trex Critique of "Irreducible Complexity Revisited"

Thomas D. Schneider

This page analyzes and dissects the following paper:

Irreducible Complexity Revisited (pdf) by William A. Dembski, PCID 3.1.4, November 2004, version 2.0, revised 2.23.04 posted at www.iscid.org
It focuses on page 18, section 3, Scaffolding and Roman Arches.

Let's dissect this.

Having laid out the basic definitions and general logic underlying the argument from irreducible complexity, let's now consider the two main objections that Darwinists have raised against it.
nothing (i.e. this is not an argument - it is just words)
I'll deal with one objection in this section and the other in the next.
nothing
These objections attempt to show that an irreducibly complex system could, on closer examination, have been produced by gradual increments apart from design.
correct
According to the scaffolding objection, for evolution to produce an irreducibly complex system, first some nonirreducibly complex system needs to arise by mutation and selection incrementally adding components.
There is no 'need'. It happens.
Then, at some point, a subsystem arises that is able to function autonomously (i.e., without the rest of the system).
A subsystem?? He means that part of the system does the whole job.
Since it can function autonomously, the other components are now vestigial and drop away.
Right.
When all have dropped away, we have a system that is irreducibly complex.
Right, but this shows that it is an empty concept.
In short, what appears to be a qualitative difference is really only the result of a lot of small quantitative changes.
Right
The scaffolding objection thus claims that eliminating functional redundancy is a plausible route to irreducible complexity.
sure.
If you will, instead of evolution achieving irreducible complexity from the bottom up by gradually adding components to a system, irreducible complexity is supposed to arise from the top down by taking a system and removing redundant components.
Ok.
For instance, there are situations in which, according to Thomas Schneider, "a functional species can survive without a particular genetic control system but ... would do better to gain control ab initio."12 In such situations, Schneider continues,
just quoting
Any new function must have this property until the species comes to depend on it, at which point it can become essential if the earlier means of survival is lost by atrophy or no longer available. I call such a situation a "Roman arch" because once such a structure has been constructed on top of scaffolding, the scaffold may be removed, and will disappear from biological systems when it is no longer needed. Roman arches are common in biology, and they are a natural consequence of evolutionary processes.13
just quoting
To build a Roman arch requires a scaffold.
No, There are at least two other methods. it could be built whole and then raised. It can be built by tiny increments: 
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So long as the scaffold is in place, pieces of the arch can be shifted in and out of position.
correct
But once all the pieces of the arch are in position and the scaffold is removed (i.e., redundancy is eliminated), each of the pieces of the arch becomes indispensable and the arch itself forms an irreducibly complex system.
Ok.
But there are two problems here.
empty claim
First, strictly speaking a Roman arch is not irreducibly complex.
It fits Behe's definition. It fits Dembski's definition on page 2 of his paper: "A functional system is irreducibly complex if it contains a multipart subsystem (i.e., a set of two or more interrelated parts) that cannot be simplified without destroying the system's basic function." Take out one of the stones and the arch will likely collapse.
Yes, each of the pieces of the arch is indispensable in the sense that if you remove a part, the remaining parts cannot be rearranged to form an arch.
Wrong, take out the keystone and the arch might (!) fall back in place.
But a Roman arch is simplifiable---a single, solid piece of rock can be made into the same shape as the arch, thereby performing the same function as the arch and doing so in essentially the same manner.
Hmm. He is shooting himself in the foot. That's one of the methods he failed to mention earlier.
Even so, one might argue that the failure of a Roman arch to be, strictly speaking, irreducibly complex is not all that serious.
He has not proven that it is NOT irreducibly complex yet!
A Roman arch, after all, is functionally integrated, and so the question remains whether scaffolds constitute a plausible route to functionally integrated systems generally and thus perhaps to irreducibly complex systems in particular.
This just muddies the water. Dembski's definition of 'functionally integrated' is on page 2: "Irreducibly complex systems belong to the broader class of functionally integrated systems. A functionally integrated system consists of parts that are tightly adapted to each other and thus render the system's function highly sensitive to isolated changes of those parts." So according to Dembski, the Roman arch is "functionally integrated" but not "irreducibly complex". But he thinks it's not irreducibly complex because you can make an 'arch' using a single block. But then no systems in biology are 'irreducibly complex' simply because there are routes to them from simpler systems. Also, one might make an arch by other routes, such as piling up earth first. Behe's definition was clear.
