Wednesday, October 5, 2011



    Why Evolution Is True

    Jerry A. Coyne, Viking, 233 pages


    It is perhaps fitting that the 200th anniversary of the birth of Charles Darwin and the 150th anniversary of the publication of The Origin of Species should see the appearance of Why Evolution Is True by Professor Jerry A. Coyne of the University of Chicago. The work is a fine exposition of the theory of evolution, both clear and readable, and certain to make its mark in the ongoing debate. Prof. Coyne shows a familiarity with Creationist arguments (which he generally treats with contempt), and interacts with them throughout his own work.

    The book, however, does not really change the nature of the debate. Prof. Coyne mainly rehashes the familiar arguments for evolution, most of them drawn from Darwin himself, whom Prof. Coyne quotes frequently and appreciatively.

    Prof. Coyne insists that evolution is a "scientific fact." What is a bit confusing to us laymen is that scientists have their own criteria for establishing a "scientific fact." According to Prof. Coyne, a scientific theory is not necessarily something debatable. A theory is a set of propositions that explain a phenomenon. If the theory seems to explain adequately the evidence, and it is confirmed by subsequent discoveries, then it is considered a "fact." A scientist like Prof. Coyne knows this as the inductive method, unbiased, objective, and incontrovertible. A lawyer like Phillip E. Johnson recognizes it as an attempt to build a case on circumstantial evidence, an argument marked by circular reasoning and logical non sequiturs. There are two major weaknesses in this kind of argument. First of all, what if the evidence does not fit perfectly, if there is something that the theory cannot explain? And secondly, What if we cannot establish a direct causal link, the proverbial "smoking gun"? In this case the question is whether or not it is even possible for evolution to take place at all.

    On the first question, let us take for example the fossil record. Prof. Coyne recites the familiar argument we have all heard before. But does the evidence really support the theory? Prof. Coyne posits a very slow process of gradual change. But that would seem to call for a vast continuum of transitional forms. What we actually see in the fossil record on the other hand is what we see today: distinct species or "discontinuities of nature," as Prof. Coyne call them. He is honest enough to make this intriguing statement: "When you look at animals and plants, each individual almost always falls into one of many discrete groups" (p. 169). That is the indisputable fact. But which theory does it support, evolution or creation? We think the latter.

    On the second question, the question of causality, it is ironic that Prof. Coyne's most original contribution to the debate, his background in genetics, serves to undermine his own argument. In the second half of the book he discusses at great length how mutations enable species to adapt to their environments, sometimes even developing new features. But all of the examples he cites involve taking existing genetic material and modifying it or recombining it in some way to generate new characteristics in the species. Once it is apparent how this "microevolution" takes place, it becomes obvious why "macroevolution" cannot take place. Macroevolution, as Prof. Coyne conceives of it, would require passing over the genetic barriers that separate one species from another. Moreover, it would involve progressing from simple forms of life to more complex. As Prof. Coyne puts it, evolution is "the amazing derivation of life's staggering diversity from a single naked replicating molecule" (p. 233). Amazing indeed it is! It is impossible! This would seemingly require adding new genetic material where it did not previously exist. A mutation modifies an existing gene; it does not create a new one. Since each species has a set number of chromosomes, and the chromosomes come in pairs, in most cases the evolution from one species to another would require adding whole pairs of chromosomes. What Prof. Coyne has not explained is where the extra chromosomes would come from. Thus, while microevolution is quite explicable, macroevolution seems genetically impossible. The "murder weapon" in the case remains to be found.     

Thus, in spite of Prof. Coyne's fine effort to produce a very readable and informative book, we are pretty much where we began: Darwinism is still vulnerable to most of the same criticisms that were leveled against it in Darwin's own day. In fact, in some ways, Prof. Coyne's explanation of the genetics involved makes the Theory of Evolution even less convincing. But the book is a useful primer for anyone interested in the controversy.

                        Robert W. Wheeler


  1. Here you are, an admitted layman in evolutionary biology, explaining to us with simplistic and misleading arguments why a full professor in ecology and evolutionary biology at the prestigious University of Chicago specializing in population and evolutionary genetics (which includes speciation, ecological and quantitative genetics, and chromosome evolution) is wrong in his assessment of why evolution is true.

    And this doesn't raise any red flags to you that maybe, just maybe, you are not in full possession of pertinent information? If I were in your position, and once upon a time I was, I'd be asking myself, "What does Jerry understand that I don't?" And then I'd begin to learn about reality rather than retreat into faith.

