EXTENSIVE AND INTENSIVE EXPANSION
THROUGHOUT the modern era, ceaseless change has been the law of economic life. Every period is, in some sense, a period of transition. The swift stream of events in the last quarter century offers, however, overwhelming testimony in support of the thesis that the economic order of the Western world is undergoing in this generation a structural change no less basic and profound in character than that transformation of economic life and institutions which we are wont to designate loosely by the phrase "the Industrial Revolution." We are passing, so to speak, over a divide which separates the great era of growth and expansion of the nineteenth century from an era which no man, unwilling to embark on pure conjecture, can as yet characterize with clarity or precision. We are moving swiftly out of the order in which those of our generation were brought up, into no one knows what.
Overwhelmingly significant, but as yet all too little considered by economists, is the profound change which we are currently undergoing in the rate of extensive expansion. It is important to integrate population growth intimately with the other factors making for expansion, including territorial expansion and technological progress. Indeed, it can scarcely be questioned that a continued growth of population at the rate experienced in the nineteenth century would rapidly present insoluble problems. This, of course, is due to the fact that we no longer have the rapid extensive expansion terri-