Re: Mammalian eyes...

Stephen Jones (sejones@ibm.net)
Wed, 11 Dec 96 21:26:18 +0800

Group

On Mon, 11 Nov 1996 18:03:08 -0800, Paul A. Nelson wrote:

[...]

PN>P.S. One example, of many. Try to find, in the literature on the
>giant panda, where someone -- anyone -- established that the panda's
>thumb is suboptimal. I've looked. Nothing exists. People believe
>it because Stephen Jay Gould told them so. And Gould believes it
>because he likes to re-design animals to his own specifications.

Interestingly, Walter ReMine claims that Gould's argument from
imperfection is actually evidence of a single Designer:

"Evolutionists have seen "odd arrangements and funny solutions" in
nature and they insist these are paths a sensible designer would never
tread. They are mistaken. Not only is it sensible, but message theory
absolutely requires it, though at first it will seem paradoxical. We
expect a designer of life to create perfect designs. Yet this
expectation itself constrains a biomessage sender to do the
unexpected. A world full of perfect optimal designs would form an
ambiguous message. In fact, it would not look like a message at all.
It would provide no clues of an intentional message. It would look
precisely as expected from a designer having no such intentions.
Life's designer created life to look like a message, and therefore had
to accept an astonishing design constraint: life must incorporate odd
designs. How can I be so utterly sure on this point? Because
evolutionists have (unknowingly) said so. In fact, they insist on it.
Every one of them-from Darwin, to Ghiselin, to Gould-has
emphasized how unreasonable it is for a designer to have created
such non-optimal, odd structures. We can rightfully conclude that if
evolutionists had the wherewithal to create life, then they would
independently go forth and create optimal perfect designs. We can
conclude that a world of perfect designs would look precisely like the
work of multiple designers acting independently. The biomessage
sender created life to look unlike the product of multiple designers,
and therefore had to use odd designs." (ReMine W.J., "The Biotic
Message: Evolution Versus Message Theory", St. Paul Science:
Saint Paul, 1993, p27)

At first I thought that Walter had overreached himself, but when you
come to think of it, only a single Designer would construct a *range*
of designs, some more "perfect" than others. If individual designers
had each had an opportunity to create a small number of designs, they
would be more likely to try to create "perfect" designs, with little
or no thought for their interraction with other designers' creations.

On Wed, 13 Nov 1996 00:49:22 +0000, Mike L Anderson wrote:

ML>Judging from the tone of Paul Nelson's post it seems that I have
>struck a nerve.
>
>Let me begin with a more conciliatory note. There is a lot in Paul's
>postings (and Brian Harper's) with which I agree. I agree that it is
>much easier to evaluate the optimality of simple systems than larger
>ones. In suggesting that there are imperfections in living things I
>am not arguing that God could have created a better world than the
>one we have, I'm merely arguing that imperfections recall an
>evolutionary past. An evolving universe with all its imperfections
>could still be an optimal one.

Mike's attempts at conciliation are appreciated, but the argument
that "imperfections recall an evolutionary past" assumes (without
warrant) that: 1. God could not produce less than perfect (in an
ideal engineering sense) designs; and 2. that evidence of a past is
necessarily an "evolutionary past".

Neither of these propositions stand up to analysis. Firstly,
Scripture does not claim that nature is "perfect", just "good" (Gn
1:31), and even that goodness is in God's sight, not ours. For
example, while humans might feels that predation is bad, Psalm
104:21,24 teaches that carnivores catching and eating their prey is
a manifestation of God's wisdom. As for the human body, the Bible
teaches only that tit is "wonderfully made" (Ps 139:14), not perfect.
If the Bible does not require an ideal engineering standard of
perfection in living things, and no modern-day Christian is defending
it, then argument from imperfection is a straw man.

Secondly, evidence that designs may have been fashioned through a
historical process is not necessarily evidence of an "*evolutionary*
past", except in a trivial sense, ie. if "evolution" is defined as
"change over time". It could equally have been evidence of
*progressive creation* over time.

[...]

MA>Goldsmith points out that that placing the retina before the
>photoreceptors is like "placing a thin diffusing screen directly over
>the film in your camera; it can only degrade the quality of the
>image." It is still not clear to me what advantages this arrangement
>has which outweigh the disadvantages. Neural processing in the
>retinal could take place with either arrangement so this does not
>seem to me to be a counter argument.

There is no scientific evidence that "placing the retina before the
photoreceptors" actually does "degrade the quality of the image".
It is simply an assertion with no evidence. What is missing is a
quantitative statement of *how much* the "quality of the image" is
"degraded", compared to the "quality of the image" received by a
cephalopod eye. Is the alleged degradation 1%? Or 0.1%? Or
0.000001%? If the alleged degradation is so low as to be below the
just-noticeable-difference (JND) threshold for vision, then for all
practical purposes there is no degradation.

