REPLY Structural or Behavioral Theory (SD6245)

[System Dynamics Mailing List]

Posted by  "Alan McLucas" <a.mclucas at adfa.edu.au>

George Richardson makes a very important point here.  Thank you.
In the application of the scientific method, hypotheses must be rigorously
tested before we might have sufficient confidence to declare that we have
(the basis for) a theory.  Rigorous testing (progressively through each
stage of development of the model) is particularly important in SD because
there are NO tests which one might use to 'prove' that the model we proffer as
being a sufficient and necessary representation of a dynamic situation is
'true'.  The best we can ever achieve is to develop models which enable us
to investigate and subsequently defend our dynamic hypotheses.  Jay
Forrester (1961:115-129) reminds us that a model must:
Firstly, generate behaviour that does not differ significantly from the real
system [when modelled our dynamic hypothesis looks like the real world], and
Secondly, explain real world behaviour through the structure and equations
which reflect the real causal relationships in the real-world system.
The first is self evident, whilst the second is not necessarily so.  However
it is the second that is critically important.
Regards,
Alan 

Dr Alan McLucas
School of Information Technology and Electrical Engineering,
UNSW at ADFA,
Australian Defence Force Academy,
Northcott Drive,
CAMBPELL  ACT 2600
AUSTRALIA
Posted by  "Alan McLucas" <a.mclucas at adfa.edu.au>
posting date  Thu, 8 Feb 2007 07:33:16 +1000