Re: [asa] Reducible complexity

David's subject line reminded me of a pet peeve I have. I'll take a
few lines here to express it.

Although Behe's phrase "irreducible complexity" caught on like wild
fire, it's really not that novel. Molecular biologists and biochemists
have always "believed in" irreducible complexity--that when you remove
a piece of a functioning molecular machine that it stops working. In
evolutionary terms, Behe likes to say that there is no function to be
selected for until the whole system is already there. David's post of
today, however, shows that it's not always true. (I'm not sure I like
the stratey of calling it "reducible" because of this, but that's not
my main point.) But, it's often the case. We utilize these sorts of
things all the time in biology: knock-out mutants, condition lethal
mutants, etc.

The notion of irreducible has to do with the current state of the
molecular machine or molecular system and as such it is non-
controversial. The evolutionary aspect is also non-controversial.
Natural selection cannot select for a function that does not exist.
(It is, however, legitimate to have natural selection select for and
perfect a primitive function--David's citation today may be such an
example.)

So, no one denies that some functions are irreducible. But irreducible
does not mean non-evolvable. That's is the bait and switch that Behe
pulls on us. And, the solution, that nearly all Behe critiques have
pointed to from the beginning, is exaptation, co-option, pre-
adaptation. These are all evolutionary bait and switches. Pieces of
the molecular mousetrap exist for other reasons and functions, but now
in a new, perhaps even, happenstance combination, they have a new,
unanticipated, albeit primitive function. Voila! Now Darwinian
selection can begin to work and perfect and "irreducibilize" the
primitive molecular machine.

Thus, the title of my now over ten year old critique of Behe:
Complexity--Yes! Irreducible--Maybe! Unexplainable--No!

TG

________________
Terry M. Gray, Ph.D.
Computer Support Scientist
Chemistry Department
Colorado State University
Fort Collins, CO 80523
(o) 970-491-7003 (f) 970-491-1801

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Received on Fri Feb 15 14:23:43 2008