I know this wasn't addressed to me, but I've never let that stop me before.
Irreducible Complexity is an attribute of a system. The existence of such systems is put forward by advocates of Intelligent Design as evidence for the insufficiency of current evolutionary theory.
The problem is that there are several different definitions of irreducible complexity kicking around the ID debate, even from the same ID proponent.
Behe, 1996 writes:
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.
This seems a fairly straightforward definition and if we take a 'part' to be a specific gene or protein we can probably find examples of such systems in living organisms.
Despite this most of the examples usually given (the eye, the bacterial flagellum and the blood clotting cascade) don't really stand up as IC by this definition and ID proponents often argue that such systems have an 'IC core' of proteins/parts which is what remains when all the non-essential parts have been removed form the putatively IC system.
However this doesn't really represent a problem for standard evolutionary models, there is no reason why a system can't evolve which relies on such a set of interconnected 'parts', there are several models based on exaptation and scaffolding which can account for them.
In response to this Behe 'refined' his definition ...
Behe, 2002 writes:
An irreducibly complex evolutionary pathway is one that contains one or more unselected steps (that is, one or more necessary-but-unselected mutations). The degree of irreducible complexity is the number of unselected steps in the pathway.
Clearly this is a
completely different argument and requires a much greater depth of historical knowledge of the evolution of the system to be able to actually define any system as IC. Indeed it is hard to see how any ID proponent could confidently claim that a system was IC under this definition assuming it also has to satisfy the original definition.
If it doesn't have to satisfy the original definition as well then there are plenty of experimental examples of apparently unselected steps being required for the development of a functional system/trait, including any 2 step mutation in the classical antibiotic/phage resistance experiments using replicate plates. Indeed there is considerable weight to the argument that deleterious mutations can provide important intermediates to the evolution of a more beneficial state.
is there a better way they could present ID OR IC?
IC would be better presented if it had a clear and concise definition and some examples which actually matched the necessary criteria or at least an understandable way to discern if a system matches the criteria. At the moment IC is one of those things like increases in genetic information, IDists can't really define it but they will know it when they see it and they never see it in any of the examples they are provided.
TTFN,
WK