Editor’s Note: We’ve had a lot of inquiries about Donald Prothero’s review of Darwin’s Doubt. We thought it was important to repost this excellent response by Casey Luskin, which serves as a decisive rebuttal to Dr. Prothero’s claims.
Since Nick Matzke at Panda’s Thumb published a review of Darwin’s Doubt that badly failed to preemptively knock down Stephen Meyer’s thesis (see here, here, here, and here), the Internet’s Darwin brigade has been hoping for something better. So the folks at Panda’s Thumb along with Larry Moran and Jerry Coyne are all excited that geologist Donald Prothero has now posted an Amazon review of Darwin’s Doubt. Their readers have eagerly voted up Prothero’s post, artfully titled “Stephen Meyer’s Fumbling Bumbling Cambrian Amateur Follies,” as the “most helpful critical review.”
According to Dr. Prothero, Darwin’s Doubt is a mess of “fumbling,” “bumbling,” “distortions,” and “blunders.” The book is an “amateur” exercise, evidence of Meyer’s “folly.” It “butchers” the subject matter; was written by a “fool” who is “incompetent,” guilty of “ignorance,” is in “way over his head” and has a “completely false understanding of the subject.” In case that’s all a little too subtle for you, Prothero says Meyer argues “dishonestly” and promotes a “flat out lie,” a “fundamental lie,” and other “lies” to promote a “fairy tale.”
Well, what justifies all the ad hominem invectives? Prothero’s first complaint is that Meyer’s Ph.D. is in the history and philosophy of science which, according to Prothero “give[s] him absolutely no background to talk about molecular evolution.” Yes that’s a lame objection (it’s called the genetic fallacy). Indeed, Meyer’s undergraduate degree is in geology and physics, and he worked as a geophysicist for four years, giving him formal training on geology-related issues — the primary issues Prothero raises in his review. Prothero, however, has already undercut his own complaint, as he admitted:
[Y]ou don’t need a Ph.D. to do good science, and not all people who have Ph.D.s are good scientists either. As those of us who have gone through the ordeal know, a Ph.D. only proves that you can survive a grueling test of endurance in doing research and writing a dissertation on a very narrow topic. It doesn’t prove that you are smarter than anyone else or more qualified to render an opinion than anyone else. (Evolution: What the Fossils Say and Why It Matters, p. 16)
Prothero’s review later complains that creationists “love to flaunt their Ph.D.’s on their book covers.” I guess that means Meyer isn’t a “creationist,” since Prothero failed to notice that Meyer doesn’t mention his Ph.D. on the cover of Darwin’s Doubt. (And isn’t it a bit ironic that Prothero touts his own Ph.D. in his bio over at Skepticblog?)
In any case, Prothero’s second complaint is that “Almost every page of this book is riddled by errors of fact or interpretation that could only result from someone writing in a subject way over his head, abetted by the creationist tendency to pluck facts out of context and get their meaning completely backwards.” Of course Prothero doesn’t list examples from “almost every page,” but at least this time he tries to give one. He claims “we now know that the ‘explosion’ now takes place over an 80 m.y. time framework.” Perhaps Prothero didn’t notice that Meyer specifically discusses Prothero’s own view on this in Darwin’s Doubt, and refutes it (see Chapter 3). I refuted the same argument in my recent response to Nick Matzke, which cited numerous articles from the mainstream technical literature stating that the Cambrian explosion took no more than 10 million years.
Prothero’s review goes on.
- He states that Meyer “dismisses the Ediacara fauna as not clearly related to living phyla,” even though that’s in fact the consensus view (see pp. 81-86, and accompanying endnotes).
- He charges that Meyer “confuses crown-groups with stem-groups” (giving no examples), when in fact Meyer explains this distinction (see pp. 419-420).
- He wrongly charges that ID is a “god of the gaps” argument, one that invokes the “supernatural,” when of course ID does no such thing, and Meyer rebuts this charge decisively in chapters 17 and 19 of Signature in the Cell.
