ABSTRACT
In Chapter 2 a preliminary model was developed which simply explored the kind of settlement pattern that would arise from the interplay of processes of positive and negative feedback that exist between jobs and people. Jobs attract jobs and people, and people attract some jobs. The system showed that reasonable urban hierarchies were the outcome of reasonable assumptions about the processes, and that many different outcomes were potentially possible. The system showed ‘lock-in’ of sub-optimal structures. An important point was that it was not necessary to assume that the distribution of people or of jobs was at equilibrium at each instant. Not only was it not necessary, but it would have destroyed much of the usefullness of the model, since even common sense tells us that the real outcome of a given situation will in fact depend critically on the actual path that it follows and the strains and stresses that are encountered ‘on the way’ to equilibrium. Furthermore, just a little bit more common sense will tell us that the system may never ‘go’ to equilibrium, since all the time there are changes in technology, in patterns of demand, in peoples desires and expectations, and in the economic and social structure that underpins the whole aggregate description used in the model. Since these models were already published in 1978, it is illuminating (with regard to the manner in which science interacts with government) to note that even today (1996) the models that are actually used by decision makers make the assumption of spatial equilibrium in modelling the ‘changing’ spatial pattern.
