From: Chris Taylor (christ@ebi.ac.uk)
Date: Sat 15 Oct 2005 - 02:00:22 GMT
> Thus it's really a question of intelligent versus
> random adaptation. As I've said, intelligence will re-enter biology one way
> or another, either via the mind of God or the minds of organisms ranging
> from bacteria to hominids.
God? Intelligence? What's all this about then?
And on the non-genetic inheritance thing; there is little in the
way of generational encoding of experience in genes in some
Lamarckian sense, but there surely is non-genetic inheritance in
everything from egg structure and constitution through to
dietary effects passed down through social class (alphas breed
alphas). These run in parallel (more or less tied to the gene
line). Just throwing that in to confuse the issue really :)
> If developing organisms merely mimic the actions of their predecessors,
> design is unnecessary. Neither genes nor the migrating cells that contain
> them need know what sort of body they're building-- so long as they hew to
> species tradition. The notion that an organism must follow a set of
> specifications is a clear-cut example of anthropomorphosis. We are
> projecting our own mechanistic ways onto the natural world. It's no
> accident that the other design-theory arises from theology, the ultimate
> exemplar of anthropomorphosis.
When you say the 'other' design theory (ID) what is doing your
designing? Evolution by natural selection is like carving out a
shape from phenotype space. Kind of like hand development (loss
of webbing) you see what sculpture is in the rock by chipping
away the bits you don't want, rather than putting in the bits
that you do want. In this case (fin to hand) I think you can
kind of assert a recapitulation argument about the degree of
refinements in sculpting organisms (reminds me of 'I went to the
shop and I bought...'); some are a bit easier to make, some
trickier and the trickier ones usually have embryos that go
through that much less exquisite stage.
> Nobody has ever calculated the correct combination of genes needed for the
> timing of penicillin production in the haploid mold Aspergilla. That's
> because the number of possible combinations is 2 to the 1000th power (or 10
> to the 300th power), way beyond the realm of calculability. This is to say
> nothing of the production of multicellular organs out of diploid genomes.
> See *Reflections on a Theory of Organisms,* by Walter Elsasser, for which
> Rubin contributes an introduction.
This is just the same old reductio Im afraid. 'It's hard' is not
a proper objection as this is a miscasting of the problem.
Consider glycoproteins etc. The number of combinations of those
things should be beyond comprehension but because of genetic
history/ancestry only certain reactions can be catalysed and so
the number of 'families' of sugar structures and indeed the
actual total number seen are vanishingly small as a percentage
of the theoretically available space of possible sugar decoration.
The point being that genes were never in blueprint form. They
are the brain of the cell, not the bauplan. They are an intimate
part of an interrelationship of parts that predates time almost.
This is also the fallacy of the 'RNA world'; why do we need a
(probably white, anglo, male, muscled, blond) molecule to step
up to the plate and sort the chemical chaos into a biosphere? It
was always more the hypercycle thing and then one sort of
compound increasingly becomes a sort of canalising information
exchange point and switching network, just like the nervous
system evolved out of the workaday cells.
To answer the penicillin point above; the possible combinations
may be astronomical but the point is that that space was never
thoroughly explored by the organism. It went where its history
(both long-term genetic and short-term metabolic) _let_ it, in
little steps, and had a hard copy of exactly where it was
(genetically and metabolically) at all times. There is nothing
awe-inspring about this; there are an almost infinite number of
paths I could walk across a football field, or even a cargo net,
but to say that retrospectively, the chance of me taking any one
path is astronomically small misrepresents the scenario. I was
always going to find a way that worked, or I couldn't have been
said to have crossed (analogue: proliferated as a species) but
how densely packed with good points (strings/ridges) is the
space of possible solutions, and how multidimensional?
I still want to know more about methylation. Obviously the
patterns are copied, but it seems like an excellent way to play
with the gene network, looking for new and interesting patterns;
toggle-able, short-term mutations effectively. Is it also
stochastically-governed? Could stress affect methylation
patterns, or some other environmental?
One last thing about explanations. Obviously there is no way to
prove a negative, or in this case that what seems perfectly
explicable given the causes to hand may actually be inextricably
affected by another unseen effect, but when modelling one should
attempt to use a measure of explanatory power and these always
penalise extra terms (when, for example modelling some
polynomial with more polys than you need). I fail to see what we
cannot currently explain, or at least where we find something to
be beyond the scope of explanation being conceivable within our
current frame of reference.
Cheers, Chris.
~~~~~~~~~~~~~~~~~~~~~~~~
chris.taylor@ebi.ac.uk
http://psidev.sf.net/
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