 Soviet central planners made decisions by checking prices on international markets, but suppose there were no information about supply and demand to be had anywhere. Suppose you are a planner, but all you know is that demands are coming in for wire and for jewelry. How do you decide whether to direct factories to make wire out of copper or platinum, or whether smiths should make jewelry out of gold or silver? How do you decide who should get silver jewelry and who should get gold? How do you decide whether anyone at all should get jewelry, as opposed to reserving all such metals for use as wire?