Re: Evolution, "adaptation", and what's currently adaptive
Len Piotrowski (lpiotrow@magnus.acs.ohio-state.edu)
Fri, 6 Sep 1996 15:43:30 GMT
In article <50ncrt$l8c@news.sdd.hp.com> geroldf@sdd.hp.com (Gerold Firl) writes:
>[snip]
>In article <lpiotrow.403.322D9FE6@magnus.acs.ohio-state.edu>, lpiotrow@magnus.acs.ohio-state.edu (Len Piotrowski) writes:
>|> In article <50ieqh$n6l@news.sdd.hp.com> geroldf@sdd.hp.com (Gerold Firl) writes:
>|> >Throughout the biosphere
>|> >there exists the complete gamut of light-sensing and imaging systems,
>|> What makes this "gamut" complete, aside, I know, from the word of Firlmeister?
>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?"
>|> >which maps very well to the developmental evolutionary pathway.
>|> Interesting mapping function here: where does this "evolutionary pathway"
>|> exist?
>In the history of living organisms.
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?
>|> > We have ... [the museum of life forms presented as ancestors, snipped]
>Lenny, the next time you're tempted to make a pronouncement on a
>subject where you don't know what you're talking about, I hope you'll
>remember ... no eyes!
OKay. Would that be the 'no structural "eye"' or the "sophisticated" eye?
>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?
>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?
>[interesting structural differences between vertebrate and mollusc eyes,
deleted]
>Mollusc
>eyes and vertebrate eyes evolved independantly, but it's too late for
>us to change; we'll just have to make do with our phylogenetic
>constraints.
Since mollusc eyes and vertebrate eyes evolved independently, how can your
museum of incremental stages be a plausible proof of an actual, complete
Mendelian evolutionary pathway? It's only a convenient fiction to illustrate
general principles without basis in an actual ground truth. The concepts of
"evolutionary pathway" and "completeness" presented previously are merely a
heuristic.
>Now lenny, there's no shame in ignorance; without ignorance, we
>couldn't learn - but try not to be so aggressive about it. Aggressive
>ignorance looks silly.
Now Firl, you know I wouldn't pick on you without reason. I like you.
>|> ? Vision systems continue to evolve *because* of the adaptive benefits that
>|> vision accrues? How come a mollusc can't see then?
>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.
>Now, before you start strumming your teleological harp, lets get this
>straight: the genes of the fish do not "know" that they're in a cave,
>or that it's dark. What happens is that eventually a mutation occurs
>which produces an eyeless fish, and not only does this new
>configuration prove to be non-deleterious, it is actually advantageous
>- "adaptive", one might even say. It eventually spreads throughout the
>entire population. No teleology involved, just random combinations of
>genes subjected to natural selection over long periods of time, acted
>upon by the competitive environment of differential survival.
I agree! No pre-defined need, no precursor purpose, no functional adaptation!
>|> I have no agenda here, Firl.
>You've been coyly cautious about divulging the nature of the chip on
>your shoulder, but you clearly have an ax to grind.
My "ax to grind" is your insulting dialog.
>It seems to have
>something to do with the role of "meaning" as it relates to
>"meaningful human behavior".
No "role" 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 must hate the ideas of marvin harris. I see you as the
>anti-harris.
No, really, I don't hate Marvin Harris!
>Have you heard of marvin harris? What do you think of him?
I liked him. Do I have to then be a cultural materialist?
>but maybe instead of sniping at others, you should present your own
>ideas.
Thinking of your contribution to such a thread is a real dampener.
>Tell me lenny, where does meaning come from?
Social interaction.
> What is the
>meaning of meaning?
It's contextually contingent.
> And if meaningful human behavior is not related to
>functional adaptations, where does it come from?
Social interaction.
>Why does it exist?
To define the situation.
>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.
>|> > if something as obviously
>|> >functional as vision didn't evolve as an adaptation, where did it come
>|> >from?
>|> What it (eyeball) can be used for (to see) says nothing about where it came
>|> from. Is this getting too taxing for you, Firl?
>Right with you, lenny old boy.
Now we're talkin', eh sprout?
>But actually, the use of the eye has a lot to say about where it came
>from. The selection pressures which drove the developement of complex
>vision systems are patently obvious, and the presence of primitive
>eyespots among unicellular organisms shows exactly how the process
>began. No mystery, no teleology, the facts are all there for you to
>see. Why don't you try asking questions instead tooting your horn?
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.
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?
Cheers,
_Lenny__
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