IN DEFENSE OF DARWIN

A Tale of Two Reputations: Why we revere Darwin and give Freud a hard time (Jared Diamond, Feb, 2001, Natural History)

Darwin's contributions came at a time when almost everyone (including scientists) believed in the divine and independent creation of species, and when
scientists were recognizing patterns in the burgeoning discoveries about fossils, taxonomy, and biogeography but still lacked explanations for those patterns. Today Darwin is best known for establishing the fact of evolution and for recognizing the major role of natural selection in driving it. Actually, he achieved far more than those two most famous of his contributions. He also recognized sexual selection as an additional evolutionary driving force, laid the foundation for today's understanding of animal behavior, published a major work on the behavior and physiology of insectivorous plants, and provided the correct explanation for hierarchically branched taxonomies as well as for the origins of biogeographic regions, coral reefs, volcanic rocks, and soils. Underlying Darwin's contributions were his very broad technical competencies in anatomy, botany, embryology, geology, paleontology, taxonomy, and zoology, as well as his threefold methodological brilliance as an observer, experimentalist, and theoretician.

In his mastery and synthesis of many types of information and his ability to utilize diverse approaches, Darwin was unique. No biologist then or since has come even
close to matching him, and that's why no one else made his contributions. While it is true that Alfred Russel Wallace and Darwin independently came up with the idea of natural selection and evolution, the reasons that Darwin, not Wallace, is regarded as the irreplaceable genius are instructive. Wallace's reasoning about natural selection, and the initial evidence he based it on, were essentially the same as Darwin's. But the papers about natural selection by Wallace and Darwin that the Linnean Society published side by side in its journal in 1858 were ignored. The world did not begin to be convinced of natural selection until Darwin published the Origin of Species a year later, making an overwhelming case by amassing evidence from many fields. Because Wallace lacked depth in many of the disciplines and approaches mastered by Darwin, Wallace could never have made the overwhelming case that Darwin did, and he frequently acknowledged Darwin's greatness thereafter. [...]

Darwin also got some big things wrong. He shared the then-widespread belief in "soft inheritance" the assumption that the environment could cause adaptive changes in the hereditary material, but his younger contemporary August Weismann showed that this could not be so. Darwin accepted the postulate of "blending inheritance" (the fusion of a mother's and father's characteristics in their offspring), even though his own experiments on pigeons refuted it. Much more surprising are two other errors: he eventually failed to acknowledge the reality of species as non-interbreeding sets of populations, and hence he also eventually failed to accept that new species originate predominantly through geographic isolation, although that precise issue underlies the title of his most famous book. What makes the latter two errors so striking is that Darwin had previously formulated both ideas correctly but then abandoned his formulations in later editions of the Origin. These mistakes had long-lasting consequences, because they were not rectified by other biologists until about eighty years later and because a significant minority of biologists persist in those errors today.

That seems a bum rap on Darwin. What he was hoping to explain is how real speciation occurs, how genuinely new species arise, not how one duck finally inbreeds so far that it can no longer breed with another variety which is still manifestly just a duck. He can hardly be blamed that after 80 years of waiting for some such speciation to occur his disciples grabbed onto the far less impressive divergence and labeled it speciation just so they could fend off the skeptics. If Darwin is right he'll be proven so in time and this mere definition change will be recalled as nothing more than an embarrassing overreach. Posted by Orrin Judd at May 10, 2003 8:00 AM