These may seem unnecessary commonplaces. But they have a vital bearing on the _modus operandi_ of economic laws. These laws do not work _in vacuo_. They work through the medium of the acts of men. The acts of men are greatly influenced by their institutions, and by their ideas of right and wrong. Both institutions and ideas may serve to smooth rather than obstruct the path of economic laws; because the laws may represent either "what should be" in the general, or "what is" in the general, and therefore "what should be" in the particular. This may hold true even of a trade union or a sense of "fair wages." The business of economic theory is not to justify a regime of _laissez-faire_, still less to show the folly of bringing morals into business. Its value is rather that it may help us, by improving our understanding, to shape our institutions, and to adopt our moral sentiments so as to promote the public welfare. With these general notions in our minds, let us turn to see how stands the case with Labor. §3. _The General Wage Level_. The term Labor may be used in a broad or in a narrow sense. It may be confined to weekly wage-earners: it may be extended to include all those who work, as the phrase goes, "with either hand or brain." It is with all classes of Labor, in the broadest sense of the term, that we must here concern ourselves. It will be convenient, however, in the first instance to ignore the differences between them, and to consider the forces which determine what we may regard as the general wage-level.