"Guy Hoelzer"  wrote in message
news:cf0iaq$1nf6$1{at}darwin.ediacara.org...
> in article cev3s2$17fm$1{at}darwin.ediacara.org, Perplexed in
Peoria at
> jimmenegay{at}sbcglobal.net wrote on 8/5/04 10:10 PM:
>
> > "Anthony Cerrato"  wrote in
message
> > news:cetl73$lte$1{at}darwin.ediacara.org...
> >> "Perplexed in Peoria"  wrote
in
> >> message news:ceru6h$48v$1{at}darwin.ediacara.org...
> >>> It seems that your slime beast is "autopoietic".
> >>> In fact, this word was invented with specifically
> >>> this issue in mind. It is an attempt to characterize
> >>> "life" as something different than reproduction or
> >>> replication.
> >>
> >> Yes indeed! That is a perfect word, if a little awkward
in
> >> common conversational use--but an autopoietic system
> >> is exactly what I meant--any dissipative structure,
i.e.,
> >> non-equilibrium dynamic system, perfectly mimics life,
be it
> >> a chemical clock reaction, or Jupiter's Great Red Spot!
It
> >> seems appropriate for a more general definition of
life,
> >> including non-replicating life. Thanks,
> >
> > Careful!  An autopoietic system and a dissipative
structure
> > are not necessarily the same thing.
>
> Hmm.  This is true in a trivial (IMHO) sense.  The
radiator in your car is a
> dissipative structure that is not an autopoietic system.
On the other hand,
> it is a functional part of the SYSTEM of the car's engine,
which necessarily
> includes homeostatic mechanisms.  Would you agree that all
autopoietic
> systems are also dissipative structural systems?
>
> > I'm not sure that
> > Maturana and Varella intended "autopoietic" to include
> > such simple systems as Prigogine's dissipative
structures.
>
> Can you specify what it is that Benard cells or a BZ
reaction lack that
> exclude them from your list of "autopoietic" systems?
>
> > Dissipative structures tend to be less homeostatic than
> > autopoietic systems.
>
> This does not make sense to me as I view all autopoietic
systems as a subset
> of all dissipative structures.  Perhaps your response to
my question above
> will help to clarify your meaning here for me.
>
> > While DSs maintain their existence
> > over a range of environments, they do not necessarily
> > maintain their form.  Nonetheless, the definition of
> > "autopoietic" could conceivably be stretched to include
them.
>
> I guess I am pushing the stretch here in your view.  Why
do you think that
> structural plasticity is inconsistent with the notion of
autopoietic
> systems?  In my view, it is an essential aspect of
autopoiesis.
>
> Cheers,
>
> Guy

Yes. Wickpedia [ http://en.wikipedia.org/wiki/Autopoiesis ]
specifically notes: "The term (autopoiesis) was originally
introduced by Chilean biologists Francisco Varela and
Humberto Maturana in the early 1970s. More precisely, the
term refers to the dynamics of non-equilibrium structures;
that is, organised states (sometimes also called dissipative
structures) that remain stable for long periods of time
despite matter and energy continually flowing through them."

I would say, the degree of plasticity in non-linear dynamic
systems in general would seem to be variable, a matter of
degree depending on the system and the scale and length of
time observed. Qualitative interpretations of the extent of
fluctuations
within the systems are somewhat subjective; also, for
example,
various BZ chemical clock reactors have a wide variety of
persistence times while the Great Red Spot has persisted
centuries. They certainly can be called plastic--a human's
structure in growing from a baby to an adult is also plastic
I would say...in fact, human structure is plastic throughout
the life cycle. Not much difference in the bigger picture
I'd say, though perhaps there are semantic arguments which
could be raised to nitpick.       ...tonyC
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