What backed the money was not gold or something of intrinsic value, but rather the collective belief that money had value because it had to have such value. Thus it was that the monetary system of the United States and every other country in the world was entirely an exercise in psychology, A thing of the mind, and as a result, so was every other aspect of the American economy. If money was simply a matter of communal faith, then so was every thing else.
– Tom Clancy