One Hundred Million Americans and a Toad

geirroeth RemoveThis @aol.com (Geirroeth) wrote in message news:<20041114151411.15947.00000653 RemoveThis @mb-m02.aol.com>...
 > Chris Friel (chrisseanfriel@hotmail.com) wrote:
 >
  > >With Lewis and the Pope (but not 45% of Americans, according to
  > >Gallop) I do not object to the theory of evolution on theological
  > >principle. Nevertheless, I have often been perplexed by what I (who am
  > >ignorant of Biology) think is a problem for Darwin.
 >
 > (snip)
 >
 > The late Stephen Jay Gould wrote an essay on "pre-adaptation" dealing
 > with this type of issue - it's available online at
<font color=purple> > <a style='text-decoration: underline;' href="http://www.stephenjaygould.org/library/gould_functionalshift.html</font" target="_blank">http://www.stephenjaygould.org/library/gould_functionalshift.html</font</a>>
 >
 > Steve Morrison

thanks very much steve. but i'm still puzzled!
I shall very briefly summarise Gould's argument. Firstly, I note that
Gould cites the objection that I made as an argument that "continues
to rank as the primary stumbling block among thoughtful and friendly
scrutinizers of Darwinism today." He notes how Darwin took the
criticisms of Mivart seriously on this point. The objection concerns
the "The Incompetency of 'Natural Selection' to Account for the
Incipient Stages of Useful Structures." Whilst a wing can have
utility: it can help you fly, half a wing does not have that utility –
you cannot "nearly fly" with "nearly-a-wing". But, since natural
selection supposes a gradual development of complex structures, how do
we explain such intermediary stages?
Darwin's solution (which Gould notes has not always been appreciated
even by professionals) concerns "preadaptation". He thinks it has made
little progress on account of its paradoxical nature – and also
because, hitherto, it has lacked empirical support.
"Preadaptation" involves "functional shift". To simplify: things that
were nearly wings once did have a function: but that function may have
had nothing to do with flight. But then, eventually, the wings changed
from being used for the function that they had to their current
function. Gould thinks it has quite beside the point to investigate
whether proto-wings might at least help you glide, say. What Gould
presents is evidence that wings may help in other ways: they cool you
down.
So, the idea: first the evolution of a proto-wing (good for cooling,
but too small for flight); later the full wing (good for flight). He
backs his ideas up by looking at how cooling you down varies with wing
size. It seems to fit.
"We could not hope for a more elegant experimental confirmation of
Darwin's solution to Mivart's challenge."
Fine. But my point was slightly different.
Firstly, I still do not see addressed the idea that certain
developments obtain simply through random selection – over vast
periods of time – with the result that structures evolve that are
survivally neutral. I am not sure how evolutionists regard this
category. Must all complex developments be either beneficial or
harmful?
Secondly, to return to wings, the "proto-wing" (that acts to cool the
insect down) is a prior condition for the later flying wing, the wing
proper. Only a percentage of those with proto-wings will go on to
develop wings – because certain conditions must obtain for the les
developed to become more complex.. Thus, at a certain time in the
past, when wings were "taking off" (so to speak) the proto-wings
(coolers) would be more numerous. But what is special about the past?
The present day is still a moment in evolution. We cannot think of
the present as having "arrived". So shouldn't there be more insects
with coolers than wings proper? Does this actually happen? Gould seems
to say, well, if wings were coolers in the past, that would make
perfect sense (for small wings are good for cooling, but as they get
bigger they end up good for flying, and big things must have once been
small) but why ask for an explanation of what once was useful? What is
more pertinent seems to be, where are all the (small) insects with
coolers on them, that don't actually fly? Of, course: they might be
there. But if such exist, isn't that obvious evidence for the
plausibility of functional shift anyway? The idea of functional shift
seems fine. But why should the old function die out? (the function
doesn't die out – wings help you fly and cool you down, but why aren't
there some insects with wings just for cooling?) But if it doesn't
there really ought to be two types of insects, and it seemed to me in
my ignorance, that that the non-flying-cooled-down-ones should be in
the majority.
To get back to my toad: A proboscis may have had a different useful
function from the one it has today. But why aren't there many other
relatives that are still around and utilising this function? Maybe
there are, of course. But then, it would seem that there is then no
mystery about this incipient structure. But, there would seem to be a
mystery, if a search has to be made for a functional shift in the
past.
CF
PS My criticism is meant to be "thoughtful and friendly" – I do
believe in evolution. My suspicion is that there is some scientific
development yet to be made that would act as a corrective to Darwin.<!-- ~MESSAGE_AFTER~ -->

Popping in late, while trying to catch up with a couple of weeks, because
the direct replies to this posting didn't satisfy me:

On Sat, 6 Nov 2004 13:19:14 UTC, chrisseanfriel.DeleteThis@hotmail.com (Chris Friel)
wrote:

 >...
 > But what occurred to me was something slightly different. It was not
 > so much the problem of explaining features emerging that possess
 > survival value, but how to account for the lack of features that don't
 > have survival value.

