This essay is an attempt to describe from three related perspectives the successes and failures characterising the short but turbulent history of urban modelling: from the broader perspectives of knowledge or scientific theory, and of action or design; and from the narrower perspective of the modelling activity itself. It is argued that modelling is concerned solely neither with science nor with design but with both; that is, it is concerned with the relationship between science and design and must be examined accordingly. Various arguments pertaining to these themes are elaborated in terms of the inadequacy of its theory and the dictates imposed by policy. Viewed from the individual perspectives of science or design, modelling is often judged a dismal failure but in this essay it is argued that as such views are necessarily incomplete, some compromise must be sought. In these terms, the field manifests a limited success. Much has been learned about the activity itself but, as in all situations involving immature science, the real value of these experiences may be in raising awareness of the conflicts and dilemmas which occur when uncertain knowledge is applied to problems whose perception is continually changing. -Author English
