More than 18 months after its publication, Darwin’s Doubt continues to stir discussion and debate, but that discussion all too often savors of a peculiar and unsatisfying incompleteness. As an observer of the debate, I often wonder if the critics read the same volume that I did. Most recently, the organization BioLogos has commenced a multi-part response, which I began reading with high hopes of finding the reviewers actually grappling with Stephen Meyer’s central theses.
Well — not yet. The first part of the BioLogos response to Meyer’s book comprises a blog post recommending Calvin College paleontologist Ralph Stearley’s December 2013 essay review about the Cambrian explosion, published in Perspectives on Science and Christian Faith, the last part of which considered Darwin’s Doubt (in addition to two other books on the topic). Stearley reprises worries put forward earlier by other critics — about such matters as the exact timing the Cambrian explosion, the "small shelly" fauna, and Cambrian ecologies — but his bottom line is so ambivalent that it is impossible to say if he agrees with Stephen Meyer or not. He certainly provided no scientific refutation of Meyer’s main scientific arguments. Instead he actually acknowledges the inadequacy of the the neo-Darwinian mechanism as an explanation for major innovation in the history of life. If Stearley had stepped into a voting booth, we would find him still there, with the curtain drawn, deliberating over his choices. I’ll comment below on why he can’t decide. It’s a philosophical, not scientific, dilemma.
First, however, let’s dispense with the peripheral issues, all of which have been previously addressed by Stephen Meyer or others. Stearley disputes what he calls Meyer’s "minimalist interpretation" of the length of the Cambrian explosion, saying that by ignoring the appearance of the "small shelly" fauna, Darwin’s Doubt exaggerates the abruptness of the event. But as Casey Luskin points out, Meyer did not ignore these fossils. Moreover, as Meyer himself explains, even expanding the geological interval (from 10 to 25 million years, or more) does little to solve the relevant problems of new information and anatomical innovation. It’s a bit like arguing about the length of a bank robbery: twenty minutes, three hours, all night? In the morning, the vault is still empty. Someone did it. The vault did not empty itself.
Nor are the ecologies of the early- to mid-Cambrian the issue of central interest. Stearley claims that "new adaptive niches" opened during the Cambrian. That may well be true, but environmental changes are hardly sufficient to cause the origin of the wide array of novel animal body plans. Paleontologist Douglas Erwin and colleagues identify this confusion of necessary and sufficient conditions. Raising the oxygen level of pre-Cambrian oceans, for instance, may have allowed oxygen-fueled animal metabolism, required for elaborate body plans, to flourish, but greater amounts of oxygen alone could never have caused the same complexity. As Erwin et al. explain, "a permissive environment does not explain innovations in metazoan architecture" (Erwin et al. 2011, p. 1094). Put a few yeast cells in an enormous chemostat, with nutrients, and slowly increase the oxygen levels, over a really, really long time. Open the chemostat. Trillions of yeast cells; no animals.
Stearley also complains about Meyer’s treatment of alternative evolutionary theories, such as those proposed by developmental biologist Eric Davidson or self-organization theorist Stuart Kauffman. Here at last we see some glimmer of the real issue, namely: what message may we take away from the ongoing failures of materialistic theories to solve the problem of the Cambrian explosion? Or, put another way — if the signal of nature appears to indicate intelligent design, may we follow that signal where it leads? Or are we constrained to seek a materialist solution, come what may?
Stearley acknowledges that many leading evolutionary theorists are deeply unhappy with the received neo-Darwinian account for major events in the history of life, such as the Cambrian explosion. Yet their unhappiness is still not enough, he argues, to move them out of the City of Materialism:
…while it is true that Goodwin and others believe that their discoveries pose a major challenge to neo-Darwinian orthodoxy, this does not cause them to abandon their belief that the history of life can be explained as the outcome of biological processes!
One shouldn’t make too much of a punctuation mark, I suppose, but Stearley’s exclamation point at the end of that passage, reinforcing the non-negotiability of materialism for evolutionary theory, is telling, especially when juxtaposed against his own ambivalence about the possibility of detecting design as a genuine empirical finding. "I admit that, by temperament," he writes, "I am inclined to see design in nature, and so I resonate with some of Meyer’s arguments."
Design, if actual, is no more a question of "inclining to see," "temperament," or "resonating," than the atomic number of an element. The evidence and arguments compiled in Darwin’s Doubt are not menu suggestions about — if mood happens to strike you, on any given day — preferring one breakfast jam over another. If real, design is a datum of nature, like it or not. Bad philosophies of science, like materialism, need to get out of the way.
And unfortunately Stearley seems not to know his own mind on this point. Although he says he is "temperamentally inclined" to see design, he pushes that inference away with his other hand. "I am not sure," he concludes, "that it is our place to know [about intelligent design]. If that is so, perhaps our efforts to obtain certainty in seeing his design will end in frustration." Stearley cannot decide if materialism — okay, methodological naturalism, to give the doctrine its domesticated name — governs science, or if design is truly detectable.
In the long run, epistemic ambivalence like that, vacillating on the horns of a philosophical dilemma, will prove sterile, if not indeed deadly, because ambivalence robs evidence of its power to yield knowledge. When one says "Sorry, but I cannot know x," then it simply does not matter how powerful or compelling the evidence for x may be. An a priori move has destroyed what should be a ready inference.
Strange asymmetry: materialist evolutionary theory may pursue its investigations, with the promise of genuine discoveries awaiting, whereas intelligent design necessarily lies beyond the horizon of knowledge in a mist of uncertainty. Those who prefer their Yes to be Yes (and No to be No) will never settle for this asymmetrical playing field. Science is hard, and inferences are tricky, but your blood really does circulate — and design, if it’s out there to be detected, awaits our hard work, and will reward us when we find it out.
Temperament? Ah, don’t worry about that. Not relevant.
Douglas H. Erwin, Marc Laflamme, Sarah M. Tweedt, Erik A. Sperling, Davide Pisani, and Kevin J. Peterson, "The Cambrian Conundrum: Early Divergence and Later Ecological Success in the Early History of Animals," Science 334 (2011):1091-97.
Image: Ralph Stearley/Calvin College.