On the nature of explanation in human geography.

Several of the approaches espoused by human geographers in recent decades have been criticized for their inability to explain the patterns and processes that they describe, and especially for their inability to explain change in those patterns and processes. A review of the criticisms indicates their validity. The alternative path to explanation that has been proposed appears to be ageographical, however, in that its focus on macro-processes and its emphasis on the unique characteristics of time and place result in little attention being paid to realizations of processes, to actual spatial patterns. It is argued that for human geographers to use the alternative approaches, theory must be developed which allows for explanation of particular realizations within the structural constraints; the study of geography and the state is used as an example. By 1975 all the isms were wasms (Robert Hughes) IN the 1950s several small groups of scholars in United States universities began the work that led to what became widely known as the 'theoretical and quantitative revolution' in human geography. The approach that they adopted and propagated was that of logical positivismalthough many, if not most, of those who followed the lead and joined the revolution were apparently only vaguely aware of the philosophy of that approach. (According to Marchand, 1979, p. 237 'A characteristic of North American social science . is an extreme disdain for philosophy': see also Johnston, 1979a, p. 62.) They believed that the human use of the earth's surface-its spatial organization-resulted from the operation of universal processes of decision-making whose characteristics could be identified by a combination of modelling, observation, and statistical analysis of the outcomes of those decisions. Successful identification of these processes would lead to the development of geographical laws in which a prime component would be the element of space, since sensible decision-making involves the efficient use of resources, such as the time and costs involved in traversing space. Thus was conceived spatial science, human geography's contribution to the logical positivist dominance of the social sciences in the 1950os and I96os. Spatial science won many converts, some of them from the previous generations of human geographers who had been socialized into the discipline's regionalism 'paradigm', but most of them from the new members of the geographical community-the graduate students who were critical of previous work and attracted to this novel approach and its apparent sophistication (see Gould, 1979; Johnston, 1979a, 1979b). By the mid-I96os its research output dominated the relevant geographical journals, and several new ones had been founded to circumvent the conservatism of establishment editors and referees. But criticism began to develop too, not just that of the previous generation which was defending its own vested interests but also that of a series of new generations who found problems with the spatial science approach. Alternatives were proposed. A 'behavioural geography' was advanced, for example, which sought to refashion spatial science on inductive foundations derived from observation of actual decision-