Darwin's Dangerous Idea (61 page)

Now let us go to the opposite extreme and consider a heresy that would be What about that other notorious heresy, Lamarckism, the belief in the truly fatal to Darwinism if it weren't such a confused and ultimately self-inheritance of acquired characteristics?4 Here the situation is much more contradictory alternative: the attempt by the Jesuit paleontologist Teilhard de interesting. The main appeal of Lamarckism has always been its promise of Chardin to reconcile his religion with his belief in evolution. He proposed a speeding up the passage of organisms through Design Space by taking adversion of evolution that put humanity at the center of the universe, and vantage of the design improvements acquired by individual organisms during discovered Christianity to be an expression of the goal—"the Omega-their lives. So much design work to do, and so little time! But the prospect of point"—towards which all evolution is striving. Teilhard even made room for Lamarckism
as an alternative
to Darwinism can be ruled out on logical Original Sin (in its orthodox Catholic version, not the scientific version I grounds alone: the capacity to get Lamarckian inheritance off the ground in noted in chapter 8). To his dismay, the Church viewed this as heresy, and the first place
presupposes
a Darwinian process (or a miracle) (Dawkins forbade him to teach it in Paris, so he spent the rest of his days in China, 1986a, pp. 299-300). But couldn't Lamarckian inheritance be an important studying fossils, until his death in 1955. His book
The Phenomenon of Man
crane
within
a Darwinian framework? Darwin himself, notoriously, included (1959) was published posthumously and met with international acclaim, but Lamarckian inheritance as a booster process (in addition to natural selection) the scientific establishment, orthodox Darwinism in particular, was just as in his own version of evolution. He could entertain this idea because he had resolute as the Church in rejecting it as heretical. It is fair to say that in the such a foggy sense of the mechanics of heredity. (To get a clear idea of how years since his work was published, it has become clear to the point of unconstrained Darwin's imagination about mechanisms of inheritance could unanimity among scientists that Teilhard offered nothing serious in the way be, see Desmond and Moore 1991, pp. 531ff, for an account of his bold of an alternative to orthodoxy; the ideas that were peculiarly his were speculations about "pangenesis." )

confused, and the rest was just bombastic redescription of orthodoxy.2 The One of the most fundamental contributions to neo-Darwinism after Darwin classic savaging was by Sir Peter Medawar, and is reprinted in his book of himself was August Weismann's (1893) firm distinction between the
germ
essays,
Pluto's Republic
(1982, p. 245). A sample sentence: "In spite of all the
line
and the
somatic line;
the germ line consists of the sex cells in an obstacles that Teilhard perhaps wisely puts in our way, it is possible to organism's ovaries or gonads, and all the other cells of the body belong to the discern a train of thought in
The Phenomenon of Man"

soma. What happens to somatic-line cells during their lifetime has a bearing, The problem with Teilhard's vision is simple. He emphatically denied the of course, on whether that body's germ line flows into any progeny at all, but fundamental idea: that evolution is a mindless, purposeless, algorithmic changes to the somatic cells die with those cells; only changes to germ-line process. This was no constructive compromise; this was a betrayal of the cells—mutations—can carry on. This doctrine, sometimes called central insight that had permitted Darwin to overthrow Locke's Mind-first Weismannism, is the bulwark that orthodoxy eventually raised against Lavision. Alfred Russel Wallace had been tempted by the same abandonment, marckism—which Darwin himself thought he could countenance. Might as we saw in chapter 3, but Teilhard embraced it wholeheartedly and made it the centerpiece of his alternative vision.3 The esteem in which Teilhard's book is still held by nonscientists, the respectful tone in which his ideas are Teilhard's views can certainly be applauded by some orthodox Darwinians. (Medawar demurs on this point.) But in any event, Huxley could not buy all that Teilhard was offering. "Yet for all this Huxley finds it impossible to follow Teilhard 'all the way in his gallant attempt to reconcile the supernatural elements in Christianity with the facts and 2. The rhetorical method of "bombastic redescription" of the commonplace was first implications of evolution'. But, bless my soul, this reconciliation is just what Teilhard's described by Paul Edwards ( 1965) in an essay on another continental obscurantist, the book is
about!"
(Medawar 1982, p. 251).

theologian Paul Tillich.

