On Sat, 02 Nov 1996 00:59:55 -0500, Brian D. Harper wrote:
[...]
SJ>Actually, it is now believed that *all* eyes, invertebrate and
>vertebrate, are derived from the *one* gene-complex, a stunning
>confirmation of my theory and a non-prediction/expectation of
>Neo-Darwinian "blind watchmaker" evolution:
BH>Thanks for the info on ey. I have a hard time understanding
>how this is a confirmation of your theory and also why its
>such a blow to Neo-Darwinism.
It was in the context of a post from Loren of 29 Oct 96 Subject: Re:
supernatural genetic engineering ... when?, excerpts as follows:
--------------------------------------------------------
LH>One of the more popular versions of Progressive Creation and ID
>theory is what I would call, "'Supernatural genetic engineering' at
>strategic historical points to introduce biological novelty and
>complexity." (Novelty and complexity which, the argument goes,
>could not have arisen from natural mechanisms.) There is a good
>reason its popularity. It elegantly incorporates the fossil data
>and the genetic and developmental data supporting common ancestry.
>(It's my favorite alternative to evolutionary creationism.)
[...]
>LH>Now here's the question: Suppose several late dino and several
>early bird species have a certain "bird" characteristic (e.g.
>beaks), but these species do not form an ancestral chain, would this
>require God to perform the same supernatural intervention at several
>different strategic points?
>SJ>...I would assume that only *one* "supernatural intervention"
>would be needed at *one* "strategic point" for the first appearance
>each new feature. One recoded, the code could remain dormant in the
>genome until needed again....
LH>An excellent answer from Steve. Now let's carry it further.
>What about bats' wings? Their common ancestor with other winged
>creatures goes back *long* before bats' wings first appeared.
SJ>"bats' wings" are an entirely different principle from bird's
>wings. They may be similar to winged reptiles (the pterosaurs). If
>they are, I would assume a common genetic code.
LH>What about the squid eye and the vertebrate eye? Both are
>complex, but their common ancestor goes back a very long ways ---
>unless I'm mistaken, well before the appearance of any complex eyes.
>In fact, I believe that the fossil record suggests that complex eyes
>arose "independently" considerably more than just twice.
SJ>Actually, it is now believed that *all* eyes, invertebrate and
>vertebrate, are derived from the *one* gene-complex, a stunning
>confirmation of my theory and a non-prediction/expectation of
>Neo-Darwinian "blind watchmaker" evolution:
--------------------------------------------------------
Brian puts a "bit of spin" on my claim that this was "such a blow to
Neo-Darwinism". I did not claim that it was "a blow to
Neo-Darwinism". No doubt ND will accommodate this data,
"...like fog accommodates landscape" (ReMine W.J., "The Biotic
Message", 1993, p24)
My point was only that this is a "confirmation of my ("Supernatural
genetic engineering") theory" and "a non-prediction/expectation of
Neo-Darwinian "blind watchmaker" evolution". The squid's eye was
thought to be the result of convergence, not common ancestry:
"Besides olfactory organs and a pair of structures that probably aid
in balancing, the squid has two large image-perceiving eyes. They
are remarkably like the human eye in construction but are developed
in quite a different way. When two similar structures having a
similar function appear in two distantly related groups, so that
THERE IS NO POSSIBILITY OF A COMMON ANCESTOR which could have
possessed such a structure, then the structure must have evolved
independently. Thus the eye of the squid and the eye of man are said
to have arisen by convergent evolution." (Buchsbaum R. "Animals
Without Backbones: An Introduction to the Invertebrates", Volume 2,
Pelican: Middlesex UK, 1966 reprint, p223. My emphasis)
BH>Dawkins discusses this in his new book <Climbing Mount
>Improbable>, however I've left the book at home and can't remember
>any details. Perhaps this is an interesting case to pursue with
>further discussions.
Dawkins indeed "discusses this in his new book <Climbing Mount
Improbable>.
