All goods to be exchanged, then, should be measurable by some standard coin or measure .... In reality, this measure is the need which holds all things together; for if man had no needs at all or no needs of a similar nature, there would be no exchange or not this kind of exchange. So a coin is a sort of substitute (or representative) for need and came into being by convention; and it is because of this that its name is "coin" (= nómisma), for it exists by regulation(= nómo) and not by nature, and it is up to us to change a given coin or make it useless.... Now this money, too, is subject to the same fluctuation in need, for its worth does not always remain the same, but it has a greater tendency to remain the same. In view of this, all things should have a price on them; for in this way an exchange is always possible, and if so, also an association of men.
(Aristotle)

And if there were no buying and selling, there would be no communication.
(Nicole Oresme)

Coinage can always bring back into the hands of its owner that which has just been exchanged for it, just as, in representation, a sign must be able to recall to thought that which it represents. Money is a material memory, a self duplicating representation, a deferred exchange.
(Michel Foucault)

Love is more serious than Philosophy
Who sees no humor in her observation
That Truth is knowing that we know we lie.
(W. H. Auden)