Sociology is one of the core disciplines of the social sciences, along with political science, economics and anthropology. So one might imagine that it is a coherent, unified, and comprehensive science with a well-defined subject matter and a clear set of methods. But as most practitioners will agree, this is not the case. And that is a good thing, because the social world is not a unified system that can be reduced to a small number of theoretical premises.
Since its founding (or emergence?) in the nineteenth century, sociology has taken on a somewhat meandering set of topics for study: classification of whole societies, analysis of large social factors (race, crime, urbanization), study of the behavior of groups, provision of tools for social policy design, and study of particular institutions, social movements, globalization, and the organization of businesses. In 2007 the American Sociological Association includes 44 sections devoted to particular topics and methods. The methods of inquiry and the models of explanation are equally varied, including quantitative analysis of large data sets, small-N comparisons, micro-sociological investigation, process-tracing, Marxism, functionalism, structuralism, and feminism.
What does this diversity of topic, method, and theory imply about the discipline of sociology today? Is it a unified discipline, or a patch-work melange of many topics and approaches, unified only by the fact that the subjects of investigation have to do with social processes and social behavior? One possible interpretation is that the vast range of potential research subjects for sociology are covered by this patchwork structure. Another possibility is that the current range of sub-disciplines is itself the product of many "random walks" down particular research approaches, with heavy coverage of some areas of potential research, sporadic coverage of some problems and no attention at all to other problems. The latter possibility suggests in turn that there is ample room for future development of sociological research, in the formulation of new empirical problems and new theoretical approaches. The discipline of sociology can continue to evolve and grow -- possibly in ways that lead to significant innovation in approach and explanatory strategy.
An earlier posting on "Racial Inequalities" illustrates this point well. There is no single methodology or theory that is uniquely suited to attempting to understand the racial outcomes that we observe in American society. Instead, we need to combine the insights of many fields and approaches, in order to have a basis for explaining the patterns of segregation and inequality that we observe.
The diversity and multi-dimensional aspects of contemporary sociology is in fact a scientific advantage, in my view. This aspect of the discipline permits researchers to seek innovative approaches and innovative explanations of the social phenomena that they consider. In fact, it is the occasional impulse towards trying to make the discipline "more scientific" by enforcing a paradigm of research and theory on junior researchers that is most debilitating to the progress of knowledge -- whether it is the rational choice paradigm in political science, Marxism in Chinese social science, or the quantitative methods paradigm in sociology. Methodological and theoretical pluralism is an intellectual advantage. Sociological researchers who are receptive to analyzing the multiple aspects of a social problem from several different points of view are more likely to arrive at truly illuminating analysis. Not all these approaches will be equally fruitful; but a mixed "portfolio" of research strategies and theoretical models is more likely to be adequate to the messy reality of a changing social world.