The Questionable Authority

Egnor and natural selection

Neurosurgeon and recent addition to the Discovery Institute’s Media Complaints Division blog Dr. Michael Egnor is at it again. He’s responded to Burt’s latest response to his prior response to Burt’s earlier response to his - you get the drift. Burt’s been doing a great job of responding to Egnor, and I don’t want to step on his toes, but Egnor says a couple of things this time that I think would benefit from the perspective of someone who is studying evolutionary biology.

First, though, I’d like to address this delightful bit of less-than-honest rhetoric:

In addition, a common Darwinist argument is that the presence on medical school faculties of scientists who study some aspects of evolutionary biology is evidence that evolutionary biology is indispensable to medicine. That argument is flawed, but it does raise an important issue.

Actually, Dr. Egnor, if you look back through your exchange with Dr. Humburg, you will see that you were the one who brought up faculty composition at medical schools. If you’ll recall, you said this in your opening entry:

Doctors don’t study evolution. Doctors never study it in medical school, and they never use evolutionary biology in their practice. There are no courses in medical school on evolution. There are no ‘professors of evolution’ in medical schools. There are no departments of evolutionary biology in medical schools.

Let’s look at the sequence of events one more time:

1: Egnor argues that the lack of “professors of evolution” in medical schools is evidence that evolution is irrelevant to medicine.

2: Burt points out the fact that there are plenty of medical school professors who have research programs that focus on evolution.

3: Egnor claims that Burt was arguing that the presence of evolutionary biologists (aka “professors of evolution”) is evidence that evolution is relevant to medicine.

4: Egnor claims that the argument in point 3 is flawed.

Nice chain of argument there.

Now, on to evolutionary biology.

Egnor writes:

These fine scientists do not, however, contribute to medicine by studying or teaching evolutionary biology. They contribute to medicine by their work in anatomy, or physiology, or microbiology, or molecular biology. The central assertion of Darwinism–that all biological complexity arises by random heritable variation and natural selection–is of interest to evolutionary biologists (and to those of us who disagree with it), but the assertion that randomness is the raw material for all biological complexity plays no role in medical education or research. Darwin’s assertion of randomness is irrelevant not only to medicine, but to much of biological science. Darwinism is, in Phillip Skell’s apt phrase, a narrative gloss applied to biology and highly superfluous. Teaching medical students about the anatomy of the brain or the molecular structure of DNA is very important. Teaching students about Darwinian speculations about the random origins of the brain or of DNA adds nothing to students’ knowledge of medicine.

As someone who studies evolutionary biology, I have a lot of problems with Egnor’s description of it. To be blunt, it’s a strawman, pretty much from top to bottom.

Let’s start with Egnor’s description of the “central assertion of Darwinism.” Actually, before we get to the description, I have a problem with that phrase itself. The mechanism of evolution by natural selection is not an “assertion.” It is a theory. It is not a dogmatic truth that must be accepted. It is a hypothesis that has been tested, retested, and tested some more, and that has done quite well along the way.

Moving on to the description itself, Egnor claims that “Darwinism” “asserts:”

that all biological complexity arises by random heritable variation and natural selection

Egnor, like many other anti-evolutionists, seems to object more to the “random” nature of evolution than anything else. In this case, I find that to be more than a little funny, since the only difference between what Darwin actually argued and what Egnor thinks Darwin argued results from Egnor’s use of the word “random.”

The theory of evolution by natural selection simply states that species change as a result of the process of natural selection acting on heritable variations. For the purposes of natural selection, it doesn’t matter whether the variation is random or not. Given a set of heritable variations that result in different probabilities of successful reproduction, natural selection will act to increase the frequency of the variants that make reproduction more likely. If, tomorrow, I were to use genetic techniques to add a new gene to a wild population, natural selection would act on the gene I added in the same way that it acts on any other gene.

So, if “random” isn’t a necessary condition of natural selection, where does it come from?

In science, “randomness” is a null hypothesis. It is the default position that we take unless there is strong evidence that this is not the case. This is not unique to evolution. It’s the way almost all scientific hypotheses are tested these days. If you want to know if a finding is significant, you usually ask if the differences between the things you are looking at differ from what you would expect if random chance was the only factor involved.

In genetics, the null hypothesis is that mutations occur randomly. If there is enough evidence that mutations are taking place in a non-random fashion under certain circumstances, the null hypothesis will be rejected under those circumstances. There are different types of mutation. For most of those, the null has not been rejected. “Random mutation” is not an assertion of evolutionary biology. It is our best scientific understanding of how mutation takes place, it is an easily tested null hypothesis that has not been rejected.

If you don’t like the idea that mutations are random, your argument isn’t with Darwin. It’s with nature.

Moving on, Egnor talks about “Darwin’s assertion of randomness.” Here’s what Darwin actually had to say about why he treated variation as random (this quote comes from the beginning of chapter 5 of the 6th edition of Origin of Species):

I have hitherto sometimes spoken as if the variations – so common and multiform with organic beings under domestication, and in a lesser degree with those under nature – were due to chance. This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation.

Darwin, like modern scientists, did not assert that variation was random. He simply used it as a null hypothesis.

Now we get to the last, and most objectionable, part of Egnor’s mischaracterization of evolution:

Teaching students about Darwinian speculations about the random origins of the brain or of DNA adds nothing to students’ knowledge of medicine.

