But it is not so. It is very possible, and very often happens, that the ‹wants› of one owe their ‹satisfaction› to the ‹efforts› of [p072] another. This is a fact. If any one of us were to pass in review all the satisfactions he enjoys, he would acknowledge that he owes them chiefly to efforts which he has not himself made; and in the same way, the labour which we undergo, each in his own profession, goes almost always to satisfy the desires of others. This tells us, that it is neither in the wants nor in the satisfactions (phenomena essentially personal and intransmissible), but in the nature of the mean term, ‹human Efforts›, that we must search for the ‹social› principle—the origin of Political Economy. It is in fact to this faculty, given to men, and to men alone, among all creatures, to ‹work the one for the other›; it is this transmission of efforts, this exchange of services, with all the infinite and involved combinations to which it gives rise, through time and through space, it is «THIS» precisely which constitutes Economic Science, points out its origin, and determines its limits. I say, then: ‹Every effort, capable of satisfying, on condition of a return, the wants of a person other than the man who makes the effort, and consequently the wants and satisfactions relative to this species of effort, constitute the domain of Political Economy.› Thus, to give an example: the act of breathing, although it includes the three terms which constitute the Economic phenomenon, does not pertain to that science, and we see the reason. What we have here to do with is a series of facts, of which not only the two extremes—want and satisfaction—are incapable of transmission (they are always so); but the mean term, ‹Effort›, is also incapable of transmission. To enable us to respire we invoke the assistance of no one; in that there is neither a service to be received nor a service to render. The fact is in its nature individual, not ‹social›, and consequently cannot enter into a science which is essentially one of relation, as its very name indicates. But if, in peculiar circumstances, people were to render each other assistance to enable them to breathe, as when a workman descends in a diving-bell, when a physician treats a patient for pulmonary complaints, or when the police take measures for purifying the air, in such cases there is a want satisfied by a person other than the person who experiences the want; there is a service rendered; and respiration itself, as far at least as concerns assistance and remuneration, is brought within the sphere of Political Economy. It is not necessary that the transaction should be completed, it is sufficient that it is possible, in order to impart to the ‹labour› employed an ‹economic› character. The labourer who raises corn [p073] for his own use accomplishes an economic fact in this respect that the corn is capable of being exchanged.