"Defending talk.origins sorts isn't really my specialty, but Keith
Robison may have had a bit more of a point than some have given him
credit for re: using the floor for the base of a mousetrap.
In order for irreducible complexity to be a fatal difficulty for
darwinian processes, the system in question must be non-functional in
the absence of any of the components, and those components themselves
must have no independent adaptive function, so that they are not just
lying about waiting the opportunity to come together into the new
functioning system. In short, the components should not be exaptive (or
pre-adaptive, in Darwin's terms).
But if the floor-stapled mousetrap is admitted to be a functioning
mousetrap, and if functional mousetraps are irreducibly complex, then
given that the floor was generated for some different purpose entirely,
that all constitutes an admission that irreducible complexity can arise
in cases where at least *some* of the components *are* exaptive. If so,
that is certainly a legitimate point worth making.
Of course, one could accept the possibility of preadaptation of some
components of a system, and still maintain that the system is in some
extended sense irreducibly complex so long as there is *at least one*
component which cannot be a result of preadaptation, but that is a bit
different than the original sort of case - at least, as I understood it.
Del"
I agree with Del completely here. To carry the mousetrap thing a
little further, I can think of several biological examples that would be
analogous to a floor-stapled mousetrap evolving to a mousetrap with its own
base. Critique/add to these freely: they're just off the top of my head.
1) chemoautotrophs --> photoautotrophs (bacteria that originally depended upon
on an inorganic chemical source for energy switching to photosynthsizing their
chemical energy)
2) aquatic life --> terrestrial life (terrestrial organisms essentially
are bags of seawater - seawater that was part of the environment of their
ancestors)
a) things like gas exchange in the lungs would be a correlary of this
(oxygen is dissolved, then taken into the blood)
3) This is a little different...insectivorous plants evolving an alternate
method for collecting nitrate not supplied in their current bog environment.
All cases where something was supplied by the environment, and the organisms
have evolved a way to become more independent of their environment for that
resource (although their root needs have not changed). Just thoughts that
seemed relevant...
Thanks,
Nick