As a recent convert to Darwinism, I found myself comparing my reasons for accepting evolution against Hunter's thesis that evolutionists are influenced more by metaphysical than strictly scientific arguments. While demonstrating that evolutionists from the time of Darwin have argued their case by appealing to a Victorian notion of God (e.g., "God would not have directly created things the way we see them..."), he fails to consider that many of these arguments may be reformulated to avoid the mention of God while nonetheless retaining their evidentiary value. For example, Hunter discusses the fact that all mammals except guinea pigs and primates are able to synthesize their own vitamin C. Guinea pigs and primates, including humans, have an apparently non-functional gene that corresponds to the gene responsible for vitamin C production in other mammals. Hunter maintains that, without certain presuppositions concerning the nature of God, this argument fails as evidence for human-primate shared ancestry. Hunter includes the following quote by theistic evolutionist Terry Gray:
"Further analysis shows that this gene is a pseudogene, i.e., it looks like a real gene, but it is not expressed due to a mutation in the gene itself or in the region of DNA that controls the expression of that gene. Now we could argue that in God's inscrutable purpose he placed that vitamin C synthesis look-alike gene in the guinea pig or human DNA or we could admit the more obvious conclusion, that humans and primates and other mammals share a common ancestor" (p. 168).
By highlighting Gray's appeal to God's nature, Hunter justifies dismissing such evidence as metaphysical rather than scientific. Throughout the book, Hunter employs this novel approach to circumvent some of the strongest evidence for common descent. As is the case with pseudogenes, however, textual critics routinely use copyist errors for determining the ancestral relationships among historical manuscripts. It would be beyond coincidence to suppose that there exists no ancestral relationship in a series of texts containing the same set of differences vis-à-vis the majority of other manuscripts. The vitamin C pseudogene is just one example of many shared between humans and primates, and the differences in the pseudogenes grow with distance from humans in the standard phylogenic tree. Contrary to Hunter's claim that evolution makes no significant, testable predictions, the existence of the human vitamin C pseudogene was predicted and then discovered by Nishikimi et al in 1992. Do pseudogenes prove common decent in a mathematical sense, and are such arguments free from all metaphysical assumptions? Perhaps not, but at the end of the day, when we look into the mirror, we must ask ourselves, are we playing games with the evidence, trying to find loopholes to excuse us from its weight, or did we in fact descend from earlier primates?
Ironically, intelligent design theorist Michael Behe, who offers praise for Hunter's book, finds the evidence for common descent from pseudogenes to be conclusive (see Kenneth Miller's "Finding Darwin's God, p. 164). One wonders how Behe and Hunter can coexist in the same camp, given their diametrically opposed views on such a fundamental question as common descent.
Though I agree with Hunter that the nature of God should be left out of any strictly scientific discussion, there is a place for such considerations when evaluating ID claims. Whatever else might be supposed about God's nature, it is generally agreed that, if He exists, He is not deceptive. This is why many creationists are now abandoning the young-earth creationists' "appearance of age" theory. Yet Hunter is disturbed when evolutionists provide evidence for evolution and assert that "God would not have done it that way." Perhaps He did do it that way, but at the risk of introducing the strong appearance of evolution.
In addition to highlighting the metaphysical underpinnings of many of the arguments for evolution, Hunter presents an array of scientific difficulties in evolutionary theory. Foremost among them is the lack of transitional forms in the fossil record. He is not content to focus simply on the relatively sparse record leading up to the Cambrian explosion, but amazingly turns the very dense record of the reptile-mammal transition in his favor:
"Douglas Futuyma echoes this sentiment: 'The gradual transition from therapsid reptiles to mammals is so abundantly documented by scores of species in every stage of transition that it is impossible to tell which therapsid species were the actual ancestors of modern mammals.' If it is 'notoriously difficult to decipher true ancestral-descendant relationships,' then how can evolutionists be so sure there is one? Certainly we can select our favorite sequence, but the fossils cannot tell us which is the correct sequence, or even whether there is a correct sequence at all" (p. 77).
The upshot is that if the record of transition is sparse, that is evidence against evolution, and if it is dense, that is also evidence against evolution. However, if we find texts that appear to be intermediate between Latin and French (a descendent of Latin), but we do not know whether they are on a direct line to modern French or on a line to a dead French patois, can this be construed as an argument that French did not evolve from Latin? As a largely historical science, evolution suffers from many of the same difficulties as historical linguistics. If Hunter were sufficiently motivated, he could no doubt uncover many difficulties with historical linguistics (e.g., Japanese is apparently not related to any mainland languages), but this would not prove that, for example, Latin did not evolve into Italian, Spanish, Portuguese and French.
I give three stars to Hunter for introducing a novel and thought-provoking argument into the tired debate over evolution, as well as for not hesitating to include a number of quotes supporting evolution. Though he attempts to refute these arguments, this may be the only exposure that many readers ever receive to the evidence for evolution.