When I first saw that the new book by Steve Meyer, Darwin’s Doubt, centered on the Cambrian Explosion, I was loathe to read it. I had been led to believe over the years that everything that could be said about the Cambrian Explosion has already been said. I was quite happy to believe that the only real discontinuities in the story of life occurred at the origin of life and at the origin of human consciousness.
I should have known better; science marches onward, and old arguments get reexamined as new data arises. Steve Meyer’s book is a wonderful, comprehensive case that the origin of the major types of animals, namely the phyla, is just as strikingly discontinuous as the the origin of life. As such, it represents a solid second volume complementary to his previous work, Signature in the Cell, which focused on the origin of life.
I had come to think that discussing the Cambrian Explosion was misguided because of two arguments: 1) that the explosion was merely an artifact of the fact that organisms before that time did not have hard bones or shells, and 2) that the explosion was short on the geological time scale, but was really quite long on the biological time scale. Meyer disposes of both of these arguments quite handily. On the first, modern science shows that soft-bodied organisms are well preserved in the strata before, during, and after the Cambrian. Also, many of the body types which appear in the Cambrian can’t even be imagined without their hard parts to give them structure. An earlier, boneless version could not have had the same body plan at all. On the second objection, Meyer shows that the geological time scale has gotten more compressed over the years, not less; best estimates now are 5-10 million years, which is quite short geologically. Meyer then spends a good number of chapters establishing what the natural time scale is for evolution.
From a physicist’s perspective, I am used to thinking of time as a relative thing (for electrons in solids, a few trillionths of a second can be a long time, while for stars in clusters, a few million years can be a short time.) What makes something a short time or a long time is the natural time scale of the system– much less than the natural time scale is short, and much longer than the natural time scale is long. A fairly convincing case has been made in the literature of molecular clocks that the natural time scale for evolution of the degree seen in the Cambrian is a billion years, not 5 million years. Even that billion-year time scale may be an underestimate, if one looks at the microscopic details of protein folding. Thus the intrinsic biological time scale is not less than the geological time scale, and the Cambrian Explosion does indeed occur in a fantastically short time. Meyer cites many evolutionists who acknowledge this problem; the Cambrian problem has not gone away for those who are really in the know, no matter what popularizers may say.
This is a solid scientific review, not a polemic diatribe. It also comes at a good time. Like Signature in the Cell, it comes after 10-20 years of debate on intelligent design. Thus Meyer can summarize the back and forth of the debate in a nice story-like approach. The story is not one of gaps in our knowledge constantly being filled, but the paradox of the Cambrian becoming sharper and sharper. Again, when evolutionists talk to each other instead of to the public, they are remarkably candid about this, and Meyer well documents this with many quotes.
After posing the problem, Meyer discusses some of the non-orthodox, semi-Darwinian proposals floated in the last few decades, such as Gould’s punctuated equilibrium and epigenetic neo-Lamarkianism. All of these are built on a surprising amount of hand-waving, invoking new terms but brushing over the actual physical mechanisms. One section I was quite happy about was the section on “self-organization”, promoted by Kaufmann, Prigogene, and others. This area has had a strong following in the physics world for three decades, but I have always thought it was sterile, for the reasons that Meyer cites. Essentially, getting “order” from natural self-organizing process and getting “information” are two totally different things. “Order” is easy– all you need is a natural length scale to arise in a system and “spontaneous symmetry breaking” will lead to orderly patterns on this length scale. This is true of atomic crystals at low temperature and rows of clouds in the sky. But the very nature of information, whether in DNA or human writing, precludes natural forces from generating it. DNA can hold information precisely because there is no natural force demanding the nucleic acids be in one location or another. All information requires this type of “contingency”, that is, openness to many possible choices; a system which is driven to one required state holds no information. (Something I was not aware of before reading this book: there is another, equally information-rich, code in biological systems, known as the “sugar code”, which is written on the outside of cells to govern their interactions. Like the DNA code, there is no force driving the locations to hold one piece of information instead of another.)
