Actually, Behe's most basic definition of IC is any structure or system in
which the removal of even one component causes the structure or system to
cease to function, hence his mousetrap example. If you remove either the
radius or the ulna, the forearm ceases to function. Yet paleontological
evidence establishes that, if anything, the forelimb of a lobe-finned fish
like _Eusthenopteron_ contained far more bones than the tetrapod limb,
and that the process of evolution eliminated useless extra bones in favor
of a few useful bones. This system evolved (or dare I say "devolved")
gradually, yet it resulted in a structure that meets Behe's most basic
definition of IC.
Part of the problem with deciding whether a structure or system is IC,
though, is that Behe initially defined IC in such a way that gives one the
impression that an IC structure or system is one that cannot evolve. As
such, any biological structure or systems can be considered IC until it can
be shown to have evolved (is that why you do not consider the forearm to be
IC?). Recognizing the oxymoronic nature of this definition, however, Behe
later complicates his definition so as to avoid this trap, but in so doing
he produces a definition in which a structure or system could have evolved
and yet is still IC. This then renders IC worthless as a way to distinguish
intelligently designed structures or systems from those that evolve
naturally. Behe recognized this as well, but had no effective way of
dealing with this issue, so he largely ignored it, as do most creationists.
Hence the best "examples" of IC structures or systems are those for which
there appears to be no plausible evolutionary mechanism, whereas structures
or systems that can be shown to have evolved are labelled as non-IC, even
though they qualify as IC under Behe's basic definition.
Here's a puzzle for ID supporters: can you solve it? Proteins contain
functional domains that must interact with each other in order for the
protein molecule to function properly. Remove even one domain and the
protein effectively looses its function. Would this mean that, generally
speaking, proteins are IC? If not, why not?
Recently, however, the technology has now made it possible for biochemists
and molecular biologists to take different functional domains from different
proteins, combine them, and get functional proteins. Once fully formed, if
you remove even one domain this Frankenstein's protein looses its function,
yet it was made from non-functional bits and pieces of other proteins.
The puzzle then is this: assuming that this proteinaceous chimera is IC,
how can you get an IC structure by assembling random non-functional parts?
Or put another way, how can a functional structure that looses its function
when even one piece is removed be made out of a random assortment of
non-functional pieces that were never "designed" to work together in the
first place, assuming that IC is a real concept? I mean, if I took random
non-functional pieces from an airplane, a helicopter, an automobile, a boat
and a bicycle (any one of which would render the vehicle in question
non-functional), then randomly assembled them together, should I expect to
get a functional vehicle as a result? Would this prove that airplanes,
helicopters, automobiles, boats and bicycles are IC? What would this then
say about a functional protein derived in the same manner? Is it IC? Were
the the proteins the domains were obtained from IC? If not, why do they
mimic ICness by loosing functionality when even one domain is removed?
Can anyone solve my puzzle?
Kevin L. O'Brien