Notwithstanding, there is a more serious problem with the scaffolding objection.
Empty statement, the previous material didn't hold any water!
Consider what it would mean for Darwinian evolution to produce an irreducibly complex system like the bacterial flagellum by means of a scaffold.
Empty statement
The Darwinian selection mechanism acts by taking advantage of, or selecting for, an existing function.
That's only part of the picture. There is also mutation to create MANY variations and replication to create many copies.
What's more, an irreducibly complex system like the bacterial flagellum obviously exhibits a basic function that is selectable.
This statement is missing the fact that the initial function of the flagellum could have been something else!
It follows that the bacterial flagellum plus any putative scaffold exhibits that same basic function, though the scaffold, by now being redundant, is destined to be eliminated by natural selection.
So, working backwards, he takes the functional system and imagines the redundant material and removes it and ...
So let's ask the following question: In building up to the aggregate system of irreducibly complex system plus scaffold, when did the basic function arise?
A nice question. "When" did the recognizer in Ev find the binding sites?
With a bacterial flagellum plus scaffold, for instance, when did bidirectional rotary motion for propelling the bacterium through its watery environment arise?
Another question.
Scaffolding does nothing to change the fact that the basic function of an irreducibly complex system arises, by definition, only after all the core components of that system are in place.
He can't see that the function arises in small steps.
Given an irreducibly complex system to be explained by scaffolding, the challenge for the Darwinist is to identify a sequence of gradual functional intermediaries leading to it.
A challenge, not an explanation.
These need to start from some initial simple system and eventually lead to an irreducibly complex system plus scaffold, whereupon natural selection then discards the scaffold once it becomes redundant.
Take the Ev program as an example.
Even though the scaffold can help build the irreducibly complex system, the scaffold is specifically adapted to the basic function of the system it is helping to construct (e.g., the flagellum).
Wrong. He is thinking about physical wooden or metal scaffolds rather than a pile of earth (for example).
What's more, the only evidence of that basic function is from the irreducibly complex system itself.
No, for example, there are many intermediate stages to eyes known if you read actual biology papers! This is not 'evidence'.
Thus, for the Darwinian mechanism to produce an irreducibly complex system by means of a scaffold, the system plus scaffold must have served a different function up until all the core components of the final irreducibly complex system became available, snapped into place, and formed a functional system.
It doesn't have to be sudden.
But in that case the scaffold metaphor becomes inappropriate---a scaffold, after all, is for constructing a structure serving a definite function and not for evolving structures whose functions are likewise evolving.
It is an example of how a supposedly 'irreducibly complex' system can come into place by incremental change.
That brings us to the next, and indeed principal, objection that Darwinists have raised against the argument from irreducible complexity.
Empty sentence.
12 Thomas D. Schneider, "Evolution of Biological Information," Nucleic Acids Research 28(14) (2000): 2794.

13 Ibid.

There is no argument here!

Dembski cites the Ev paper but he does not deal with it. The Ev program clearly generates an 'irreducibly complex' system, precisely as defined by Behe, and it does so using a purely evolutionary mechanism. Thus Behe's idea collapses. Ignoring this challenge is not a valid response! Dembski was clearly aware of this challenge because he cited the Ev paper. Trying to change the definition would be a valid response, but Dembski does not do this and Behe has never suggested any variation.

Dembski's problem is that he is stuck in thinking about the current function of the system. He can go and look at the Ev program to see how the system is built up by small incremental steps. In the end one has a recognizer that recognizes a set of binding sites perfectly. If you remove any site or mutate the recognizer, that organism is instantly in the half that gets killed by the next generation. So it is 'irreducibly complex' - removal of any part destroys the system, by selection! Yet it appeared by a purely Darwinian mechanism. Thus Behe's thesis collapses and Dembski's defense fails.

Mark Perakh's commentary on Dembski paper: 774 614 836 602.




Schneider Lab
origin: 2005 Jun 16
updated: 2005 Jun 16