The Science of Political Economy
Book III, The Production of Wealth*
The Second Factor of Production -- Labor
Showing That Labor Is the Human or Active Factor In All Production
All human actions, or at least all conscious human actions, have their source in desire and their end or aim in the satisfaction of desire. The intermediary action by which desire secures its aim in satisfaction, is exertion. The economic term for this exertion is labor. It is the active, and from the human standpoint, the primary or initiative, factor in all production -- that which being applied to land brings about all the changes conducive to the satisfaction of desire that it is possible for man to make in the material world.
In political economy there is no other term for this exertion than labor. That is to say, the term labor includes all human exertion in the production of wealth, whatever its mode. In common parlance we often speak of brain labor and hand labor as though they were entirely distinct kinds of exertion, and labor is often spoken of as though it involved only muscular exertion. But in reality any form of labor, that is to say, any form of human exertion in the production of wealth above that which cattle may be applied to doing, requires the human brain as truly as the human hand, and would be impossible without the exercise of mental faculties on the part of the laborer.
Labor in fact is only physical in external form. In its origin it is mental or on strict analysis spiritual. It is indeed the point at which, or the means by which, the spiritual element which is in man, the Ego, or essential, begins to exert its control on matter and motion, and to modify the material world to its desires.
As land is the natural or passive factor in all production, so labor is the human or active factor. As such, it is the initiatory factor. All production results from the action of labor on land, and hence it is truly said that labor is the producer of all wealth.