Home » Tree of life » He doubted Darwin’s tree of life, but he was just a creationist. Then …

He doubted Darwin’s tree of life, but he was just a creationist. Then …

A topic that (in 1997) was largely the province of one lonely ID philosopher of biology, namely, How would we know if the theory of universal common descent were false? began to bubble away in the literature. Carl Woese published his broadside “The universal ancestor” in PNAS in 1998, saying there never was such an organism, and then the hydrant opened.

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W. Ford Doolitle, Michael Syvanen, Elliott Sober, Malcolm Gordon (at UCLA), and others said, in major publications, “Hey, what if there never was a single Tree of Life? What then?” And the genomics revolution turned up an array of anomalies wholly unanticipated when I started on my dissertation (e.g., the appearance of widespread lateral gene transfer, and so-called ORFan sequences). Back to the computer keyboard. – Paul Nelson

Agnostic mathematicial David Berlinski put in an even more fundamental question:

Before you can ask ‘Is Darwinian theory correct or not?’, You have to ask the preliminary question ‘Is it clear enough so that it could be correct?’. That’s a very different question. One of my prevailing doctrines about Darwinian theory is ‘Man, that thing is just a mess. It’s like looking into a room full of smoke.’ Nothing in the theory is precisely, clearly, carefully defined or delineated. It lacks all of the rigor one expects from mathematical physics, and mathematical physics lacks all the rigor one expects from mathematics. So we’re talking about a gradual descent down the level of intelligibility until we reach evolutionary biology. – from Expelled April 18 2008 29.33

Professor: We cannot know whether a thing is true if we cannot know if it is false.

Parent fighting nonsense on school curriculum: But prof, there is a third category that is neither true nor false: What all the “in” people believe. It’s a bigger handicap to education than illiteracy.

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18 Responses to He doubted Darwin’s tree of life, but he was just a creationist. Then …

  1. 1
    Elizabeth Liddle

    Darwin’s theory was not a “theory of common descent”.

    His theory was a theory about how the evidence for common descent of very different species, namely Linnaeus’s nested hierarchies of species on the basis of their morphological characters, could be accounted for.

    Linnaeus’ taxonomy revealed a highly non-random structure to the distribution of morphological characters. This strongly suggested a family tree, i.e. common descent. But a family tree in itself does not explain why the populations at the ends of the branches should differ so radically.

    His theory was so simple it is almost a syllogism: That if things replicate with variance, and if the variants differ in the efficiency with which they self-replicate, variants that replicate most efficiently will come to dominate the next generation.

    This is clearly true.

    What needs to be demonstrated, if it is to be accepted as an explanation for the Linnaean nested heirarchies (or tweaks thereof) is that things do replicate with the kind of variance that result in phenotypic differences in reproductive success.

    This has been demonstrated, many times.

    What has also emerged is that sheer drift is also a factor, and that lateral transmission mechanisms contribute to allelic diversity, and that therefore the common descent picture is bushier than originally conceived.

    It may well be that Darwin’s theory is not adequate to explain the full picture (few theories are); indeed we know already that the picture is far more complicated than the one his simple, elegant syllogism paints.

    But that is not the same as claiming that his theory isn’t rigorous. It is, and also beautiful in its simplicity.

    But the theory is perfectly clear, perfectly rigorous, and makes good testable predictions, many of which have been subsequently supported by data, both in the lab and in the field.

  2. Darwin’s theory was not a “theory of common descent”.

    Oh please. No less an authority than Ernst Mayr disagrees with you.

    What is Darwinism?

  3. 3
    Elizabeth Liddle

    I don’t mind who disagrees with me!

    Clearly his theory was an account of how, if common descent were the explanation for nested hierarchies, the differences between species at could be accounted for.

    But Darwin’s theory is actually independent that of the theory of common descent of all living things.

    As he says, explicitly, in the final paragraph of Origins, that, having started from “few forms or one”, diversity could evolve according to his theory.

