"Irreducible Complexity and The Problem of Biochemical Emergence"

Bruce Weber,

Dept. Chem. Biochem. CSU Fullerton.

Biology and Philosophy 14:593-605 (1999).

Reviewed by David Tyler

Ó 1999 David Tyler

This article is another critical review of Michael Behe's book, "Darwin's Black Box," covering much of the same material included in other reviews but also including some commentary on the two years since the original publication of Behe's book, and referencing prior reviews.

Weber does include many of the same issues raised by others, but I find his general argument fascinating.

In brief, Weber does not respond using any of the standard neo-Darwinian arguments. There is nothing of the "Climbing Mount Improbable" approach here to explain the origin of complexity. Rather he builds his response around self-organization and emergence. "[Behe] virtually ignores a whole area of current research on self-organizing, emergent phenomena" (p.595).

Weber has a paragraph on the bacterial flagellum. After reviewing a number of issues, he writes: "The self-organizing tendencies of biochemical systems may help guide the formation of complex, pattered structures that can subsequently acquire functional value for which improvements can be selected. This does not pretend to provide a complete explanation, but it does suggest directions for future research .. .." (p.595) This argument is typical of many others, and from it I note two things. First, there is a tacit admission that neo-Darwinism is not delivering a satisfying response to Behe.

Second, that a full response to Behe cannot be put together at this point in time, so an exploratory, initial response is necessary - pointing to where the answers may come. Similarly, in the discussion of blood clotting, the response it to point the way to a discovery of answers. "We are at the point of accumulating enough data from DNA sequences and three-dimensional structures of proteins to make a number of tests of putative evolutionary explanations in the near future". (P.597).

Although Behe does not major on abiogenesis, Weber devotes several pages to discussion of this topic, primarily focusing on emergence and self-organization. Stuart Kauffman, for example, is suggested to have provided "important insights". Whilst Behe does briefly critique Kaufmann, Behe is far more concerned about the answers neo-Darwinism gives to the origin of irreducibly complex systems. Weber may have things he wants to say here, but they are hardly adequate responses to Behe.

After abiogenesis, Weber does move on to the domain of Darwinian evolution. But he does not wish to relinquish his interest in emergence and self-organization. "Selection may not have to do everything, nor only in a gradual manner, since selection can be allied with self-organization to generate order and organization, sometimes in a global manner. Clearly, neither does self-organization have to do everything by itself. Nor should any rational person expect that chance alone could generate order out of chaos. All three should be considered as acting together, to various degrees in specific instances, in order to generate robust explanations of emergence. The application of 'complex systems dynamics' to biological problems is still in its infancy". (p.600).

I have quoted this at some length because it seems to me (a) that although Darwinians could adopt this emphasis, it has not emerged from mainstream neo-Darwinism, (b) that the major answers necessary to respond to Behe are suggested to come from complex systems dynamics, which is still in its infancy. (b) seems to me to suggest that the established neo-Darwinian views are impotent to address Behe's argument.

To reinforce this latter point, take Weber's comment on page 601: "We can respond to [Behe's arguments] in at least two ways. First, biologists with greater imagination and information may come up with explanations invoking only selection; second, the application of complex systems dynamics may show how to understand the emergence of the type of functional complexity that concerns Behe. Either is an incomplete work in progress, which is the characteristic of a living science that works with a human perspective". In other words, we do not have satisfactory answers yet!


So why not acknowledge that Behe may be right and that the data compels us to make the design inference? "The demand for an immediate and complete explanation that can only be satisfied by a "God's-eye view" would not create a new paradigm so much as inhibit research on the problem of emergence. The very idea is inconsistent with the fundamentals of science". (p.601). So there we have it: 'Behe cannot be defeated by logical argument (with our present state of knowledge), so we portray his view as inhibiting research and we apply a demarcation principle so that the design inference lies outside science altogether.'

One further avenue is explored in Weber's critique: that of developmental biology. "It can take remarkably few genetic changes to produce major morphological changes. .. .. A given trait or complex structure might arise from a rather small number of changes in organization of the developmental genes, taking advantage of duplicated and divergent genes that may have arisen by neutral or self-organizational processes. Developmental biology is being transformed by molecular genetics, and problems for evolutionary biology that might seem intractable to Behe, or indeed many others, may soon be tractable". (p.602).

Here again I observe two things: (a) that if evolutionary change is thus explained by this type of developmental change, the traditional arguments of neo-Darwinism are revealed to be suited only to explain minor adaptations (finch beaks and lizard legs) driven by natural selection. (b) that if the major evolutionary innovations are linked to mutations in the developmental genes, we are back into a discipline in its infancy. There is much talk, but very little hypothesis testing. The outcomes may well turn out to be contrary to Weber's expectations.

Weber adds: "A number of ways in which developmental biology might inform evolutionary theories lie outside of the Darwinian Research Tradition. One new approach, however, that may be compatible with Darwinism is Developmental Systems Theory. This approach, which emphasizes the role of the entire organism's life cycle on the developmental pattern, shares at least some conceptual territory with the complex system dynamic approach to evolution in a mutually illuminating manner." (p.602)

As I indicated at the outset, I find this very interesting. The preponderance of "may be", "we will probably see", and "it might have been possible" phrases reveals a highly tentative position that is on the defensive against Behe's argument. Intellectual credibility is preserved only by the assertion that the understanding Behe offers lies outside science. Neo-Darwinism has little to contribute: but if we think hard enough, we might be able to find a niche for it in the emerging theory of evolution, so that we can talk about "progress" rather than a paradigm shift.

I confess to having an interest in this debate, because I have a review article of Behe's book on the web. http://www.pages.org/bcs/bcs081.html. After reading this critique, I can think of a number of ways of strengthening my recommendation that people read and digest what Behe has to say.

On a number of occasions, I have commented on the problem that Theistic Evolutionists (or fully-gifted creationists) have in addressing the topic of design. At very least, I would expect these people to see the necessity for emphasizing self-organization and emergent phenomenon in order to realize God's design conceptualization. At least, this allows the Christian who believes in design to develop a coherent position. However, the only writer to do this is Michael Denton ("Nature's Destiny") - who rightly sees that this means a rejection of the relevance of neo-Darwinian theory.

The Weber review stirs me to return to this argument: many people who are outside the Christian community are seeing the impotence of Darwinism and are exploring other avenues. Why is it that the Christian Theistic Evolutionists are so accommodating to neo-Darwinism, which is so strong on theory but so weak when it comes to handling the data of science?