Pufendorf: On the Duty of Man and Citizen according to Natural Law

1. After ownership of things had been introduced, the custom of exchange soon followed. For then as now all things were not of the same nature nor had the same usefulness to human needs, and no one individual had as much for his own use as he desired. Hence it often happened that things of different nature or use needed to be passed from one person to another. To prevent either party suffering in an exchange of that kind it was necessary to assign, by agreement between men, some quantity in terms of which things could be compared and equated with each other. This was also the case with actions which one was unwilling to do for others’ benefit for nothing. This quantity usually goes by the name of ‘value’ [pretium].

2. Value is divided into common value and eminent value. Common value is found in things and actions, or Services, which enter into commerce because they give us use and pleasure. Eminent value is seen in money, since it is accepted as virtually containing the value of all goods and Services and as providing them with a common measure.

3. The foundation of common value in itself is the suitability of the thing or Service to make a direct or indirect contribution to the needs of human life and to render it fuller and more agreeable. Hence things that have no use at all are normally said to have no value. There are, however, some things which are very useful to human life on which no definite value is understood to be set. This is because either they are and must be without ownership, or because they are incapable of being exchanged and therefore excluded from commerce, or because in commerce they are regarded only as appendages to something else. Again, human or divine law has set certain actions apart from commerce or has forbidden them to be done for pay, and so is understood to have withdrawn them from the sphere of value.