Abstract
The analogy of historical development with the life cycle has played a great role throughout the history of western thought. From the nineteenth century up to the present the dominant model for explaining social change has been evolutionary theory. Some of these theories derive their inspiration from biological evolution while others regard history as possessing an internal mechanism that gives rise to change. The representative of the latter group is Herbert Spencer. This group of theories, usually unilinear, holds that history will progress until the final stage (for Comte the positive stage, or for Marx communism) is reached. Modern approaches have abandoned the grand schemes that aim to find the explanatory principles of history. Their more relativistic perspective explains change in terms of the complex interplay of ecological, social, and economic factors as developed by Lenski, Diamond, and Tainter. Modern theories of change differ according to their emphasis on institutions or values as the main determinant of social change.