A PROGRAMME FOR SOCIAL STUDY 859
sets a limit to the number of people which a given area will sus- tain. However productive the soil may be, and however care- fully cultivated, it cannot be made to yield an indefinitely increasing amount of that form of wealth which serves as food. This is due to the well-known law of diminishing returns which may be stated as follows : In certain industries, of which agri- culture is perhaps the best example, a point will by and by be reached beyond which an increased expenditure of labor and capital will not bring a proportionate return. That is to say, a farmer, although by doubling the labor and capital which he applies to his land might succeed in doubling the amount of produce once, twice, or thrice, could not go on doing so indef- initely. Now, since food is derived chiefly from the soil, this fact of diminishing returns from land practically places a limit on pop- ulation, and this is an important consideration in social study. For it is plain that the population can by no means increase beyond the food supply, that is, beyond the amount of that form of wealth which is used to sustain life. The effects here described of land upon population and wealth, so obvious in society at large, are always present in any social group however small, and consequently must always in every attempt at social study be a subject of investigation.
Turning now to wealth, the effects of its character and amount upon the welfare of a society are in a general way evi- dent to all. I have already referred to the fact that wealth, in the form of food, and population bear a certain relation to each other. This relation is formulated in the following law, known the world over as the Malthusian law of population : Population tends to increase more rapidly than food is capable of being increased. The importance of this law cannot easily be overes- timated. Notwithstanding all its so-called refutations, it must be taken account of in every scheme for social reform. The struggle for existence is not limited to the lower animals. Man. wherever he has been found, has been engaged in conflict. This conflict is for the means of satisfying his desires, one of the most important of which is the desire for physical comforts.
