But even if we happen to want nothing at the moment, money is a sort of guarantee that we shall be able to make an exchange at any future time when we happen to be in need; for the man who brings money must always be able to take goods in exchange.

Money is, indeed, subject to the same conditions as other things: its value is not always the same; but still it tends to be more constant than the value of anything else.

Everything, then, must be assessed in money; for this enables men always to exchange their services, and so makes society possible.

Money, then, as a standard, serves to reduce things to a common measure, so that equal amounts of each may be taken; for there would be no society if there were no exchange, and no exchange if there were no equality, and no equality if it were not possible to reduce things to a common measure.