4. I restrict Lamarckism to inheritance of acquired characteristics
through the genetic
3. Teilhard's book had an unlikely champion in England, Sir Julian Huxley, one of the
apparatus.
If we relax the definition, then Lamarckism is not clearly a fallacy. After all, contributors to—indeed, the baptizer of—the modern synthesis. As Medawar makes human beings inherit (by legacy) acquired wealth from their parents, and most animals plain, what Huxley admired in Teilhard's book was largely its support for the doctrine of inherit (by proximity) acquired parasites from their parents, and some animals inherit the continuity of genetic and "psychosocial" evolution. This is a doctrine I am myself (by succession ) acquired nests, burrows, dens from their parents. These are all phenom-enthusiastically supporting under the heading of the unity of Design Space, so some of ena of biological significance, but they are not what I.amarck was getting at—heretically.

322 C

Three Losers: Teilhard, Lamarck, and Directed Mutation
323

ONTROVERSIES CONTAINED

Weismannism still be overthrown? Today the odds against Lamarckism as a often been overlooked, or even shunned, by biologists who confused it with major crane look much more formidable (Dawkins 1986a, pp. 288-303). For some dread Lamarckian heresy. The saving grace for the Baldwin Effect is Lamarckism to work, the information about the acquired characteristic in that organisms pass on
their particular capacity to acquire
certain charac-question would somehow have to get from the revised body part, the soma, to teristics, rather than any of the characteristics they actually acquire. This
does
the eggs or sperm, the germ line. In general, such message-sending is deemed have the effect of taking advantage of the design explorations of individual impossible—no communication channels have been discovered that could organisms, as we saw, and hence is a powerful crane under the right carry the traffic—but set that difficulty aside. The deeper problem lies with circumstances. It is just not Lamarck's crane.

the nature of the information in the DNA. As we have seen, our system of Finally, what about the possibility of "directed" mutation? Ever since embryological development takes DNA sequences as a recipe, not a blueprint.

Darwin, orthodoxy has presupposed that all mutation is random;
blind
There is no point-for-point mapping between body parts and DNA parts. This chance makes the candidates. Mark Ridley (1985, p. 25) provides the stan-is what makes it extremely unlikely—or in some cases impossible—that any dard declaration:

particular acquired change in a body part (in a muscle or a beak or, in the case of behavior, a neural control circuit of some sort) will correspond to any Various theories of evolution by directed variation' have been proposed, discrete change in the organism's DNA. So, even if there were a way of but we must rule them out. There is no evidence for directed variation in getting a change order
sent
to the sex cells, there would be no way of mutation, in recombination, or in the process of Mendelian inheritance.

composing
the necessary change order.

Whatever the internal plausibility of these theories, they are in fact wrong.

Consider an example. The violinist assiduously develops a magnificent vibrato, thanks largely to adjustments built up in the tendons and ligaments of But that is a mite too strong. The orthodox theory mustn't
presuppose
any her left wrist quite different from the adjustments she simultaneously builds process of directed mutation—that would be a skyhook for sure—but it can up in her right wrist, the wrist of her bowing arm. The recipe for wrist-leave open the possibility of somebody's discovering nonmiraculous mech-making in human DNA makes both wrists from a single set of instructions anisms that can bias the distribution of mutations in speed-up directions.

that takes advantage of mirror-image reflection (that's why your wrists are so Eigen's ideas about quasi-species in chapter 8 are a case in point.

much alike ), so there would be no simple way to change the recipe for the In earlier chapters, I have drawn attention to various other possible cranes left wrist without making the same (and unwanted) change in the right wrist.

that are currently being investigated: trans-species "plagiarism" of nucleotide It is not hard to imagine how "in principle" the embryological process might sequences (Houck's
Drosophila),
the crossovers made possible by the be cajoled into rebuilding each wrist separately after the initial construction innovation of sex (Holland's genetic algorithms), the exploration of multiple takes place, but even if this problem can be overcome, the chances are small variations by small teams (Wright's "demes") that return to the parent indeed that this would be a
practical
mutation, a localized and smallish population (Schull's "intelligent species"), and Gould's "higher level species revision in her DNA, that corresponds closely to the improvements her years sorting," to name four. Since these debates all fit comfortably within the of practice have created. So almost certainly her children will have to learn commodious walls of contemporary Darwinism, they don't need further their vibrato the same way she did.

