Darwinian/Neo-Darwinian, and codes (was Memes and Things)

John Wilkins (wilkins@wehi.edu.au)
Wed, 03 Feb 1999 10:00:36 +1000

Date: Wed, 03 Feb 1999 10:00:36 +1000
From: John Wilkins <wilkins@wehi.edu.au>
Subject: Darwinian/Neo-Darwinian, and codes (was Memes and Things)
To: memetics@mmu.ac.uk
In-Reply-To: <199902020907.JAA18865@alpheratz.cpm.aca.mmu.ac.uk>

Hans-Cees Speel <hanss@sepa.tudelft.nl> wrote in reply to me:
>> >> So, I think that there is a sense in which a type is low fidelity but
>> >> transmitted without a replicator, and that this is still within the
>> >> evolutionary paradigm, so construed. I also think that there is an
>> >> operational issue: we can best investigate the high fidelity
>> >> replicators, and that is where we should start, as I argue in my
>> >> forthcoming JoM-EMIT reply to Gatherer.
>> >
>> >transmitted without a replicator? Do you mean that there is no geno-phe=
>> >distinction, or something else?
>> No, this is a claim about necessity. I think that Darwinian evolution
>> occurs on reproduced types (what Griesemer calls "reproducers"), while
>> neo-Darwinian selection occurs over replicators. The latter certainly
>> applies in most cases, but that does not exhaust the range of Darwinian
>> process.
>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....

As Darwin originally presented his theory, and in the most general version =
it as I reconstruct it, selection is selection over variation of types. In
biology, this might be types of organisms, sure, but it might also be types=
behaviours, antlers, immune cells or environmental stress resistance.

Neo-Darwinian evolution stresses the relevance of genes as replicators. Thi=
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=
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.=20

But when, eg, Dennett says "And since memes are no more multicellular than
they are sexual, the fact that there is no clear way---no "principled" way,=
they used to say at MIT--of distinguishing mutations from phenotypic
acquisitions hardly shows that they are disqualified from a neo-Darwinian
treatment.(6) Most--much more than 99%-- of the life forms on this planet h=
evolved under just such a regime, and neo-Darwinism certainly covers their
evolution handily." <http://ase.tufts.edu/cogstud/papers/MEMEMYTH.FIN.htm> =
is just plain wrong. *Darwinian* evolutiona ccounts for it, but the only wa=
this is Neo-Darwinian evolution is to treat it as a limit case where the
geno-pheno distinction is insensible, and this is, to me, semantic salvatio=

Griesemer, J. 1998. The case for epigenetic inheritance in evolution. Journ=
of Evolutionary Biology 11 (2):193=AD200.

Griesemer, J. 1998. Epigenetic Inheritance and Evolution, the Lamarckian
Dimension =AD E Jablonka, M Lamb. Biology & Philosophy 13 (1):103=AD112.

Jablonka, Eva, and Marion J. Lamb. 1995. Epigenetic inheritance and evoluti=
the Lamarckian dimension. Oxford; New York: Oxford University Press.

Jablonka, E., and M. J. Lamb. 1998. Bridges Between Development and Evoluti=
Biology & Philosophy 13 (1):119=AD124.

Rollo, C David. 1995. Phenotypes: their epigenetics, ecology and evolution.
London: Chapman & Hall.

> > >In my thoughts i see memetics
>> as a mix of systems where there >are evolutionary feed-back loops
>> (learning and evolutionary >selection leading to adaptation) and
>> transmission where there is >just spread, and perhaps struggle for
>> survival without adaptations.
>> Analogous to selection and adaptation, and drift and neutral variation,
>> but I cannot make sense of the third option. If system S struggles to
>> survive, then it needs some processes of acquiring and utilising
>> resources, even in the absence of competition with conspecifics or
>> allospecifics. If these work, then I cannot think they aren't adaptation=
>> in at least one sense. Especially since variations will drive a refining
>> in progeny of those traits and mechanisms.
>I simply mean that species, and organisms too, can outcompete
>each other. If this happens we need no adaptations, and we have
>only weeding out of less fitting. Some call this adaptation, but I
>don't automatically, because the feedback loop is then even
>ourtside the species. A lot of change in nature is simply the going
>away of species from places, new species arriving and some
>competition. It is more the ecological view on evolution I quess.

Sensu "species sorting" then. Species sorting is sorting on emergent
properties of species. The reason this is not adaptive is because it is not
selection - there is no reproduction going on. You can get a good feel for
this from the essay by Eldredge listed below, and from the volume edited by
Stomit and Peterson on Punctuated Equilibria (ref not to hand).

Eldredge, Niles. 1989. Macroevolutionary dynamics: species, niches, and
adaptive peaks. New York: McGraw-Hill.
>> >I wonder if this doesn't touch on the ability of 'things' to be both
>> >genotype and phenotype in special situations.
>I could have written this:-)

You will, Oscar, you will ;-)
> I guess I could claim that
>> >all things are 'code', most simply have low fecundity and reproductive
>> >fidelity. I could also claim that all things are the result of
>> >antecedent processes and thus phenotype.
>> >
>> >Would you agree?
>I think the material that holds code can be in selective processes,
>and thus by definition phenotype. But to be code you also need to
>have decoding and encoding. So not all phenotype is involved with
>> The notion of a "code" (as opposed to a mapping of prior to subsequent
>> states in a set of processes) is an analytic tool that says as much abou=
>> us as cognisers as it does about the systems being studied. IMNSHO.
>But it does say something about the physical structure aswel
>IMHO, namely that it stands for something else: that physicla thing
>that can be produced by a decoding process.

The very notion of en/de-coding is subjective. When is something a code and
when not? Well, it depends on how you characterise the physical systems
concerned, and a lot also on the scale at which you do so. Is the expressio=
of a given enzyme from a codon of nucleotides a decoding of those nucleotid=
Most say yes, but there are other properties of nucleotides - such as their
structure in water - that we do not call decoding but just physical
peoperties. When does a codon "stand for" (note the semantic nature of that
phrasing) something and when not? When we so characterise the relationship =
heuristic purposes.=20

The scalar relationship between nucleotides and phenotypic properties is su=
that because some features of organisms, and indeed the organisms themselve=
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.


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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