And the claim that "Neural processing in the retinal could take place
with either arrangement..." misses the point that if this "Neural
processing" does compensate for any degradation of the "quality of
the image", then again, for all practical purposes there is no
degradation. In any event, in judging the performance of the
verterbrate eye, the vision *system* needs to be considered *as a
whole*. If an Intelligent Designer has designed a `computer image
correction and enhancement' sub-system as part of a *total visual
system package*, then it is inadequate to judge the "quality" of
"image" merely at the front-end of the system. What matters is the
"quality" of the *final* "image".

[...]

MA>A better subject [to illustrate suboptimality] is nerve pathways.
>It is very curious that the recurrent laryngeal nerve should pass
>from the brain, down to the heart and back up to the larynx.
>What adaptive advantage could there be to such a roundabout
>route? It is easy to come up with a better design. Send the nerve
>straight to the larynx. The actual pattern is easy to understand
>as an accident of history as fish evolved into the higher vertebrates.
>Standard comparative morphology texts tell the story.

I have no problem with "the higher vertebrates" having a common
ancestor with "fish". But I do not consider this necessarily was
"evolution" in the Darwinian sense. It could equally have been the
result of progressive creation, where God progressively modified
existing genetic code at strategic points.

But I did consult some "Standard comparative morphology texts" (eg.
Van De Graaff K.M.. & Fox S.I, "Concepts of Human Anatomy and
Physiology", Wm. C. Brown, Dubuque IA, Second Edition, 1989, p482)
and they do *not* "tell the story". They have diagrams that show
that the "recurrent laryngeal nerve" does not "pass from the brain,
down to the heart and back up to the larynx" but rather branches off
in the lower neck, *before* the heart:

"recurrent laryngeal nerves, n. branches of the vagus, the 10th pair
of cranial nerves. The recurrent laryngeal nerves leave the main
trunk LOW IN THE NECK, especially on the left side, and run up again
to supply the muscles of larynx concerned with phonation. One of
these nerves is commonly involved in neck cancer, the first sign of
which may be severe loss of voice from paralysis of one vocal cord."
(Youngson R.M., "Collins Dictionary of Medicine", HarperCollins:
Glasgow, 1992, p517. My emphasis)

MA>Ken Miller of Brown University used this very example in his
>debate with Mike Behe and me at the ASA meeting in 1995. He
>had a beautiful slide, actually, of the neck of the giraffe, where
>the recurrent laryngeal nerve makes a truly long trip, down down
>down, and then back up again to the larynx.

This is just using an extreme example for effect. The giraffe has
the longest neck in vertebrates, so naturally its nerve pathways make
a "truly long trip, down down down". But Mike Behe could equally
have shown a slide of a mouse where the "trip" would be short!

In any event, Mike Behe accepts common descent but not
Darwinian evolution:

"I find the idea of common descent (that all organisms share a common
ancestor) fairly convincing, and have no particular reason to doubt
it. I greatly respect the work of my colleagues who study the
development and behavior of organisms within an evolutionary
framework. and I think that evolutionary biologists have contributed
enormously to our understanding of the world. Although Darwin's
mechanism-natural selection working on variation-might explain many
things, however, I do not believe it explains molecular life. I also
do not think it surprising that the new science of the very small
might change the way we view the less small." (Behe M.J., "Darwin's
Black Box: The Biochemical Challenge to Evolution", Free Press: New
York, 1996, pp5-6)

[...]

MA>There is no KNOWN functional reason for a long pathway. Could
>there be a functional reason for the long pathway? Sure. Anything is
>possible - especially in biology. All we can do is to discuss the
>available evidence. You have to provide evidence of a function
>otherwise you could be accused of doing the armchair theorizing of
>which you accuse others. Worse, you could be accused of a fallacy
>(hypothesis contrary to fact) or of doing less than dignified
>science. Biologists do have an explanation for the recurrent nerve.
>It was originally the 4th branch of the vagus nerve in the fish. Here
>the route is direct. The nerve followed the same route through the
>higher vertebrates but as the neck became longer the detour came to
>look increasingly absurd.

I have no problem with the "the recurrent nerve" being a design
modification based "originally" on "the 4th branch of the vagus nerve
in the fish". Indeed, I would regard this as evidence of the
Designers' *ingenuity* in re-using an original design for something
else. I would definitely not regard it as looking "absurd".

[...]

God bless.

Steve

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