Re: evolution as "diffusion"

Kent Paul Dolan wrote:
Tim Tyler wrote:
> Arkalen wrote:
>> Tim Tyler <seemy...@xxxxxxxxxxxxxx> wrote:

>>> Evolution has discovered science and genetic
>>> engineering - two new, useful survival tricks,
>>> two more notches on the ratchet of technological
>>> progress that leads up to a galactic
>>> civilization.

Well, except that you are completely muddling
cultural evolution with biological evolution. The
latter is a precondition for the former, but they
are not the same thing, and may work at cross
purposes.

Biological evolution includes cultural evolution in
my book - because of the definition of "biological":

``Biology: the science of life or living matter in all its
forms and phenomena, esp. with reference to origin, growth,
reproduction, structure, and behavior.''

If I wanted to contrast, I would contrast cultural
evolution with, say, nucleic-acid evolution.

Indeed. More to the point, arguing that "Gould is
wrong" about biological evolution because of effects
limited to _cultural_ evolution is simply brain
dead.

I don't think that was quite my line of argument.

> I mean natural evolution is progressive - and not
> just in Gould's "random walk" sense: various
> useful features of organisms persist once they
> have been invented for extended periods
> selectively - i.e. through natural selection.

That's a distinction without a difference. The
"ratchet" _is_ natural selection. If a change
improved reproductive success, and the environment
remains such that it still does so, then devolving
that change away would involve decreasing
reproductive success, and natural selection would
(probabilistically) remove individuals displaying
that change from the gene pool.

That adds no new insight to Darwin's original work.

Nor did I intend it to do so.

More than that, you are mistaking Gould's entire
argument, which is not an argument about what
natural selection _does_, but about what fitness
_is_: in part it is "ability successfully to
out-compete others for the current environmental
niche", but also in part it is "ability successfully
to compete in a different, less crowded or
unoccupied niche".

Gould's argument about progress in Life's Grandeur
is what I was criticizing.

If you accept that much, diffusion follows
naturally, by "random variation, natural selection"
as always; an organism whose random variations
happen to make it better suited to a new niche with
better resource availability are by that very fact
"more fit", able to colonize that niche, and perhaps
to speciate within it, over time.

Gould's diffusion theory in Life's Grandeur
does not "follow naturally". It is a claim that
complexity is selectively neutral, and therefore
follows a random walk. Complexity is correlated
with size, which doesn't follow a random walk.
It is correlated with genome size - which doesn't
follow a random walk either.

Complexity is not really something that is
selected directly - but that doesn't mean it
is totally neutral.

>> If your point is that evolution is directed
>> towards big brains and space flight in a way that
>> diffusion doesn't account for, and/or is directed
>> *especially* towards big brains and space flight
>> (and whatever other "technological advances" you
>> think evolution is directed towards) as opposed
>> to just about anything in the space of
>> possibilities... then you need some evidence for
>> your point.

> Big brains are useful for doing science and
> technology. Space flight is useful for seed
> dispersal.

Wonderful, but those are cultural evolution
arguments against Gould's thesis, which most
profoundly was not a thesis about cultural
evolution, and arguments which focus on "big brains"
as if they were the only meaningful improvements
evolution ever chose by natural selection.

Gould was concerned with the past in his book.
I only take him as claiming that life was not
progressive until recently.

Perhaps he would have thought culture represented
an evolutionary flip - from a non-progressive
into a progressive mode.

From my point of view, no flip is needed. Evolution
has *always* been progressive. The progress is only
now accelerating to the point where is has become
totally obvious.

I think to argue against Gould's dispersion thesis
for _biological evolution_, you _must_ exclude
humans from consideration, because human evolution
is so contaminated by _cultural evolution_ concerns.

It would be a myopic perspective. The conclusion
would be that evolution exibited property X only
during its early incubation phase. No such myopia
is necessary. Evolution is in a progressive mode
now - and it always has been. All that has happened
is that the progress has got faster over time,
as synergy between evolution's inventions has
gradually started to kick in.

Do you have any arguments against Gould's diffusion
thesis _on his own grounds_?

There are many arguments which have been given
already which make no mention of human technology.
Inventions of useful survival tools did not begin
with humans. The progressive accumulation of survival
tools began long ago, and includes useful things
like enzymes, translation, transcription, DNA, lipid
cell walls, photosynthesis - and so on. But the
best illustration of the directionality of such
development comes from human culture. Why would
I want to argue with one hand behind my back, ignoring
a whole bunch of useful and relevant observations
about evolution? I'd rather leave that sort of
thing to others. Maybe if Gould had stopped to
think for a moment about the future of evolution,
he would have realised how silly his characterisation
of it was. Laws of evolution that break down
half way through the process are pretty useless
in my book.

Biologists who are interested in their work lasting
should attempt to characterise evolution - and not
just the little bit of it we have seen unfold so
far, but the whole thing.

For example, pronouncements along the lines of
"evolution doesn't have foresight", are little
more than short-sighted foolishness.

