Generic Structures and Molecules
Posted: Fri Apr 12, 1996 7:06 am
The discussion on Archetypes, Causal Loop Diagrams and Stock and Flow
Diagrams has been interesting. I have noted a tendency to use cryptic
abbreviations and fear that this may make things very hard to understand
for many (I confess to having had problems at times).
Benny Budimen has brough molecules into the discussion and I think it is
important to note that molecules as defined by Jim Hines and myself are
quite different from archetypes. Molecules are commonly used building
blocks from which models can be constructed. For example an aging chain,
one of the most tangible stock and flow constructs available, is a molecule.
I think that Benny does have a valid point in that the purpose of
categorizing molecules is to make it less time consuming to focus on the
nitty gritty physical issues and easier to capture a dynamic hypothesis
(feedback). A great mason should understand how to make bricks, but that
does not mean that she should start every job in the clay pits. The
question for the mason is where does she add the most value. The question
we face is where do we learn the most. The molecules are intended to
focus us in on the place where we can do that, but with better quality
building material than we otherwise would have.
Jim Hines and I will be presenting a paper on Molecules at the System
Dynamics Conference.
Bob Eberlein
vensim@world.std.com
Diagrams has been interesting. I have noted a tendency to use cryptic
abbreviations and fear that this may make things very hard to understand
for many (I confess to having had problems at times).
Benny Budimen has brough molecules into the discussion and I think it is
important to note that molecules as defined by Jim Hines and myself are
quite different from archetypes. Molecules are commonly used building
blocks from which models can be constructed. For example an aging chain,
one of the most tangible stock and flow constructs available, is a molecule.
I think that Benny does have a valid point in that the purpose of
categorizing molecules is to make it less time consuming to focus on the
nitty gritty physical issues and easier to capture a dynamic hypothesis
(feedback). A great mason should understand how to make bricks, but that
does not mean that she should start every job in the clay pits. The
question for the mason is where does she add the most value. The question
we face is where do we learn the most. The molecules are intended to
focus us in on the place where we can do that, but with better quality
building material than we otherwise would have.
Jim Hines and I will be presenting a paper on Molecules at the System
Dynamics Conference.
Bob Eberlein
vensim@world.std.com