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Ken Miller talks about the bacterial flagellum

Succinct refutiation of the "Irreducible Complexity" design argument


evangelical said…
Ken Miller's basic argument here is that ID crumbles if IC crumbles and then goes on to explain why the bacterial flagellum is not irreducibly complex (or IC). But I think that Mr. Miller has misunderstood the concept of IC (and, incidentally, ID).

I remember reading once a counter-rebuttle by Mr. Behe regarding the build-a-better-mousetrap challenge. The idea is that a mousetrap qua mousetrap needs all of its parts to function. In other words, according to Behe, it is IC.

The critic (I forget who he was) went on to explain that a mousetrap may be made of a single wire, manipulated in a particular way (by an intelligent designer?) on the floor. The mouse walks up to it and gets inadvertantly ensnared. So, says the critic, a mousetrap is not IC after all.

However, in Behe's counter-rebuttle, he stated that this so-called better mousetrap still had all the same parts required for functionality that a traditional mousetrap has. For example, instead of the traditional base (normally made out of wood, of course, with the other parts attached to it), the floor now serves as a nontraditional base. It seems to me that one really can't argue with such a counter rebuttle.

So what is the point? Well, imagine that we are having a conversation with Behe about our nontraditional mousetrap. We ask, "before adding the (intelligently designed?) wire to the floor, did the floor serve a purpose?" I don't wish to put words in his mouth but I can only suppose that he no doubt would admit that the floor, say, held up the house. So it seems that even Behe would admit the possibility that what shall later become a piece of a complex system may have functionality before hand. It is not, I think, functionality with respect to the as yet non-existent complex system, but nevertheless, it is not totally functionless as Miller implies it must be on Behe's view.

It seems therefore almost certain that Miller has misrepresented IC and, by implication, ID. I think that I am correct in saying that Miller's objection is the most common criticism of the ID movement. And so, we may only conlude, that there might really be something to "trojan-horse creationism" after all.
exapologist said…
Hi Evangelical,

Thanks for your response. I see your point about the reply to the criticism -- the one where there was an irreducibly complex system in the revised mousetrap (b/c in that case, there were just different parts that played the same roles as a standard mousetrap). Your point is well-taken.

However, that doesn't seem to be the point MIller is making here. To clarify: let's distinguish two claims involved in Behe's argument:

(i) At least some biochemical structures are irreducibly complex (i.e. some structures are such that they require all of their parts to perform their function. I.e., if you eliminate one or more parts, it can't perform that function at all).

(ii) Irreducibly complex structures can't be created in step-wise evolutionary fashion.

Now the point you raise in response to Miller is aimed at (i). However, that doesn't address Miller's point. For he's critiquing (ii). His point here is that while it may be true that some functional entity is composed of a set of parts, all of which it needs to perform its function, that entity could still have evolved in step-wise evolutionary fashion. And the way it could do so is as follows:

Time t1: x1, composed of parts A, B, and C, requires all those parts to perform its function F.

Time t2: x1 changes into object x2, by adding part D to existing parts A, B, and C. And together, these parts perform a new function G.

In short, an object with a set of parts required to perform a funciton can evolve from an antecedent object with one or more less parts that performed a different function. MIller backs this up with plausible scientific details, involving a sequence of actual biochemical systems.

Paul Draper has written a nice, careful article in Faith and Philosophy that spells out the details of the logic here. So I think the combination of the logical model and the plausible evolutionary sequence provide an undercutting defeater for Behe's claim.

However, I agree with you that ID doesn't depend on IC. So, for example, Dembski and Meyer argue against evolutionary theory on the grounds that some biological structures (e.g., DNA) exhibit complex, specified Shannon information, and that such information can't arise from non-intelligent causes (as he argues by way of his notion of an explanatory filter). As you nicely point out, those arguments must be dealt with independently of IC, even if IC is undercut.


evangelical said…
I just rewatched the clip above. Is Miller arguing that at t1 we have the type III secretory system (fully functional) then at t2 we have the bacterial flagellum? I would be hard pressed to deny it. But the problem is that that is a straw man. Once Miller admits, as he does in the clip, that the bacterial flagellum serves a different function than the type iii secretory system he has stepped out of the realm of IC. Is this his point? Perhaps it is but he wants us to think that that is the idea Behe is proposing. In other words, Behe's definition of an IC system allows for such a movement and Miller has misrepresented, very badly, the whole concept of IC. It is my understanding that Behe (and other proponents of IC) have continually pointed out this misunderstanding to critics, including Miller, yet nobody seems to be paying attention. If one has evidence in neo-darwinism against ID or IC then one is free to appeal to it as such. However, it does nobody any good to redefine IC as something it is clearly not and then argue against what IC is not. Such a move is misleading at best and downright dishonest at best. Weren't the people who are now arguing against the ID movement, the same people who, a few years back, were complaining that young-earth-literalistic creationists will quote them (the evolutionary biologists) out of context and misrepresent what they are saying?
exapologist said…
HI Evangelical,

I'm not sure I follow the point you're making: what is it about the fact that the two structures serve different functions that makes MIller's point irrelevant to Behe's argument?


evangelical said…
Okay EA, here is the point I am trying to make. Behe says, "IC may be defined as x." Then Miller says, "according to Behe, IC is defined as some thing other than x." He (i.e. Miller) goes on to refute "some thing other than x." Finally, Behe says, "of course 'some thing other than x' is false-contrary to what Miller says, I have never affirmed this 'some thing other than x' and have always admitted it was false."

In other words, Miller is debunking a straw man in the above video clip.

