Neo-Darwinism is one of the most dynamic and successful research programmes in contemporary science.footnote* New developments in theory and method—including molecular biological investigations of genetic structures and processes, and computer-simulations of the competitive interactions of organisms within an environment—have greatly increased the scope and power of evolutionary explanations. This research programme includes morphological, experimental, and ethological investigation of the behaviour of countless organisms and species, studies of the growth of organisms, including the human brain, from their cellular origins, and simulations of complex, multi-generational developmental patterns which would not have been possible without modern computers.

This programme has also found its way spectacularly into the public domain. Scientists like Richard Dawkins and Stephen Jay Gould have become popular writers. Philosophers, such as Daniel Dennett, and scientific journalists like Matt Ridley, have greatly enriched this debate by synthesizing and presenting findings from this vast research programme to a wider public. Debates about Darwinism and its implications have become a metaphorical space for arguments about human nature and the proper relationship between mankind and other species, taking place in many different registers, from natural history films on television to philosophical texts. The first recent phase of the debate on the implications of evolutionism for society, the movement known as ‘sociobiology’, was polemical and reductionist in its approach, in part because of a conventional social scientific denial of any biological constraints on social behaviour. But more strident assertions of the effects of the genetic inheritance of mankind—arguments about territoriality, innate selfishness, and so on—have given way to a more nuanced approach, and there is now a complex and important debate taking place on the influences of genetic predispositions on human behaviour and culture.

It is all but certain, in this situation, that social scientists will find themselves having to reconsider the relevance of the neo-Darwinian research programme for their own fields of study. There have, of course, been many forerunners for such attempts, in the works of Spencer, Durkheim, the functionalist school of anthropology, and Talcott Parsons, for example. These earlier projects of synthesis between the biological and the social had foundered in the face of various difficulties. These included the teleological assumptions of much social evolutionism; the recognition that societies were conflictual entities whose normative coherence could not be pre-supposed; and the large difference that ‘culture’ makes to the understanding of social processes and social change. Associated with this was a rejection of the ‘naturalistic fallacy’—the elision of facts and values—that seemed inherent in evolution-inspired sociology. The framing of sociological inquiry around ideas of functionality or evolutionary succession seemed, to sociological critics, to confuse justification—of the normality or inevitability of a particular version of ‘modernity’—with its explanation. ‘Society’ was thus reinterpreted in the 1970s as a field of conflicts between collective social actors, or, alternatively, in terms of social constructionism, and evolutionist sociology was banished to an unfashionable periphery.

The first volume of Runciman’s Treatise (published in 1983), which was devoted to methodology, was in part intended to overcome the errors of earlier neo-evolutionist approaches in sociology. His discriminations between report, explanation, description and evaluation have as one of their main objects the avoidance of ‘functionalist’—and other—elisions of fact and value in sociological writing. He argued that previous sociologists—certainly Marx and Durkheim, even Weber—had erred in persistently confusing justification and advocacy (of a social interest, ideal or utopia) and the explanation of social facts and causal relations between them. Runciman’s ambitious project sought to substitute for these hybrids of sociology and social philosophy a completely value-free social science. This would provide theoretical resources which would enable explanations to be given of why some social variants had succeeded, and others had failed, in a process of competition. Evaluations and social choices were, he said, a different issue, to be made in the light of what can be shown to be possible, and in the light of what social actors themselves prefer, but as a matter for separate decision. Runciman thus sought the same ‘neutrality’ towards his social subject-matter as he believes natural scientists have been able to adopt towards theirs. What shaped the agenda for Runciman’s project, when he began to conceive it in the 1960s, seems to have been, on the one hand, a wish shared by many at the time to set sociology on a genuine scientific basis, and, on the other, a rejection of unduly prescriptive and ideologically committed modes of sociological writing which he must have thought, as his project proceeded through the politicized 1970s, was becoming a substitute for what social science should be. Runciman sought to exclude moral evaluation from his own writing—a demanding goal—holding that his empirical findings should stand quite independently of ethical preferences. He expressed the hope that his own moral evaluations might remain invisible within the context of his scientific project.

The three connected volumes of Runciman’s Treatise set out to re-establish a sound relation between evolutionism and sociology as the basis of a scientific sociology. This project had great prescience, considering the fertile developments that have been taking place in evolutionary science during this period. But undertaking this work in media res, given the pace of advance in the adjacent evolutionist field, has involved some unavoidable risk too, as he himself acknowledges at the outset of Volume iii. Developments in the Darwinian field, from which his proposed sociological method derives, have been proceeding at a great pace, as a vast international scientific programme of research reports the findings of many investigations. Runciman’s project is, by contrast, a single-handed one. The fact that sociologists still disagree about the foundations of their subject, and continue to work within different theoretical frameworks on quite disparate projects, means that the natural and social sciences remain worlds apart. One of Runciman’s several large, if discreetly-stated ambitions, is to establish a methodology which would bring social science much nearer to the practice of the natural sciences.footnote1