But in what sense is even this part attributable? Not in the sense that the labor is the original source of value which imparts that value to its products. The usufruct of wealth is the basis of rent; the need to pay rent is not the cause of value in the product. Likewise, product is the basis of wages, labor is not the origin of value. Labor, like the forces and qualities of wealth, is the cause of technical changes. These changes, if favorable, cause the goods to take on a higher value which is reflected back to the labor. The labor itself has not a predetermined, ascertainable value, but only a resultant, derived value. An exception to this statement appears on a superficial view of the value of labor hired under the wage contract to make a particular product. The labor having a market value because of a large number of well-known alternate uses, can be diverted to a particular use only on condition of a definite payment. Labor here, as viewed by the employer, appears to have an original value; products, a derived value. But in the logical view, labor is seen to impart technical qualities to the goods; in turn, the goods to impart value to the labor. Man hunts throughout industry for those things to which his labor can be applied usefully. He foresees in them the changes that will increase the value. It is only as he has judged rightly that the value taken on by the things is reflected back to the labor attributed to it. [Sidenote: No unit of labor to serve as a standard of value]