ABSTRACT
When it is necessary to change an automobile tyre, open an abscess or plough a vineyard, it is easy to manage a quite limited operation. The elements on which the action is brought to bear are not completely isolated from the rest of the world, but it is possible to act on them as if they were: one can complete the operation without once needing to consider the whole, of which the tyre, the abscess or the vineyard is nevertheless an integral part. The changes brought about do not perceptibly alter the other things, nor does the ceaseless action from without have an appreciable effect on the conduct of the operation. But things are different when we consider a substantial economic activity such as the production of automobiles in the United States, or, a fortiori, when it is a question of economic activity in general.
