The Primary, Secondary, Tertiary and Quaternary Sectors of the Economy

The recognition of differences among the major sectors of the economy, such as agriculture, commerce, or manufacturing, has a considerable tradition in economic thinking. Also, there is evidence that important national and international predicaments of our time are closely related to sectoral‐structural developments. Yet economists in the developed countries are often disinclined to study the shifts among the megasectors. This paper suggests that an intensified study of the topic may be profitable. In order to support this proposition it first reflects on the traditions of sectoral emphasis in literature. Second, it considers the evidence for the ascendancy of the quaternary activities. Third, it deals with the input‐output relations among the four megasectors of the economy. Thereafter it points to the emergence of potential inefficiencies among quaternary activities and raises the possibility of a megasector misequilibrium. Finally it outlines certain connections to the thoughts of Leontief and Sraffa; considers services in the neoclassical framework; explores the relationships to institutional thought; and ponders the extension of its basic hypothesis to the developing nations, the socialist countries, and to historical analysis.