Re: [asa] RE: (irreducible complexity and evolution) design and the nature of science (was: Re: [asa] Re: Gingerich on TE and ID)

From: Cameron Wybrow <>
Date: Tue Jun 16 2009 - 16:55:09 EDT


Your reply is good, and we understand each other now. I think I can make this short.

Yes, you are right that it is the definition of irreducible complexity over which we have disagreed; that's what I tried to say in my initial response to you -- that you weren't using Behe's definition, but Miller's tampered-with definition. (And OK, I shouldn't have said "malicious", but "mischievous" was too weak; let me just say that, rhetorically speaking, Miller does not always exactly "play cricket" in debate with Behe.)

The Conservapedia entry is more accurate than the Wikipedia entry. Unlike the Wikipedia entry, it clearly separates the definition proper from the subsequent reasoning. It of course would never be a policy option for the Wikipedia people to conduct themselves honestly, and to restrict themselves to Behe's definition, rather than to creatively amplify it so as to overload it, making it easier to attack later. But contrary to the Wikipedia people, "irreducible complexity" as a concept doesn't "assert" anything about evolution at all.

Good wisecrack about "godless liberals". These discussions could use a bit more humour.

I think the best way of putting the matter is this: In principle, we can identify when a system is "irreducibly complex". The argument is then over whether "irreducibly complex" systems can be produced by Darwinian means.

You are right that the definition of IC doesn't rule out the possibility of co-option. I granted that in my last post. But co-option is a mere abstract possibility, until some detailed mechanical proposals are given. If all you have is two systems that have a subset of proteins in common, you have no evidence for Darwinian evolution. Example: CRT television screens were used as computer monitors, but it doesn't follow that CRT television screens evolved into computers by a chance process. The designers of the first personal computers made use of the existing complex component (the CRT television screen) as a component in a new irreducibly complex system (keyboard-monitor-computer). For all we know, some designer incorporated the already existing design of the TTSS because it was a perfect component for the bacterial flagellum. In order to establish that the TTSS (or whatever precursor you imagine) became the flagellum by Darwinian means, you would need to provide a hypothetical pathway, a set of changes likely to occur without guidance or foresight, that could be tested for genetic soundness, selectability, etc. In other words, the onus is on the person who is convinced that the flagellum arose via Darwinian means, to show how it did so.

I think some ID proponents overstate their case when they say that the flagellum "couldn't possibly" have arisen through a series of co-options. It's virtually impossible to prove a negative. I think that the proper ID argument is that "there is no known pathway to the flagellum, or to any identified irreducibly complex biological system, via Darwinian processes". And the proper response of Darwinian theory is to try to find at least one case, somewhere in the organic world, where a plausible pathway can be shown. If there is one such pathway, there may be more. But the Darwinians have yet to find that first pathway.

Anyhow, I agree with you that the mere fact of irreducible complexity doesn't disprove the possibility of Darwinian evolution. Rather, it gives Darwinian evolution a huge hill to climb. I think it would be a fair compromise if ID people would cease to use the word "impossible", and if Darwinians would acknowledge the hugeness of the hill and the fact that they don't know how to climb it.


  ----- Original Message -----
  From: Iain Strachan
  To: Cameron Wybrow
  Cc: asa
  Sent: Tuesday, June 16, 2009 2:16 PM
  Subject: Re: [asa] RE: (irreducible complexity and evolution) design and the nature of science (was: Re: [asa] Re: Gingerich on TE and ID)


  I must admit I find it hard to digest your rather lengthy responses and be sure I've not missed something, so I'll try and respond to what I see as the main point and try to be brief. I don't have the time to read the large number of lengthy essays that get posted on ASA listserv - if I did there would be nothing else that got done during the day!

  On Tue, Jun 16, 2009 at 2:16 PM, Cameron Wybrow <> wrote:


    We are still not connecting. You write as if I offered this sentence --

    "To disprove the claim that the flagellum is irreducibly complex, one would need to rip out a part of the flagellum and have it still function *as a flagellum* (not as a Type III secretory system)."

    as the basis of an argument that, if the flagellum evolved via Darwinian means, it had to have evolved from a series of less effective flagella, and that as this is impossible, the flagellum could not have evolved by Darwinian means. But this was not what I had in mind when I wrote the sentence. It was intended only to show that your previous remarks (about the possibility of co-opting existing proteins) had not disproved the irreducible complexity of the flagellum, and in fact were based on a misunderstanding of Behe's use of the term "irreducible complexity". That is, *even if it is true* that the flagellum evolved from some earlier system (which could have been the Type III secretory system, or something else) by making use of ready-made sets of proteins, it does not follow that the flagellum, as we have it now, is not irreducibly complex.


    As I said to Bernie, the question "Is this system irreducibly complex?" is distinct from the question "Could this irreducibly complex system have evolved via Darwinian means?" The notion of "irreducible complexity" is not by definition connected with the notion of "unevolvability" (in the way that the notion "having no legs" is by definition connected with the notion "unable to walk"). IC may have *implications* for evolutionary speculations of certain kinds -- Darwinian speculations -- but those implications aren't part of the definition.

    ***"Irreducible complexity" is an "engineering" description of the functioning of a system, not a statement about lack of evolvability. ***

  I'll focus on this sentence as it seems to be the kernel of where we disagree. I think the argument from irreducible complexity is at least a statement that leads to the belief that something couldn't evolve. It's what convinced me when I read DBB, and had me believing that Intelligent Design was a viable proposition for a while, until I found the idea of change of function, when the whole thing collapsed (fortunately I didn't pin my faith on it, so that's still intact).

  Here's what Wikipedia says about Behe:

  Behe is best known for his argument for irreducible complexity, a concept that asserts that some structures are too complex at the biochemical level to be adequately explained as a result of evolutionary mechanisms and thus are the result of intelligent design.

  That certainly states that the implication of irreducible complexity is that evolutionary mechanisms are inadequate to explain complex structures, ie they are not evolvable.

  OK, one might say that Wikipedia is written by a lot of godless liberals and is biased. So let's see what the right wing and creationist friendly Conservapedia has to say about Behe:

  He argues that molecular machines, such as the bacterial flagellum are irreducibly complex. Such machines require all of their parts to function, Behe says, and so could not have come into being through an unguided process. He considers this evidence that the flagellum must have been designed.

  Well, that looks pretty much the same as the Wikipedia entry, with a little more detail.

  Thus the commonly accepted implication of Irreducible Complexity is that unguided evolutionary processes can't account for something and that this is evidence for intelligent design.

  If you want to say that the definition of Irreducible Complexity doesn't exclude change of function, then it's useless for the purpose of drawing the conclusion of design. If all the bits were present and being used happily for something else before forming the flagellum, then that's a whole lot more plausible than if a few dozen absolutely useless pieces of equipment occurred by chance before they came together as a flagellum. In the first case, evolution is plausible and there is no need to draw a design inference, but in the second case, evolution is implausible.

  Miller's example (and all the other information we have of proteins in the flagellum having other uses) tend one towards the first case.

  Which brings me back to my main point. If irreducible complexity only applies to the function of given system and not other systems that might have evolved earlier, then the only response has to be a big "So what?"



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Received on Tue Jun 16 16:56:28 2009

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