DONELLA H. MEADOWS,
DENNIS L. MEADOWS, JØRGEN RANDERS
& WILLIAM W. BEHRENS III
The Limits to Growth
Every person approaches HIS problems . . . with the help of models. A model is simply an ordered set of assumptions about a complex system. It is an attempt to understand some aspect of the infinitely varied world by selecting from perceptions and past experience a set of general observations applicable to the problem at hand. . . .
Decision-makers at every level unconsciously use mental models to choose among policies that will shape our future world. These mental models are, of necessity, very simple when compared with the reality from which they are abstracted. The human brain, remarkable as it is, can only keep track of a limited number of the complicated, simultaneous interactions that determine the nature of the real world.
We, too, have used a model. Ours is a formal, written model of the world.★ It constitutes a preliminary attempt to improve our mental models of long-term, global problems by combining the large amount of information that is already in human minds and in written records with the new information-processing tools____________________