factors, contagions of depression and enthusiasm, patriotic support, "gold market" manipulations, etc., entered to break the working of the credit theory of paper money as applied to the American Greenbacks. I may here express the opinion that the credit theory is the fundamental principle in the explanation of the value of the Greenbacks, however. But we have not the banker's psychology to any such extent as the extreme forms of that theory would assume. "Uncle Sam's money is good enough for me," is a phrase I have heard from the Populists,--who, by the way, were pretty good quantity theorists! "The government is behind it." There are plenty of men for whom that assurance would be enough. Indeed, the general notion that in some way, not specified, perhaps not yet known to anybody, the government will do what is necessary to maintain the value of its money is a ground which might well influence even the most sophisticated banker. I think such a general confidence in the English government has clearly been a factor in the price of Sterling exchange since the balance of trade turned so overwhelmingly against England in the present War.[123] Our monetary history, I may add, has been in considerable measure a struggle between these two opposing psychological reactions on that point. The utter breakdown of the _fiat_ theory came in Rhode Island, and in connection with the Continental Currency, in the days before the Constitution was adopted. On the other hand, I do not believe that those who put a banker inside every one of us can prove that their principle has been a complete explanation at any stage of our monetary history. But clearly considerations like these take away all mathematical certainty from the matter. The foregoing analysis makes clear, I trust, that the notion that the money function alone can make an otherwise valueless money circulate is untenable. There must be value from other sources as well. All that is conceded is that there need not be a physical commodity as the basis of the money. Value is not necessarily connected with a physical commodity.