On Friday April 8, 1994, at the invitation of biologist George Ayoub, the Yale- and Berkeley-trained developmental biologist Jonathan Wells spoke at Westmont College (Santa Barbara, CA) on the topic of a critical analysis of neo-Darwinian theory. Wells, whose first Ph.D. (from Yale) was in theology -- dealing with the Protestant theologian Charles Hodge's reaction to Darwinism -- recently completed a second Ph.D. in molecular and developmental biology at Berkeley, studying early amphibian development. Wells's critical interest in evolution and Darwinism is long- standing.
Wells began his talk by distinguishing various issues on both sides of the controversy, such as the very term "evolution." He distinguished change in general from the notions that species change, that diverse species are related by common descent, and that their diversity is due to Darwin's mechanism: random variation and natural selection.
This was primarily a conceptual exercise, emphasizing that one could acknowledge, based on the fossil record, that many species which lived long ago are quite different from those living now, without necessarily affirming that modern species are modified descendants of ancient ones -- much less that the modifications are due to the Darwinian mechanism. Wells further distinguished between microevolution, or descent with modification at the level of subspecies, species, and perhaps some genera, and macroevolution at the level of kingdoms, phyla, classes, etc.
Wells then developed three principal theses:
1. Macroevolution by random mutation and natural selection has little empirical support.
Wells began by briefly summarizing the major evidence for microevolution by the neo-Darwinian mechanism, such as artificial breeding, pesticide resistance, observations of peppered moth predation, and -- less directly -- the circular overlap of similar species. He pointed out that even this evidence is questionable: breeding is incapable of overcoming the species barrier, anomalies have surfaced in the peppered moth evidence, and circular overlap could be due to non-Darwinian as well as Darwinian processes. None of the evidence, however, bears directly on macroevolution. In fact, Wells continued, it bears indirectly on macroevolution only to the extent that one assumes, without evidence, that macroevolution is merely an extrapolation of microevolution. Indeed, Wells said, were he to rewrite his talk abstract now, he might be inclined to say that "macroevolution by random variation and natural selection has no empirical support."
2. Many findings of biological science are contrary to the predictions of Darwin's theory.
Wells dwelt primarily with embryology, his specialty, pointing out that neo-Darwinian predictions concerning the basis of homology are contradicted by developmental data. For instance, the expectation that early embryogenesis in related forms (e.g., vertebrates) should be conserved by natural selection, is spectacularly contradicted by the actual diversity of modes of cleavage, in such forms as amphibians, reptiles, or mammals. Wells also touched on paleontology. Darwin's theory, he noted, implies that many transitional forms must have existed linking the disparate fossils that were known in his day. Darwin ascribed their absence to the imperfection of the fossil record, and hoped that a more complete record would reveal the intermediates required to confirm his theory. But if over a century of global fossil-hunting has confirmed anything at all, it is that the gaps are real: species appear rather suddenly in the fossil record, fully formed and identifiable, then persist substantially unchanged until they disappear from the record. Modern Darwinists, Wells observed, have of course come up with explanations for this anomaly after the fact, for instance, postulating isolated geographical speciation coupled with that vintage Darwinian explanation, imperfect preservation. The bottom line, however, is that what Darwin predicted has not been found, and the revised versions of his theory merely paper over this embarrassing fact.
3. The continuing hegemony of Darwin's theory depends more on anti-religious philosophical assumptions than it does on evidence.
By "Darwin's theory" in this context, said Wells, he meant the theory that macroevolution is due to random variation and natural selection. Since there is little or no evidence to support the theory, the question remains why it prevails in circles otherwise committed to testing theories empirically. Wells did not elaborate on this, but in notes released (via the Internet) after the talk, he said that had he been challenged, he would have responded somewhat as follows.
In the course of their normal work, scientists are very cautious about inferring cause-and-effect relationships in biology. Claims about such relationships are usually regarded with considerable skepticism until repeatable, well-controlled experiments are consistent beyond a reasonable doubt with the notion that X causes Y. Even evolutionary biologists, when discussing their research with each other, are usually cautious on this point: for example, Wells has heard them discuss anomalies in the peppered moth evidence and question the notion that natural selection accounts for the data. In such in-house discussions, it would be considered a joke if one of the participants were then to infer, say, that monarch butterflies had evolved from peppered moths.
Yet when confronted in public by the inadequacy of the evidence to warrant macroevolutionary theory, many of these same biologists will claim that we "know" that macroevolution is basically Darwinian. Their justification for this surprising logical leap is that the only alternative is some sort of divine creation.
In other words, they justify Darwinian macroevolution on the basis of excluding creation, not on the basis of evidence. (A good example of this kind of thinking can be found in Richard Dawkins's The Blind Watchmaker.) Now, it may be true that "science" cannot deal with divine activity (though as a biologist with theological training, Wells has no trouble conceiving of a "science of God"); but the fact that our empirical methods may be incapable of dealing with something does not mean that something does not exist and have real effects.
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File Date: 6.02.95