Ventana software support forum

Posted: **Wed Apr 23, 1997 3:14 pm**

Dear colleagues

A colleague on an Action Learning list has made the following comment.

QUOTE
I have seen some significant critiques of SD as THE answer from some of the
Complexity and Chaos texts. Again I am at the limits of my knowledge here,
but I think they regard SD as a special case of a more general
methodological approach. As always the problem is then to identify the
special circumstance.
UNQUOTE

Is anyone prepared to have a shot at a response? In particular, what might
the special case be?

Cheers

John
------------------------------------------------------------------
John Wolfenden
New England Ecological Economics Group
(http://www.une.edu.au/cwpr/NEEEG/neeg.html)
Centre for Water Policy Research
University of New England, Armidale, NSW, 2351, Australia

Phone (02) 67732420 Fax (02) 67733237
International 61 2 67732420 (ph); 61 2 67733237 (fax)
email jwolfend@metz.une.edu.au; Mobile 0412 245 234

Committee Member and Postgraduate Coordinator, Australia New Zealand
Society for Ecological Economics

Posted: **Thu Oct 23, 1997 9:51 am**

All approaches are special cases of more general approaches.

Its critically important to bound an approach in order to accomplish
something creative.

A good analogy is verbal composition in English. A novel (or a sonnet
or a limeric) has rules. The novel is a special case of the general
class of all English composition that also includes monkeys typing on
typewriters. But, the rules for a novel provide enough definition so
that creativity can have a useful shape.

Approaches that foster creativity restrict some things and allow freedom
in others. In system dynamics the "rules" include looking for feedback
loops, dividing everything into stocks and flows, requiring at least one
level in every loop, etc. Areas of freedom include application area
(finance, projects, commodities ...); and the freedom to combine the
basic elements (following certain rules) into an infinite number of
cases.

Regards,
Jim Hines
JimHines@interserv.com
MIT and LeapTec

Posted: **Thu Oct 23, 1997 9:09 pm**

John,

I think there is little overlap in the areas of interest and application of
SD and "self-organizing systems" (aka Complexity Theory).

Please read M.Mitchell Waldrops excellent book, Complexity: The Emerging
Science at the Edge of Order and Chaos. Its five years old now, but is
VERY well and interestingly written, and it tells everything (as of 1992)
about this new mode of scientific inquiry, one much better suited for the
real world complexities of the future than the old "scientific" method.
Waldrops book rewards persistence, because there is so much new, BUT
Waldrop does the best job of anyone I have read in communicating new,
powerful, and sometimes abstract ideas. He is extraordinarily gifted in
making complex and unfamiliar ideas and theories accessible, and he does it
through the eyes and lives of the pioneers in the field!

Please read it and pass it on. If Jay Forrester and the Sante Fe Institute
people dont get along, they havent been properly introduced: Ill do it,
if need be.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Robert H. Murray huskynet@wolfenet.com
Issaquah, WA, USA 1-425-391-2363
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Posted: **Fri Oct 24, 1997 9:26 am**

John -

Great question you passed along.

>QUOTE
>I have seen some significant critiques of SD as THE answer from some of the
>Complexity and Chaos texts.

Id be really interested to know WHICH Complexity and Chaos texts were
talking about. I think its incredibly important to think about the
limitations of SD, especially with respect to the type of training and R&D
we should be pursuing in the field.

>Again I am at the limits of my knowledge here,
>but I think they regard SD as a special case of a more general
>methodological approach.

I would agree that the models that fall under the Complexity and Chaos
heading are a superset of normal SD practice. Discrete-time chaos, genetic
algorithms, and detailed disaggregation of agents or spatial dimensions are
common Complexity topics that are not often part of SD work. To the extent
that we can keep aware of these areas, and blend them with our work, I think
we benefit (though discrete time chaos seems pretty useless to me).

At the same time, I dont see much of a coherent problem-solving methodology
in complexity and chaos research. SD, by contrast, has well-developed
traditions for eliciting knowledge from stakeholders, building and testing
models, and communicating or implementing results. SD also has a fairly
strong set of principles for the appropriate representation of behavior. In
applications of complexity research I too often see genetic algorithms used
as a model of behavior, without empirical justification, where Occams Razor
might suggest a simple hill-climbing process instead.

Some of the management literature Ive seen makes appealing metaphorical use
the insights that come from complexity research. However, when you try to
actually tie down assertions about management principles to modeling
particulars, you find nothing but rubbish. I know several colleagues who
could go on at greater length about this. The same can be said of some
management allusions to quantum physics, which sometimes seem to me to imply
that, because Schrodingers cat can exist in multiple states, I can step in
front of a speeding bus without being killed.

This is damaging to all modeling disciplines; it erodes our hard-won
credibility by using pseudoscience as a bogus source of authority. If the
espoused management principles are really worthwhile, then it should be
possible to demonstrate them explicitly and subject them to formal criticism.

As always the problem is then to identify the
>special circumstance.

Id venture to say that the special circumstance is exactly the areas in
which SD is thriving, especially modeling the dynamics of particular
businesses or public organizations. It might be easier to identify areas in
which SD is infrequently applied or has trouble making an impact. Ill leave
that thought dangling for the next taker.

- Tom

****************************************************
Thomas Fiddaman, Ph.D.
Ventana Systems http://www.vensim.com
34025 Mann Road Tel (360) 793-0903
Sultan, WA 98294 Fax (360) 793-2911
http://home1.gte.net/tomfid/ tomfid@premier1.net
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Ventana software support forum

SD a special case of Complexity/Chaos?

SD a special case of Complexity/Chaos?

SD a special case of Complexity/Chaos?

SD a special case of Complexity/Chaos?

SD a special case of Complexity/Chaos?