Secondly, the simpler statements of the action of the factor of relative plenty and scarcity, such as are represented by the marginal diagrammatic expositions familiar in economics, obscure the fact that distribution is a process in which human wills are actively engaged. The constant assertion of will is a real force in the working out of distribution. Each group with a claim to a share of the product, by organization, agitation, and other tricks of the market place strives to forward its interest. It explores, by pressure upon the price mechanism and otherwise, the full extent of the dependence of the industrial system upon it or its product, as when monopolists control prices, or a trade union strikes to enforce a wage demand. Each group or agent tends to favor or resist changes in laws, industrial methods, and institutions according as it expects to be benefited or otherwise by the change. This may be seen in the discussions surrounding the introduction of the eight hour day, or concerning the limitation of immigration. However, it is a careless exaggeration to state, as is frequently stated, that the attitude of groups to economic legislation must inevitably be determined by their economic interest. Every part of the industrial system yields at some time and occasion to the impact of the human will. Even changes in the arts of production may result therefrom, as is well exemplified in Mr. Clay's analysis of the way in which the standard of life of the wage earners may exert an influence over wage rates.... This conception of a standard of life, though fluctuating, is a relatively fixed thing in the flux of forces determining distribution. The workman, by combination tacit or explicit, fixes it and his employer adjusts production to it. The employer will do all in his power, usually with success, to secure an increase in output in return for every increase of wages, and where the local standard compels him to pay higher wages than his competitor in other districts to extract an amount of work correspondingly greater.[25] Or, take the hope entertained by the advocates of the living wage, that its enforcement would produce a better type of management in those industries to which the legislation is applicable. It is characteristic of the present industrial situation that no group should rest quietly under the dictation of what it is told is economic law or necessity. Given its way, each group tests anew the habits and arrangements by which it is constrained. Every time an industrial method is modified, the agents which share in distribution strike a slightly new balance. The direction of the stream of product changes with every modification of its banks. Some of these modifications occur so unexpectedly that they are not to be found upon the maps. The pilot, as Mark Twain said of the Mississippi, must carry the conformation in his head.