“All that the State need do, and can do, in order to preserve the monetary system undisturbed, is to refrain from such intervention. That is the essence of the monetary theory of the classical economists and their immediate successors, the Currency School. It is possible to refine and amplify this doctrine with the aid of the modern subjective theory; but it is impossible to overthrow it, and impossible to put anything else in its place. Those who are able to forget it only show that they are unable to think as economists.”