- He bizarrely misrepresents Meyer as saying Niles Eldredge and Stephen Jay Gould “are arguing that evolution doesn’t occur” when Meyer said absolutely nothing of the kind.
Thus, a pattern in Prothero’s review is that he puts words in Meyer’s mouth, while failing to engage Meyer’s actual arguments. As another example, Prothero writes:
Meyer deliberately and dishonestly distorts the story by implying that these soft-bodied animals appeared all at once, when he knows that this is an artifact of preservation. It’s just an accident that there are no extraordinary soft-bodied faunas preserved before Chengjiang, so we simply have no fossils demonstrating their true first appearance, which occurred much earlier based on molecular evidence.
Of course Meyer never says the Cambrian animals appeared “all at once.” And did Prothero miss Chapter 5 of Darwin’s Doubt, where Meyer discusses in great detail the “molecular evidence” mentioned by Prothero, meticulously critiques the molecular clock hypothesis, and clarifies why it doesn’t account for the absence of evolutionary precursors in the Precambrian? Or what about Chapters 2 and 3, where Meyer explores the artifact hypothesis in much detail, and makes clear why many Cambrian experts feel it doesn’t explain away the Cambrian explosion? As Meyer observes, the Cambrian fossil record is full of soft-bodied organisms, making it difficult to argue that the lack of fossils from a particular group simply means they were too “soft-bodied” to have been preserved (see pp. 62-64). So it’s not as if Meyer doesn’t engage and discuss these objections in great detail; indeed Meyer cites many authorities to show why these objections don’t resolve the Cambrian explosion. Prothero complains a lot, but neither engages with nor mentions any of these discussions.
Prothero asserts that the “rates of evolution during the ‘Cambrian explosion’ are typical of any adaptive radiation in life’s history.” Again, did he not read Section II of Darwin’s Doubt where Meyer argues that even if there were tens of millions of years available to evolve the Cambrian animals (as Prothero asserts), unguided evolutionary mechanisms still don’t work fast enough to produce many of their complex features?
Prothero gives no indication that he has appreciated this section. Indeed his only specific objection is that Meyer supposedly “repeats many of the other classic creationist myths, all long debunked, including the post hoc argument from probability (you can’t make the argument that something is unlikely after the fact).” This is a bizarre claim. Does Prothero not realize that many arguments for common ancestry are after-the-fact and probability-based — e.g., two similar gene sequences are unlikely to have arisen independently, and are thus said to have derived from a common ancestor?
My favorite part of Prothero’s review comes when he says, “For a good account by real paleontologists who know what they’re doing, see the excellent recent book by Valentine and Erwin, 2013, which gives an accurate view of the ‘Cambrian diversification’.” Excellent indeed! Prothero is referring to Douglas Erwin and James Valentine’s 2013 book, The Cambrian Explosion. Let’s look once again at what Erwin and Valentine have to say.
Regarding the length of the Cambrian explosion, they write:
[A] great variety and abundance of animal fossils appear in deposits dating from a geologically brief interval between about 530 to 520 Ma, early in the Cambrian period. During this time, nearly all the major living animal groups (phyla) that have skeletons first appeared as fossils (at least one appeared earlier). Surprisingly, a number of those localities have yielded fossils that preserve details of complex organs at the tissue level, such as eyes, guts, and appendages. In addition, several groups that were entirely soft-bodied and thus could be preserved only under unusual circumstances also first appear in those faunas. Because many of those fossils represent complex groups such as vertebrates (the subgroup of the phylum Chordata to which humans belong) and arthropods, it seems likely that all or nearly all the major phylum-level groups of living animals, including many small soft-bodied groups that we do not actually find as fossils, had appeared by the end of the early Cambrian. This geologically abrupt and spectacular record of early animal life is called the Cambrian explosion. (The Cambrian Explosion, p. 5, emphases added)
So it seems that unlike Prothero, Erwin and Valentine don’t believe “the Cambrian explosion” took 80 million years, but rather that it took place during “a geologically brief interval between about 530 to 520 Ma.”
