1. _Wage in the broad sense is the income due to labor, in distinction from that due to the control of material agents._ The uses of material agents, studied under the subject of rent, are sometimes called "material services." The adjective refers to the source or bearer of the use, and does not imply that the service is to be thought of as a material thing. In its last analysis a service is never a material thing, but a psychic effect on men and their wants. Material services and human services are merely specific kinds of the genus services (or utilities), and it would doubtless be a better usage to speak of labor's services and wealth's uses. Wages bear the same relation to man's services that rent does to the material uses of wealth. Wages are more like rent than like interest in that neither wages nor rent are expressed as a percentage. While rent is the value of the uses of things, wages is the value of the services of men. In discussing interest, wealth is capitalized; but, in discussing wages, men are thought of as affording utilities for a time, as is wealth under the renting contract. The resemblance thus is very close between rent and wages, but not so close between wages and interest. Despite this interesting analogy, it is not well to speak, as some do, of "the rent of labor"--as well might one speak of the wages of wealth. Such a usage only beclouds the distinction between two concepts, suggesting identity where there are important differences. The aim of scientific classification is missed when contrasts are thus concealed under a single term. [Sidenote: Nature of the law of wages] 2. _A law of wages is a statement of the relation of the general causes of value to the value of human services._ In real life no one agent is valued independently of other goods. The felt importance of a good depends on the degree to which other wants are gratified. If men are starving, they attach less importance to ornaments; if cold, more importance to clothing and fuel, being willing to part even with some needed food to secure them. That is, man's desire for each thing is affected by his general condition and by the existence of other goods and wants. A similar relation exists between the values of indirect agents, and must exist between wages and rent. We are to discuss the law of wages. An economic law does not state a command; it is not a political law; it states merely an observed relation. Things do not need to happen actually according to any law of wages that can be formulated, but they will happen in the measure that the assumed conditions exist. The law states a tendency of wages, just as the law of gravitation states a tendency and does not predict positively whether a given object will fall at a given moment. The "law of wages," therefore, is to be understood as a hypothetical statement of the value that will be attributed to labor under a given set of conditions. [Sidenote: Economic wages and contract wages]