And this is also the problem with identifying where the information came from. Many anti-ID critics demand that ID proponents identify the physical process by which the information came into being. But by its very nature, information is fungible–it can be exchanged into many different forms. Any system with many physical possibilities and no force driving the system to any of them can hold the same information. Thus the demands of the anti-ID critics are like a person who would demand that you deduce from reading a novel whether it was first written with pen and ink, or with a typewriter, or with a modern computer processor. While one can easily identify information when one has it, the very fact that information can remain the same while being embodied in any number of different media, makes it impossible to deduce a physical cause for it.
A few small things that I would have liked to see Meyer address: 1) in his discussion of the molecular clock data, he points out the variation in the numbers over a wide range, but doesn’t discuss at all the scientific concept of “uncertainty”. Having different numbers for the same measurement vary by a factor of ten or more does not mean the numbers are meaningless, unless the claimed uncertainty is much less than the scatter. 2) He mentions that the molecular clock data don’t work at all for histones, but doesn’t mention that the reason histones are highly conserved is because they are an integral part of the reproduction system– one change there and you die. A proper molecular clock calibration would be a “weighted average” in which each gene is weighted by the likelihood that a change will kill the organism. Apparently this has not been done in the literature yet in any quantitative way.
One of the fascinating side stories, which I have heard in ID circles for years but have not before seen documented as Meyer does, is the problem of making consistent genetic trees. I have often heard evolutionists, such as Francis Collins, make the argument for universal common descent by showing two genes in different species that have remarkable similarity but key differences, such as a fusion of two genes or a viral insertion. The argument basically goes: species 1 has the pattern A-B-C-D-E-F, while species 2 has the pattern A-B-C-X-D-E-F. What is the likelihood that these would be so similar in two unrelated species? Is this not clearly an insertion of X going from 1 to 2, or a deletion of X going from 2 to 1? Sounds good as far as it goes, but the problem comes when you try to do it for many more than two species. Let’s write this relationship as 1> 2. Suppose now that you look at four organisms, and find the relationships 1>2, 2>3, 3>4, and 4>1 in four separate genes. Can you make a consistent tree from that? What if I further tell you that 1 is a plant, 2 is an insect, 3 is an animal, and 4 is a worm? Now, this is a fictional example, but are you willing to bet the farm that no such relationship can exist in nature? It turns out that relationships like this are all over the place. To explain it, some evolutionists invoke “convergent genetic evolution”, which means that that same gene (same sequence of DNA) arose two times, independently. I could sort of buy convergent structural evolution (e.g. placental wolves and marsupial wolves that look nearly identical but have very different DNA), but convergent gene sequences? It defies the imagination. I once met a German scientist who told me he lost his faith in Darwinism after realizing he could not make self-consistent genetic trees (but he is not willing to come out of the closet out of fear for his career). In general, although I don’t think there are a lot of theological stakes in the question of universal common descent, I am surprised at how weak the case for it is.
Meyer ends with general thoughts on ID, similar to his arguments at the end of Signature in the Cell. His experience, like mine, is that some people literally can’t “see” God as an explanation, because they have defined God-explanations as non-explanations. Meyer doesn’t go into detail about the jump from knowing what human intelligence can do, to invoking non-human (presumably divine) intelligence as a similar causal agent, but the case can be easily made. I addressed this in an essay in PSCF.
Overall I don’t expect this to change the views of diehard atheist evolutionists, but I would hope that my theistic evolutionist friends will give this book a close reading. A caution: this is a tome that took me two weeks to go through in evening reading, and I am familiar with the field. Like the classic tome Goedel, Escher, Bach, it simply can’t be gone through quickly. I was struck that the week it was released, within one day of shipping, there were already hostile reviews up on Amazon. Simply impossible that they could have read this book in one night.