> Like other useful inventions before them:
> photosynthesis, DNA, lipid cell walls, sexual
> recombination, such inventions are likely to
> persist, once they have arisen.

> The persistence of such useful technologies is
> written into the fossil record.

Yep, but its simply natural selection at work. The
big "oh by the way" of which is that evolution
abandoned "improvements", most often by extinction,
far more often than evolution retained them unto the
present from the distant past.

It doesn't matter if *some* stuff is forgotten.
What matters is that some stuff is remembered for
vast periods of time. Imagine what it would take
for organisms to forget about DNA, enzymes,
photosynthesis, etc. A huge meteorite that
obliterates all life might do it, but not much
else would. Evolution really does remember
important tricks like those. The knowledge
builds up in ecosystems over time. Progressively.

To requote Dawkins - since the message is obviously
not sinking in:

``The origin of the chromosome, of the bounded cell, of
organized meiosis, diploidy and sex, of the eucaryotic cell,
of multicellularity, of gastrulation, of molluscan torsion,
of segmentation - each of these may have constituted a
watershed event in the history of life. Not just in
the normal Darwinian sense of assisting individuals
to survive and reproduce, but watershed in the sense
of boosting evolution itself in ways that seem entitled
to the label progressive. It may well be that after,
say, the invention of multicellularity, or the invention
of metamerism, evolution was never the same again. In
this sense there may be a one-way ratchet of progressive
innovation in evolution.''

http://www.world-of-dawkins.com/Dawkins/Work/Reviews/1997-06fullhouse.shtml

"We" surviving species are still pretty much running on
half-billion year old chemistry, but not carting
around very much on balance of the "improvements"
since.

Except for the recent ones which you seem to want
me not to talk about.

Chemistry may not have changed, but look at
what happened to, say, brain size over that period.

Did brain size follow a random walk? Was it
equally likely to grow as shrink? No. These
days the common mammals have systematically
bigger brains than their reptile-like predecessors,
and the reason is down to selection, not chance.

> Darwin noted the phenomenon many years ago:

> "The inhabitants of each successive period in the
> world's history have beaten their predecessors in
> the race for life, and are, in so far, higher in
> the scale of nature; and this may account for that
> vague yet ill-defined sentiment, felt by many
> palaeontologists, that organisation on the whole
> has progressed."

> - On the Origin of Species

Right, but he wasn't, that I can see, _arguing_ for
that viewpoint, merely acknowledging it, probably as
misguided.

Pah:

``As all the living forms of life are the lineal descendants of
those which lived long before the Silurian epoch, we may feel
certain that the ordinary succession by generation has never
once been broken, and that no cataclysm has desolated the
whole world. Hence we may look with some confidence to a
secure future of equally inappreciable length. And as
natural selection works solely by and for the good of
each being, all corporeal and mental endowments will
tend to progress towards perfection.''

- On the Origin of Species

> We see the effect writ large in today's cultural
> evolution - where the pace of progress has
> accelerated to the point where it is easily
> observable in an individual's lifespan, indeed,
> even within six months or so.

Bzzzt. "Cultural evolution" isn't an effective
argument against Gould's "diffusion", it is a
complete red herring when dragged into that
discussion.

> I can hardly believe we are discussing the issue
> these days.

That's because you are so incredibly confused here.

It's actually because progress has become so blindingly
obvious.

> Doubts about the directionality of technological
> progress in evolution make less sense now than
> ever before. If you do not think evolution is
> progressive, practically all you have to do these
> days is look out of the window.

You've poisoned your mind with that word
"technological"; it is a very poor fit to
discussions of "biological evolution" and seems to
be constantly distracting you to muddle cultural
evolution into discussions where it as no proper
place. Try replacing it with something more
appropriate, maybe "developmental", and see if
that helps reduce your self-confusion.

Technological is indeed an awful word to use here -
but there is no correct word that I know of to describe
the concept I am referring to. Sometimes I say 'tools'
instead - but that is vague. Sometimes I refer
to "inventions", but that is worse than "technological".
"Developmental" is not the concept I am aiming at.

I find myself constantly having to fight against the
anthropomorphic language in this area.

Dawkins presumably felt the same when he coined the
word "designoid" - which plays a similar role to the
concept I am aiming at.

IMHO, "technological" is about the best short term
I can come up with to refer to the concept of
"development of survival equipment, by any means".

It has precisely the correct connotations in the
case of human equipment, and plenty of wrong ones
in the case of designoid equipment produced by
mutation and natural selection - but it seems better
than any alternative.

It also has the progressive overtones I want it to
have.

Everyone alreadly knows about technological progress.
They just have to realize that it is not really a
new phenomenon, and that nature has been "inventing"
survival tools since the start - and that the modern
rate of change is the result of gradually increasing
synergy between its "inventions".
--
__________
|im |yler http://timtyler.org/ tim@xxxxxxxxxxx Remove lock to reply.

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