Playing Devil’s Advocate: Sudden Origins and Irreducible Complexity
|February 20, 2006||Posted by Patrick under Evolution, Intelligent Design, Darwinism|
One thing that has always irked me is that rarely on this site do we find any critics of ID attempting to challenge the tools/methods of ID directly. For example, one could claim that “CSI isn’t a reliable indicator of intelligence” or “the explanatory filter breaks down under certain conditions” or “ID regularly produces false positives under x conditions” or “Irreducible Complexity can indeed be overcome via a Direct Pathway” and then show why and/or how. Instead, arguments are almost always made against the implications or we’re arguing over the interpretation of various data. Perhaps these challenges are not made because it’s so difficult to make sustainable arguments in this regard but I’d like to at least see people try. As such, I decided to make a topic on this myself with the last challenge to ID as the subject: “Irreducible Complexity can indeed be overcome via a Direct Pathway”
Behe has claimed there isn’t an evolutionary mechanism that can hope to overcome the IC information barrier via Direct Pathways. The possibility of Indirect Pathways does nothing to change the fact that forming a complex machine via a Direct Mechanism like RM+NS appears impossible. The role of Direct Pathways are, by definition, what makes the bacterial flagellum IC in the first place. The existence of possible Indirect Pathways does not change the designation of IC. But what if another evolutionary mechanism besides the modern synthesis aka Neo-Darwinism/RM+NS is capable of forming an IC structure Directly?
A quick refresher on Jeffrey Schwartz’s Sudden Origins:
The mechanism, the authors explain, is this: Environmental upheaval causes genes to mutate, and those altered genes remain in a recessive state, spreading silently through the population until offspring appear with two copies of the new mutation and change suddenly, seemingly appearing out of thin air. Those changes may be significant and beneficial (like teeth or limbs) or, more likely, kill the organism.
First off, I’ll admit I have not read Schwartz’s book on the subject so I may not do a good job of representing it. As an overall concept it seems to me that these “genes in a recessive state” are like a temporary buffer. In every generation changes are made to this buffer via random mutations, but without harming the survivability of the organisms. If this buffer is implemented before it’s a functional design Natural Selection will kill the organism off. Eventually it’s claimed the mutations in this buffer will result in a successful design and then will be merged with the rest of the organisms. The key to a Direct Pathway is that the evolving mechanisms keep the same function during each revision. Sudden Origins avoids this problem by making it so the function is only required to be active in the final form. By this manner Sudden Origins produces IC Directly.
So unless I’m missing something (besides the obvious possibility–read: I don’t know–of reality not meshing with the details of Sudden Origins) Schwartz’s work in its basic form appears to at least offer a “conceptual challenge” to Behe’s Irreducible Complexity. I myself heavily doubt the validity of Sudden Origins but it would be interesting to point out that it might be a “solution” to the IC Problem which at least is a far better answer than clinging to implausible Indirect Pathways. Schwartz’s own theo…er, posited idea seems to rely far too much on Homeobox genes to do its magic but the concept of a separate buffer where new design plans can be tested and modified without harming the survivability of the species is an interesting one.
Here is a book review of Sudden Origins:
Now that I’m done playing Devil’s Advocate, let me review at a high level the basics of how Homeobox genes work. Homeobox genes determine which genes are expressed and which are not during genetic development. They basically give instructions to build certain components in specific coordinates. Thus, mutations in Homeobox genes can be cause large scale changes. They are also very similar throughout all life. The Pax-6 regulatory group–which is about 130 amino acids long–shares a 94 % similarity between humans and insects. Zebra fish and humans are even closer at 97 percent.
To give a more common example, Homeobox genes resemble a construction site foreman who orders groups of workers to build various building structures in a particular location. However, it’s important to note that this particular foreman doesn’t know how to build walls or windows himself. He just knows how to give orders and couldn’t wield a hammer to save his life. Despite this, the different workers know exactly how to construct the particulars of the items that they are instructed to build. Some workers know how to build concrete walls and others brick walls, windows, archways, etc. In laymen’s terms, without these specialty workers, our foreman is out of a job.
Similiarly, Homeobox regulatory genes work at a high level and don’t get too involved in the details of what they regulate. Even so, Homeobox genes are still extraordinary powerful which is Schwartz relies on them for Sudden Origins. They can “decide” what goes where and how many components get built. But what Homeobox genes cannot is what is truly revelant to this discussion. Homeobox genes do not create *new* genetic information in the traditional sense. Mutations in these regulatory gene sets can cause biological components to not be built (an animal losing their hind legs). They can result in more than the correct number of elements being built (as in the case of Hox-4.6 in chickens which create an extra “thumb”). They can even result in the construction of components in the wrong places. Ultimately, manipulations to these genes can only result in the rearrangement of elements already present in the biological development plan for a given organism.
Homeobox genes reveal complexity, structure and a hierarchical approach to biological development. All of which speak of designer re-use. Any engineer worth his degree realizes the importance and benefit of well organized subsystems. Indeed, these genes represent a level of biological abstraction that Darwinism did not predict. Not to mention, how do you gradually evolve a regulatory gene in the first place? What value does a regulatory gene serve without the genes that know how to “build” components? And if the genes that “build” components existed prior to the appearance of regulatory genes then what selective short term advantage by itself would the ability to regulate other genes have?
A couple weeks back a critic of ID posed the case of humans born with “tails”-a couple extra vertebrae in the spine. I wouldn’t be surprised if these incidents could be traced back to mutations in homeobox genes. But instances of finite macro-level changes do little to advance their case against ID.