The Cracked Haeckel Approach to Evolutionary Reasoning - Evolution News & Views

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The Cracked Haeckel Approach to Evolutionary Reasoning

There's an old lawyers' joke about the "cracked kettle" approach to legal argumentation. Jones sues Smith for borrowing her kettle and returning it with a crack in it. Smith's lawyer then defends her with the following arguments (in order):

    1. Smith didn't borrow the kettle.
    2. The kettle was cracked before Smith borrowed it.
    3. When Smith returned the kettle, it wasn't cracked.
    4. There never was a kettle.
In my book Icons of Evolution I described a 2000 conference talk in which Kevin Padian (President of the National Center for Science Education) used argumentation very much like this to defend his claim that birds are modified descendants of dinosaurs.1 Darwinists are now using a similar approach to defend Ernst Haeckel's embryo drawings.

Historical Background

Charles Darwin thought that "by far the strongest" evidence that humans and fish are descended from a common ancestor was the striking similarity of their early embryos. According to Darwin, the fact that "the embryos of the most distinct species belonging to the same class are closely similar, but become, when fully developed, widely dissimilar... reveals community of descent." 2 To illustrate this, German Darwinist Ernst Haeckel made some drawings in the 1860s to show that the embryos of vertebrates (fish, amphibians, reptiles, birds and mammals) look almost identical in their earliest stages.

But Haeckel faked his drawings. Not only do they distort vertebrate embryos by making them appear more similar than they really are (in a way that Stephen Jay Gould wrote "can only be called fraudulent" 3), but they also omit classes and stages that do not fit Darwin's theory. Most significantly, Haeckel omitted the earliest stages, in which vertebrate embryos are strikingly different from each other. The stage he portrayed as the first is actually midway through development. Yet according to Darwin's logic, early dis-similarities do not provide evidence for common ancestry.

Haeckel used his faked drawings to support not only Darwinian evolution, but also his own "Biogenetic Law," which stated that embryos pass through the adult stages of their ancestors in the process of development. In Haeckel's words, "ontogeny [development] recapitulates phylogeny [evolution]." Darwin also believed in recapitulation; he wrote in The Origin of Species that early embryos "show us, more or less completely, the condition of the progenitor of the whole group in its adult state." 4

Haeckel's drawings were exposed as fakes by his own contemporaries, and his Biogenetic Law was thoroughly discredited by 20th century biologists. It is now generally acknowledged that early embryos never resemble the adults of their supposed ancestors. A modern version of recapitulation claims that early embryos resemble the embryos of their ancestors, but since fossil embryos are extremely rare, this claim is little more than speculation based on the assumption that Darwin's theory is true.

Biology Textbooks

Many modern biology textbooks inform students that Haeckel's dictum, "ontogeny recapitulates phylogeny," has been discredited, but the same textbooks often use Haeckel's drawings (or modern versions of them) to persuade students that human embryos provide clues to our evolutionary history and evidence for Darwin's theory. For example, the 1994 edition of the college textbook Molecular Biology of the Cell features Haeckel's drawings and claims that neo-Darwinian mechanisms explain why "embryos of different species so often resemble each other in their early stages and, as they develop, seem sometimes to replay the steps of evolution." 5

The 1999 edition of Raven and Johnson's textbook, Biology, accompanies a colorized version of Haeckel's drawings with the caption: "Notice that the early embryonic stages of these vertebrates bear a striking resemblance to each other." Elsewhere the book explains: "Some of the strongest anatomical evidence supporting evolution comes from comparisons of how organisms develop. In many cases, the evolutionary history of an organism can be seen to unfold during its development, with the embryo exhibiting characteristics of the embryos of its ancestors." 6

Dozens of other biology textbooks published since 1990 have used Haeckel's drawings (or modern versions of them) as evidence for Darwinian evolution. These include textbooks published as recently as 2004. 7

Flock of Dodos

Evolutionary biologist-turned-filmmaker Randy Olson has now produced a film titled "Flock of Dodos: The Evolution -- Intelligent Design Circus." 8 The film pokes fun at both sides in the debate, though it clearly favors the Darwinists.

Assuring me that he would be fair to both sides, Olson interviewed me for the film in August 2005 and asked me to comment on Haeckel's embryo drawings. In the finished film, Olson concedes that the drawings are fraudulent, but he states on camera that "you don't find them" in recent textbooks as evidence for Darwinian evolution. In one scene, Olson hands Kansas attorney (and Darwin critic) John Calvert a recent biology textbook and challenges him to find Haeckel's drawings in it. Taken by surprise, Calvert can't do it. Afterwards, Olson displays a 1914 textbook containing the drawings but claims they haven't been used since then. The film then compares my book Icons of Evolution to a supermarket tabloid.

Calvert later faxed Olson pages from a recent textbook containing Haeckel's drawings, but Olson gives no hint of that in his film. Furthermore, Olson claims to have read Icons of Evolution, but if had he would have known that eight widely used biology textbooks with copyright dates between 1998 and 2000 contain versions of the faked drawings. I sent Olson an email in May 2006 citing three more textbooks with copyright dates of 2004 that contained Haeckel's drawings, and I suggested: "You owe it to your audiences to acknowledge that in this respect your film is promoting a demonstrable lie." 9

Olson ignored me.

