Richard and I are really two seperate people. I'm younger, taller and
much better looking. ;) The above quotes are his; not ours.
>
>Kevin O'Connor wrote:
>> Replicators also tend to reach and get stuck on sub-optimal peaks.
>
>Richard Brodie wrote:
>> That statement is in direct opposition to what scientists are saying
>> about replicators. Dawkins, Dennett, and even Gould agree that
>getting
>> caught at local maxima is an inherent quality of evolution by
>natural
>> selection. That is why, for instance, our eyes have nerves coming
>out
>> the front instead of the back.
>
>0) Can't resist this: You must have some strange looking eyes Richard.
>
>1) If evolution got stuck, it wouldn't be evolution. I challange you
>to find _any_ evolutionist of repute who says evolution gets stuck.
>Name dropping doesn't count, let's see something solid.
In defiance of copyright law KMO emancipates the following memes from
Chapter 4 of Richard Dawkins' "The Blind Watchmaker:"
"My second example of an evolutionary progression that didn't happen
because of disadvantageous intermediates, even though it might ultimately
have turned out better if it had, concerns the retina of our eyes (and
all other vertebrates). Like any nerve, the optic nerve is a trunk
cable, a bundle of separate 'insulated' wires, in this case about three
million of them. Each of the three million wires leads from one cell in
the retina to the brain. You can think of them as the wires leading from
a bank of three million photocells (actually three million relay stations
gathering information from an even larger number of photocells) to the
computer that is to process the information in thet brain. They are
gathered together from all over the retina into a single bundle, which is
the otic nerve for that eye."
"Any engineer would naturally assume that the photocells would point
towards the light, with their wires leading backwards towards the brain.
He would laugh at any suggestion that the photocells might point away
from the light, with their wires departing on the side nearest the light.
Yet this is exactly what happens in all vertebrate retinas. Each
photocell is, in effect, wired in backwards, with its wire sticking out
on the side nearest the light. The wire has to travel over the surgace
of the retina, to a point where it dives through a hole in the retina
(the so-called 'blind spot') to join the optic nerve. This means that
the light, instead of being granted an unrestricted passage to the
photocells, has to pass through a forest of connecting wires, presumably
suffering at least some attenuation and distortion (actually probably not
much but, still, it is the principle of the thing that would offend any
tidy-minded engineer!)."
"I don't know the exact explanation for this strange state of affairs.
The relevant period of evolution is so long ago. But I am ready to bet
that it had something to do with the trajectory, the pathway through the
real-life equivalent of Biomorph Land, that would have to be traversed in
order to turn the retina the right way round, starting from whatever
ancestral organ preceded the eye. There probably is such a trajectory,
but that hypothetical trajectory, when realized in actual bodies of
intermediate animals, proved disadvantageous - temporarily
disadvantageious only, but that is enough. Intermediates could see even
less well than their imperfect ancestors, and it is no consolation that
they are building better eyesight for their remote descendants! What
matters is survival in the here and now."
"'Dollo's Law' states that evolution is irreversible. This is often
confused with a lot of idealistic nonsense about the inevitablility of
progress, often coupled with ignorant nonsense about evolution 'violating
the Second Law of Thermodynamics' (those that belong to the half of the
educated population that, according to the novelist C.P. Snow, know what
the Second Law is, will realize that it is no more violated by evolution
than it is violated by the growth of a baby.) There is no reason why
general trends in evolution shouldn't be reversed . If there is a trend
towards large antlers for a while in evolution, there can easily be a
subsequent trend towards, there can easily be a subsequent trend towards
smaller antlers again. Dollo's Law is really just a statement agbout the
statistical improbablility of following exactly the same evolutionay
trajectory twice (or, indeed, any particular trajectory), in either
direction. A single mutational step can easily be reversed. But for
larger numbers of mutational steps, even in the case of the biomorphs
with their nine little genes, the mathematical space of all possible
trajectories is so vast that the chance of two trajectories ever arriving
at the same point becomes vanishingly small. This is even more true of
real animals with their vastly larger numbers of genes. There is nothing
mysterious or mystical about Dollo's Las, nor is it something that we go
out and 'test' in nature. If follow simply from the elementary laws of
probability."
Note: The biomorphs with nine genes to which Dawkins makes reference in
the passage I transcribed are the entities who generated by a computer
program that Dawkins wrote to demonstrate the variety that can acrue from
cumulative selection. I'm sure you can download it from some web site.
Anybody know the appropriate URLs?
I'm not remonstrating here or chastizing any one for "not doing their
homework" here, but how many people on the list have read "The Blind
Watchmaker?" I'm just currious. I haven't read Dawkins new book,
"Climbing Mount Improbable," but I've read his other four books, and "The
Blind Watchmaker" is second only to "River Out of Eden" in accessibility.
It's a fun read and I recommend it.
>
>Kevin, this is why I choose not to stop participating in this thread.
>Every new definition of Level 3 is either meaningless, useless,
>completely
>personal, or contradicts several other definitions. CoV claims to
>have
>some level of rationality and this so-called "Level 3" undermines
>this.
>It makes us hypocrites.
David, I love these "conclusions" which come right out of left field.
You have this tendency to write for a while, and then throw out some
unrelated ad hominum attack and trust that it's position at the end of
your post will cause people to see it as the culmination of a process of
argument. Nothing that you wrote in the quoted post prior to that last
paragraph even remotely sets the stage for your claim that "[e]very new
definition of Level 3 is either meaningless, useless, completely
personal, or contradicts several other definitions." Still, you did
prompt me to dig out my use-worn copy ot "The Blind Watchmaker" and put
Dollo's Law on the table for evaluation and use by the discussion
participants.
Take care. -KMO