Perhaps a quote from Wikipedia's article "Irreducible complexity" shall be helpful here:
"Biochemistry professor Michael Behe, the originator of the argument of irreducible complexity, defines an irreducibly complex system as one "composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning"."

It is interesting that whoever wrote this article did not seem to realise, right after giving the definition, that an argument like that of Miller's totally misrepresents the point Behe was trying to make. Be that as it may, we see, in Behe's own definition, that a. the parts must be well matched (requiring ID?) and b. it is the system itself which no longer functions with the removal of a part. To say that a bacterial motot functions as a pathogenic injector is to admit Behe's point. Romove a part and destroy the motor not remove a part and destroy all functionality in an unqualified sense. Apparently the idea or IC as Behe envisions it is that, yes, you could have many fully-functional parts put together to produce a new system. However, who is going to put the parts together? An intelligent designer would seem to be needed for this. And what is more, it is not necessary that the intelligent designer immediately create without evolutionary processes.

Whether you agree with me or not, do you now understand what I am trying to say?

Talk to you soon dood.
exapologist said…
Hi Evangelical,

Hmm. It seems that we should provide a framework for this discussion to serve as a point of reference. How about this:

Miller is addressing Behe's argument that occurs in his Darwin's Black Box, the structure of which is laid out in the first 40-50 pages or so of the book. On p. 39 of my copy, Behe defines an irreducibly complex structure as one "composed of several well-matched, interacting parts that contribute to the basic function, wherein removal of any of the parts causes the system to effectively cease functioning."

With Behe’s definition of an irreducibly complex structure in place, the relevant portion of his argument can be expressed as follows.

1. There are irreducibly complex biological structures.
2. If there are irreducibly complex biochemical structures, then if evolution is true, then evolution can create such structures via a gradual process.
3. Evolution can’t create such structures via a gradual process.
4. So, evolution is false.

The argument is valid; so, if the premises are true, then the conclusion follows of necessity. Now Miller grants (1) and (2) in the video. But why are we supposed to accept (3)? Miller gives Behe’s key line of reasoning in support of (3) 25 seconds into the clip:

“[A] An irreducibly complex system cannot be produced directly by numerous, successive, slight modifications of a precursor system, because [B] any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional.”

And the key point that Miller is making in the clip is that the move from [B] to [A] in this line of reasoning in support of (3) fallacious. To see this, recall Behe’s definition of irreducible complexity I mentioned from p. 39 of my copy:

An irreducibly complex structure is one "composed of several well-matched, interacting parts that contribute to the basic function, wherein removal of any of the parts causes the system to effectively cease functioning."

But as Miller argues, that definition only rules out

(1) There is an evolutionary precursor to an irreducibly complex structure that has no function.


(2) There is an evolutionary precursor to an irreducibly complex structure that has a different function.

But Behe needs (2) as well as (1) to rule out evolutionary pathways to irreducibly complex structures. And Miller is arguing that there's a plausible sequence whereby evolution produced irreducibly complex structures by the sort of route suggested in (2). The sequence Miller has in mind is that of the sort I mentioned in a previous comment:

Time t1: x1, composed of parts A, B, and C, requires all those parts to perform its function F.

Time t2: x1 changes into object x2, by adding part D to existing parts A, B, and C. And together, these parts perform a new function G.

Now you argue that this is of no help, since the precursors Miler mentions are themselves irreducibly complex. But, first, notice that this sort of response grants, at least for the sake of argument, Miller's point that Behe's argument fails (as it grants, at least for the sake of argument, that (3) is false or otherwise insufficiently justified). For then we're no longer arguing that no irreducibly complex structure could have evolved, but rather that not all irreducibly complex structures could've evolved. Perhaps your revision of the argument can be expressed, then, as follows?

1. There are irreducibly complex biological structures.
2’. If there are irreducibly complex biochemical structures, then if evolution is true, then evolution can create all such structures via a gradual process.
3’. Evolution can’t create all such structures via a gradual process.
4. So, evolution is false.

Like the previous argument, this argument is valid as well; so, if the premises are true, the conclusion follows of necessity. But my worry is that Miller’s argument in the clip has the materials to undercut the line of reasoning in support of (3’) of the revised argument just as much as it undercuts the line of reasoning in support of (3) in the original argument. To see this, notice that Miller has suggested a recipe for generating irreducibly complex structures via gradual evolutionary sequences:

Step 1: Take a structure x, composed of parts a1-an, with function F.

Step 2: Add a new part an+1 to x, with the result that the structure performs a different function G.

Given this recipe, it looks as though we can generate a complete gradualistic evolutionary chain of irreducibly complex structures. For if each irreducibly complex system in an evolutionary chain evolved from a slightly less sophisticated structure with a different function in this way – i.e., by adding a part to each predecessor structure in a way that changes the function – then there seems to be no obstacle in principle to starting the process with a simple, one-piece entity x with function F, and then having x combine with a new piece y, with the result that xy performs a new function G. From there, we get all the new structures via the sort of evolutionary recipe I mentioned earlier.

So I’m inclined to think that Miller’s point in the clip has considerable force against Behe’s argument, as well as the revised version I constructed above.
evangelical said…
EA, we are making some real progress here (or at the very least, having an intelligent disagreement). I say this because we are going back to the definition of IC, as it were, straight from the horses mouth.

Let me see if I understand the current state of the discussion. I appeal to the definition and say, "it allows for Miller's pseudo-counter example." Then you appeal to the same definition and say, "no evangelical, it is you who have misunderstood the definition, not Miller, and Miller does persuasively debunk the concept of IC." Is this where we are in our dialogue together? I want to make sure we are both on the same page and not talking past one another. That is an all too common tendency, I think, in debate. Do you agree with this summary of our discussion?

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