I know of absolutely no evolutionary biologist who would call the origin of the brain – or, for that matter, the eye, the stomach, the heart, the lungs, the gills, the fins, etc – “random.” Natural selection is a fundamentally non-random process. It does not preserve variants at random. It selects (hence the name) variants non-randomly, based on their effect on the organism’s ability to produce the next variation.

Anyone who thinks that natural selection is a random process clearly does not understand natural selection, and is definitely not qualified to discuss evolution.

Comments

  1. #1 Orac
    March 16, 2007

    Damn it. I said I was going to ignore Egnor for a while, having eviscerated him multiple times recently, but he just keeps posting spectacularly idiotic things that get my blogging fingers twitching on the keyboard of my computer….

  2. #2 John Pieret
    March 16, 2007

    Anyone who thinks that natural selection is a random process clearly does not understand natural selection, and is definitely not qualified to discuss evolution.

    While you’re right that Egnor doesn’t understand natural selection, and is unqualified to discuss evolution, I think his confusion may be at least partly related to a meaning of “random” different than what the rest of of think of.

    Creationists don’t mean “highly contingent” or “undetermined” when they complain about the “randomness” of evolution. I think they mean “unintentional.” To them, anything that is not directly intended by God must be random. And, of course, the null hypothesis to them is goddidit, so showing that Darwin held to a different idea of what “null” means wouldn’t help them to understand any better.

  3. #3 Reed A. Cartwright
    March 17, 2007

    I’ll add that when evolutionary biologists talk able random mutations, they are saying that mutations occur randomly with respect to the needs of an organism.

  4. #4 Torbjörn Larsson
    March 17, 2007

    I salute your tenacity in going after ID’s displays of egnorance. It was notable early on how alike Egnor is to Salvador Cordova in smarminess and underlying abysmal ignorance combined with truly inept argumentation. That he made the metaphorical equivalent of establishing a ring species and ended up claiming his own argumentation was flawed is consequential.

    But hilariously funny, thanks for pointing it out.

    This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation.

    It seems funny to discuss Darwin on a thread discussing evolution, since creationists thinks he constructed a dogma. Never the less, today it feels appropriate, and they shouldn’t control the agenda.

    So, I’m a layman and haven’t read Darwin. But the more I see of his work, the more the brilliance of the man shines through. People note Newton and Einstein for their efforts that seems so revolutionary. This is of course not quite so, and I have very little idea of the background of the amount of failed evolutionary ideas surrounding Darwin. But it seems he had a genuine understanding of nearly all aspects of his work, quite like the aforementioned had.

    Of course there are mistakes, mostly by ignorance. Einstein for example included his cosmological constant in models to get a steady-state universe where we today think it may imply an acceleration of the expansion. The nature of science is that it doesn’t promote the mistakes. (Even if that has started to change as people realize that publishing the mistakes and duds is quite useful.) But considering the considerate nature of quotes as above, I wager there weren’t many in Darwin’s work.

    In short, the dude knew where the good grass where to be found.

  5. #5 Torbjörn Larsson
    March 17, 2007

    it may imply an acceleration of the expansion

    Considering Darwin as a good example, here it is more apt to say that it may predict the observed acceleration of the expansion.

  6. #6 Anthony Rasmussen
    March 17, 2007

    To them, anything that is not directly intended by God must be random.

    My strategy when dealing with faithheads is to refer to natural selection as “natural breeding”. The idea of ‘breeding’ is easily understood, and they can more easily connect the dots to survival and reproduction in an environment. Nature selects what works best for breeding.

  7. #7 QrazyQat
    March 17, 2007

    So, I’m a layman and haven’t read Darwin.

    I would encourage everyone to read Darwin’s actual works, or at least “Origin” and “Descent”. First, you see what a fantastic, very thorough scientist he was, and then you see that he was even better at explaining the science. He is, or should be, an inspiration and someone to emulate in science writing. He makes what he’s saying so simple and clear, yet accurate (not as easy as it sounds). Plus you can download all his work for free from several sources, or if you prefer paper, you can buy his main books super cheap either new or in almost any used book store.

  8. #8 Mike Kinsella
    March 18, 2007

    Yes to “Origin” and “Descent”, but the most fun to read is the heroic voyage of the young man: “Voyage of the Beagle” is a must-read. (Please forgive my first-ever delurk)

  9. #9 Dennis
    March 18, 2007

    Glad to to talk with you I am a gradute from UH, SOEST GeoPhysics. No university has a degree in Darinism. Now that my personal declaration is done! I think, you have cleaned Dr Egnor’s clock. Please realize that any attention given him plays to his vanity. I wouldn’t go to him for a cure for athelets foot. He must be a quack! Thats all that needs to be said. Any medical Doctor that doesn’t accept drug immunity in viruses, bacteria, or parasites doesn’t deserve a license to practice. I need to say that on his blog I suppose.

  10. #10 Niket
    March 19, 2007

    He must be a quack!
    You don’t have to know Newton’s laws to be a champion race-car driver. He might be a great neuro surgeon (I don’t know, I take your word for it). He feels evolution is irrelevent to his field because he doesn’t actively use it everyday.

    But when presented with mountains of arguments that clearly show his arguments to be incorrect, I would think he will be smart enough to say “Oh duh! My bad.”