THE concept of a socialist economy has from time to time been employed by economists as an abstract term of comparison by which to throw into relief the specific features of an individualist economy, or else (as has been more frequent) to illustrate the alleged universality of economic laws. Such comparisons in the pre-war era were invariably of a very abstract kind, resting on a definition of socialism and of capitalism in terms of some single aspect of the difference between them separated from all the rest.