During my recent trip to the Creation Museum I picked up a copy of David DeWitt’s book Unraveling the Origins Controversy. DeWitt is the Director of the Center for Creation Studies at Liberty University. It’s been a while since I’ve read an actual YEC book, and I was growing nostalgic for the experience.

And wouldn’t you know it! Almost as soon as DeWitt turns from religious questions to scientific ones, the quote-mining begins. Consider this:

Often the evidence that is used to support common ancestry is the similarities between organisms. Mayr explained:

Since all members of a taxon must consist of the descendants of the nearest common ancestor, this common descent can be inferred only by the study of their homologous characters. But how do we determine whether or not the characters of two speices are homologous? We say that they are if they conform to the definition of homologous: A feature in two or more taxa is homologous when it is derived from the same (or a corresponding) feature of their nearest common ancestor. (Emphasis in Original).

Or consider this from a recent biology textbook:

Similar structures in two or more species are called homologous structures if the structures are similar because they evolved form the same ancestral structure.

Notice the circular reasoning that is being applied here. Common ancestry is inferred by studying homologous (similar) characters and yet homologous characters are defined as being derived from a common ancestor. This becomes extremely problematic and only works if you assume that common ancestry is true. (pp. 100-101) (Emphasis in Original)

Circular reasoning? That second quotation doesn’t seem to have any reasoning at all. It merely defines a technical term.

But it’s that Mayr quote I want to focus on. You’ll find it on page 16 of his book What Evolution Is. It appears in a lengthy chapter describing some of the evidence for common descent. Curiously, though, it does not appear in the portion of the chapter describing how morphological similarities (between the forelimbs of various mammals, for example) provides evidence for descent. It is actually in a section on the fossil record.

DeWitt began the Mayr quote with the second sentence of the paragraph. The first sentence is this:

The study of phylogeny is really a study of homologous characters.

We then have the quote as presented by DeWitt, followed by this:

This definition applies equally to structural, physilogical, molecular, and behavioral characteristics of organsims. But how are we to determine whether homology is substantiated in a particular case? Fortunately, there are numerous criteria (see Mayr and Ashlock 1991). For structures this includes the position in relation to neighboring structures or organs; by connecting two dissimilar features by intermediate stages in ancestors; by similarity in ontogeny; and by intermediate fossils. The best evidence for homology has been provided in recent years in molecular biology.

There follows several more sentences elaborating on this.

Gives rather a different impression from DeWitt, wouldn’t you say? Is Mayr inferring common descent from homologous characters, and then defining homologous characters as those that arise from common descent? Of course not. He’s pausing a discussion on the importance of the fossil record to describe briefly some practical issues that arise in trying to recreate specific lines of descent. Mayr does, in fact, provide a discussion of how certain patterns of similarities and differences across organisms provides further evidence of common descent, but you will find that discussion elsewhere (on pages 22-27, to be exact).

Ah, creationist sleaze. How I’ve missed you.

Comments

  1. #1 Betul
    July 6, 2008

    I just heard about this museum from your blog, at first I didn’t want to believe it. Creation museum? Though it does exist, for real! After surfing on their museum store for a bit, here is my favorite:

    A book called: “4 power questions to ask an evolutionist”

    “…. Mike Riddle equips you to turn the tables by asking your evolutionist friends four simple–yet powerful–questions:

    1. Where did the universe’s original matter come from?
    2. How did life begin?
    3. Where are all the supposed transitional fossils between the Precambrian and Cambrian periods?
    4. Where did the dinosaurs come from?

    “Each “power question” is compelling in itself and leads the evolutionist to understand that he is relying on faith and not empirical science.”

    I am really wondering the writer’s answers to these questions? Or maybe it is not that hard to wonder since;

    1.God
    2.God
    3.God
    4.God

    Quiet compelling indeed!

    ~betul

  2. #2 Ryan
    July 6, 2008

    This is just another example of how successful Jonathan Wells has been in distorting science and spreading it from the IDers all the way to the fringe of young earth creationism. It is a confusing issue, but the way I understand it is this:

    *For a structure to be homologous, it must share a deep similarity (biochemically, anatomically, and developmentally. Homologous structures may or may not have the same precise function.

    *Homologous structures are then inferred as being inherited from a common ancestor.

    *On the problem of convergent evolution: There are always mutliple solutions to a similar problem. For instance, one may move through the water by moving the tail vertically (like whales) or horizontally (like fish), or by rotating the arms (as humans do). Then again, one may “clap” their legs together in order to swim, just as frogs do. So a similar environmental pressure may occasionally produce similar features, but by comparing a large number of features, we may know whether convergent evolution has taken place. On a side note, genetics and fossils may be helpful as well in determining ancestry.

    Answers in Genesis BUSTED!
    http://aigbusted.blogspot.com

    Sincerely,
    Ryan

  3. #3 Dr. Kate
    July 7, 2008

    “…. Mike Riddle equips you to turn the tables by asking your evolutionist friends four simple–yet powerful–questions:

    1. Where did the universe’s original matter come from?
    2. How did life begin?”

    This illustrates one of the Creationists’/IDers’ favorite games: confusing the issue. The theory of evolution doesn’t actually have anything to say about the origins of life or of the matter in the universe. Those belong to different fields of study. Which isn’t to say we don’t have some good ideas about the answers to those first two questions–I just find it instructive that nearly every YEC/ID diatribe I’ve read somewhere manages to confuse the theory of evolution with the Big Bang theory, or with hypotheses of abiogenesis.

  4. #4 Jay
    July 7, 2008

    Coincidentally, this exact same issue (with almost the exact same quotes used) was discussed on one of the internet E/C forums a few months, down to the allegations of circular reasoning.

    There aren’t many new weapons in the creationist arsenal, it seems.

  5. #5 temizlik
    July 7, 2008

    1. Where did the universe’s original matter come from?
    2. How did life begin?”

    Of course these are relative to evolutionary theory, if that theory is being used to support atheism. You know, goose, gander and all that jazz.

    But there is only one question that has even God stumped, which is where did he come from?

  6. #6 mountaingirl08
    December 20, 2008

    The term “creation science” is an oxymoron. Intelligent design has nothing to recommend it as an intelligent pursuit of scientific thought. I detest that religious fundamentalists are doing their darnedest to cram their ignorance down the throats of normal intelligent American citizens. As if our country wasn’t already viewed w. contempt in the rest of the world. The creationist view of reality has more in common w. the Taliban than w. normal Christianity. All religious extremists are the same under the surface.

  7. #7 film izle
    June 6, 2009

    Coincidentally, this exact same issue (with almost the exact same quotes used) was discussed on one of the internet E/C forums a few months, down to the allegations of circular reasoning.

    There aren’t many new weapons in the creationist arsenal, it seems.

  8. #8 TomH
    September 28, 2010

    After first reading Mayr’s quote I thought: “At the very least, Mayr’s writing contains a mistake.”

    But then I saw the second quote from a text, so I gather that Mayr’s “mistake” is actually accepted doctrine in evo bio.

    But then there’s the issue that Mayr’s sentences following the quotation state that the doctrine is substantiated, so it seems that the “definition” was, at some point, actually tentative. However, this is not clearly stated in any of the text presented here. At the very least, Mayr’s writing is a bit confusing. Dewitt should have been more careful, however, assuming that the issue has been presented accurately here.