Darwinism: Science or Philosophy

Original author's comments on this response.

SOME THINGS ARE SAID more precisely in one language than in any other. The French have a saying, jeter de la poudre aux yeux. The Nouveau Petit Larousse defines it as "causing someone to believe (something) by dazzling (them) with words or manners.'' It is a perfect description of Professor Wilcox's paper; that is, there's a lot less there than meets the eye. The biology in it is OK but so what?

Wilcox begins by reiterating the focus of this symposium (albeit worded in a subtly different way, which could be significant but is not from my perspective, so I'll let it pass). He wants to know if the success of the "Darwinian paradigm'' is due to its perceived metaphystcal necessity or to its successes as a scientific explanation of empirical phenomena. He then makes an important distinction that suggests a sound logical structure to come: he decouples evidence for ancestry from mechanisms generating morphological novelty. (I suppose there are some people today who still confuse the two. Historically, this has been mostly a vitalist or orthogenetic error, and vitalism is clearly a manifestation of something other than ideological materialism; orthogenesis might or might not be strictly materialistic, depending on how the innate evolutionary "tendencies" are "explained." There is also an element of confusion in the claim by advocates of punctuated equilibrium that morphological novelty and speciation occur simultaneously. This is a somewhat different kind of confusion and at any rate is patently falsified by neontological data; it is the sort of error one would expect paleontologists to make, since the only "species" they can see are morphospecies.)

Very quickly, however, Wilcox lapses into debater's tactics by attacking a straw man of his own making.

"The first problem is a matter of simple logic," he asserts. "How can natural selection be a creator of new morphology when it does not write genetic messages, but only chooses among them?" Wilcox has the privilege of revealing philosophical secrets that have been well known since 1859. Whence comes the implicit equivalence of evolution (or the "Darwinian paradigm") with natural selection, such that natural selection is required to be a "creator of new morphology"? Again, "given a rabbit in the hat, a magician can pull it out-but how do rabbits get into the genetic hat? That, too, natural selection must answer if it is to be the genetic maestro." If natural selection were a financial commentator on the evening news, it might have to explain how the Federal Reserve regulates the money supply. But no sensible person expects it to do that Who but anti-evolution debaters expects natural selection to be the "genetic maestro," anyway? By Michael Ruse's terminology, "ultra-Darwinians" do. I don't know any, but if they exist, they are probably busy writing economic treatises for the Cato institute. Anyway, the omnipotence of natural selection is certainly not a logical necessity of evolutionary theory.

At several points in his essay Wilcox alludes to hierarchical phenomena Hierarchy theory experienced a limited degree of trendiness in biological circles a few years ago, largely for sociological reasons. But that doesn't mean it isn't sometimes useful (though usually not). The levels-of-selection controversy has been a fecund one both conceptually and empirically. Although natural selection cannot be expected to explain everything, it actually has impacts on the genesis of variation that are subtle and once removed from the mutation process per se.

Several decades ago the Oxford ecological-genetics school correctly forecast that selection would tend to build up complexes of modifiers that would define allelic dominance by controlling expression in heterozygote phenotypes. They also developed the concept of the supergene, which involves tight linkage developed by selection of adaptive chromosomal reorganizations. This originally emerged from studies of the mimetic butterfly Papilio dardanus, dovetailed with studies of chromosome inversions in Drosophila by Dobzhansky and his collaborators, and later fed into various ideas about speciation, developmental genetics, linkage disequilibrium, and genomic constraints on design, some of which seem to bother Wilcox.

It was an easy step from there to the idea that DNA repair mechanisms were themselves subject to selection, which means that forward and back mutation rates can be seen as adaptive phenomena, rather than arbitrary "givens" in the system. (Because directed mutation is potentially so adaptive, its recent revival as a real possibility is no surprise; the idea is attractive not for ideological reasons but because if mechanisms exist for it to occur, a good Darwinian would predict that they would be selected for.) (When geographic races of Drosophila are hybridized, a short-term increase in mutation rates is sometimes seen, which is interpreted as a result of rendering heterozygous various loci involved in mutation repair in the different genomes.) All of this is evidence for the creativity of natural selection, but it does not add up to the claim of omnipotence that Wilcox thinks is required by the "Darwinian paradigm."

