The nation as such is not a large subject that has needs, that works, practices economy, and consumes. . . . Thus the phenomena of “national economy” . . . are, rather, the results of all the innumerable individual economic efforts in the nation and . . . must also be theoretically interpreted in this light. . . .Whoever wants to understand theoretically the phenomena of “national economy” . . . must for this reason attempt to go back to their true elements, to the singular economies in the nation, and to investigate the laws by which the former are built up from the latter.