But first let's look at Dawkins original explanation for the origin of
the eye:
"Some single-celled animals have a light-sensitive spot with a little
pigment screen behind it. The screen shields it from light coming from
one direction, which gives it some 'idea' of where the light is coming
from. Among many-celled animals, various types of worm and some
shellfish have a similar arrangement, but the pigment-backed light-
sensitive cells are set in a little cup. This gives slightly better
direction-finding capability, since each cell is selectively shielded from
light rays coming into the cup from its own side. In a continuous
series from flat sheet of light-sensitive cells, through shallow cup to
deep cup, each step in the series, however small (or large) the step,
would be an optical improvement. Now, if you make a cup very deep
and turn the sides over, you eventually make a lensless pinhole
camera. There is a continuously graded series from shallow cup to
pinhole camera..." (Dawkins R., "The Blind Watchmaker", Penguin:
London, 1991, p85)
"Cumulative selection, by slow and gradual degrees, is the
explanation, the only workable explanation that has ever been
proposed, for the existence of life's complex design...It would be
untamed chance if once there was no eye, and then, suddenly, in the
twinkling of a generation, an eye appeared, fully fashioned, perfect
and whole...To 'tame' chance means to break down the very
improbable into less improbable small components arranged in series.
No matter how improbable it is that an X could have arisen from a Y
in a single step, it is always possible to conceive of a series of
infinitesimally graded intermediates between them. However
improbable a large-scale change may be, smaller changes are less
improbable. And provided we postulate a sufficiently large series of
sufficiently finely graded intermediates, we shall be able to derive
anything from anything else, without invoking astronomical
improbabilities." (Dawkins, 1991, pp317-318).
The impression Dawkins' originally gave was that eyes evolved
slowly, step-by-step from a "a light-sensitive spot". But now Dawkins
claims that it was "fast", so fast that there is no palaeontological
evdience for it:
"Nilsson and Pelger's conclusion is that the evolution of the lens eye
could have been accomplished in less than half a million years. And
that is a very very short time indeed, by geological standards. It is so
short that, in the strata of the ancient eras we are talking about, it
would be indistinguishable from instantaneous. The plaint that there
hasn't been enough time for the eye to evolve turns out to be not just
wrong but dramatically, decisively, ignominiously wrong....Nilsson's
estimate for the rate of evolution of a camera eye was, you will recall,
that it was by geological standards more or less instantaneous You'd
be lucky to find fossils that recorded the transitional stages. Exact
estimates have not been done for compound eyes or any of the other
designs of eye, but I doubt if they'd be significantly slower. One
doesn't ordinarily expect to be able to see the details of eyes in fossils,
because they are too soft to fossilize. Compound eyes are an
exception because much of their detail is betrayed in the elegant array
of more or less horny facets on the outer surface. Inset Figure 5.28
shows a trilobite eye from the Devonian era, nearly 400 million years
ago. It looks just advanced as a modern compound eye. This is what
we should expect the time it takes to evolve an eye is negligible by
geological standards. A central message of this chapter is that eyes
evolve easily and fast, at the drop of a hat." (Dawkins Richard,
"Climbing Mount Improbable", Penguin: London, 1996, pp154,174)
Dawkins, after an illuminating (pun intended! <g>)discussion of
how the eye might have developed by mutation and natural selection,
mentions almost as an afterthought, the most important element
of the vision system of all:
"On the face of it, this message might seem challenged by an
intriguing set of experimental results, recently reported by a group of
workers in Switzerland associated with Professor Walte Gehring. I
shall briefly explain what they found, and why it does not really
challenge the conclusion of this chapter...George Halder, Patrick
Callaerts and Walter Gehring discovered an experimental
manipulation that led to ey's being expressed in other parts of the
body. By doctoring Drosophila larvae in cunning ways, they
succeeded in making ey express itself in the antennae, the wings and
the legs. Amazingly, the treated adult flies grew up with fully formed
compound eyes on their wings, legs, antennae and elsewhere ...That
is remarkable fact number one.
