Dear Discovery Institute,
Today I have been thinking about the work of Michael Behe of Lehigh University. Behe's concept of irreducible complexity appears sufficient to support Design theory, until it is critically considered at least. Today we will investigate exactly why the concept of irreducible complexity is flawed, and requires more support before it is accepted as a valid scientific concept.
First, we will critically consider some of "Darwin's Black Box", considered by many to be the seminal work (along with Philip Johnson's "Darwin On Trial") on Intelligent Design. First, Behe seems to confuse the definition of evolution (the diversification of life) with that of abiogenesis (the origin of life). Lets hear it in his own words:
evolution means a process whereby life arose from non-living matter and subsequently developed entirely by natural means. (Behe 2006 p.xi).
While the natural cause explanation clause is a major part of the definition of science (Behe has that statement correct),he is obviously confused about the very definition of Darwinian evolution, the theory which his entire book attempts to debunk. That fact raises major credibility questions. However, lets give Behe the benefit of the doubt for now. Let's consider his irreducibly complex structures.
Behe's poster child for irreducible complexity is the bacterial flagellum. If this stucture can be shown to be "evolvable", then this raises major questions about the validity of irreducible complexity. NJ Matzke has done just that with his article "Evolution in (Brownian) space: a model for the origin of the bacterial flagellum". While I suggest reading his entire piece (cited and linked below), here is the abstract of Matzke's piece, which shows exactly why the words "irreducibly complex" fail to describe the bacterial flagellum:
"The bacterial flagellum is a complex molecular system with multiple components required for functional motility. Such systems are sometimes proposed as puzzles for evolutionary theory on the assumption that selection would have no function to act on until all components are in place. Previous work (Thornhill and Ussery, 2000, A classification of possible routes of Darwinian evolution. J Theor Biol. 203 (2), 111-116) has outlined the general pathways by which Darwinian mechanisms can produce multi-component systems. However, published attempts to explain flagellar origins suffer from vagueness and are inconsistent with recent discoveries and the constraints imposed by Brownian motion. A new model is proposed based on two major arguments. First, analysis of dispersal at low Reynolds numbers indicates that even very crude motility can be beneficial for large bacteria. Second, homologies between flagellar and nonflagellar proteins suggest ancestral systems with functions other than motility. The model consists of six major stages: export apparatus, secretion system, adhesion system, pilus, undirected motility, and taxis-enabled motility. The selectability of each stage is documented using analogies with present-day systems. Conclusions include: (1) There is a strong possibility, previously unrecognized, of further homologies between the type III export apparatus and F1F0-ATP synthetase. (2) Much of the flagellum’s complexity evolved after crude motility was in place, via internal gene duplications and subfunctionalization. (3) Only one major system-level change of function, and four minor shifts of function, need be invoked to explain the origin of the flagellum; this involves five subsystem-level cooption events. (4) The transition between each stage is bridgeable by the evolution of a single new binding site, coupling two pre-existing subsystems, followed by coevolutionary optimization of components. Therefore, like the eye contemplated by Darwin, careful analysis shows that there are no major obstacles to gradual evolution of the flagellum." (Matzke 2006).
There it is, right in Matzke's article. An allegedly "irreducibly complex" structure shown to be evolvable. Science once again trumps the Intelligent Design movement. Bad arguments in favor of supposed design do not qualify as science, especially when the "designer" in question, as well as the presence of "design" itself, remains inherently untestable.
But let's play Behe's game. The blood clotting mechanism in blood is Behe's other major "irreducible complex" structure. And as with the bacterial flagellum, it is shown to be evolvable. For example, check out the work of Kenneth Miller (a good rebuttal to Behe's blood clotting argument is available on the following site, which will not be cited because it is linked within the text: http://www.millerandlevine.com/km/evol/DI/Clotting.html )
On the site linked, Kenneth Miller does an absolutely beautiful job of refuting Behe's research on "irreducible complexity". It's sad that so many people have accepted Behe's concept of irreducible complexity when he has not even been able to provide an "irreducibly complex" structure that has withstood scrutiny. All of his examples have been shown to be evolvable. The argument from personal incredulity is not a valid argument to use to disprove Darwinian evolution. Strong evidence in favor of your viewpoint is provided. Behe has failed to provide this.
In conclusion, while scientists are still working to understand the exact nature of abiogenesis (the origin of life), that fact does not make Darwinian evolution false. Darwinian evolution does not attempt to explain how life arose; it only explains how it has subsequentially diversified. Those people claiming that evolutionary theory is sufficient to explain the origin of life are grasping at straws. Darwinian Natural Selection, by nature, requires reproduction to occur, which, in turn, requires life to be in existance. Darwin's black box? Not quite.
Behe, MJ. "Darwin's Black Box: The Biochemical Challenge to Evolution". Free Press, NY. 2006. 10th Anniversary edition.
Matzke, NJ. "Evolution in (Brownian) space: a model for the origin of the bacterial flagellum". originally published 2003, updated 2006. http://www.talkdesign.org/faqs/flagellum.html