    He made no claim to demonstrate whether there were “few forms or one”.

    At least not that I recall. It’s a theory of how diversity could arise within a lineage, not the theory that all lineages go back to a single ancestral population.

  4. I love Berlinski’s observation, which is so apt. Unlike experimental science, Darwinism is a loose collection of anecdotes, often poorly and vaguely constructed, coupled with vast amounts of imagination. In a purely logical sense it might be true, but pinning down what is actually posited is exceedingly difficult.

  5. Elizabeth: “He made no claim to demonstrate whether there were “few forms or one”.”

    Not in the Origin, but he does allude to origin of life possibilities in later correspondence, which at least implies he was comfortable with, and even supportive of, the following ideas: (i) abiogenesis, and (ii) common descent from a “few forms or one.”

    Common descent and universal common descent are not necessarily the same. Darwin clearly supported and espoused common descent — that is the whole basis of the Origin — but, as you say, he didn’t put a stake in the ground that I am aware of as to whether he thought there was universal common descent from a single form. In that sense, he would be in very good company with most modern defenders of the theory, who also leave that question open.

  6. But Darwin’s theory is actually independent that of the theory of common descent of all living things.

    Whether it’s a theory of common descent from a single LUCA or a theory of common descent from a few it’s still a theory of common descent.

    Did you even read the link I posted?

    Darwin’s theory is a theory of common descent. You said it wasn’t.

    Further evidence that contradicts your claim, from Darwin himself:

    Tree of Life

    Looks like a theory of common descent to me.

  7. http://pandasthumb.org/archive.....ment-25771 is the direct link to Paul Nelson’s comment. (You now have to root around to find Nelson’s comment if you follow the Panda’s Thumb link given above, as it’s been buried under more recent comments.)

  8. Elizabeth Liddle:

    You said, “What needs to be demonstrated, if it is to be accepted as an explanation for the Linnaean nested heirarchies (or tweaks thereof) is that things do replicate with the kind of variance that result in phenotypic differences in reproductive success.

    This has been demonstrated, many times.”

    If I understand your meaning, you are saying that random mutation has been demonstrated (many times) to produce sufficient variation to account for the emergence of all the immense variety of form and function that we observe in currently extant species as well as in the fossil record. I am not aware that this has been demonstrated even once.

    Could you please give some examples of such demonstrations?

  9. 9
    Elizabeth Liddle

    I meant that it has been demonstrated as a mechanism – i.e. “that things do replicate with the kind of variance that result in phenotypic differences in reproductive success.”

    It is another matter to show that this is, in fact, the mechanism that accounts for all variety, and indeed, we know it does not. Drift is also a huge factor (heritable traits that may or may not result in phenotypic difference and which do not lead to differences in reproductive success but nonetheless propagate stochastically through the population). And not all variance arises from the replication process itself – horizontal gene transfer is another factor, and there are many others.

    But the observation that things replicate with the kind of variance that results in phenotypic difference in reproductive success has been shown both in the lab and in the field.

    I don’t think this is controversial, is it?

  10. 10
    Elizabeth Liddle

    OK, Mung, I will retract that claim, and rephrase:

    Darwin’s theory was a theory to account for what looked, on Linnaeus’s taxonomy, to be a tree of life.

    So in the sense that it was a theory in support of the tree of life, yes, it was a theory of the tree of life.

    But the essence of his theory was not that “All things have a common ancestor” but a theory of how, from a common ancestor (whether universal or not), species diverge.

    In other words it was advanced to explain a puzzle: the Linnaean system looked like a family tree, but in the family trees we are familiar with, the descendents are not different species – they look similar and can interbreed.

    Darwin’s theory accounted for how a single lineage could result in different species.

    So yes, in that sense, it’s a theory of common ancestry. It is, however, quite independent of the theory that living things have a common ancestry, and indeed, is invoked by some creationists to explain the “microevolution” that they believe produced radiation from the pairs and sevens of animals on the ark.

