Abstract
This book summarizes in a compact volume Runciman's arguments to comparative sociologists that their discipline belongs under the theoretical umbrella of neo-Darwinian selectionism. In his view, heritable variation and competitive selection govern cultural and social as well as biological evolution. Runciman makes a strong case for the usefulness of selectionism, but two of the theory's central features are problematic: his choice of units of selection; and the notion that culture can be distinguished from society historically as well as analytically. No one friendly to the basic project would argue against the need for hypotheses about units that undergo selection, but arguments can be made, also on pragmatic grounds, that he has chosen the wrong kinds of units. Runciman's learning and wisdom show to good effect in the book's fundamental approach: in the overall human story, the biological, cultural, and social coevolve. The quickly accumulating evidence of evolutionary psychology, anthropology, sociology, and neuroscience strongly supports the hypothesis that there is a biological basis for a great deal of human behavior, and also that sociocultural evolution modifies genes. History, in this way of thinking, is like a "braided stream" of unpredictably mutating, blending, and coevolving biological, cultural, and social processes. The old Darwinian image of branching fails to capture the complexity of evolutionary processes in biology, culture, and society. Runciman outlines a unified bio-social science relying upon information theory. If his program were carried out consistently it would relegate to a non-scientific level the traditional historical narratives about "carriers" or "vehicles". The scientific-explanatory level would instead feature replicators. Gametheory strategies play a prominent role in the selectionist picture. The emphasis on units of information stored in human brains or in exosomatic brain prostheses pushes neuroscience and information theory to the fore. An argument for the analytic-heuristic value of "memes" and "practices" should be weighed against the value of other hypothetical units undergoing selection in a sociocultural evolutionary approach.