Among the poorer classes very different motives operate. After the first few years the parents' income is increased by the earnings of the children, both on the farm and in the factory districts if the laws do not prohibit child labor. Moreover, when the children are grown, their wages will depend on the general labor market, not upon the number of their brothers and sisters. So, according as the family income is from rents or from wages, the motives of the parents differ.
Motives in volitional control
Postponement of marriage must be classed as a mode of volitional control of population. The average age of marriage, both of men and women, is higher in the classes of greater wealth and ambition than in the poorer classes. The contrast in this regard between civilized and savage peoples is likewise noteworthy. The failure to marry, from whatever cause, is, in the social view of the question, volitional control. It is rare that the motive is directly and immediately the wish to avoid parenthood; now it is religious zeal, again it is disappointed sentiment; here it is conflicting duty, and there it is the individual selfish wish to retain an undivided income for one's own enjoyment. By countless strands of motive in the form of sentiments, social institutions, and interests, the primitive impulses of humanity are firmly bound; and in varying degrees, in different classes, the enormous possibilities of reproduction are controlled by human volition.
§ III. CURRENT ASPECT OF THE POPULATION PROBLEM
The many motives controlling population
1. Changes in population are resultants of many forces: those favoring a high birth-rate and low death-rate, and those limiting births or survival. Whether the population on the whole shall grow, stand still, or diminish, depends upon the relative strength of contending forces making for life or death. But this control may lose its cruder aspect and may be waged in the realm of motive. More and more it is volition that controls in human society the growth of population; less and less it is the objective limit of the food-supply. Dire need resulting in ill-health and even in starvation, is still acting in some portions of society, but less to-day than ever before. The growth of population in this stage is not "fatalistic," as there is no inevitable tendency to increase or to decrease. It depends on the interaction of a number of forces, clearly distinguishable, by which population actually is kept far within the limits of food resources. Volitional control is not by a central and unified despotism determining human action, but it is by motives of the most complex sort, diffused throughout society and acting upon every member of it.
The standard of life in Asiatic countries
2. The desire to maintain and raise the standard of life is the most effective motive limiting population in our society. The phrase "standard of life" expresses the complex thought of that measure of necessities, comforts, and luxuries considered by any individual to be indispensable for himself and his children; that measure which he will make great sacrifices to secure. This standard differs from land to land, and from time to time. In the Asiatic countries it is so low that it touches in large classes the minimum of subsistence. Despite adverse influences and the uninterrupted series of famines, the population of India in the last century under English rule increased from two hundred millions to three hundred millions. Such a population "lets out all the slack" of income, and never takes up any. The great public works of irrigation, forestry, and transportation, and the development of industry under English rule, gave an opportunity for a higher standard of living; but it was used instead to permit the existence of a greater number of men in the same old misery. These facts have a bearing upon the question of Oriental immigration to America. The emigration of millions of Chinese from their native land would leave no void in their numbers. Peopling their own land constantly down to their own standard of living, they have the power, if they are tempted hither in great numbers, to people this continent also to the same density.
The American standard