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

150 PRIMING DARWIN'S PUMP Back Beyond Darwin's Frontier 151
gene, let alone any of the molecular machinery underlying it. Darwin was an
intrepid deducer, but he also knew when he didn't have enough premises to
go on. Besides, there was his concern for his beloved wife, Emma, who
desperately wanted to cling to her religious beliefs, and who could already
see the threat looming in her husband's work. Yet his reluctance to push any
farther into this dangerous territory, at least in public, went beyond his
consideration for her feelings. There is a wider ethical consideration at stake,
which Darwin certainly appreciated.
Much has been written about the moral dilemmas that scientists face when
the discovery of a potentially dangerous fact puts their love of truth at odds
with their concern for the welfare of others. Under what conditions, if any,
would they be obliged to conceal the truth? These can be real dilemmas, with
powerful and hard-to-plumb considerations on both sides. But there is no
controversy at all about what a scientist's ( or philosopher's) moral
obligations should be regarding his or her speculations. Science doesn't often
advance by the methodical piling up of demonstrable facts; the "cutting edge"
is almost always composed of several rival edges, sharply competing and
boldly speculative. Many of these speculations soon prove to be misbegotten,
however compelling at the outset, and these necessary by-products of
scientific investigation should be considered to be as potentially hazardous as
any other laboratory wastes. One must consider their environmental impact.
If their misapprehension by the public would be apt to cause suffering—by
misleading people into dangerous courses of action, or by undercutting their
allegiance to some socially desirable principle or creed—scientists should be
particularly cautious about how they proceed, scrupulous about labeling
speculations as such, and keeping the rhetoric of persuasion confined to its
proper targets.
But ideas, unlike toxic fumes or chemical residues, are almost impossible
to quarantine, particularly when they concern themes of abiding human
curiosity, so, whereas there is no controversy at all about the principle of
responsibility here, there has been scant agreement, then or now, about how
to honor it. Darwin did the best he could: he kept his speculations pretty
much to himself.
We can do better. The physics and chemistry of life are now understood in
dazzling detail, so that much more can be deduced about the necessary and
(perhaps) sufficient conditions for life. The answers to the big questions must
still involve a large measure of speculation, but we can mark the speculations
as such, and note how they could be confirmed or discon-firmed. There
would be no point any more in trying to pursue Darwin's policy of reticence;
too many very interesting cats are already out of the bag. We may not yet
know exactly how to take all these ideas seriously, but thanks to Darwin's
secure beachhead in biology, we know that we can and must.
It is small wonder that Darwin didn't hit upon a suitable mechanism of
heredity. What do you suppose his attitude would have been to the speculation
that within the nucleus of each of the cells in his body there was a
copy of a set of instructions, written on huge macromolecules, in the form of
double helixes tightly kinked into snarls to form a set of forty-six chromosomes?
The DNA in your body, unsnarled and linked, would stretch to the
sun and back several—ten or a hundred—times. Of course, Darwin is the
man who painstakingly uncovered a host of jaw-dropping complexities in the
lives and bodies of barnacles, orchids, and earthworms, and described them
with obvious relish. Had he had a prophetic dream back in 1859 about the
wonders of DNA, he would no doubt have reveled in it, but I wonder if he
could have recounted it with a straight face. Even to those of us accustomed
to the "engineering miracles" of the computer age, the facts are hard to
encompass. Not only molecule-sized copying machines, but proofreading
enzymes that correct mistakes, all at blinding speed, on a scale that supercomputers
still cannot match. "Biological macromolecules have a storage
capacity that exceeds that of the best present-day information stores by
several orders of magnitude. For example, the information density' in the
genome of E coli, is about 10 27 bits/m 3 " (Kiippers 1990, p. 180).
In chapter 5, we arrived at a Darwinian definition of biological possibility
in terms of accessibility within the Library of Mendel, but the precondition
for that Library, as we noted, was the existence of genetic mechanisms of
staggering complexity and efiiciency. William Paley would have been transported
with admiration and wonder at the atomic-level intricacies that make
life possible at all. How could they themselves have evolved if they are the
precondition for Darwinian evolution?
Skeptics about evolution have argued that this is the fatal flaw in Darwinism.
As we have seen, the power of the Darwinian idea comes from the way
it distributes the huge task of Design through vast amounts of time and space,
preserving the partial products as it proceeds. In Evolution: A Theory in
Crisis, Michael Denton puts it this way: the Darwinian assumes "that islands
of function are common, easily found in the first place, and that it is easy to
go from island to island through functional intermediates" (Denton 1985, p.
317). This is almost right, but not quite. Indeed, the central claim of
Darwinism is that the Tree of Life spreads out its branches, connecting
"islands of function" with isthmuses of intermediate cases, but nobody said
the passage would be "easy" or the safe stopping places "common." There is
only one strained sense of "easy" in which Darwinism is committed to these
isthmus-crossings' being easy: since every living thing is a descendant of a
living thing, it has a tremendous leg up; all but the tiniest fraction of its
recipe is guaranteed to have time-tested viability. The lines of genealogy are
lifelines indeed; according to Darwinism, the only hope of entering this
cosmic maze of junk and staying alive is to stay on die isthmuses.