This fact does not force to the conclusion that industrial inequality as it exists to-day, the great disparity of incomes, correctly or justly reflects the degree of difference in men's qualities, either native or acquired. It does not follow that a thousand-dollar income represents ten times the ability of a hundred dollar one--far from it. But to those who ignore the inequality of men, the whole problem of industrial remuneration must remain a mystery. A crude socialism is possible only to those who are blind to the enormous differences in human capacity. [Sidenote: Scarcity of labor is essential to wages] [Sidenote: Unlimited demand for labor] 7. _The scarcity of human services, relative to wants, is the fundamental fact in the problem of wages._ It is clearly seen that some qualities of service are scarce. Most women will confess that they cannot warble as Patti could, most men will admit that they have not the mercantile ability of John Wanamaker. The man of mediocre capacity recognizes even through the fog of his self-esteem that there is a reason for the high value of certain rare services. But it must also be recognized that the commonest services have value only because they are scarce. There are many things to be done if there were labor enough to do them. There is no need to "make work," in the popular sense; it is here, but labor is lacking to do it. It is true there may be a temporary superfluity of human labor at a time of an industrial crisis. There is at all times a superfluity of "useless" human agents whose qualities are such that they have no net utility. The ignorant, insane, feeble-minded, vicious, drunken, and debauched, can give to the world only negative utilities. But services that are in any degree useful are nearly always in demand, and the higher services are so rare that they are in great demand. The proverb, "There's always room at the top," is seen to be true when conditions are thus analyzed. There is a large, though limited, supply of the commoner kinds of services at the bottom of the scale, but in every branch of human effort there is a never-ending lack of that higher qualification and training required for the best results. CHAPTER 21 THE SUPPLY OF LABOR § I. WHAT IS A DOCTRINE OF POPULATION? [Sidenote: The employer's and the social view of supply of labor]