The other important function of money recognized is as a guaranty (ἐγγυητής) of future exchange. It represents the abiding, rather than the temporary, need, and is thus a standard of deferred payments.686
The importance of money in the fulfilment of these functions is great, in the opinion of Aristotle. The possibility of fair exchange, or indeed the very existence of organized society depends upon it.687
He is also clearer than Plato and Xenophon in his definition of the relation between money and wealth. He severely criticizes the current mercantilistic theory of his day, which identified wealth with a quantity of current coin (νομίσματος πλῆθος).688
He immediately follows this, however, with a more extended presentation of the opposite error of the Cynics, that money is mere trash (λῆρος), depending for its value entirely upon convention (νόμῳ). This theory, he points out, is based on the fact that, if money ceased to be recognized as legal tender, it would be useless; that it satisfies no direct necessity; and that one might starve like Midas, though possessed of it in superabundance.689
Aristotle is here somewhat ambiguous as to his own attitude toward this doctrine. He fails to object that money does not necessarily become valueless when it ceases to be legal tender, and that a similar argument might be used to prove that clothing is not wealth. Instead, he uses the idea as a means of refuting the opposite error, which is more obnoxious to him, and on the basis of it he plunges into his discussion of the true and false finance.690
This, together with a passage in the Ethics, might point to the conclusion that he agreed with the doctrine of the Cynics on money. He