Part of a continuing series
A few days ago I posted a short comment on creationist Steven C. Meyer’s book Darwin’s Doubt, which came out in 2013. Previously (2009) I reviewed his Signature in the Cell. This series of posts is going to be a continuation of my comments on the more recent book.
The first 56% comprises the main book, what the book is about. The remainder is Meyer’s response to critiques of the initial edition followed by acknowledgements, references to cited sources, and such. My immediate concern will be with the main text.
Reading through the first 250+ pages I came to realize I have insufficient knowledge of biology and paleontology to appreciate Meyer’s arguments, so for the most part my critique is going to reflect the findings of experts. Certain comments and claims made by Meyer fall within my range of knowledge, and I will offer a personal response to those.
Here’s an overview: Meyer’s previous book deals with supposed outside intelligence and its influence on biological evolution and biogenesis. Darwin’s Doubt is about the Cambrian explosion and how Darwinian evolution (natural causes) cannot account for it.
Nick Matzke posted a lengthy (9000+ words) critique of the book the day after it was offered for sale. Meyer wonders at this prodigious feat, and I would as well. Except, skeptic that I am, I suspect Matzke obtained an early copy, although this is never openly discussed. Here is an excerpt from Meyer’s response:
According to Matzke, cladistic analysis has established the existence of “transitional” and “intermediate” forms between the animals that first arose in the Cambrian. In his view, cladistics has solved the problem of the missing ancestral fossils discussed in Part 1 (Chapters 1– 7) of the book. As he asserts, “phylogenetic methods can establish, and have established, the existence of Cambrian intermediate forms, which are collateral ancestors of various prominent living phyla.” Matzke argues that my failure to inform readers of this disqualifies the book from serious consideration as an analysis of the Cambrian explosion.
Of course, in making this argument, Matzke scarcely addresses the central argument of the book: the problem of the origin of biological information.
Meyer, Stephen C. (2013-06-18). Darwin’s Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design (Kindle Locations 7631-7638). HarperCollins. Kindle Edition.
This I find to be so very quaint. The problem of the origin of biological information was supposed to have been the subject of Signature in the Cell. Matzke aside, my reading of Darwin’s Doubt gave me the impression the book was supposed to be an analysis of the Cambrian explosion.
I will start by analyzing the dispute outlined above. Meyer says that Matzke asserts “phylogenetic methods can establish, and have established, the existence of Cambrian intermediate forms, which are collateral ancestors of various prominent living phyla.” This actual quote appears in a subsequent post by Matzke titled “Luskin’s Hopeless Monster,” and is the one cited in the book. I find this in Matzke’s original post, and I have highlighted the relevant text:
Yet another confusion that Meyer exhibits relates to the idea of “ancestor”. As with all creationists, Meyer exhibits no understanding of the fact that phylogenetic methods as they exist now can only rigorously detect sister-group relationships, not direct ancestry, and, crucially, that this is neither a significant flaw, nor any sort of challenge to common ancestry, nor any sort of evidence against evolution. Distinguishing between a close sister-group relationship and an exact ancestor is just a level of precision that we cannot expect in most cases. It’s just a by-product of the method and the data available. (This is not quite the end of the discussion on this topic – eventually, we will have Bayesian methods that will assign probabilities to hypotheses of direct ancestry, although this will require formal definition and then data-informed estimation of what “ancestral lineage” means in terms of morphological variability within a lineage, the biogeographic and stratigraphic range of “morphospecies” through times, etc. End nerdy sidetrack.) But phylogenetic methods can and do regularly and rigorously identify collateral ancestry – sister group relationships, and ancestral grades and clades. We can say that birds descend from dinosaurs with essentially 100% statistical confidence, without knowing which if any currently-described fossils are exact direct ancestors rather than closely-related sister groups.
For all of the above reasons, almost every page of Meyer’s discussion of Cambrian organisms contains howlers of the first order. For example, in chapter 2:
First, the great profusion of completely novel forms of life in the Burgess assemblage (feature 3) demanded that even more transitional forms than had previously been thought missing. Each new and exotic Cambrian creature – the anomalocarids (see Fig. 2.10), Marrella, Opabinia, and the bizarre and appropriately named Hallucigenia– for which there were again no obvious ancestral forms in the lower strata, required its own series of transitional ancestors. But where were they?
Meyer’s response to Matzke is notably weak. He does not attempt to refute any of the critique, but only complains that Matzke is missing the point of the book. One has to wonder, if this topic does not contribute to the point of the book, when why is Meyer discussing it? Meyer’s only defense seems to be an attempt to deflect attention away from this and other noted flaws.
At this point I need to illustrate what is meant by phylogenetic methods. Here is a simple diagram:
Such a diagram can be constructed by a number of ways, but all methods employ extant organisms. Comparing similar body features (homology) one can determine the order of branching illustrated above. At one point in the past the line of descent of sharks branched from that of other fishes, never to merge again. Ultimately mammals, including us, derived from the right-hand branch and not from the shark branch.
Homology is a coarse-handed way to compare organisms. A finer-grained way is to use protein sequencing and even DNA sequencing. This is because similar forms can disguise true ancestry, which ancestry is more accurately revealed by comparing molecules.
Matzke continues his argument:
Again, it is only by refusing to depict and specifically discuss of the inter-relationships of these sorts of taxa, and the data that supports them, and to mention the statistical support for the resulting relationships, that Meyer manages to pretend to his readers that these questions are not even partially answered, are unanswerable, and that “poof, God did it” is a better explanation. Here’s the cladogram from Legg et al. (2012) again:
Matzke drives home his point with some force:
What goes into diagrams like this? They represent summaries of the morphological character data, which in this case you can see right here. Many readers, and virtually all creationists/IDists, will have little idea of the scale of effort that goes into constructing a dataset like this. These researchers, and the previous researchers that they are building upon, identified 580 individual, variable characters, each of which has to be identified, defined, divided up into discrete character states, and encoded. This laborious process had to be repeated for (in this case) 173 fossil taxa (correction – some are living, e.g. Drosophila). A lot of fossils are missing a lot of characters – typical and expected in paleontological analyses – but it is still a lot of work. After this, one runs a cladistic or other phylogenetic analysis (whole textbooks and courses are devoted just to this step of the process, and articles devoted to testing the reliability of phylogenetic methods, and improving the methods, are continually being published) and calculates support statistics. The support statistics are important since they tell you whether or not your data have any phylogenetic tree structure. Usually this doesn’t get major emphasis in scientific publications, because almost any biological dataset typically has extremely statistically significant tree signal, and this is true whether or not it agrees precisely with other analyses, and whether or not all relationships of interest to the researcher are precisely resolved with high support.
To anyone familiar with this work, it is simply laughable and pretty much insulting to see Stephen Meyer proclaim throughout his book that fossils with transitional morphology don’t exist, that the Cambrian body plans look like they originated all-at-once in one big sudden step. These statements don’t respect scientific process, they don’t respect the peer reviewed literature, they don’t respect the intelligence and knowledge of people who actually do know what they are talking about, they don’t respect the hard work of all the scientists that went out in the field and found these fossils, and then spent countless hours preparing them, describing them, inspecting them in microscopic detail, coding them in a morphology database, and analyzing them, all with care and effort and detail never taken by any creationist/IDist writer in any effort of comparative biology. And most importantly, Meyer’s statements don’t respect the data. They don’t follow the evidence wherever it leads, mostly because Meyer is ignoring most of the evidence.
A lot of Meyer’s book has to do with disputing the lineage of Cambrian animal life. In future installments of this series I will mine additional instances and also comment on some of his absurd claims related to information and intelligence.