scrutiny from us, fascinating though they are. Almost always, the issue in This is not quite conclusive, however, and hypotheses that have features at evolutionary theory is not possibility in principle, but relative importance, least strongly reminiscent of Lamarckism keep popping up in biology and are and the issues are always
much
more complex than I have portrayed them.6

often taken seriously, in spite of the general taboo against anything smacking There is one area of ongoing controversy, however, that deserves a some-of Lamarckism.5 I noted in chapter 3 that the Baldwin Effect has what fuller treatment, not because it threatens something hard or brittle in the modern synthesis—however it comes out, Darwinism will still be stand-5. Dawkins (1986a, p. 299) issues the right caveat: Lamarckism is "incompatible with embryology as we know it," but "this is not to say that, somewhere in the universe, there 6. To those who want to explore these and other controversies more fully, 1 recommend may not be some alien system of life in which embryology
is
preformationistic; a life-form the following books as particularly clear and accessible to neophytes
willing to work
that really does have a 'blueprint genetics', and that really could, therefore, inherit ac-bard. Buss 1987, Dawkins 1982, G. Williams 1992, and, as an invaluable handbook, Keller quired characteristics." There are other possibilities that might be called Lamarckian as and Uoyd 1992. Mark Ridley 1993 is an excellent textbook. For a more accessible primer, well. For a survey, see Landman 1991, 1993; for another interesting variation on the Calvin 1986 is a ripping good story, with enough bold speculation thrown in to whet your appetite for more.

theme, see Dawkins' account of "A Lamarckian Scare" (Dawkins 1982, pp. 164-78).

324 CONTROVERSIES CONTAINED

Cui Bono?
325

ing strong—but because it has been
seen
to have particularly upsetting presumably most of them would, if Wilson's long-held homily is true ), that implications for the extension of evolutionary thinking to humanity. This is would be just fine, but people were afraid that Wilson had his priorities the debate over the "units of selection."

backwards.

This is an example of a topic of perennial and proper human concern.

Lawyers ask, in Latin,
Cui bono?,
a question that often strikes at the heart of 3. Cui BONO?

important issues: Who benefits from this matter? The same issue arises in evolutionary theory, where the counterpart of Wilson's actual dictum would

"What's good for General Motors is good for the country."

be: "What's good for the body is good for the genes and vice versa." By and large, biologists would agree, this must be true. The fate of a body and the

—not said by Charles E. Wilson, 1953

fate of its genes are tightly linked. But they are not perfectly coincident.

What about those cases when push comes to shove, and the interests of the In 1952, Charles E. Wilson was president of General Motors, and newly body (long life, happiness, comfort, etc.) conflict with the interests of the elected U.S. President Dwight Eisenhower nominated him to be his Secretary genes?

of Defense. At his nomination hearing before the Senate Armed Services This question was always latent in the modern synthesis. Once genes had Committee in January 1953, Wilson was asked to sell his shares in General been identified as the things whose differential replication was responsible Motors, but he objected. When asked if his continued stake in General for all the design change in the biosphere, the question was unavoidable, but Motors mightn't unduly sway his judgment, he replied: "For years, I thought for a long time theorists could be lulled, like Charles Wilson, with the re-what was good for the country was good for General Motors and vice versa."

flection that by and large what was good for the whole was good for the part Unfortunately for him, what he actually said did not have much replicative and vice versa. But then George Williams (1966 ) drew attention to the ques-power—though just enough for me to locate a descendant in a reference book tion, and people began to realize that it had profound implications for our and reproduce it once again in the preceding sentence. What replicated like a understanding of evolution. Dawkins made the point unforgettable by fram-flu virus in the press reports of his testimony, on the other hand, was the ing it in terms of the concept of the selfish gene (1976), pointing out that mutated version used as the epigraph for this section; in response to the from the gene's "point of view," a body was a sort of survival machine created ensuing furor, Wilson was forced to sell his stock in order to win the to enhance the gene's chances of continued replication.