Jonathan Wells at Books and Culture reviews a new book on evo devo (evolutionary development)which purports to solve some of the last major problems of evolutionary theory. According to Wells, the book actually does no such thing. Here are some excerpts from his review:
Darwinian evolution is widely advertised to be a fact, as firmly established as the shape of the Earth. Defenders of the theory insist that there is no scientific controversy over it, and people who question or criticize it are typically accused of being ignorant or religiously motivated. Yet every few years a book comes along-written by scientists-claiming to remedy some major flaw in evolutionary theory.
The Plausibility of Life, by Marc W. Kirschner and John C. Gerhart, is such a book.
There are other major transitions in the history of life that Kirschner and Gerhart also concede remain unexplained. One of these was the "invention" of the first eukaryotes, cells with nuclei that are very different from bacteria. "Generating the first eukaryotic cell was a major and enduring accomplishment," they write. "Extensive innovation showed up in the complexity and organization of the eukaryotic ancestor." Another major transition was the origin of multicellular organisms, which require complex mechanisms for cells to aggregate and communicate with each other. Still another unexplained transition was the origin of animal body plans in the Cambrian explosion. "Once again," write Kirschner and Gerhart, "a new suite of cellular and multicellular functions emerged rather quickly and was conserved to the present."
Some other major transitions that Kirschner and Gerhart concede remain unexplained are the origin of limbs in the first land vertebrates, the origin of neural crest cells that sculpt the heads and nervous systems of vertebrates, and the origin of the neocortex in vertebrate brains. "The origin of these processes and properties would seem to be the primary events of evolution, requiring high novelty," but the authors admit they cannot explain them. So, what does their theory explain?
Their theory purports to explain how organisms that share a given set of conserved core processes-say, land vertebrates-can diversify into a wide variety of forms.hat are we to make of The Plausibility of Life? Its authors claim to complete Darwin's theory by closing its last remaining major gap, yet they concede that the completed theory has no explanation for the origin of core processes in the first cells, the first eukaryotes, the first multicellular organisms, animal body plans, or vertebrate limbs, heads and brains. There seem to be more gaps in evolutionary theory now than there were before Kirschner and Gerhart got started.
Despite the dubious nature of their theoretical proposal, Kirschner and Gerhart imply that anyone who continues to be skeptical of Darwinian evolution is close-minded. In particular, people who think that intelligent design might provide a better explanation for some features of living things are dismissed as ignorant, religiously motivated, and covertly seeking ways to evade the law. Like many of their fellow Darwinists, Kirschner and Gerhart ultimately resort to personal insults.
Does the theory of facilitated variation make life plausible? Not at all, since it assumes the existence of life in the first place. Does the theory of facilitated variation rebut intelligent design? Not at all, since it assumes the existence of irreducibly complex core processes in the first place. The principal take-home lesson from The Plausibility of Life is that evolutionary theory still suffers from major weaknesses, but anyone who says so without reaffirming Darwinism and condemning [intelligent design] is a close-minded, ignorant, Bible-thumping subverter of the Constitution.
Where's the novelty in that?
The very title of the book is a rhetorical ploy to lead the reader away from the manifest fact that life itself is extraordinarily implausible. The chances that a living metabolizing, reproducing cell could have emerged from a primordial broth of its constituents purely by the action of blind, mechanical processes has been compared to the chances that a tornado sweeping through a junkyard would leave in its wake a fully assembled, fully functional jet airliner. And that was an estimate given by someone (Fred Hoyle) who was sympathetic to the evolutionary program.
Pace Kirschner and Gerhart life is not at all plausible. It is indeed prohibitively improbable unless the processes which led to it were somehow guided by an intelligent agent. More and more people are coming to this conclusion. It's only the Darwinian naturalists, holding out like isolated Japanese soldiers who continued to fight years after WWII was lost, who think otherwise.
Read the rest of Wells' review at the link.