Fact number two is even more remarkable. There is a gene in mice
called small eye and one in humans called aniridia. These, too, are
named using the geneticists' negative convention: mutational damage
to these genes causes reduction or absence of eyes or parts of eyes.
Rebecca Quiring and Uwe Waldorf, working in the same Swiss
laboratory, found that these particular mammal genes are almost
identical, in their DNA sequences, to the ey gene in Drosophila. This
means that the same gene has come down from remote ancestors to
modern animals as distant from each other as mammals and insects.
Moreover, in both these major branches of the animal kingdom the
gene seems to have a lot to do with eyes.
Remarkable fact number three is almost too startling. Halder,
Callaerts and Gehring succeeded in introducing the mouse gene into
Drosophila embryos. Mirabile dictu, the mouse gene induced ectopic
eyes in Drosophila. Inset Figure 5.29 (bottom) shows a small
compound eye induced on the leg of a fruitfly by the mouse
equivalent of ey. Notice, by the way, that it is an insect compound
eye that has been induced, not a mouse eye. The mouse gene has
simply switched on the eyemaking developmental machinery of
Drosophila Genes with pretty much the same DNA sequence as ey
have been found also in molluscs, marine worms called nemertines,
and sea-squirts. Ey may very well be universal among animals, and it
may turn out to be a general rule that a version of the gene taken
from a donor in one part of the animal kingdom can induce eyes to
develop in recipients in an exceedingly remote part of the animal
kingdom.
What does this spectacular series of experiments mean for our
conclusion in this chapter? Were we wrong to think that eyes have
developed forty times independently? I don't think so. At least the
spirit of the statement that eyes evolve easily and at the drop of a hat
remains unscathed. These experiments probably do mean that the
common ancestor of Drosophila, mice, humans, sea-squirts and so on
had eyes. The remote common ancestor had vision of some kind, and
its eyes, whatever form they may have taken, probably developed
under the influence of a sequence of DNA similar to modern ey. But
the actual form of the different kinds of eye, the details of retinas and
lenses or mirrors, the choice of compound versus simple, and if
compound the choice among apposition or various kinds of
superposition, all these evolve independ-ently and rapidly."
(Dawkins Richard, "Climbing Mount Improbable", Penguin: London,
1996, pp174-177)
The above last paragraph gives the whole game away. If the "remote
common ancestor" already "had vision of some kind" due to the
"influence of a sequence of DNA similar to modern ey", then that
is the *really important* bit and "the details of retinas and
lenses or mirrors, the choice of compound versus simple, and if
compound the choice among apposition or various kinds of
superposition", are interesting but only secondary. The primary
question is, where did the master gene complex comprising of
hundreds (if not thousands) of amino acids arranged in a precise
way that codes for all the basic requirements of all vision system
that have ever existed, come from? What would be the use of it, on
the way to becoming a master vision system.
It is clear that Dawkins cannot explain it, because he uses his
usual rhetorical trick of mentioning it in passing, as though it
is a minor problem:
"Of course there are some other details of a full-fledged eye that
Nilsson and Pelger have not yet dealt with and which might although
they don't think so) take rather longer to evolve. There is the
preliminary evolution of the light-sensitive cells-what I have been
calling photocells - which they regarded as having been accomplished
before the start of their model evolution system. There are other,
advanced features of modern eyes such as the apparatuses for
changing the focus of an eye, for changing the size of the pupil or 'f-
stop', and for moving the eye. There are also all the systems in the
brain that are needed for processing the information from the eye."
