As you know there are two metal-organic molecules which
are essential for life: Hemoglobin, the iron-containing
oxygen-transport protein in the red blood cells
of vertebrates, and Chlorophyll, the magnesium-containing
photosynthesis protein in the green leaves of plants.
Therefore it would be interesting if metal-organic
structures have a deeper role in the history
of life. At least one can say that without metals
in the periodic table, no life as we know it would
be possible.
-J.
----- Original Message -----
From: "Eric Smith" <desm...@santafe.edu>
To: "The Friday Morning Applied Complexity Coffee Group" <friam@redfish.com>
Sent: Monday, September 06, 2010 9:07 PM
Subject: Re: [FRIAM] FRIAMer /. alert
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
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FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
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============================================================
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
