Critique of Dembski’s not-so-new argument, at PT

We interrupt all this philosophy for a brief announcement: I have written a critique of the arguments William Dembski used in his talk on 14 August at the Computations in Science Seminar at the University of Chicago, which can watch on this Youtube video. These were based primarily on the Conservation of Information (CoI) argument of William Dembski and Robert Marks, and these were in turn based on their earlier Search For a Search (SFS) argument. Neither those arguments nor my response are new, but I hope that the new post will explain the issues clearly.

The critique will be found here, at Panda’s Thumb.

I suspect that most of the discussion will occur at PT but I will try to respond here as well.

20 thoughts on “Critique of Dembski’s not-so-new argument, at PT

  1. Joe,

    Regarding your point #8:

    8. Dembski and Marks implicitly acknowledge, though perhaps just for the sake of argument, that natural selection can create adaptation. Their argument does not require design to occur once the fitness surface is chosen. It is thus a Theistic Evolution argument rather than one that argues for Design Intervention.

    I asked Dembski about that in 2009, posting as ‘beelzebub’:

    85 beelzebub
    May 3, 2009 at 1:47 pm

    Dr. Dembski,

    As far as I can see, nowhere in the paper do you and Dr. Marks express skepticism regarding the ability of Darwinian evolution to account for the diversity of life. Rather, you seem to grant that Darwin was right that random mutation and natural selection are sufficiently powerful, provided that fitness has a teleological origin.

    That seems like a huge departure from your former indictment of Darwinian theory as flawed and unsupported by the evidence.

    Have you in fact shifted your position?

    How has the ID camp reacted to your paper?

    86 William Dembski
    May 3, 2009 at 4:28 pm

    Beelzebub: This paper was written under the supposition that common descent holds and that natural selection is the principal mechanism behind it. Writing under a supposition does not mean accepting it. My own views of the truth of the matter are clearly spelled out in THE DESIGN OF LIFE (http://www.thedesignoflife.com). In particular, I think that irreducible complexity at the molecular level (especially in the origin of DNA and protein synthesis) provides compelling evidence for discontinuity in the history of life.

    87 beelzebub
    May 3, 2009 at 6:07 pm

    Dr. Dembski,

    I understand what it is to assume something for the sake of argument, and I do it myself quite often. I’m just surprised that you didn’t state that the assumption was contrary to your own position, when a short disclaimer would have made this clear, e.g.:

    The authors remain skeptical that Darwinian evolution explains the full diversity of life on earth. However, we show in this paper that if it does, it is necessarily teleological.

    It’s interesting that he and Marks spend most of their time these days defending not ID itself, but a fallback position which, as you point out, is very much like the view espoused by the hated TEs. I wonder if Dembski gets flak from within the ID movement for that.

  2. keiths: I wonder if Dembski gets flak from within the ID movement for that.

    Thanks for that quote, I was looking for exactly that quite recently. I also think this is the reason why the good Dr Dr does not engage at UD any more.

    This paper was written under the supposition that common descent holds and that natural selection is the principal mechanism behind it.

    Hardly going to go down well with the likes of KF and his ilk, is it?

  3. I see ID as a US political movement. The goal of this seminar appears to have been political, not scientific. That is, the very fact that the seminar was held in a mainstream academic setting will be used to score political points by ID supporters

    If the goal was scientific, then there would have been (computational) biologists present who could have presented the counter-arguments that Dr Felsenstein repeats in the PT entry. As far as I can tell from Dr Felsenstein’s summary at PT and a brief skim of the Q&A portion on YouTube, there was no one there from that community.

    If the Dembski work was intended only to discuss mathematical consequences of
    certain assumptions about genetic search algorithms, then not inviting biologists would be fine. But if the goal is to apply that mathematics to biology and evolution, then a scientific approach requires analysis and criticism of the assumptions of the model in the biological framework, as Dr Felsenstein has provided.

  4. OMagain:

    Hardly going to go down well with the likes of KF and his ilk, is it?

    He is attempting to make an argument by contradiction: assume X, show that assumption leads to a contradiction, hence deny X.

    The problem is that when you use argument by contradiction, you have to look at all the assumptions, not just a one.

    Dr Felsenstein points out some of the other wrong assumptions that Dembski makes that need to be questioned.

