Re: Evolution increases the computational ability of organisms.

r norman wrote:

On Sun, 23 Sep 2007 21:12:52 +1000, j.wilkins1@xxxxxxxxx (John
Wilkins) wrote:


Tim Tyler <seemysig@xxxxxxxxxxxxxx> wrote:


*Hemidactylus* wrote:


If we take the notion that evolution implies progress and that humans
are at the pinnacle of this progressive journey (towards us...unlike
apes or Geico cavemen we evolved) as the populist view that dominates
or has dominated, that would to me be the "received view" and measures
of progress (or singular direction) like "computational complexity"
merely reinforce a preconception.

The Gouldian view is the one that challenges the reader to shed their
preconceptions (everything from inherent progressivism and the
adaptionism that goes hand in hand).

The problem with Gould's view - is that it's total nonsense:

``In a book on the subject, Gould claimed evolution lacked a
progressive character - while Dawkins wrote in [a review of
that book]:

``Notwithstanding Gould's just scepticism over the tendency to
label each era by its newest arrivals, there really is a
good possibility that major innovations in embryological
technique open up new vistas of evolutionary possibility and
that these constitute genuinely progressive improvements
(Dawkins 1989; Maynard Smith & Szathmary 1995). 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.''

...and concluded:

``For this reason over the long term, and because of the
cumulative character of coevolutionary arms races over the
shorter term, Gould's attempt to reduce all progress to a
trivial, baseball-style artefact constitutes a surprising
impoverishment, an uncharacteristic slight, an unwonted
demeaning of the richness of evolutionary processes.''''

- http://originoflife.net/direction/

The Transitions view of evolution has a basic logical flaw in it.

Take any pathway for the Urancestor to any modern species. Each one has
a bunch of "major transitions" that are special to it. Lichens had a
major transition when an algae and a fungus joined as commensuals. Is
that a "major transition"? If not, why not?

In fact I think the "informational transitions" is an artifact of the
things that *we* find interesting and salient. It is just a modern form
of the great chain of being.


I must protest. You find everything important about the world merely
things that *we* find interesting but are not actually "out there".

I would argue that there indeed is a ratchet to the process of
evolution and that ratchet indeed is the source of ever increasing
complexity. Evolution is not simple diffusion or random walk
specifically because of the ratchet phenomenon -- once you accumulate
something particularly useful it is very difficult to eliminate it
completely;

This idea goes back at least to Darwin, and I think he realized that
your ratchet requires that whatever that "something" is, it's necessary
that it be useful in all environments. The question is whether there are
any such universally useful structures. I doubt that there are.

it remains as part of the infrastructure, the toolkit if
you will, that gets carried forward to future generations. It may be
disabled or crippled but it persists. That increasing accumulation is
the growth of complexity.

Why would something that was disabled nevertheless persist? Experience
suggests that it would eventually be lost through drift alone, even if
there were no cost to its maintenance.

As a result, there is an irreversible flow to evolution.

If there were any such impossible-to-eliminate features, that would be true.

The only
problem is the notion of 'progress'. There is no particular direction
that is selected. So lichens irreversibly took one pathway, animals
another, plants still another. But once you are started on the animal
path, there is no going back.

There might be. Some animals have certainly abandoned almost everything
we associate with the idea of "animal". What of placozoans or mesozoans?
And as far as I can tell there's no particular reason that some animals
might not have abandoned multicellularity altogether, though I don't
think we know of any examples.

There is only what weird sort of animal
you will become. And so each 'advance' in evolution is added onto the
existing collection of advances. But different organisms followed
different pathways with different notions of what 'advance' means.

All that really prevents going backwards is simple probability -- with a
lot of varying parts it's unlikely that all parts would return to the
same ancestral state simultaneously. But there are plenty of individual
reversals, including losses of entire organs, and that would seem to
prevent this ratchet of yours from being anything interesting.

.

Relevant Pages

  • Re: Direction of Evolution?
    ... It is widely believed that evolution is progressive. ... Yes, better adapted (but no species is better than another, just ... in progress? ... yields greater reproductive success than another existing variant, ...
    (sci.bio.evolution)
  • Re: Evolution increases the computational ability of organisms.
    ... of progress like "computational complexity" ... evolution was never the same again. ... evolution and that ratchet indeed is the source of ever increasing ...
    (talk.origins)
  • Re: evolution as "diffusion"
    ... >>> progress that leads up to a galactic ... cultural evolution with biological evolution. ... > selectively - i.e. through natural selection. ... already which make no mention of human technology. ...
    (talk.origins)
  • Re: Evolution increases the computational ability of organisms.
    ... of progress like "computational complexity" ... evolution itself in ways that seem entitled to the label ... be a one-way ratchet of progressive innovation in evolution.'' ...
    (talk.origins)
  • Re: Evolution increases the computational ability of organisms.
    ... evolution was never the same again. ... is no less a product of evolution than a species that has gastrulation ... They weren't on the same ratcheting path to progress ... how does adding a little ratchet to the "evolution as ...
    (talk.origins)