Dear Bob and colleagues,
Great that you brought the book to our attention. I ordered it, this
morning.
Although I agree with most what you say, I cannot follow why the relation
between information and thermodynamics would needed to be bridged:
S = k(B) H
S is thermodynamic entropy, H probabilistic entropy. H is dimensionless and
can be applied to any probability distribution. S is expressed in
Joule/Kelvin (because of k(B) ) and is only meaningfull in the physical
domain.
What has to be bridged? It seems clear to me.
Best wishes,
Loet
_____
Loet Leydesdorff
Amsterdam School of Communications Research (ASCoR),
Kloveniersburgwal 48, 1012 CX Amsterdam.
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681
<mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] ;
<http://www.leydesdorff.net/> http://www.leydesdorff.net/
<http://topics.scirus.com/Measuring_Research_Output_with_Science_Technology_
Indicators.html>
http://topics.scirus.com/Measuring_Research_Output_with_Science_Technology_I
ndicators.html
_____
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Pedro Clemente Marijuan Fernandez
Sent: Wednesday, June 04, 2008 11:30 AM
To: [email protected]
Subject: [Fis] (msg. from Bob Ulanowicz)
Asunto:
Re: [Fis] order/disorder
De:
Robert Ulanowicz <mailto:[EMAIL PROTECTED]> <[EMAIL PROTECTED]>
Fecha:
Tue, 3 Jun 2008 14:42:30 -0400 (EDT)
Para:
[email protected]
Just another word about the nature of information:
As humans we are naturally self-centered and self-interested. Well and good.
But we often miss connections by not casting our nets of interest a little
wider.
In particular and as regards information, there is a tendency to become
bogged down in the theory of communication and digital forms of information,
because that's what's closest to our immediate interests. But analog
information was around long before evolution brought digital forms on the
scene.
What's more, the calculus of information theory, patterned after the leads
of Boltzmann and Shannon, apply nicely to analog information as well.
In the larger sense information can be regarded as constraint -- that which
causes a non-random response to a random input. The beauty of this
identification is that it allows information to be tied to the concept of
work. This is done quite nicely by Stu Kauffman in Chapter 7 of his latest
book, "Re-inventing the Sacred".
Stu follows the lead of Peter Atkins in defining work as "the constrained
release of energy into a few degrees of freedom". Stu then marries that
definition with the notion of information cum constraint and the result is a
work function resembling my own "ascendency", which Stu refers to without
naming it.
Notice there's nothing in the narrative about senders or receivers or
alphabets. Those are particular instantations of a much more general
phenomenon.
And Boltzmann's calculus generalizes without difficulty, as well.
I realize many are impatient with the Boltzmann/Shannon type of information,
feeling that it cannot apprehend the concept of "meaning". Simply put, I do
not agree. The *mutual* information between two distributions captures
proto-meaning quite well. One can use it, for example, to quantify such
things as the correspondence between the protein structures of antigen and
antibody to each other. The mutual information between their surfaces peaks
when they match in lock-and-key fashion -- precisely when each has greatest
importance (meaning) to each other.
The gulf between information and thermodynamics has now been bridged. The
late Gregory Bateson once lamented,
"Ecology has currently two faces to it: the face which is called
bioenergetics-the economics of energy and materials and, second, an
economics of information, of entropy, negentropy [exergy], etc. These two do
not fit together very well precisely because the units are differently
bounded in the two sorts of ecology."
But identifying information with the constraint that identifies work
melds the two faces into one (with consistent dimensions, I might add.)
The best to all,
Bob
-------------------------------------------------------------------------
Robert E. Ulanowicz | Tel: (410) 326-7266
Chesapeake Biological Laboratory | FAX: (410) 326-7378
P.O. Box 38 | Email <mailto:[EMAIL PROTECTED]>
<[EMAIL PROTECTED]>
1 Williams Street | Web
<http://www.cbl.umces.edu/%7Eulan> <http://www.cbl.umces.edu/~ulan>
Solomons, MD 20688-0038 |
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