The Idea of Stages — from Tacitus to Karl Bücher and Carlota Perez

History – it has been said – was created to prevent everything from happening simultaneously. History implies that events happen in sequence. Stage theories are attempts, based on different criteria, to organise history in sequential stages. In their most general form, stage theories postulate that a key factor in the process of socio-economic development is the mode of subsistence, i.e. what, how, and with which tools a society produces. Stage theories are tools that can be used to study both the qualitative changes in the division of labour over time, and the processes of institutional design and change which accompany these changes. Stage theories point towards areas where the focus of human learning is concentrated at any point in time, and as such they serve as a basis for a qualitative understanding of processes of techno-economic change and of income inequality. [177]

Theories of periods and stages have been used in most of the social sciences. In the history profession the material from which Man's tools were made (e.g. stone or bronze) has become universally accepted as the basis for establishing early historical periods: the Stone Age (Mesolithic, Neolithic), the Bronze Age. Other criteria could have been used, e.g. based on social organisation, but the technology variable was chosen. Not only in the history profession, but also in anthropology the idea that technology is an important determinant for society is an old one; the discussion of the relationship between irrigation and centralised government being a classical example. In political science, the idea of stages of Man's development is born – with Jean Bodin's (1530– 1596) study of the Republic – with the commencing of the science itself. If we define sociology as starting with Auguste Comte (1798– 1857), the idea of stages was there from the very beginning of that science as well. In economics, theories of stages were central both to the important French economist and statesman Robert Jacques Turgot (1727– 1781) and in the teachings of Adam Smith (1723– 1790).