🚀 go-pugleaf

In article 92Jun3170645@SAIL.Stanford.EDU, jmc@SAIL.Stanford.EDU (John McCarthy) writes:
> The Meadows model lumps all commodities into one.  This conceals the
> fact that the Forester System Dynamics system allows only linear
> relations and can't express demand saturation effects.  If you
> fit a DYNAMO model to the growth of American beef production between
> 1865 and 1875, you will probably reach a conclusion that unless
> something drastic is done, every American would have to eat a cow
> a day by 1930.  Garbage in - garbage out.
> 
> However, the predictions of the Meadows model have not been refuted
> by experience.  Since they removed the scales from the graph both on
> the time axis and the axis on which production, resources and pollution
> are plotted, the model makes no specific predictions at all and
> therefore cannot be falsified by experience.
> --
> John McCarthy, Computer Science Department, Stanford, CA 94305
> *
> He who refuses to do arithmetic is doomed to talk nonsense.


Although the Club of Rome work has its shortcomings, as I have pointed out
elsewhere, and although many people have fastened on those shortcoming to try
to deny or refute its policy implications, the dismal reality is that more
sophisticated modeling efforts that avoid those shortcomings (like mine)
nevertheless yield similar predictions of economic and ecological collapse.

The main failing of the Limits to Growth model is that it neglected to consider
the possibility of totally separating the life-support system for humanity
from the natural ecosystem (sans homo sapiens) and the geosystem. If this is
done, the dismal projections of the Forrester-Meadows models can be avoided,
at least for a segment of the population that moves into cities designed and
operated like multigeneration starships. For the remainder, it is the future.

Unfortunately, the kind of modeling effort required for this subject is highly
complex -- beyond the complexity that even top computer experts seem to be
able to handle.

---

starflt@uunet.uu.net, jdr@starflight.corp.sun.com
Jon Roland
Starflight Corporation, 1755 E Bayshore Rd #9A,
Redwood City, CA 94063-4142, 415/361-8141