(Dawkins Richard, "Climbing Mount Improbable", Penguin: London,
1996, p154)
Behe comments on Dawkin's oversimplification of the problem of the
eye:
"We are invited by Dawkins and Darwin to believe that the
evolution of the eye proceeded step-by-step through a series of
plausible intermediates in infinitesimal increments. But are they
infinitesimal? Remember that the "light-sensitive spot" that
Dawkins takes as his starting point requires a cascade of factors,
including ll-cis-retinal and rhodopsin, to function. Dawkins
doesn't mention them. And where did the "little cup" come from?
A ball of cells-from which the cup must be made-will tend to be
rounded unless held in the correct shape by molecular supports.
In fact, there are dozens of complex proteins involved in
maintaining cell shape, and dozens more that control extracellular
structure; in their absence, cells take on the shape of so many
soap bubbles. Do these structures represent single-step
mutations? Dawkins did not tell us how the apparently simple
"cup" shape came to be. And although he reassures us that any
"translucent material" would be an improvement (recall that
Haeckel mistakenly thought it would be easy to produce cells
since they were certainly just "simple lumps"), we are not told
how difficult it is to produce a "simple lens." In short, Dawkins's
explanation is only addressed to the level of what is called gross
anatomy." (Behe M.J., "Darwin's Black Box: The Biochemical Challenge
to Evolution", Free Press: New York, 1996, p37)
[...]
>LH>Suppose we have a complex biological feature which we believe
>probably required supernatural intervention. Now suppose this
>feature is found in multiple groups whose common ancesters go back
>well before the first appearance of that feature? Should we
>hypothesize multiple instances of supernatural intervention to
>achieve similar features? Does this seem less "elegant" than a
>single intervention? Should we hypothesize a single intervention
>with a very long dormancy? Or would this pattern suggest to you
>that, perhaps, that *particular* feature probably arose through
>natural mechanisms? If so, why?
SJ>I would assume "a single intervention with a very long dormancy".
>It may even be that all the entire gene complexes in the animal
>kingdon were built-in right from the Cambrian Explosion, but only
>activated or unmasked later when needed. In fact, that would be my
>(but not necessarily God's) preferred most "elegant" method.
BH>That was a really great question by Loren (Loren, how do you think
>up such questions? :) and also a pretty good reply by Steve.
I appreciate Brian's affirmation of Loren's questions and of my
reply.
BH>Before I go on let me say that I do not intend in any way to
>criticize Steve's or anyone else's views about what is more elegant
>than what. This seems a matter of personal taste strongly
>influenced by one's view of God and how He goes about His business.
I don't mind my "views" being "critized". That's how they get better
and stronger! :-) But I agreed that it is largely a "matter of
personal taste" and of "one's view of God and how He works. That's
why I said that it "would be my (but not necessarily God's) preferred
most `elegant' method." But part of elegance is surely related to
simplicity and therfore I argue that a single intervention is more
elegant than multiple interventions (other things being equal). Mike
Behe wrote:
"...the simplest possible design scenario posits a single cell-formed
billions of years ago-that already contained all information to
produce descendant organisms..." (Behe, 1996, pp230-231)
BH>Let me try to summarize the dilemma as I see it regarding
>elegance. One intervention seems somehow more elegant
>than multiple interventions, at least when such interventions
>involve the same or very similar feature.
In once sense, it is not even an issue of "elegance". If there were
"multiple interventions" (say to produce the 40 different types of
eyes), it would be indistinguishable from a natural process. Even if
biologists did not know the details of the process, they could assume
it was was a natural process. But if the eye arose only *once* in
biological history in the form of a master gene complex, and that
subsequent eyes are only variations on the original themes encoded in
the DNA of that original mster gene complex, then this is (at least
to me) unmistakable evidence of intelligent design.
Even a non-theist like Berlinski recognises the implications of this
discovery of the universality of the ey gene:
"This strongly suggests (the inference is almost irresistible) that
ey function is universal (universal!) among multicellular organisms,
the basic design of the eye having been their common property for
over a half-billion years. The ey gene clearly is a master control
mechanism, one capable of giving general instructions to very
different organisms. No one in possession of these facts can imagine
that they support the Darwinian theory. How could the mechanism of
random variation and natural selection have produced an instrument
capable of anticipating the course of morphological development and
controlling its expression in widely different organisms?"
