Less is More, More is Different: Complexity, Morphology, Cities, and Emergence

The critical point of general system theory which emerged from biology and physics in the 1930s is best summed up in the phrase: `̀ the whole is greater than the sum of its parts''. Accredited to Ludwig von Bertalanffy (1972), the idea that you could not assemble the complete object by merely adding up the bits was the watchword of those who sought to counter science's long-standing quest to reduce everything to fundamental particles. Biology was the natural focus of this movement for clearly no one knew then or knows now how sentient activity could be produced from the basic chemistry of life. Merely adopting this viewpoint however, although revolutionary and controversial at the time, was no guarantee that we could devise new and practical theories of how `wholes' might be synthesized from `parts'. Indeed the 1960s when general systems theory was in full sway, was dominated by how logical the idea was to so many of the more ill-defined sciences and social sciences but little was achieved in showing how wholes could be derived from parts. Take economics for example. Its history had been structured around theories based on describing how a prototypical individualörational economic manömight allocate resources to optimize some personal utility and this microeconomics was shown to be consistent with the way markets of such individuals fixed prices and remained stable. But an entirely different theory was required for showing how entire economies allocated their resources. Macroeconomics shifted the focus to aggregations of individuals and their interaction, without even showing how microeconomic theory might be consistent with the way the macroeconomy worked. These two levels were not necessarily inconsistent, they were simply `different'. Some worried about the aggregation problem but in general it has not proved possible to integrate these two perspectives. In the study of cities, a similar difference exists. Models of the micro-urban and macro-urban economy were developed from the 1950s on; the micro appealed to an urban economics based on showing how individuals located in space, specifically consumers in particular markets such as housing, whereas the macro focused on interactions between aggregatesöpopulationsöwhich appealed to physical analogies, particularly gravitation and potential. In fact, one of the great triumphs of the 1960s in this field was the clear demonstration that disaggregate models of individual resource allocation in space based on utility-maximizing were consistent with macro-models of spatial interaction based on ideas from entropy-maximizing. Consistency of a kind between spatial scales was established. Yet this was somewhat of a hollow triumph. The real issue of how parts could be added to produce wholes was sidestepped for, although showing the consistency of theory between hierarchical levels was an achievement in reconciling differences, the essential mechanisms for showing how actual systems developed from the parts were impossible to fathom.What had been demonstrated for city systems was that at a cross section in time, local decisionmaking could be added up to aggregate decisionmaking but how the city grew, prospered, diversified, developed, and changed was simply not on the agenda, at any spatial level. In short, systems theories of the city were structured around parts adding up to wholes in terms of an equilibrium which could not cope with any form of change other than that with the most local impacts. John Holland (1995) sums up the problem rather well when he says: `̀ . a city is a pattern in time. Editorial Environment and Planning B: Planning and Design 2000, volume 27, pages 167 ^ 168