As a historian of science I enjoy observing the behavior and argumentative strategies of critics of intelligent design (ID) theory. Often such critics say that ID does not stimulate new research or is not scientifically testable. Nevertheless, the "irreducible complexity" component of the intelligent design theory has been tested numerous times and it has stood its ground quite well. Thus, this component of ID is testable and has contributed to scientific research. At ENV there is a technically challenging review of a chapter of a recent book that illustrates my point. The reviewed book chapter is entitled "Irreducible Complexity? Not!" I shall offer a simple summary of that review here.
First some background pulled from the Parent's Guide to Intelligent Design that I mentioned in my last blog:
In applying ID to biology, ID theorists often discuss “irreducible complexity,” a concept popularized and elaborated by Lehigh University biochemistry professor Michael Behe. Irreducible complexity is a form of specified complexity, which exists in systems composed of “several interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning.”
Because natural selection only preserves structures that confer a functional advantage to an organism, irreducibly complex systems would be unlikely to evolve through a Darwinian process because there is no evolutionary pathway wherein they could remain functional during each small evolutionary step. According to ID theorists, irreducible complexity is an informational pattern which reliably indicates design, because “[i]n all irreducibly complex systems in which the cause of the system is known by experience or observation, intelligent design or engineering played a role [in] the origin of the system.”
In the "Irreducible Complexity? Not!" chapter of the book Microbes and Evolution: The World that Darwin Never Saw, two of the world's leading experts on bacterial flagellar assembly weigh in on ID theory in this tiny domain of life. The fact that they claim to refute the "irreducible complexity" component of the intelligent design theory, but then fail to refute it successfullly, is telling. It is one of many indications that ID is good for science. Darwinists are engaging specific theories crafted by ID advocates, and finding it hard to refute these specific theories.
This attempt to refute the irreducibly complex status of the bacterial flagellum fails because the subsystems of the bacterial flagellum that microbiologists have discovered operating in various bacteria speces in various non-flagellar functional capacities does not give us knowledge of a plausible path of evolutionary change by which all these subsystems could have been brought together and integrated into a functioning outboard motor (flagellum) for bacteria. Also, only a few of these clusters of flagellar motor parts are unnecessary for outboard motor function in bacteria. The majority of those parts have to all exist and have to all be coordinated just right to get any outboard motor function whatsoever. As the review explains, the indespensible nature of most of these parts is proven by mutating the gene or genes that code for these parts and then observing non-motility (lack of outboard motor function) in the bacteria.
Here is how ENV concludes its review:
To conclude, the claim of Hughes and Blair to have refuted Behe on the bacterial flagellum is unfounded. Although there are sub-components of the flagellum that are indeed dispensable for assembly and motility, there are numerous subsystems within the flagellum that require multiple coordinated mutations. The flagellar motor is not the kind of structure that one can at all readily envision being produced in Darwinian step-wise fashion. Read more.
Would you like to watch Dr. Behe lecture at the University of Toronto on the topic "What Are the Limits of Darwinism?" Go here to do so. In this public lecture Behe shows what is woefully weak within evolutionary theory.