The film showed in Seattle on February 7, 2007, and afterwards several people in the audience asked Olson about Haeckel's embryo drawings. The next day he wrote on an Internet blog 10:

While it's important that everyone keep straight the absurdity of wrangling over Haeckel's embryos, it is much more important that a single word is kept in mind throughout this -- TRIVIA. Everyone needs to stay focused on the larger issue which is the subtitle of Wells's book, 'Why much of what we teach about evolution is wrong.' As I point out in Dodos, he doesn't say 'some,' or 'a little bit,' or 'a few things.' He says MUCH.

The important thing is that the whole process needs to begin with THE BURDEN OF PROOF being on him to prove that his case consists of more than just trivia... The burden of proof needs to remain on him to make the case for this word "much." With the Haeckel's embryos anecdote he is implying that the entire field of evolutionary embryology is faulty just because of this piece of teaching trivia which is a crusty artifact from the world of science history.

And this is all a part of this larger syndrome that I think of as "Trivia Tackling" -- the idea of trying to take down a large institution, idea or individual, not by assailing the large and significant parts, but by doggedly locking on to pieces of trivia... It's fine to split hairs about the last remaining vestiges of Haeckel's artwork in the teaching of embryology, but the important issue is whether "much of what we teach about evolution is wrong." It isn't.

The Cracked Haeckel Argument

So Olson makes the following arguments (in order):

    1. Haeckel's drawings were faked, but they're not used in recent textbooks.
    2. They're used in recent textbooks, but not as evidence for Darwinian evolution -- only as a "crusty artifact" of science history.
    3. When they ARE used in recent textbooks as evidence for Darwinian evolution, the fakery is "trivial" -- because there's lots of other evidence.
This looks a lot like the "cracked kettle" argument. The only element missing is the claim that "there never were any fake drawings." Fortunately, other Darwinists supply the missing link.

One who comes close is the host of the blog on which Olson posted his comments, Paul Z. Myers of the University of Minnesota. Writing about Haeckel's embryos, Myers states: "The point is still valid; there is an interesting phenomenon going on in development, in which there is a period during which the body plan of vertebrates is roughly laid out, and biology has some explanations for it." The drawings (or modern versions of them) "reveal deep homologies that support evolutionary explanations of the origins of animal diversity." In other words, the drawings aren't fundamentally wrong.

This view is stated more plainly by other Darwinists. Eugenie Scott, Executive Director of the National Center for Science Education, has said that Haeckel "may have fudged his drawings somewhat," but "the basic point that's being illustrated by those drawings is still accurate." Textbook-writer Douglas J. Futuyma euphemistically concedes that Haeckel "did improve his drawings," but he falsely insists that early vertebrate embryos "really are more similar, overall, than the animals are later in development." 11

In other words, Haeckel may have fudged or improved his embryos, but they more or less accurately represent what's really going on in vertebrate development. They weren't faked at all.

This completes the Cracked Haeckel argument:

    1. Haeckel's drawings are fake, but they're not used in recent textbooks.
    2. They're used in recent textbooks, but not as evidence for Darwinian evolution.
    3. They're used as evidence for Darwinian evolution, but it doesn't matter because there's lots of other evidence.
    4. The drawings aren't fake.
Now, that's funny. In fact, it's funnier than anything in "Flock of Dodos."


NOTES

1 Jonathan Wells, Icons of Evolution: Why much of what we teach about evolution is wrong (Washington, DC: Regnery Publishing, 2000), pp. 132-134. iconsofevolution.com

2 Charles Darwin, in a September 10, 1860 letter to Asa Gray, in Francis Darwin (editor), The Life and Letters of Charles Darwin (New York: D. Appleton & Company, 1896), Vol. II, p. 131. Available Online Here
Charles Darwin, The Origin of Species, Sixth Edition, Chapter XIV, section on "Development and Embryology." Available Online Here

3 Stephen Jay Gould, "Abscheulich! Atrocious!" Natural History (March, 2000), pp. 42-49.

4 Charles Darwin, The Origin of Species, Sixth Edition, Chapter XIV, section on "Development and Embryology." Available Online Here

5 Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts & James D. Watson, Molecular Biology of the Cell, Third Edition (New York: Garland Publishing, 1994), pp. 32-33.

6 Peter H. Raven & George B. Johnson, Biology, Fifth Edition (Boston: WCB/McGraw-Hill, 1999), pp. 1181, 416.

7 Cecie Starr & Ralph Taggart, Biology: The Unity and Diversity of Life, Tenth Edition (Belmont, CA: Thomson Learning, 2004), p. 315.
Joseph Raver, Biology: Patterns and Processes of Life (Dallas, TX: J. M. LeBel Publishers, 2004), p. 100.
Donald Voet & Judith G. Voet, Biochemistry, Third Edition (Hoboken, NJ: John Wiley & Sons, 2004), p. 14.
[NOTE: Several of these have subsequently responded to criticisms by removing the drawings.]

8 Randy Olson, "Flock of Dodos: The Evolution -- Intelligent Design Circus," 2007. flockofdodos.com

9 Jonathan Wells, "Flock of Dodos, or Pack of Lies?" Evolution News and Views, February 9, 2007. Available Online Here
"Hoax of Dodos," Evolution News and Views, February 7, 2007. Available Online Here

10 Randy Olson, "Greetings from Seattle," February 8, 2007. Available Online Here

11 Eugenie Scott, interview in "Icons of Evolution," Coldwater Media, 2002. coldwatermedia.com
Douglas J. Futuyma, Evolution (Sunderland, MA: Sinauer Associates, 2005), p. 535.


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