Orthodoxy’s case against SFEcon, being grounded principally in tradition and ethics, came down an unresolvable standoff as to whether or not materialism is to be approached by scientific technique. The heterodox case is much more formidable because it resides with us in the wholly scientific realm, and issues from the world’s foremost technical faculty. The System Dynamics Group SD at MIT’s Sloan School embodies ...

not just another Kunian science revolution as suggested by Forrester. System dynamics is the unifying theory of domain specialties ...
The system dynamics revolution has the potential to initiate a paradigm shift in all domain specialties, not just one, including revolutions in the institutions of education and science.1
Where conventional academic divisions separate the scientific domains ...
SD should seriously consider marketing itself as the universal modelling science and claim that it is the only thing that can unite all the other fields of study.
We are not a science in ourselves, we are the framework that unites the sciences. We can give them the direction, relevance and credibility they have been lacking ... and the power of concerted effort.2
SD’s unifying power was first brought to fame through Germeshausen Professor Jay Wright Forrester’s invention of environmental chic in the 1960’s and 70’s. Their advance has not been deterred in the least by their nonpareil anticipation of the global environmental collapse circa 1984. On the contrary, their revelation continues to command ever greater initiatives down to the present; and the authority of their heroes now places them in reason’s pantheon:
Before the 21st century, physicists and mathematicians were the gods of science. Think of Newton, Leibniz, Kelvin, Fermi, Einstein. The 21st century gods of science are the biologists, computer scientists, artists and engineers — people who are well-versed in the power and manipulation of emergence (behavior over time) in everyday life. Think of Darwin, Andronov, Forrester, Kaufman 3
Explanations for the empirical irrelevance of SD’s ‘World’ models are of course available in orthodox economics, i.e.: the SD models’ failure to consider substitutabilities among resources.4 We can only expect that SD has valid reasons for having rejected enlightenment from these sources: economics has, after all, long been included among the domains it spans. Their National Economic Policy Model has been either under development or in release or in some sense the subject of commentary since at least 1973.5 Its declaration of suspended release in October 2008 included notice that papers on its development should be read nonetheless.6

Professor Michael J. Radzicki, Forrester’s intellectual heir apparent and past president of both the System Dynamics Society and its Economics Chapter, has ...

devoted much of [his] career to determining how SDers and economists can be brought together in a manner that is scientifically acceptable/credible to both camps. For what it's worth, I think I have an answer ... Basically you have to talk to the right kinds of economists. That is, economists who adhere to schools of economic thought that are similar in spirit to system dynamics. The principal schools of economists who tend to value SD include: Institutional economists, Post Keynesian economists, Ecological economists, [and] Behavioral economists.7
Professor Radzicki apparently sees this process as one of simply revealing connections beyond the ken of mere domain specialists:
In fact, many of these economists are essentially SDers and don't even know it.8
He is also quite specific in limiting the economic domains acceptable to the dynamics cognoscenti by their heterodoxy:
Orthodox economists typically reject SD models b/c they typically do not adhere to the tenets of neoclassical economics (e.g., maximizing rational behavior of economic agents, unique and stable equilibria, etc.). Of course, SD can be used to create such models, but SDers do not typically believe that this is the right way to go.9
It might be noted that in passing Professor Radzicki shares an opinion often stated among those who agree with one another as to their peculiar competence in matters dynamic, viz.: should such a task ever become worth the candle, they can always create a proper rendering of neoclassical dynamics.

Dr. George Backus, an SD alumnus who once examined SFEcon on behalf of Sandia National Labs, agrees by characterizing SFEcon as an SD 101 student exercise; and he has been good enough to elaborate his thinking for the benefit of one of our fellow-travelers in an email:

There is a difference between system dynamics and dynamics. SFEcon does show a mathematical dynamic but it is more the cobweb iteration rather than the actual casual dynamics of behavioral intent (economic forces explicitly fighting one another). In that Forrestonian context, the model is not dynamic. It is only a mathematical algorithm that attempts convergence.
Thus the source of heterodoxy’s tussles with SFEcon over formal dynamics can be reasonably given their definitive resolution by Professor Radzicki:
It [SFEcon] really has nothing to do with SD.10
Well. At least we can be certain that SFEcon fails to secrete some certain ichor that has remained as insensible to our theoretical guru (Sloan, ’71) as it apparently was to Gottfried Leibniz and Leonhard Euler. While the SD establishment professes an ability to inculcate their faith among K-12 students11 as well as economists, those trained elsewhere in engineering dynamics might well be past help. And the mere flouncing of sufficiently important academic petticoats would appear to answer inquiries as to why such might be the case.

Alternate explanation: practitioners of environment alarmism do not wish anyone to be made aware of economic causation’s having been realized by models operating in the same realm as their own, lest these two modeling impulses be unified to the end of perhaps discovering that our age has no more to fear than any other.
_____________________
1        Turnock, 8 Jan 2006: SD Listserver 5775 Scientific Revolution.
2        Invigilator, 2 Dec 2005: SD Listserver 5655 Characterizing System
         Dynamics
.
3        Lyon, 28 Nov 2005: SD Listserver 5639 Characterizing System
         Dynamics
.
4       See for example Simon and Kaufman, 1984: The Resourceful Earth.
5       Forrester, Jay W.; Mass, Nathaniel J.; and Ryan, Charles J. “The system
         dynamics national model: Understanding socio-economic behavior and
         policy alternatives”. Technological Forecasting and Social Change:
         Volume 9, Issues 1-2, 1976, pp. 51-68.
6        Forrester, 16 Oct 2008: SD Listserver 7242 Economic Systems.
          < full context >
7        Radzicki, 6 Sep 2008: SD Listserver 7223 Explaining System Dynamics
          to Economists
.
8        Radzicki: Memo of 9 Aug 2005 to SD/Econ Chapter President Elect
         David Wheat Economic Dynamics and Complex Systems.
9        Radzicki: 2005, Ibid.
10      Radzicki: Memo of 11 Dec 2005 to SD/Econ Chapter President
         Oleg Pavlov.
11      http://www.systemdynamics.org/DL-IntroSysDyn/origin.htm