    Now there could be a philosophical argument about why it is scientific to question those assumptions before questioning the mechanisms of evolutionary theory, but such a philosophical argument clearly has no place in this thread.

  5. I’m afraid I lack the mathematical tools to contribute to this debate, so I will limit myself to expressing my understanding, ad to asking how far off base I am.

    I think of the natural world as something of a Markov model and a Markov selector with regard to living systems.

    I would replace the term natural selection with natural constraint. The word selection suggests an active or directed process, whereas constraint is like the bottom of a pond that determines the perimeter of the water.

    Variations survive or not, based on the laws of chemistry and on the particulars of the ecosystem. I see no conceptual difference between neutral and beneficial mutations. The population — the distribution of variants — is shaped by the bottom of the pond, which is irregular.

    Evolution feels its way through configuration space because mutations include all possible nearby configurations. If there were no natural constraints, genome sequences would appear random. All mutations would survive with equal probability. They do not, because chemistry is such that some mutations are non-viable, and some — for reasons not entirely foreseeable — are more successful or less successful.

    So what evolution does is transfer information about the shape of the pond bottom to the genome. This is, of course, a rather loose metaphor.

    If I have a point, it is that nothing in this metaphor suggests that there is anything special or designed about the pond bottom.

  6. petrushka:

    So what evolution does is transfer information about the shape of the pond bottom to the genome. This is, of course, a rather loose metaphor.

    If Ihave a point, it is that nothing in this metaphor suggests that there is anything special or designed about the pond bottom.

    You are free to change terminology (“constraint” for “selection”) but getting the new terms widely accepted will be a hard slog.

    Dembski and Marks take precisely the position that the information that is put in the genome is already around, in the shape of the fitness surface.

    Even if you grant that, they then need to show that the fitness surface that allows natural selection to work well is a very unlikely one under our world’s physics and chemistry. That is their position, but I have suggested that they are wrong about that “because physics”.

  7. Somehow I’m not at all surprised that two mathematicians forget about physical reality. The size of nomologically possible worlds is much smaller than the size of logically possible worlds; we don’t need to a Designer in order to pick out the actual world from the set of all logically possible worlds. (Interestingly, this point indicates a deep convergence between Dembski/Marks and Leibniz.)

  8. KN,

    Somehow I’m not at all surprised that two mathematicians forget about physical reality.

    Marks is an engineer, not a mathematician.

    The size of nomologically possible worlds is much smaller than the size of logically possible worlds; we don’t need to a Designer in order to pick out the actual world from the set of all logically possible worlds.

    Dembski and Marks believe that God is the author of natural law, which is highly contingent, so your objection does not apply to their argument.

  9. keiths: Marks is an engineer, not a mathematician.

    I hadn’t realized that. I guess that only increases my bafflement at their error, if Joe is right about the error that they made.

    I do find it interesting that (1) engineers tend to deal with fairly simple systems, whereas biologists tend to deal with very complex systems, and (2) engineers are highly sympathetic to design arguments, whereas biologists are not. What’s the relationship between the two?

    Dembski and Marks believe that God is the author of natural law, which is highly contingent, so your objection does not apply to their argument.

    I don’t quite follow. Would you mind elaborating?

  10. KN,

    I do find it interesting that (1) engineers tend to deal with fairly simple systems…

    Not computer engineers! Transistor counts are in the billions now for the largest processor chips, and the designs are very complicated.

    …and (2) engineers are highly sympathetic to design arguments, whereas biologists are not.

    In my experience, engineers are generally not very sympathetic to design arguments. A lot of IDers and creationists are engineers, but not very many engineers are creationists and IDers. This topic comes up fairly often in conversations with my engineering colleagues, and only a tiny number turn out to be anti-evolution.

    However, the percentage of engineers who are IDers or creationists is certainly higher than that of biologists.

    What’s the relationship between the two?

    I think it’s pretty straightforward. Biologists learn about evolution, while engineers often don’t. It’s easier to doubt evolution when you don’t understand how it works or how well-supported it is evidentially.

    KN:

    The size of nomologically possible worlds is much smaller than the size of logically possible worlds; we don’t need to a Designer in order to pick out the actual world from the set of all logically possible worlds.

    keiths:

    Dembski and Marks believe that God is the author of natural law, which is highly contingent, so your objection does not apply to their argument.