  11. 11
    Elizabeth Liddle

    I guess what I’m saying is that Special Creation or ID could be proved (or rather demonstrated beyond doubt :)) tomorrow, and Darwin’s theory would still hold.

    It accounts for the adaptation of populations to, and the divergence of populations into, their environmental niches, regardless of how many ancestral populations there were and how different they were from their descendents.

    It does not account for the source of variation, which Darwin did not know, and could be from intelligent design (as per Behe, or in the case of genetic engineering).

    But given the replication-with-variance, the principle clearly works, as many IDists and even YECs accept.

    Anyway, Mung, thanks for keeping my toes to the fire :)

  12. 12

    What if the conclusions of geology were put aside entirely!
    That is no conclusions of time passing relevant to fossils.
    Then how would evolution stand as a biological idea???

    Enen Chuck Darwin brought this up and said put down his books until geological presumptions are accepted.
    Otherwise evolution is not worthy to persuade merely on biology.

  13. EL:

    I guess what I’m saying is that Special Creation or ID could be proved (or rather demonstrated beyond doubt ) tomorrow, and Darwin’s theory would still hold.

    No, it wouldn’t as Darwin’s theory is directly at odds with both SC and ID.

    Even Darwin admitted such a thing in letter to collegues-> no teleology allowed.

  14. Hello News,

    “Carl Woese published his broadside “The universal ancestor” in PNAS in 1998, saying there never was such an organism …”

    You seem to imply that Carl Woese is somehow “anti-Darwinian” but neglect to mention that instead Woese proposes a tree of life with a huge diversity of early microbial lineages. He advocates horizontal gene transfer as a major evolutionary process, with lateral transfer responsible for the rapid early evolution of complex biological structures. In short, Woese has made a substantial contribution to evolutionary theory. As Elizabeth Liddle(3) points out, Darwin stated in the final paragraph of Origins that, having started from “few forms or one”, diversity could evolve according to his theory. The work of Woese does nothing to contradict Darwin’s basic ideas.

  15. 15
    Elizabeth Liddle

    Joseph:

    EL:

    I guess what I’m saying is that Special Creation or ID could be proved (or rather demonstrated beyond doubt ) tomorrow, and Darwin’s theory would still hold.

    No, it wouldn’t as Darwin’s theory is directly at odds with both SC and ID.

    Even Darwin admitted such a thing in letter to collegues-> no teleology allowed.

    In that case Darwin was wrong about his own theory (I’d like to see the letter though). It is perfectly applicable to both SC (cf Todd Wood and John Sanford) and ID (cf Behe).

    In fact I have yet to meet an “anti-Darwinist” who does not agree that “microevolution” occurs on exactly the principle that Darwin proposed, although many of course insist that it has “limits”.

    It is true that Darwin appeared to believe that his principle could account for a single Tree of Life (and I agree with him) but the principle itself can account for any branching from a node, and including nodes could have been established during Creation Week, or sampled on the Ark.

    And Darwin provided no mechanism for variance. Again, that could be (and is) provided by Intelligent Design (again cf Behe, but also Sanford, a genetic engineer, who actually states that he relies on natural selection, which he characterises as the same thing as differential reproduction to recover the engineered material).

    In fact Darwin himself espoused at one point the idea of Lamarckian mechanisms for variance, which would actually be “teleological” in the sense that behaviour by intelligent agents in one generation (giraffes, for instance) would affect the traits passed onto he next.

  16. Elizabeth Liddle:

    OK, Mung, I will retract that claim, and rephrase

    You retracted it then repeated it.

    That’s not much of a retraction.

  17. Elizabeth Liddle:

    It accounts for the adaptation of populations…

    It was supposed to account for adaptations, you know, those features, such as eyes and wings, which themselves are supposed to account for the adaptation of populations to their environments.

    Design without a Designer, and all that.

  18. waiting…

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