Aristotelian philosophy establishes four axes of causality within the reality : material, formal, final and efficient. Applying Aristotle to economics and financial practices implies four analytical elements in the price : nominal, real, credit and insurance. These elements cannot be calculated in anticipation of future reality without a framework both real and conceptual. The link between nominal price, real object, credit of value and insurance of personal ownership of value is provided by market. Not only a virtual market but a real space where subjects and objects are actually visible and verifiable.
So value is the choice of each subject on objects. Price is the common value within plurality of subjects. Uniqueness of price means market equilibrium on object exchanges. Economy is really possible if market is defined by political law materialized by one money. So money is the logical link between a specific law state and a defined market. If money is cleared by real transactions and specifies the exchange market, it may count value with fair prices. Money may be material of credit and credit may be material of real value in present and future.
The actual system crisis may be explained by denial of law in so called free capital markets. Markets have been virtualized by finance and therefore disconnected from reality of law, credit and liquidity. Economy may be restablished by a two levels monetary system with local and global currencies. The global currencies should be international credit standards within regional markets.