really want to abandon reason you shouldn't trust me if I claimed to do so—why am I presenting them?

when reason is on your side. You are sightseeing with a loved one in a Because my purpose is philosophical: I wish to break down a prejudice, the foreign land, and your loved one is brutally murdered in front of your eyes. At conviction that a certain sort of theory couldn't
possibly
work. We have seen the trial it turns out that in this land friends of the accused may be called as how Hume's philosophical trajectory got deflected by his inability to take witnesses for the defense, testifying about their faith in his innocence. You seriously an opening in the wall that he dimly saw. He
thought he knew
that watch the parade of his moist-eyed friends, obviously sincere, proudly there was no point in heading any further in that direction, and, as Socrates proclaiming their undying faith in the innocence of the man you saw commit never tired of pointing out, thinking you know when you don't is the main the terrible deed. The judge listens intently and respectfully, obviously more cause of philosophical paralysis. If I can show that it is
conceivable
that the moved by this outpouring than by all the evidence presented by the Darwinian idea can carry through "all the way down," this will pre-empt a prosecution. Is this not a nightmare? Would you be willing to live in such a family of glib dismissals that is all too familiar, and open our minds to other land? Or would you be willing to be operated on by a surgeon who tells you possibilities.

that whenever a little voice in him tells him to disregard his medical training, he listens to the little voice? I know it passes in polite company to let people have it both ways, and under most circumstances I wholeheartedly cooperate 2. MOLECULAR EVOLUTION

with this benign arrangement. But we're seriously trying to get at the truth here, and if you think that this common but unspoken understanding about
The smallest catalytically active protein molecules of the living cell
faith is anything better than socially useful obfuscation to avoid mutual
consist of at least a hundred amino acids. For even such a short mol-embarrassment and loss of face, you have either seen much more deeply into
ecule, there exist 20'°° ~ 1013° alternative arrangements of the twenty
this issue than any philosopher ever has (for none has ever
basic monomers. This shows mat already on the lowest level of com-156 PRIMING DARWIN'S PUMP

Molecular Evolution
157

plexity, that of the biological macromolecules, an almost unlimited variety
algorithm,
bare, minimal self-reproducing mechanisms—remarkably like the
of structures is possible.

computer viruses that have recently emerged to fascinate and plague us (Ray

—BERND-OIAF KUPPERS 1990, p. 11

1992, Dawkins 1993)1 Since these pioneer macros reproduced, they met the necessary Darwinian conditions for evolution, and it is now clear that they
Our task is to find an algorithm, a natural law that leads to the origin of
spent the better part of a billion years evolving on Earth before there were
information.

any living things.

—MANFRED EIGEN 1992, p. 12

Even the simplest replicating macro is far from simple, however, a composition with thousands or millions of parts, depending on how we count the In describing the power of the central claim of Darwinism in the previous raw materials that go to make it. The alphabet letters Adenine, Cytosine, section, I helped myself to a slight (!) exaggeration: I said that every living Guanine, Thymine, and Uracil are bases that are not too complex to arise in thing is the descendant of a living thing. This cannot be true, for it implies an the normal course of prebiotic affairs. (RNA, which came before DNA, has infinity of living things, a set with no first member. Since we know that the Uracil, whereas DNA has Thymine.) Expert opinion differs, however, on total number of living things (on Earth, up till now) is large but finite, we whether these blocks could synthesize themselves by a series of coincidences seem to be obliged, logically, to identify a first member—Adam the into something as fancy as a self-replicator. The chemist Graham Cairns-Protobacterium, if you like. But how could such a first member come to Smith (1982, 1985) presents an updated version of Paley's argument, aimed exist? A whole bacterium is much, much too complicated just to happen into at the molecular level: The process of synthesizing DNA fragments, even by existence by cosmic accident. The DNA of a bacterium such as
E coli
has the advanced methods of modern organic chemists, is highly elaborate; this around four million nucleotides in it, almost all of them precisely in order. It shows that their chance creation is as improbable as Paley's watch in a is quite clear, moreover, that a bacterium could not get by with much less. So windstorm. "Nucleotides are too expensive" (Cairns-Smith 1985, pp. 45-49).

here is a quandary: since living tilings have existed for only a finite time, DNA exhibits too much design work to be a mere product of chance, Cairns-there must have been a first one, but since all living things are complex, there Smith argues, but he then proceeds to deduce an ingenious—if speculative couldn't have been a first one!

and controversial—account of how that work might have been done. Whether There could only be one solution, and we know it well in outline: before or not Cairns-Smith's theory is eventually confirmed, it is well worth sharing there were bacteria, with autonomous metabolisms, there were much simpler, simply because it so perfectly instantiates the fundamental Darwinian quasi-living things, like viruses, but unlike them in not (yet) having any strategy.2

living things to live off parasitically. From the chemist's point of view, A good Darwinian, faced yet again with the problem of finding a needle in viruses are "just" huge, complex crystals, but thanks to their complexity, they a haystack of Design Space, would cast about for a
still simpler
form of don't just sit there; they "do things." In particular, they reproduce or self-replicate, with variations. A virus travels light, packing no metabolic machinery, so it either stumbles upon the energy and materials required for self-replication or self-repair, or eventually it succumbs to the Second Law of 1. Warning: biologists already use the term
macroevolution,
in contrast to microevolu-Thermodynamics and falls apart. Nowadays, living cells provide concen-tion, to refer to large-scale evolutionary phenomena—the patterns of speciation and trated storehouses for viruses, and viruses have evolved to exploit them, but extinction, for instance, in contrast to the refinement of wings or changes in resistance to in the early days, they had to scrounge for less efficient ways of making more toxins within a species. What I am calling the evolution of macros has nothing much to copies of themselves. Viruses today don't all use double-stranded DNA; do with macroevolution in that established sense. The term
macro
is so apt for my some use an ancestral language, composed of single-stranded RNA (which of purposes, however, that I have decided to stick with it, and try to offset its shortcomings with this patch—a tactic Mother Nature also often uses.

course still plays a role in our own reproductive system, as an intermediary