He writes about "complex specified information" (CSI) and "irreducible complexity" (IC). According to Barry Arrington ...
The answer is that the hypothesis is, in principle, falsifiable.We need a good definition of irreducible complexity. I like the one proposed by Michael Behe in Darwin's Black Box.
All it would take is even one instance of CSI or IC being observed to arise through chance or mechanical necessity or a combination of the two. Such an observation would blow the ID project out of the water.
By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional.If you read this carefully you'll see the catch. What Behe is saying is that a true irreducibly complex system can only arise by a single mechanism, namely one where the precursor has the same function. But the precursor can't, by definition, have the same function if it's missing some of the parts required in the final version. Thus, the only way for an irreducibly complex system to arise—by definition—is if it is created instantaneously as a complex system.
Behe is correct in his claim that such systems cannot evolve by any known mechanisms of evolution. Therefore, if a true irreducibly complex system exists, it cannot be as a result of evolution.
Let's look at an example. The citric acid cycle is a cycle of eight interacting enzymes that catalyze the oxidation of a 2-carbon molecule (an acetyl group) to CO2. The pathway won't work if you remove any one of the enzymes. Thus, it seems on the surface to be an example of an irreducibly complex system.
However, we have a very good understanding of how the citric acid cycle evolved from simpler pathways. Most species of bacteria don't have a citric acid cycle. Instead they have two separate pathways, reductive and oxidative, that are similar to the left and right halves of the citric acid cycle respectively. We can easily construct a plausible scenario that joins the two branches to create a cycle. Does this mean that we have a good example of the evolution of an irreducibly complex system, thus blowing ID out of the water?
Of course it does. But the IDiots will never admit it. Instead, they note that such a pathway involves precursors that don't have the same function as the complete citric acid cycle; therefore, the citric acid cycle wasn't really irreducibly complex. In order to be irreducibly complex, sensu Behe, it has to be impossible for it to arise by evolution.
The bacterial flagellum is another example of a postulated irreducibly complex system. But we now have a pretty good idea of how it evolved. It evolved from a primitive type III secretion mechanism. Even if the IDiots were to accept this explanation—they don't—it would not refute irreducible complexity since the type III secretion mechanism has a different function. All this means is that the bacterial flagellum wasn't really irreducibly complex to begin with because irreducibly complex systems can't arise by natural means. You can't win.
Where does that leave us? It leaves us with a tautology: "... a series of self-reinforcing statements that cannot be disproved because the statements depend on the assumption that they are already correct." Irreducibly complex systems are, by definition, things that cannot evolve. If you postulate that something is irreducibly complex, then show later on how it evolved, it wasn't irreducibly complex to begin with. The definition is not falsifiable. The best that can happen is that the number of postulated irreducibly complex systems gets smaller and smaller until there are none left. The number is not likely to ever reach zero since the IDiots are really good at combing the scientific literature in order to discover something that almost nobody is working on.
This is not science. It is simply a rhetorical attack on the concept of evolution. That's what Intelligent Design Creationism is all about.1
1. Attacking evolution is scientific. After all, lots of us question certain aspects of evolution and still call ourselves scientists. It's the concept of Intelligent Design Creationism as an explanation for observed events that's not scientific. Intelligent Design Creationism never explains anything. You're never going to see an IDiot explain how the bacterial flagellum arose—not even in a creationist textbook.