; as Tylor demonstrated so well, the art of writing has developed through a series of stages, which began with picture writing, progressed to hieroglyphic writing, and culminated in alphabetic writing. In the realm of social organization there was a development from territorial groups composed of families to segmented societies (clans and larger groupings). Sociocultural evolution, like biologic evolution, exhibits a progressive differentiation of structure and specialization of function. A misunderstanding has arisen with regard to the relationship between evolution and diffusion. It has been argued, for example, that the theory of cultural evolution was unsound because some peoples skipped a stage in a supposedly determined sequence; for example, some African tribes, as a consequence of diffusion, went from the Stone Age to the Iron Age without an intermediate age of copper and bronze. But the classical evolutionists did not maintain that peoples, or societies, had to pass through a fixed series of stages in the course of development, but that tools, techniques, institutions--in short, culture--had to pass through the stages. The sequence of stages of writing did not mean that a society could not acquire the alphabet without working its way through hieroglyphic writing; it was obvious that many peoples did skip directly to the alphabet....
