[...] Money is not principally a means of buying 'stuff' but a way of coping with an uncertain future. We do not know which new goods and services will exist in the future, nor what their relative prices will be. There is no auction mechanism today that will allow us to discover that. Maintaining a reserve of purcashing power denominated in a monetary unit reduces the risk from placing one's eggs in the basket containing only contracts that can be written today. [...]