This persistence as private firms continued because it ensured the maximum of anonymity and secrecy to persons of tremendous public power who dreaded public knowledge of their activities as an evil almost as great as inflation.

When goods are exchanged between countries, they must be paid for by commodities or gold. They cannot be paid for by the notes, certificates, and checks of the purchaser's country, since these are of value only in the country of issue.

A civilization is complicated, in the first place, because it is dynamic; that is, it is constantly changing in the passage of time, until it has perished.

To know is not too demanding: it merely requires memory and time. But to understand is quite a different matter: it requires intellectual ability and training, a self conscious awareness of what one is doing, experience in techniques of analysis and synthesis, and above all, perspective.

After years of work in both areas of study, I concluded that the social sciences were different, in many important ways, from the natural sciences, but that the same scientific methods were applicable in both areas, and, indeed, that no very useful work could be done in either area except by scientific methods.

It is not easy to tear any event out of the context of the universe in which it occurred without detaching from it some factor that influenced it.

No scientist ever believes that he has the final answer or the ultimate truth on anything.