Regarding the reality of the Cambrian explosion, Erwin and Valentine write:
Taken at face value, the geologically abrupt appearance of Cambrian faunas with exceptional preservation suggested the possibility that they represented a singular burst of evolution, but the processes and mechanisms were elusive. Although there is truth to some of the objections, they have not diminished the magnitude or importance of the explosion. … Several lines of evidence are consistent with the reality of the Cambrian explosion. (The Cambrian Explosion, p. 6, emphases added)
So it seems, contra Prothero, that Valentine and Erwin don’t believe the Cambrian explosion is merely an “artifact of preservation.”
Regarding rates of evolution during the Cambrian explosion, Erwin and Valentine write:
As geologists, we view this tension as a debate over the extent to which uniformitarian explanations can be applied to understand the Cambrian explosion. Uniformitarianism is often described as the concept, most forcefully advocated by Charles Lyell in his Principles of Geology, that “the present is the key to the past” (Lyell 1830). Lyell argued that study of geological processes operating today provides the most scientific approach to understanding past geological events. Uniformitarianism has two components. Methodological uniformitarianism is simply the uncontroversial assumption that scientific laws are invariant through time and space. This concept is so fundamental to all sciences that it generally goes unremarked. Lyell, though, also made a further claim about substantive uniformitarianism: that the rates and processes of geological change have been invariant through time (Gould 1965). Few of Lyell’s contemporaries agreed with him (Rudwick 2008). Today, geologists recognize that the rates of geological processes have varied considerably through the history of Earth and that many processes have operated in the past that may not be readily studied today.
…One important concern has been whether the microevolutionary patterns commonly studied in modern organisms by evolutionary biologists are sufficient to understand and explain the events of the Cambrian or whether evolutionary theory needs to be expanded to include a more diverse set of macroevolutionary processes. We strongly hold to the latter position. (The Cambrian Explosion, p. 10, emphases added)
In other words, Erwin and Valentine are skeptical that “uniformitarian explanations can be applied to understand the Cambrian explosion.” Why? One reason could be because evolutionary mechanisms we observe in the present day operate at rates that are too slow to explain what took place in the Cambrian period. They are careful not to put it in such plain terms, but that is the essence of their argument. But they do acknowledge that there was an “unusual period of evolutionary activity during the early and middle Cambrian” (p. 6) and later expressly state:
Because the Cambrian explosion involved a significant number of separate lineages, achieving remarkable morphological breadth over millions of years, the Cambrian explosion can be considered an adaptive radiation only by stretching the term beyond all recognition. … the scale of morphological divergence is wholly incommensurate with that seen in other adaptive radiations. (The Cambrian Explosion, p. 341, emphasis added)
In other words, unlike Prothero, Erwin and Valentine think the Cambrian explosion was a real event, took far less than 80 million years, and involved unique mechanisms that acted more rapidly and at a greater scale than other radiations. These directly contradict Prothero’s core claims, but there’s more.
Probably the most striking statement by Erwin and Valentine comes when they concede that we lack resolved evolutionary explanations for how the diversity of the Cambrian animals arose, and why these basic body plans haven’t changed since that time:
The patterns of disparity observed during the Cambrian pose two unresolved questions. First, what evolutionary process produced the gaps between the morphologies of major clades? Second, why have the morphological boundaries of these body plans remained relatively stable over the past half a billion years? (The Cambrian Explosion, p. 330, emphasis added)
Thus, when recently reviewing Erwin and Valentine’s book, the journal Science stated: “The grand puzzle of the Cambrian explosion surely must rank as one of the most important outstanding mysteries in evolutionary biology.” Likewise, a 2009 paper in BioEssays stated, “elucidating the materialistic basis of the Cambrian explosion has become more elusive, not less, the more we know about the event itself.”
That pretty much nixes Prothero’s confident, unbacked assertion that “scientists have explained most of the events of the Early Cambrian and find nothing out of the ordinary that defies scientific explanation.”
What more is there to say? I wonder who in the community of Darwin-defenders will have a go at Darwin’s Doubt next. The best of luck to them.