    The fact of this matter is that conflicting claims between science and religion when it comes to our origins is that only a minority of Americans—16%—accept that humans evolved via a purely naturalistic process (the current scientific consensus), 38% agree with a theistic evolution of humans guided by God, and 40% of Americans think that humans were directly created by God in their present form within the last 10,000 years or so. These percentages reveal the power of the common religious truth claim that we are the products of a creator. This power is not based on knowledge or honest scientific inquiry but religious belief alone. What your post represents is very typical, and inaccurate in typical fashion, that the religious viewpoint is backed by nothing but the faith-based belief that the science must be wrong.

    But it's not...

  2. How do we know the science isn't wrong? Well, because our medical technologies keep working and predictions based on it keep panning out. Over and over. Every time. All the time.

    Sometimes it's easy to forget that it doesn't have to be this way. But it is. And this is the point that creationists do forget: that evolutionary theory works and informs knowledge on which we base medicines and treatments and technologies - to use but one common field as an example - that can and does save lives and improves the quality of life for millions. This is not a trivial point nor can it be explained by the idea of a creator. As Coyne so succinctly writes:

    Every day, hundreds of observations and experiments pour into the hopper of the scientific literature… and every fact that has something to do with evolution confirms its truth. Every fossil that we find, every DNA molecule that we sequence, every organ system that we dissect supports the idea that species evolved from common ancestors. Despite innumerable possible explanations that could prove evolution untrue, we don’t have a single one. We don’t find mammals in Precambrian rocks, humans in the same layers as dinosaurs, or any other fossils out of evolutionary order. DNA sequencing supports the evolutionary relationships of species originally deduced from the fossil record. And, as natural selection predicts, we find no species with adaptations that benefit only a different species. We do find dead genes and vestigial organs, incomprehensible under the idea of special creation. Despite a million chances to be wrong, evolution always comes up right. That is as close as we can get to a scientific fact.

    Having worked with ice core samples, I can tell you that the genetic composition of various pollens trapped in deep ice aligns exactly with independent verification from modern day plant varieties that contain identical sequences although of an entirely different species. Creationism makes no sense of this, whereas evolutionary theory successfully predicts it.

    If you wish to dismiss evolutionary theory on only cherry picked data you believe reveals problems with it, you then have to account for the mountains of independent lines of inquiry that provides very strong evidence that directly supports it. This is where creationism through its store front of ID utterly fails; it cannot offer any reasonable and equivalent explanation other than 'godidit'. And that's not science. It's faith incompatible with honest inquiry.

  3. "What Prof. Coyne has not explained is where the extra chromosomes would come from"

    In fact he devotes several pages to precisely this question, and gives mechanisms for it to happen (pp175-178 in my copy).

  4. In my copy of the book (the 2009 Viking hardcover edition) what he discusses on pp. 175-178 is speciation through geographical isolation. However he does mention duplication on p.139, in the middle of a section entitles "Can Selection Build Complexity?"

  5. The difference between the fact of evolution and the theory of evolution is not that the theory of evolution is so proven that they call it fact. The difference is between _whether_ evolution occurred (fact) and _how_ it occurred (theory).

    I haven't read Coyne's book, but if he really explained that evolution is a fact because the theory is so well proven, then he's wrong. You won't find good scientists saying that. They differentiate the way I explained in my first paragraph.

    The "fact" that evolution occurred can be called a fact in the same way that the geologic column can be called a fact. The geologic column is not a theory. It's something that can be seen and cataloged. In the same way, the progress from microbes to complex bacteria to multicellular animals to shell-based animals to bony fishes to amphibians to reptiles to mammals can be seen and cataloged in the geologic column.

    How fossils came to be arranged that way is where theory comes in, and it is the place where scientists argue with one another.

  6. Coyne certainly regards himself as a "good scientist," but his book is written for us laymen. He cites the Oxford English Dictionary's definition of a "scientific theory": "a statement of what are held to be the general laws, principles, or causes of something known or observed." Coyne goes on to say that a scientific theory is "a well-thought out group of propositions meant to explain facts about the real world."
    Where I think he runs into trouble is when he says that a scientific theory "must be testable and make verifiable predictions." But how is the theory of evolution "testable"? He argues that if subsequent discoveries also conform to the theory, then "it gives us more confidence that the theory is true." He then makes this statement:"Because a theory is accepted as 'true' only when its assertions and predictions are tested over and over again, and confirmed repeatedly, there is no one moment when a scientific theory suddenly becomes a scientific fact. A theory becomes a fact (or a 'truth') when so much evidence has accumulated in its favor -- and there is no decisive evidence against it -- that virtually all reasonable people will accept it."
    Coyne then concludes his first chapter by saying "As we'll see, all the evidence -- both old and new -- leads ineluctably to the conclusion that evolution is true." He then spends the rest of his book trying to prove his point.