(Berlinski D., "Denying Darwin: David Berlinski and Critics",
Commentary, September 1996, p28)
BH>But an intervention many millions of years before it is required
>doesn't seem to me to jive too well with the general concept of
>"intervention".
No doubt Brian is referring to a YEC-style "general concept of
`intervention' ". Behe points out that immediate use is not an
esential component of design theory:
"The third reason why Miller's argument misses the mark is actually
quite understandable. It arises from the confusion of two separate
ideas-the theory that life was intelligently designed and the theory
that the earth is young...That is not a part of intelligent-design
theory. The conclusion that some features of life were designed can
be made in the absence of knowledge about when the designing took
place...The irreducibly complex biochemical systems that I have
discussed in this book did not have to be produced recently. It is
entirely possible, based simply on an examination of the systems
themselves, that they were designed billions of years ago and that
they have been passed down to the present by the normal processes of
cellular reproduction. Perhaps a speculative scenario will
illustrate the point. Suppose that nearly four billion years ago the
designer made the first cell, already containing all of the
irreducibly complex biochemical systems discussed here and many
others. (One can postulate that the designs for systems that were to
be used later, such as blood clotting, were present but not "turned
on. " In present-day organisms plenty of genes are turned off for a
while, sometimes for generations, to be turned on at a later time.)
Additionally, suppose the designer placed into the cell some other
systems for which we cannot adduce enough evidence to conclude
design. The cell containing the designed systems then was left on
autopilot to reproduce, mutate, eat and be eaten, bump against rocks,
and suffer all the vagaries of life on earth..." (Behe, 1996,
pp227-228)
I am personally quite relaxed about intervention not being immediate,
since long-range planning is in fact an exclusive hallmark of
intelligent design, and not the blind watchmaker:
"Natural selection, the blind, unconscious, automatic process which
Darwin discovered, and which we now know is the explanation for the
existence and apparently purposeful form of all life, has no purpose
in mind. It has no mind and no mind's eye. It does not plan for the
future. It has no vision, no foresight, no sight at all. If it can
be said to play the role of watchmaker in nature, it is the blind
watchmaker." (Dawkins R., "The Blind Watchmaker", Penguin: London,
1991, p5)
A sudden appearance of something that is used right away, could be
either creation or evolution (ie. saltation). An appearance of
something millions of years before it is needed, is a mark of
long-range planning, and therefore can only be creation. The
non-Darwinian evolutionist Taylor recognised this in the
transmutation of the fish's lateral line into the mammalian inner
ear:
"But the insoluble problem is how and why did a balance organ become
an organ of hearing? As van Bergeijk pointedly asks: 'What prompts
the fish to begin developing a sensory apparatus that will respond to
a stimulus about the very existence of which the fish knows nothing?'
...what kind of mutations could bring about the major changes I
have described? Could cause a tube to roll up into a helix? Could
cause other tubes to form semi-circular canals accurately set at
right angles to each other. Could grade sensory hairs according to
length? Could cause the convenient deposit of a crystal in the one
place it will register gravity? Even more amazingly, some fishes do
not trouble to secrete a crystal but incorporate a bit of sand or
stone. What kind of mutation could achieve this - when and only when
a natural crystal is not formed? The purpose is fulfilled, the means
are unimportant. It just doesn't make sense." (Taylor G.R., "The
Great Evolution Mystery", Abacus: London, 1983, p106).
BH>It also starts to look more and more like TE. There are many
>folks who consider themselves TE's yet believe that God intervened
>once at the origin of life, or perhaps once at the origin of the
>first replicator. Or perhaps just once at the origin of the
>universe. Why would these views not be even more elegant than a
>delayed intervention at the Cambrian and other strategic points.
