Richard Alexander wrote:No he doesn't. Please read what you have quoted again. He does
> > > > IIRC what has been
> > > AFAIK, the only way to produce an irreducibly complex structure is
> > Hemoglobin is IC.
> I don't know why you think so. Behe makes the case in DBB that
argue that we can't infer design from hemoglobin. He does not
argue it isn't IC.
I will add more about Behe's attempt to minimize the functional
> One of the conditions for being IC is that the systemAgain, Behe did not make a case that hemoglobin is not IC, rather he
> cannot be produced by simply re-arranging the component parts. Behe
> makes discusses hemoglobin on Page 207.
> "There is also another protein, called myoglobin, that is very similar
says it makes a poor case for design. It would be more honest of him
to say it is a well studied case that is fully explainable by the
well studied mechanisms of evolution.
Behe mentions cooperativity but does not say what it is or why it is
There are however, many observable intermediates between organisms
> Behe cites the case of hemoglobin in his sub-section, "MakingAgain, Behe is distancing himself from an inference of design, not from
> Distinctions," in which he states,
> "Just because we can infer that some biochemical systems were designed
the systems being IC. IC is not the same as design as Behe is sometimes
careful to point out. The point seems to be lost in some readers, perhaps
because Behe isn't clear enough. Hemoglobin is IC by the definition and
standards that Behe employs. It is not only true that "the case for design
is weak": rather the case for evolution of hemoglobin is very very strong.
> > The Krebs cycle is IC.Refer to Behe's definition of IC. Remove one of the enzymes of the
> Again, I don't know why you think so, but maybe that is due to my
> ignorance of the system? Behe makes the point that the AMP cycle is
> IC, because AMP is required to make AMP in all known organisms. I
> never studied the citric acid cycle, so I don't know why you consider
> the Krebs cycle to be IC.
Krebs cycle and the cycle is broken. This means it stops cycling:
it would cease to function.
There are alternative cycles. You may consider those as "scaffolding"
If you apply some critical thinking, you'll quickly see that "systems"
> > The evolution of these systems do not require scaffolding.Again, reread what you quoted. You seem to be missing what Behe
> Well, apparently they aren't IC, either, so that they require no
> scaffolding is no wonder.
explicityly says as well as missing his switching standards.
> > To the extent that blood clotting is IC, it does not require scaffolding.Behe says that hemoglobin is a poor case for design. He does not say
> To form? Why do you say so?
> > So what are you talking about?
> Let's deal with the basics, first, and then maybe the other questions
> will have answers.
> > Consider mammalian hemoglobin with alpha and beta chains. Just
> > mamalian beta won't make a functional hemoglobin and neither
> > will just mammalian alpha.
> I'm guessing from their names that the two are variations of each
> other? Are both required for the production of either? Of course,
> that's moot, because Behe already pointed out that hemoglobin is not
it isn't IC. Even if he does say it isn't IC, it fits his definition
of IC because if you remove either alpha or beta hemoglobin, your
blood won't be able to transport enough O2 from your lungs to your
tissues to support a viable existence. This is the standard he uses
for criticisms of his claim that blood clotting is IC. Either you use
the same standards all the time or else you don't have standards
and it's more like something out of Alice in Wonderland.
> > It is likewise currently requiredIf one looks a O2 transport in humans, one must consider the
> > that a fetus express variant forms of hemoglobin to extract O2
> > from the placenta.
> I do not see what steps your logic has taken in your argument.
case of a mother's lungs being used to supply O2 to a developing
fetus. This requires a hand off of O2 in the placenta. For this
to be effective, the fetus must have hemoglobin with a higher
affinity of O2 than does the mother. This is accomplished by
yet another variant hemoglobin chain beyond alpha and beta.
The seqeunce of delta (fetal) hemoglobin is similar to beta
I believe. It fits a model of gene duplication and divergence.
It represents yet another "system" of O2 transport that is more
complex than lungs --> tissue --> mylogobin and requires three
distinct genes rather than two. As per the definition of IC,
if you remove any of the proteins in question, the system will
fail to function. The evolution of this system requires duplication
and divergence but does not require any "scaffolding". It thus
refutes your contention that scaffolding is required to produce
I agree with Behe that these systems are poor cases for design.
> > How does the evolution of these systems require scaffolding?Feel free to show that using the definition of IC. The parts are
> Maybe they don't, because it appears the systems you named aren't IC.
alpha and beta hemoglobin. The function if O2 transportation
in mammals. Alternatively, the parts are alpha, beta and delta
hemoglobin and the function is reproduction of viable babies
in humans. Remove any part and the systems ceases to function.
Is that, or is that not the very definition of IC?
> > > There have been several challenges to Behe's suggested examples ofOthers have presented that the precursors of blood clotting are related
> > > irreducible complexity. Here is a snippet from one of his replies:
> > > "In Darwin's Black Box: The Biochemical Challenge to Evolution I
> > > "I will give their arguments below and my response. Here is a brief
> > > "3) Keith Robison proposed that a cascade might begin with a single
> > That's very untrue. Keith made the situation clear enough. There isn't
> I don't know very much about this, but I can see that clotting must be
molecules that trap pathogens in Invertebrates. It's been discussed
elsewhere in this thread.
The primative systems create a fiberous mesh to trap a pathogen. The
As to inventing parts, refer to Keith's presentation. The "invention"
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