    KN:

    I don’t quite follow. Would you mind elaborating?

    I’d be happy to.

    As you mentioned, the number of nomologically possible worlds is smaller (much smaller!) than the set of logically possible worlds. However, you go on to argue that a Designer is unnecessary because the former is so much smaller than the latter. I don’t think that’s true, because in the process of creation, God selects both the laws of nature and a particular world that is compatible with those laws.

    In other words, to Dembski and Marks, God really does select our world out of all of the logically possible ones, not merely the nomologically possble ones.

  11. Dembski and Marks take precisely the position that the information that is put in the genome is already around, in the shape of the fitness surface.

    I can’t tell you the number of times I have heard the claim that the information in the genome comes from the environment. Could you explain the difference between that claim and the claim made by D/M?

  12. keiths

    Marks is an engineer, not a mathematician.

    So? The two are mutually exclusive?

    http://neoswarm.com/

    Here’s an idea, let’s disregard anything Joe Felsenstein says about evolution because he’s a mathematician.

  13. Joe f:

    What Dembski and Marks’s argument doesn’t do

    It is notable that Dembski and Marks’s argument is not actually an Intelligent Design argument. It argues that a Designer is needed to explain the shape of the fitness surface, but once that surface is smooth enough, natural selection and other evolutionary forces do the rest. So there is no Design Intervention needed.

    The argument argues that a Designer is needed, but it’s not actually an Intelligent Design argument.

    Because no design intervention is needed to explain a smooth fitness surface, no intelligent designer is needed to explain any fitness surface.

    Fair summary?

  14. Mung:
    Joe f:

    [quote of me snipped. JF]

    The argument argues that a Designer is needed, but it’s not actually an Intelligent Design argument.

    Because no design intervention is needed to explain a smooth fitness surface, no intelligent designer is needed to explain any fitness surface.

    Fair summary?

    No. I argue that physics predisposes to smoother fitness surfaces than are implied by D&M’s use of the Bernoulli Principle on mappings from genotypes to fitnesses.

    My argument does not rule out the possibility that an Intelligent Designer might have set up a fitness surface — how could we ever rule that out? But it rejects D&M’s argument that such a Designer is necessary to bring about a fitness surface smooth enough for evolution to succeed in achieving adaptations.

  15. Joe Felsenstein: But it rejects D&M’s argument that such a Designer is necessary to bring about a fitness surface smooth enough for evolution to succeed in achieving adaptations.

    Allow me to loudly agree with you, Joe: your objection is that physics shows us why the fitness landscape is not white noise. And insofar as D&M were arguing for design on the assumption that the fitness landscape is white noise, you’ve shown why their argument fails.

    But, it should also be emphasized, this objection doesn’t show that physics tells us that the fitness landscape really is smooth enough for selection to arrive at adaptation. Against this particular argument for positing a designer, your objection works quite well; it doesn’t rule out the possibility of positing a designer on some other grounds.

    However, most design proponents don’t even recognize that the postulation of a designer needs to be motivated by good reasons. The abductive leap is neither mere speculation nor a “that’s just how it seems to me!”

  16. Mung: I can’t tell you the number of times I have heard the claim that the information in the genome comes from the environment. Could you explain the difference between that claim and the claim made by D/M?

    The issue would be whether the information is in the fitness surface (as D&M argue) or “in the environment”. As I’m not sure what the people who say the latter mean, I can’t explain that difference any further.

  17. Joe Felsenstein: The issue would be whether the information is in the fitness surface (as D&M argue) or “in the environment”. As I’m not sure what the people who say the latter mean, I can’t explain that difference any further.

    It’s semantics, but I would be tempted to call the laws of chemistry and physics a fitness surface, and the ecosystem the environment.

    The difference in my mind is that chemistry is unchanging, and the ecosystem is dynamic. Chemistry constrains metabolism, and the ecosystem constrains variants at a different level.

  18. Alan Fox:
    Dembski responds to Professor Felsenstein here. Summary is “strawman. Do too have a good model. Buy my book.”

    It’s still rubbish to model evolution as a search for a specific configuration. So his premise is wrong.

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