Abstract
One reason for the problematic status of the social sciences is that their claim to legitimacy has been undermined by two opposite models of inquiry: the nomothetic idea of science, with its emphasis on universal laws, and the idiographic conception of history as a record of particular events. It can be argued that both of them excluded the temporal dimension of socio-historical reality; more precisely, they were ill-equipped to analyze the unstable structures which emerge and undergo transformations over varying periods of time. This previously excluded middle has been rediscovered by pioneering scientists on both sides of the divide; the paper compares Prigogine's critique of Newtonian natural science with Braudel's reorientation of history. The former line of argument privileges time, the latter duration, but they lead to similar conclusions.