Art and money have much in common. Both are spheres of social activity that carry symbolic values. A coin is simply a piece of metal, stamped with signs to give it symbolic meaning, to give it a value, a value that changes with the vicissitudes of its economic life, or, when no longer legal tender, with its life as a collectable. A painting is a piece of canvas, stretched on a frame to make it taut, which is then covered with pigment, brushed with...