Received: by alpheratz.cpm.aca.mmu.ac.uk id FAA15994 (8.6.9/5.3[ref firstname.lastname@example.org] for cpm.aca.mmu.ac.uk from email@example.com); Sat, 28 Jul 2001 05:22:14 +0100 Message-ID: <000d01c1171c$6783d260$ddd9b3d1@teddace> From: "Dace" <firstname.lastname@example.org> To: <email@example.com> References: <2D1C159B783DD211808A006008062D3101745FCC@inchna.stir.ac.uk> Subject: Re: Logic Date: Fri, 27 Jul 2001 21:18:46 -0700 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: firstname.lastname@example.org Precedence: bulk Reply-To: email@example.com
> >> What view of evolution, in your view, is plausible?
> <When our hominid ancestors developed a method of scavenging for
> meat in the
> > hottest part of the day (after most animals have retreated to the shade)
> > they soon began developing sweat glands and losing their hair. The
> > phylogenetic shift occurred in tandem with the behavioral shift. This
> > the norm, and it suggests that our own actions help determine our
> > evolution.
> > We shape ourselves. If we'd had to wait around for a couple million
> > for a random mutation to give us the necessary glands under our skin,
> > still be waiting. Since we can't pass on acquired characteristics
> > directly
> > to our offspring, there must be a kind of nonmaterial, species memory
> > which
> > evolves in accord with the shifting behavior of individual organisms.
> > This
> > is akin to Aristotle's notion that the form of the organism is
> > by
> > the species, not through machine-like processes arising from the nuclei
> > our cells.>
> I'm sorry, this is pants. Did our ancestors make the days hots?
> Evolution doesn't need 'a kind of non material, species memory', in other
> words a macguffin to make it work. All you need is a process where there
> replication, variation and selection.
In other words, a macguffin?
These "pants" you refer to were worn by all the early evolutionists,
including Spencer, Wallace, Darwin, and Lamarck. All were in agreement that
evolution was driven by direct adaptation to environmental constraints.
Virtually no one took seriously the idea of a mechanical method of evolution
centered on the nuclei of cells. Though a few theorists suggested just such
a scenario even before Weismann and the rediscovery of Mendel, it was mostly
assumed, even by positivists like Spencer, that the whole of the organism,
in its actions and intelligence, is primarily responsible for the evolution
of its species.
So, what happened in the 20th century to change our minds? What do we
really know about these "genes?" Well, we know we can alter morphology by
"engineering" them. And we know there are 30,000 of them in the human
genome, which correspond to roughly 30,000 proteins. Does this mean that
genes "code" for the structure of proteins? No, actually they just contain
the models for chains of amino acids. As to how these chains fold up
correctly, this does not appear to be a mechanically driven process. From
protein on up, no form in the body has been linked to the sequence of
nucleic acids buried in our chromosomes. We know the alteration of genes
and protiens can have effects at various levels of the body's structure, but
we don't know that the form of these structures reflects "information"
residing in genes. Just because a gene might change your eye color doesn't
mean it contains a program by which the eye itself is constructed. If we
alter the tuning on our radio, the station we're listening to might sound
quite different, but does that mean it's somehow located inside the
circuitry of the radio?
As the late physicist Walter Elsasser observed, developmental biology is
merely descriptive. At no point is any organic structure or process
explained. Saying that DNA is responsible for the goings-on within the body
is like saying God does it. The point is, *how*? How does DNA account for
the form of the organism? More to the point, what is it that makes a living
organism alive? Why doesn't it just disintegrate into its chemical
constituents? Wouldn't that be more logical, from a mechanistic standpoint,
than going on with this endless buzzing about? I mean, why don't we all
just fall over dead? Funny that neo-Darwinism doesn't have a lot to say on
that particular matter.
You can't trust a theory that invokes the name of someone who explicitly
rejected its central tenet. Darwin was certainly aware of the "germ-plasm"
theory. He dismissed it on the basis of the absence of monsters in nature.
If phenotypic characteristics could be individually molded on the basis of
units of germ-plasm, then alterations in these units should produce
grotesque changes in outer form. If the "germ" for ears mutated in such a
way as to increase their size by three-fold, the world might soon witness
the onset of a race of Mickey Mouses. Yet this doesn't happen. Clearly,
it's because the body's form is governed holistically. This is why
evolution is driven according to the sensible behavior of the organism
rather than the blind workings of its macromolecules. The atomistic model
of inheritance is unsuitable for evolution. Aristotle, Goethe, Whitehead,
and yes, even Bergson (despite his vitalism), tell us far more about life
than Crick and Watson ever could.
Blame the wee folks for all this mischief. What we're up against is the
"homunculi" meme. We've never been able to drop the idea that outer form is
a scaled-up version of inner form. Just as Newton updated Plato's Forms
into "laws of physics," Weismann refashioned the homunculus as a set of
(genetic) instructions. Mechanistic evolution made a lot more sense when
speciation was given plenty of time to unfold in simple, discrete steps.
Yet we know, based on jumps in the fossil record, that evolution occurs in
brief bursts punctuated with great gulfs of calm. Mechanistic ontogeny made
a lot more sense when the body contained vast numbers of genes and proteins.
But the recent revelation that the genome is one-third smaller than
previously imagined did nothing to call into question the reduction of
morphology to genetics. The power of the meme against all logic ensures
that the genetic model, both evolutionary and developmental, remains
> also, natural selection doesn't work at the level of individuals, but at
> level of the genes,
It works, not at the level of individuals, but at the level of species. The
form of the species evolves. As to whether this collective form is
reducible to DNA, we don't know.
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