This topic deals with another way to show IC does not support ID: the fact that IC systems cannot even be IDENTIFIED objectively. If IC systems cannot be identified, and if ANY system can be seen as an IC system, how can it possibly support ID?
Not only can IC systems not be identified, but people like Behe arbitrarily focus on molecular IC systems. You can just as easily argue that the human body is a IC system. If you removed someone's heart, they would cease to function. It's not as if biologists are claiming that humans evolved by first evolving a skeleton, and then some skin and muscles to go on it, then a pancreas, then maybe kidneys, then a heart, then a brain, etc. Just as human bodies did not evolve in this fashion, neither did the complex metabolic pathways or molecules within it. More often, traits start out with one function, and as they are slowly modified, gradually take on a new function.
E.g. ID proponents often use the bacterial flagellum as an example of an IC system. However, molecular biologists, investigated this, and found the Type-III Secretory System (TTSS):
At first glance, the existence of the TTSS, a nasty little device that allows bacteria to inject these toxins through the cell membranes of its unsuspecting hosts, would seem to have little to do with the flagellum. However, molecular studies of proteins in the TTSS have revealed a surprising fact - the proteins of the TTSS are directly homologous to the proteins in the basal portion of the bacterial flagellum. As figure 2 (Heuck 1998) shows, these homologies extend to a cluster of closely-associated proteins found in both of these molecular "machines." On the basis of these homologies, McNab (McNab 1999) has argued that the flagellum itself should be regarded as a type III secretory system. Extending such studies with a detailed comparison of the proteins associated with both systems, Aizawa has seconded this suggestion, noting that the two systems "consist of homologous component proteins with common physico-chemical properties" (Aizawa 2001, 163). It is now clear, therefore, that a smaller subset of the full complement of proteins in the flagellum makes up the functional transmembrane portion of the TTSS.
Stated directly, the TTSS does its dirty work using a handful of proteins from the base of the flagellum. From the evolutionary point of view, this relationship is hardly surprising. In fact, it's to be expected that the opportunism of evolutionary processes would mix and match proteins to produce new and novel functions. According to the doctrine of irreducible complexity, however, this should not be possible. If the flagellum is indeed irreducibly complex, then removing just one part, let alone 10 or 15, should render what remains "by definition nonfunctional." Yet the TTSS is indeed fully-functional, even though it is missing most of the parts of the flagellum. The TTSS may be bad news for us, but for the bacteria that possess it, it is a truly valuable biochemical machine.
These quotes are from
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"There are three kinds of lies: lies, damned lies, and statistics."
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