Re: Evolution, "adaptation", and what's currently adaptive
Gerold Firl (geroldf@sdd.hp.com)
10 Sep 1996 20:26:27 GMT
In article <lpiotrow.423.323046A2@magnus.acs.ohio-state.edu>, lpiotrow@magnus.acs.ohio-state.edu (Len Piotrowski) writes:
|> In article <50ncrt$l8c@news.sdd.hp.com> geroldf@sdd.hp.com (Gerold Firl) writes:
|> >I say "complete" because it ranges from a very simple ability to sense
|> >light and dark, with no structural "eye" at all, to the sophistication
|> >of humans and raptors, who can discriminate thousands of colors and
|> >extremely fine details, with all the intermediates between.
|> The "completeness" is merely determined by your implicit classification. You
|> have no independent notion as to how complete "completeness" is for your
|> perception of "eyeness." I take note of your distinction between the ' no
|> structural "eye"' and the "sophisticated" eye; a classificatory hedging for
|> the sake of "completeness?"
You're lost in the words, lenny. The gamut of vision systems ranges
from the simple ability of plants to move their leaves to maximise
solar gain, to the non-imaging eyespots of unicellular organisms which
also allow them to orient to light, to lens-less pinhole eyes which
provide rough imaging, to eyes with lenses which can focus images on a
retina, to the the eyes of raptors and humans, which are as good as we
get on this little planet. I don't know what you're going-on about,
with your talk of "eyeness"; "eyeness" is a non-sequiteur as far as I
can tell.
|> Your mapping of history to evolution is not very convincing. Do you seriously
|> propose that the "eye" stalks of terrestrial gastropods are ancestral to the
|> human eye? Or for that matter, do you really propose that any of the current
|> life forms listed in your museum of "evolutionary" progress were actually
|> ancestral life forms related through direct Mendelian inheritance to coeval
|> living human beings?
There you go again, lenny. Yes, that is what I am saying. The eyes of
vertebrates *are* the direct evolutionary outgrowth of ancestral
phyla. I recommend you take a look at _five kingdoms_, a wonderful
book by margulis and schwartz which describes all the phyla of life
and their probable evolutionary relationships. If I recall correctly,
vertebrates are thought to have evolved from annelids (worms, that
is).
|> >Molluscs do have eyes;
|> Under your broad "completeness" classification, no doubt any light sensitive
|> receptor is an "eye" by this definition - including those of plants, eh?
We've gone over this before, lenny.
Light sensitive organs or receptors are not necessarily eyes. Eyes
evolved from simpler light-sensitive structures, but no plants have
eyes. Many different animals and protozoa have eyes however, and it is
estimated that eyes have independantly evolved something like 8 times
(if I recall correctly); vertebrate eyes did not evolve from mollusc
eyes.
|> >indeed, it is one of those contingent facts of
|> >history much beloved by semioticians posing as biologists that the
|> >mollusc eye has some aspects which are intrinsically superior to
|> >vertebrate eyes.
|> ... indeed! Historical contingency of mollusc "eyes" proves they were
|> ancestral to vertebrate "eyes," eh?
Lenny, the word "superior" is a different word from the word
"ancestral".
|> >Some molluscs can't see, just like some vertebrates can't see. Fish
|> >which have lived in underground caves for many generations will lose
|> >their eyes; it isn't worth it for them to make the investment in
|> >growing eyes which are useless anyway.
|> "Worth" is another one of those concepts that doesn't help in understanding
|> the problem. It implies to "them" a judgement upon their own fate. I don't
|> think that is what you want to say. However, it illustrates a similar problem
|> with the use of "purpose" as the reason for the development or lack of
|> development for a function.
That's like saying that dawkins is all wrong because genes can't be
selfish, they're just units of base-pairs on a dna molecule; we've
also gone over why your argument from teleology is null and void.
I realise that it's difficult to picture how the incremental
accumulation of natural selection and mutation at the level of the
gene could produce such amazingly complex structures as are seen in
the natural world, but that's just something you need to think about
more carefully. Read some books on evolutionary biology, lenny. It
really works. You just need to understand the huge spans of time
involved.
|> >For some reason, you object to the idea
|> >that "meaningful human behavior" could be related to an underlying
|> >function.
|> By definition, meaningful human interaction is expressive, and thus, not
|> practical. That doesn't mean there is no human behavior that is practical, or
|> that meaningful human interaction doesn't serve a function.
You still haven't explained just what you mean by the recurring phrase
"meaningful human interaction". It's not practical? Lets take an
example:
A mother teaches her child to talk, to read, to count; real basic
stuff, happens all the time, all over the world, it's very meaningful
and - suprize surprize - it's *practical* too!
A mother teaches her cub to stalk, to pounce, to kill - ever watched a
cat and her kittens? - the separation you draw between humans and
other animals is absurd.
|> >You must hate the ideas of marvin harris. I see you as the
|> >anti-harris.
|> No, really, I don't hate Marvin Harris!
I didn't ask whether you hated *him* - I asked how you felt about his
ideas. Don't be shy. I don't think you'll hurt his feelings.
|> >Have you heard of marvin harris? What do you think of him?
|> I liked him. Do I have to then be a cultural materialist?
That depends. In _cows, pigs, wars, and witches_ harris presents very
convincing arguments in favor of the view that "meaningful human
behavior" is adaptive and practical. He uses the example of the sacred
cow in hindu ideology, arguing that this is just as much a practical
idea as a spiritual one. I would expect you would disagree with that.
Why are you so coy about it?
|> >And since humans do function, and they do adapt, how can it be that
|> >their meaningful behavior is unrelated to their functional
|> >adaptations?
|> In it's expressive, non-practical aspect.
Expressive, non-practical ... art for arts sake, eh? All human
interaction (or only interaction for interactions sake?) is
non-practical?
You're fooling yourself.
|> The "eye" says nothing; the "selection pressures" are not obvious, only
|> conjectured; "eyespots" on unicellular organisms "show" nothing, let alone
|> the beginnings of a "process." Your attempt at an explanation just muddles
|> clear understanding. The proof of a Complete Evolutionary Pathway of the Eye
|> is merely a kludge of selected living organisms into a rickety framework of
|> suggested ancestral relationships without any ground truth. Your zoological
|> garden of serial progress is contradicted by your own admission to independent
|> processes. Your "explanatory" model truly is a mystery, and, in as much as it
|> suggests facts outside of contexts, exhibits an expressive design that
|> confuses relationship.
Only to someone lacking in comprehension of the processes and
relationships involved.
Some eyes evolved independantly, others are related by direct lineage.
You need to trace the branches of the evolutionary tree to see which
is which. Again, I invite you to do a little research. Try it, you
might like it.
|> Earlier you complained about me asking too many questions, and now you
|> admonish me to ask more. Do you really expect me to believe this to be an
|> sincere request for dialog, Firl?
That seems pretty far-fetched, at this point, doesn't it? I have made
a sincere attempt to understand your point of view.
--
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=-=-=-=-=-=-=-=-=-=-=-=-=-=---- Gerold Firl @ ..hplabs!hp-sdd!geroldf
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