Hi Jochen,
Thank you. I was actually a little surprised, because Ligand Field
Theory has been around for a very long time. An important early
worker in this area was none other than Leslie Orgel, who seems to
have largely dropped interest in metal-organic interactions and gone
over to RNA chemistry with applications to early life, for which he is
much better known. But Harold has a talent for allowing people to
see new opportunities in areas where they haven't been looking.
Doug's question about the point of calling something emergent is a
good one. And then what?
This is an area where there is a good discussion to be had between
thermodynamics people, control theorists, and evolutionists.
I tend to be pretty conservative in my use of the term "emergence" --
moreso than Harold, because I think we have built up a good body of
both technical results and intuition around the equilibrium phase
transitions. This makes them a good place to start (Nick and I have a
years-old ongoing conversation about this). The math we know about
equilibrium phase transitions, large-deviation behavior, and so forth,
will not do everything everybody wants, but my own opinion is that we
learn more that is precise by seeing where it falls short, and then
looking from there, than we can from many investigations that don't
make use of that backlog of results and intuition.
The interesting discussion, having to do with the question "and then
what" concerns the directions in which constraints act, and in which
information could be said to "flow", when there are hierarchies of
ordering transitions, as we find in the biosphere. Much of the
intuition from equilibrium is that constraints formed at small scales
are enormously important for whole-system stability. They can be
altered by collective interactions at higher levels, but often those
alterations come in the form of deformations, not as replacements for
the deeper stabilizing mechanisms. Thus, nuclear stability makes
atoms possible. The atomic orbitals, with modest deformations to form
molecular orbitals, make molecular stability possible. In many cases
(though not all; the best counter-example being mineral crystals),
molecular form constrains molecular aggregates from crystallized
proteins to biological complexes. And so on. Herb Simon used to
write about this, emphasizing that Alexander the Great could only take
over other empires; he could not have built his empire up from single
individuals.
But if one looks at the ways people think about both evolutionary
dynamics, and many problems in optimal control, they have a paradigm
that seems (to me) to be strongly shaped by the notion of information
flow from large-scale, aggregate layers, down onto the underlying
substrate. Harold's (and my) interest in small-molecules and other
catalytic systems comes from an attempt to understand where order can
be produced in relatively "flat" systems, such that it might serve as
a foundation for the stability of more hierarchical organization,
instead of relying on hierarchical control in order to exist in
ordered form at all.
I don't think that the fact that evolving and control-systems are non-
equilibrium really leads to as severe a change in the basic
requirements for whole system stability as the disconnect between the
physical, engineering, and evolutionary points of view, because most
of the large-numbers counting that is responsible for the behavior of
equilibrium hierarchies maps fairly comfortably through to entropies
of dynamical systems. (These are variously Kolmogorov-Sinai or Metric
Entropies, or simpler versions such as the entropy rates of simple
stochastic processes, used also by Jaynes and more recently in
articles by Ken Dill that I think Nick posted here some months ago).
So the value, I think, that one should want from calling something
emergent (in my narrow usage) is a kind of guideline for how the math
might fit together, in areas where we don't have many worked examples
or the structural complexity makes them hard to produce. The question
of the direction of constraints (small -> large vs. large -> small),
and in what mixtures and roles, is one where smart and thoughtful
people nonetheless disagree strongly because we don't have good ways
to resolve the question.
Many thanks,
Eric
On Sep 6, 2010, at 12:31 PM, Jochen Fromm wrote:
Eric Smith is one of the authors, he is on this list as well, right?
Congratulations, Eric ;-)
-J.
----- Original Message ----- From: "Marcus G. Daniels" <mar...@snoutfarm.com
>
To: "The Friday Morning Applied Complexity Coffee Group" <friam@redfish.com
>
Sent: Monday, September 06, 2010 3:24 AM
Subject: [FRIAM] FRIAMer /. alert
http://science.slashdot.org/story/10/09/05/2118241/Transition-Metal-Catalysts-Could-be-Key-To-Origin-of-Life
http://www.biolbull.org/cgi/reprint/219/1/1
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
