 First, since a note has no intrinsic value, there was nothing to stop issuing authorities from printing more of it than they had specie to back it with.Second, because it increased the money supply, it increased inflationary pressures, a fact observed by David Hume in the 18th century.The result is that paper money would often lead to an inflationary bubble, which could collapse if people began demanding hard money, causing the demand for paper notes to fall to zero.