The early Darwinians were very open to a variety of mechanisms at work simultaneously in evolution. As is well enough known, evolution itself was much more popular than natural selection, and selection was in fact eclipsed for decades by a potpourri of what were seen as sexier explanations, including macromutauon and various forms of vitalism. The triumph of selection was the fruit of the great success of theoretical population genetics in the hands of Fisher, Haldane, and Wright and, paired with it, that of the empirical Ford-Kettlewell-Dowdeswell Cain school at Oxford, whose theoretical mentor was Fisher.

Again, everybody knows that the overemphasis on microevolutionary process and the efficacy of natural selection inspired a reaction, triggered by Eldredge and Gould, Gould and Lewontin, in their critique of the "Panglossian paradigm" and the notion of punctuated equilibrium. It also included a revival of interest in Goldschmidt's premature synthesis, in the 1930s, of evolution and developmental biology under the rubric "physiological genetics." All of this was seized upon by critics of various stripes, from Fundamentalist Christians to Marxists, as proof that "Darwinism" was dead.

An engineering approach, stressing the properties of biomaterials in morphogenesis, developed; it was intended to explain innate constraints on morphology but helped briefly to fuel an essentially stillborn effort to transplant structuralist ideology from anthropology and linguistics into biology. Structuralism was correctly rejected by the vast majority of biologists because it was synchronic (and thus useless for addressing questions of ultimate causation, which are clearly diachronic) and because it summoned up memories of German idealistic morphology, which some of us would rather forget. We cannot, of course, because it so subtly and thoroughly interpenetrated so much of biology, and lies very near the heart of cladistics.

I rehash this recent history, lest anyone think there is anything new in Wilcox's philosophical complaints. There isn't. Even his pseudostructuralist language is derivative; and the recency of his citations merely shows how easily new wine can be poured into old bottles when evolution is at issue. Perversely, Wilcox almost seems to be saying that the more we know about biology, the more we need nonmaterialistic explanations. Why should that be true of the genome but not of the aurora borealis? Were the ancients better scientists because, knowing less, they speculated more than we do?

I will not respond at a technical level to Wilcox's citations because their content is so pervasively irrelevant to the matter at issue here. I will say that a proper cybernetic approach to genomic organization might be interesting (cf. Dembski), though its robustness would remain in question, given how little we actually know. That is, most of Wilcox's paper boils down to an assertion that this might be a problem worth pursuing.

That said, I want to talk twisters. Here in Texas tornadoes are a well-known, much-feared natural phenomenon. I happen to do meteorology as a hobby. Modern meteorology is highly technical and theoretical. It is just as mathematical as population genetics. Now here's a dirty little secret: we do not have a really satisfactory mechanistic understanding of how tornadoes work. We are, however, quite good at predicting where and when they are likely to occur. We can spot the conditions that spawn them and warn people who might be in their way, though we don't really understand why we can (Davies-Jones, 1992).

What does that say about our meteorological paradigm? Does it say that it "has been constructed both under a metaphysical commitment to (global) materialism, and under the methodological commitment of science to use strictly material causal explanations' Does it say that "the seamless robe of meteorological (materialistic) stories would seem to have enough fundamental flaws to make it reasonable to question seriously the adequacy of the ruling metaphysical and even methodological paradigms? And if so, should we seriously re-examine the conclusions we have reached while working under the materialist agenda?"

You bet.

You won't catch me arguing that God can't make tornadoes anywhere and any time he pleases. If he chooses to stick 'em only onto certain kinds of thunderclouds under very predictable conditions, shoot, that's his right. After all, he's God.

So why do I have this nasty suspicion that if we got a tornado warning right now, Professor Wilcox would set aside his doubts about the "materialist agenda" in his rush for the cyclone cellar?