Throughout history, many different articles have been used as forms of money; such as stones, salt, shells and beads. From the beginning, silver and gold have displaced all other mediums of exchange. The invention of the printing press enabled the use of paper currency along with it. However, no government has ever successfully substituted paper for real money, because no government can print silver.
In general, silver prices are anticipatory rather than reactionary. Once the forces of the inflation index begin to cause a shift, investors will buy into the market to make sure they are in position before the general public. Their buying will drive prices upward.