On Sunday, February 21, 2016 at 5:49:42 PM UTC-5,
riskys...@gmail.com wrote:
> On Friday, February 19, 2016 at 4:24:48 PM UTC-5, Kalkidas wrote:
>
> > It's amazing the lengths some people go to to "prove" that there is no
> > such thing as irreducible complexity.
>
> On the contrary, I have never seen anyone deny the existence of irreducible
> complexity;
Meet Bob Casanova:
Would those be slogans like "irreducible complexity" and
"intelligent design", for which no actual evidence has been
provided and which have been firmly rebutted?
https://groups.google.com/forum/#!original/talk.origins/RJqHymfuDco/o3KnwC7jGQAJ
Message-ID: <
pofpbb56a8ikbioc0...@4ax.com>
Subject: Re: Open questions in biology, biochemistry, and evolution
Date: Thu, 11 Feb 2016 10:04:50 -0700
Casanova seems to think that the existence of irreducible
complexity has been firmly refuted; that could mean a
number of things. Chances are, it means that he hasn't got the
definition of Irreducible Complexity (IC) disentangled from the
concept of Intelligent Design. This is a malaise that seems to infect
one internet forum after another.
>only the implication that its existence is a problem for a standard biology
> that is explicitly expected to produce irreducible complexity.
"explicitly expected" is a mistake innumerable people make
by looking at out-of-context quotes by Muller almost a
century ago. Others, who are familiar with the context,
simply don't know the definition of IC, even if they do
not conflate it with that of ID, but blindly take the word
of those who say that Muller's concept was the same as Behe's.
It isn't.
> Irreducible complexity is perfectly fine evidence against an
> evolutionary trajectory that no one supports - each current
> "component" of a system added one at a time.
Surprise! There is plenty of evidence that the majority
of factors in the two cascades to which Behe devotes
individual chapters DID evolve with one component added
at a time! But then having each component gradually modified
until each and every component became indispensible.
Ironically, the process by which this is believed to have
happened DID happen in "small, Darwinian steps." It is
only the few components of the cascades that are not
serine proteases that pose a real problem for evolutionary
biology. [Well, OK, one serine protease to rule them all,
and the other factors.]
> But how it tells us that any current structure or function could
> not have been arrived at by any conventional means is beyond me.
Yes, I believe Behe greatly overrates the significance of IC.
It does give "more bang for the buck" by having to account for
a "scaffolding" which has more components than the IC system
which is hypothesized to result from the original system. As
Behe put it:
Even if a system is irreducibly complex (and thus cannot
have been produced directly), however, one can not definitely
rule out the possibility of an indirect, circuitous
route. As the complexity of an interacting system increases,
though, the likelihood of such an indirect route drops precipitously.
-- _Darwin's Black Box, p40
[Kudos to Rolf for posting this already last week.]
In the case of the two cascades, the much smaller original
systems were probably IC, and that is where the circuitous route
with "more bang for the buck" comes in. But since there were so
few components, the likelihood was probably within the bounds
needed for evolution in the ca. 300-400 my time frame.
The bacterial flagellum, with 35 components identified by
Minnich, poses a much more difficult problem. There is
a common "rebuttal" involving hypothesized evolution from
a Type III secretory system, but that only accounts for two pieces
being exapted, at least one of which had many components and
was IC itself.
> I suspect that the past and current inventory of life on earth has
> scarcely made a dent in catalog of possible creature types that
> "life as we know it" could support.
Yes, but don't you find it remarkable that only one phylum
out of 30 has evolved large terrestrial animals with internal
skeletons, and only one has evolved terrestrial animals with
jointed legs? Yet both went on to produce winged representatives,
capable of sustained flight.
> And a large part of the reason for that is that some "possible"
> creatures have not (yet) been within genetic "reach".
Nor are any expected in the form of new body plans. The conventional
wisdom about the Cambrian explosion is that it exhausted the extreme
malleability of animal types that was possible before ca. 550 mya.
For example, no phylum besides Chordata is expected to be capable of
evolving something like a vertebral column able to support its
members on land.
Hemichordates have something resembling a very short notochord,
but nothing has come of it for 500 million years.
I've left the rest of what you wrote unremarked, but if you
think the above hasn't taken care of the main points, feel
free to let me know.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
University of South Carolina
http://people.math.sc.edu/nyikos/
PS What name would you like to be known by?
riskys...@gmail.com
is awkward, and isn't even your full e-mail address; but the
rest is hidden due to masking by New Google Groups.