> >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."
Good quote Kevin. The problem refered to here is called "The problem of
the incipient stages of useful structures". Dandy name, huh?
Notice that Dawkins never claimed evolution to be "stuck". If this problem
caused evolution to be stuck, how would it have solved much harder problems
like turning reptile scales into bird feathers (as opposed to simply improving
an eye)? Yes, evolution is in a rough spot here and, as Dawkins shows, there
are paths which it can't go down. But there are _always_ paths evolution can't
go down. There are _always_ difficulties to be overcome. This doesn't mean
evolution is stuck.
S.J. Gould offers a counter-example to Dawkins. This example does not mean
that Dawkins is wrong (he's not), but shows how evolution can overcome problems
like the one presented above:
"In a brilliant resolution to this conundrum, Darwin proposed that organs
explicitly adapted by natural selection for one function also posses latent
potential for working in other ways, if later environmental shifts encourage
such an evolutionary response.
[An example of this principle in action, changing reptile scales to birds
wings, follows. To conserve space, I've clipped it.]
Much of evolution's novelty arises from the actualization of such latent
potentials, not from the slow and explicit improvement of an unchanged
function by natural selection." - Discover Magazine, October 1996
The "eye" example serves not as a valid example of the problems with
evolution, but as an example of the problems with the so-called "Level 3".
The intelligent man looks at the eye and thinks "We could do better than
this.". But evolution is not intelligent. Nor is it stupid. The term
simply doesn't apply. It acts randomly. It's non-deterministic. It's
tireless. When presented with a problem, we have no way of knowing how
it will solve that problem. For example, the human eye cannot see in the
dark, yet in our society there are times when this is needed. Did evolution
take an engineering approach and add this ability to the eye? No. Instead,
to "solve" the problem it gave us brains. We use these brains to build
infa-red goggles.
Evolution _never_ gets stuck. The eye is the way it is because at this
point in time there is no evolutionary advantage for it to be otherwise.
Short-comings in the design of the eye have been solved in ways that have
nothing to do with eyes. These solutions are general-purpose and offer
additional benefits which spending lots of resources on eye-design could
never hope to offer. Evolution blows the poor Engineer out of the water.
Saying that the so-called "Level 3" mind causes replicators to become
unstuck is to say it solves problems which don't exist.
> 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,
I've never done my homework. I've always spent my free time having sex
with large-breasted lovelies (or small-breasted lovelies).
> >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."
There's an entire thread of postings on this topic, not just mine. Inside
these postings are the heap of reasons the so-called "Level 3" is "either
meaningless, useless, completely personal, or contradicts several other
definitions." The "stuck replicators" definition is now added to the heap.
> 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.
Thanks.
-- David Leeper dleeper@gte.net Homo Deus http://home1.gte.net/dleeper/index.htm 1 + 1 != 2 http://home1.gte.net/dleeper/CMath.html