Date: Tue, 09 Feb 1999 16:18:29 +1000
From: John Wilkins <wilkins@wehi.edu.au>
Subject: Re: Darwinian/Neo-Darwinian, and codes (was Memes and Things)
To: memetics@mmu.ac.uk
Mario Vaneechoutte wrote:
| Hans-Cees Speel wrote:
|
| > > >You go too fast for me:-) Darwinian in your words means
selection
| > > >on individual organisms, and neo-darwinian selection on
| > > >replicators? Else please elaborate becuase then I have definitly
lost you
| > > >here....
| > >
<snip>
| > > Neo-Darwinian evolution stresses the relevance of genes as
replicators.
| > > This is fine, but there are exotic cases where this is not
relevant, such
| > > as in epigenetic inheritance (non-nucleotidal inheritance,
including,
| > > arguably, development systems - see the refs below). So, IMO,
| > > Neo-Darwinian evolution is a special case of Darwinian evolution,
the kind
| > > where there *is* a strict soma-germ sequestration, or, in modern
jargon,
| > > where the genotype and the phenotype are qualitatively distinct.
| >
| > OK, I agree with this line of thought.
|
| Well, I don't or at least I don't understand what you want to proof
| here. I think you confuse genotype/phenotype with soma/germ.In
| unicellular organisms soma and germ are identical, while in
| multicellulars certain cells specialize in reproduction (germ) while
the
| rest of the colony forms a temporary existing construct (soma), but
| genotype and phenotype are different in both uni and multicellulars.
In
| a unicellular the nucleotides are the genotype and the rest of the
cell
| and its behaviour are phenotype. Still, this classical distinction
has
| its limitations. Take membrane lipids which are artefacts made by
| enzymatic activity. You could name these lipids phenotypic artefacts.
| But then we have to consider newly formed nucleotide strands as
| phenotypic artefacts as well!
This is sort of my point: the distinction (the Hull-Dawkins Distinction
between replicator and interactor), which is the lineal descendant of
the Weismann Germ Sequestration Dogma, is more or less an arbitrary one.
I say more or less, because there clearly *are* some real differences,
but appropriately characterised they are differences of degree.
The notion of a replicator is useful in many contexts, but if we push it
too far (as Dawkins sometimes does - see
<http://www.onthenet.com.au/~stear/dawkinschallenge.htm>) it becomes a
case of misplaced concretism. Plotkin and Ghiselin both worry about the
notion of replicators as "things", and so do I. They are entities
alright, but not replicators in virtue of the kind of entity they are,
rather in virtue of the *role* they play in a certain characterisation
of a process. Recharacterise that process of reproduction and evolution,
and replicators evaporate. Just so long as the notion has heuristic
value, so long should we make use of it.
Ghiselin, Michael T. 1997. Metaphysics and the origin of species.
Albany: State University of New York Press.
Plotkin, Henry J. 1994. The nature of knowledge: concerning adaptations,
instinct and the evolution of intelligence. Harmondsworth UK: Allen
Lane/The Penguin Press.
.....
| > > the semantic nature of that phrasing) something and when not?
When we so
| > > characterise the relationship for heuristic purposes.
| >
| > isn't everything we say heuristic then?
|
| Good question
Yes, and my answer is, well, yes. What else could it be? And when a
heuristic fails, drop it and select another. In the limit cases being
discussed here, the replicator concept breaks down. Since evolution
occurs anyway, the notion is not an essential feature of
characterisations or models of evolution. Since so far as we know there
is no other kind of evolution than Darwinian evolution, there must be
something wrong with neo-Darwinian exclusivity, such as we find in
Dennett and Dawkins (but not, IMO, Maynard Smith, for all that he claims
to be a methodological reductionist)
| > > The scalar relationship between nucleotides and phenotypic
properties is
| > > such that because some features of organisms, and indeed the
organisms
| > > themselves, are perceptually salient to *us*, and there is some
(more
| > > complex than most think) relationship between those and genes, we
consider
| > > that mapping a codical one. Other properties we do not. --
| >
| > I do not see the point of this ?
|
| Neither do I. Encoded information needs interpretation to 'mean'
| something. This is obviously the case for genes and for texts. From
the
| informational point of view, it does not matter which characteristics
a
| nucleotide strand has in water or how much place a book takes on a
| shelf. So, let us not get too philosophical and stick to the
| informationally 'useful' points of view.
I may be importing a dispute I'm having in another context. "Information
content" in Shannon-Weaver terms implies some value of uncertainty in
the sequence of symbols. To be sure what the sequence is, as opposed to
noise, you need to have an encoding protocol. There is an obvious and
almost universal protocol in the Watson-Crick pairing and the so-called
xNA coding, but in the case of memes, there is no "objective" encoding
protocol, and we must build it up as we research our domain.
Of course, we have prior access to the semantic world of our subjects,
but my point is that what counts as a replicator is relative to the
encoding procedure. How, for example, can one tell if something written
in Japanese textbooks is really an instance of Einsteinian relativity
theory, which was first written in German? Through the use of a
translation lexicon. Anyone who has read Quine knows there are some, to
put it mildly, issues about translation (although not as many as Quine's
radical indeterminacy thesis implies).
Incidentally, I am of the view that the hydrophilic properties of
nucleotides are directly related to their ability to act as code
molecules. And in the case of large print books for visually impaired
readers, there can be informational features of size :-)
regards
--John Wilkins, Head, Graphic Production The Walter and Eliza Hall Institute of Medical Research Melbourne, Australia <mailto:wilkins@WEHI.EDU.AU><http://www.wehi.edu.au/~wilkins> Homo homini aut deus aut lupus - Erasmus of Rotterdam
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