Firstly, Van Till correctly points out that claiming that "God
intervened...just once at the origin of the universe" is Deism:
"If we draw the line on the assumption that creation requires divine
action but natural processes do not, then we have slipped into the pit
of deism; the unavoidable implication is that God is required for
initiating the cosmos, but once initiated it can run on its own. The
deist contends that the universe needed a divine push to get it rolling,
but having gotten started, it can now coast naturalistically." (Van Till
H.J., "The Fourth Day: What the Bible and the Heavens are Telling
us about the Creation", Eerdmans: Grand Rapids MI, 1986, pp224-
225)
Secondly, if "TE" wants to claim that God intervened more than "just
once at the origin of the universe", eg. "at the origin of life,
or...at the origin of the first replicator", then good for it!
:-) But I would regard that as a weak form of PC. If I were an
evolutionist, I would have thought the consistent position is *no*
intervention is needed because the evolutionary mechanisms are
adequate. If they are not adequate to explain the "origin of the
first replicator", how do we know they were adequate in the origin of
other complex systems?
Perhaps the real difference is one of emphasis on "evolution?
Creationists would regard "evolution" as a *secondary* principle that
varied the original design. Evolutionists would regard "evolution"
as a *primary* principle that actually created the original designs.
In the case of the eye, the original design appears to have been the
ey gene-complex, that stands behind all other eyes, from the original
light-sensitive spot to the camera eyes of vertebrates and
cephalapods. It is this ey gene complex that creationists would see
as prime evidence of intelligent design and forward planning, that no
plausible combination of unguided natural processes could ever
produce.
Behe, after describing the fantastic complexity of even a
light-sensitive spot, that makes a TV camera seem low-tech,
summarises:
"Now that the black box of vision has been opened, it is no longer
enough for an evolutionary explanation of that power to consider only
the anatomical structures of whole eyes, as Darwin did in the
nineteenth century (and as popularizers of evolution continue to do
today). Each of the anatomical steps and structures that Darwin
thought were so simple actually involves staggeringly complicated
biochemical processes that cannot be papered over with rhetoric.
Darwin's metaphorical hops from butte to butte are now revealed in
many cases to be huge leaps between carefully tailored
machines-distances that would require a helicopter to cross in one
trip. Thus biochemistry offers a Lilliputian challenge to Darwin.
Anatomy is, quite simply, irrelevant to the question of whether
evolution could take place on the molecular level...The fossil record
has nothing to tell us about whether the interactions of
11-cis-retinal with rhodopsin, transducin, and phosphodiesterase
could have developed step-by-step...This is not to say that random
mutation is a myth, or that Darwinism fails to explain anything (it
explains microevolution very nicely)...Until recently, however,
evolutionary biologists could be unconcerned with the molecular
details of life because so little was known about them. Now the
black box of the cell has been opened, and the infinitesmal world
that stands revealed must be explained." (Behe, 1996, p22)
BH>Now, I really don't expect that you will agree that this is more
>elegant, but hopefully you can understand why some of us
>think it is.
I don't really understand Brian's point here. What exactly is *he*
proposing that is "more elegant"?
But before we get to deeply into a debate on this, I would point out
that it was *Loren* who first raised the issue of the relative
"elegance" of multiple or single interventions, namely: "...Should
we hypothesize multiple instances of supernatural intervention to
achieve similar features? Does this seem less "elegant" than a
single intervention?
I answered Loren's question in his words with what I thought would be
the "most `elegant' method", namely "a single intervention with a
very long dormancy", for example, "all the entire gene complexes in
the animal kingdom being "built-in right from the Cambrian Explosion,
but only activated or unmasked later when needed." But I made it
quite clear that this "would...not necessarily [be] God's ...most
`elegant' method."
Indeed, I would be interested to find out what is Brian's "most
`elegant' method"! :-)
God bless.
Steve
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| 3 Hawker Avenue / Oz \ Steve.Jones@health.wa.gov.au |
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