This is a sensible question. Sometimes a feature that has no real use may
be a handicap, getting in the way or requiring extra energy to grow and
maintain; these, of course, will be selected out. But often one runs into
arguments that glibly *assume* that something useless will fall away.
You're not required to believe them every time. For instance, a family of
mammals that subsist largely on fruit may have no need to synthesize their
own vitamin C, and lose the ability. It happened to primates; hence we can
get scurvy. It's often argued that the ability was lost because carrying
the ability will waste energy, but there's no real supporting evidence for
this, just an assumption.

 > Suppose probability of (growing a large proboscis) = a thousand to one
 > & p(getting a sensitive spot on the back ) =a thousand to one
 > & assuming independence ( I wonder about this?)
 > & suppose 1000000 occasions ¹ all the above seem plausible.
 > Then P(proboscis and spot) = a million to one.
 > Now, I have no problem about a million to one chance happening in a
 > million trials (63% likely, in fact, by my calculations).
 > But, shouldn't there be 2000 other toads, half of those with proboscis
 > but no spot, the other with spot and no proboscis? Does this happen?
 > There doesn't seem to be any positive reason to lose that spot. Just
 > because something doesn't have survival value doesn't mean it won't or
 > shouldn't survive. It seems to me that if evolution is true which I
 > believe (help my unbelief!) then such intermediary forms should be
 > apparent at all stages including our own stage. But do we identify
 > such forms?

This is the kind of objection raised by people who read popular treatments
written by people who haven't thought seriously about the problems. I.e.,
you are outwitting the authors of the works you've read; here's my version
of what they've missed.

First of all, a new mutation occurs, generally, in one individual. Even
if it's neutral, it's chancy whether that individual will survive and
reproduce, or die early, the mutation dying with it. Even if the new
mutation spreads a little, the chances of its eventually getting wiped out
by chance are considerable. There's a respectable mathematical theory of
population genetics that predicts this kind of thing; it can be seen in
microcosm in the tendency of uncommon family names to disappear. So the
half-way forms will not be found all over the place.

Which makes it look even more unlikely that two things will usefully come
together, since your hypothetical probability of 1/1000 is probably too
generous! That's where pre-adaptation comes in. For instance, it takes a
whole lot of changes to get from reptile (more properly, dinosaur) to
bird. How did they come together? Is a half-bird well adapted to
anything? (A point often raised by anti-evolutionists) You need feathers
*and* the right bone structure for a wing, for instance. This is now an
easy one: feathers are also good for heat insulation; in fact, birds still
need them for that purpose. It has become clear that some small dinosaurs
developed feathers, well before they could fly, presumably for insulation.
(See how careful I am with the "presumably"?) Then the feathers turned
out to have really good aerodynamic qualities for a flying creature. This
is still a bit glib; we don't have all the Missing Links; but in fact
Archaeopteryx is a remarkably good half-way form, much better than its
discoverers knew. The case hangs together as well as it can, given that
the fossil evidence is always chancy and incomplete.

 >
 > Now, I really don't know much about Darwin's theory, but I now and
 > again catch this or that popular spokesman who, purports to give an
 > explanation for such and such. These "true disciples" cause me
 > scandal.

Good. People are always explaining things, sounding as if they're talking
established science, when in fact they're just giving reasonable stories,
backed by no particular evidence. Evolutionary just-so stories, in fact.
(Stephen Jay Gould's term.) This distracts from the things that really
are understood in detail.

 > For again, on Darwin's theory, it seems to me that there are
 > many things, the result of random variation, that possess no survival
 > value, and require no explanation at all. They are simply down to
 > chance. (Toss a coin 100 times. You get 46 heads. Why not 47? No
 > reason, that's just chance. It's roughly 50%, and that's what
 > matters). So why don't such Darwinist's say this?

Because you didn't ask them Seriously, what I said about books written
glibly without expecting serious critical readers. (And don't let's
mention TV programs! Spare Ann's feelings, and maybe mine.)

In fairness, lots of evolutionists do talk about chance. Stephen Jay
Gould talked so much about it that he irritated a lot of colleagues. (But
with luck we can avoid rehashing that debate.) In fact, at the molecular
level, lots of truly neutral little mutations are happening all the time,
and some survive indefinitely.

In a DNA molecule, one nucleotide may be replaced by another, but the new
combination (they work in threes) may specify the same amino acid, so it
makes absolutely no difference. Or the new triplet may specify another
amino acid that's so similar as to make no difference in that particular
protein. Most of these changes disappear at random, as I mentioned; some
survive. The accumulation of these random little useless variations
permits the tracing of which species split off from which, and how long
ago. So they're not only known, they're _useful_ to the evolutionists.
And <sigh of relief> they generally confirm the genealogies that were
worked out long ago by studying fossils. With interesting exceptions and
surprises, of course; what fun would science be without those?

 >...
 > So where is my mistake?

No mistake that I noticed. Then again, I have probably missed something,
valid or invalid, in writing this rambling, reactive screed. Please
hammer on any points I've missed; and if there are arguments that don't
hang together, and you still care after all this verbiage, let's hear
about it.

--
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