of effort and self-denial. In either case one is passing judgment on what is inevitably fixed, and on which the approval or condemnation of man can produce no effect. The facts and laws are, once and for all, so, and for us men that is the end of the matter. The only persons for whom there would be any sense in the question whether life is worth living are primarily the yet unborn children, and secondarily the persons who are proposing to found families. For these latter the question would take a somewhat modified form: Will life be worth living for children born of me? This question is, unfortunately, not put to themselves by the appropriate persons as it would be if they had been taught sociology. The sociologist is often asked if he wants to kill off certain classes of troublesome and burdensome persons. No such inference follows from any sound sociological doctrine, but it is allowed to infer, as to a great many persons and classes, that it would have been better for society, and would have involved no pain to them, if they had never been born.
In further illustration of the interpretation which sociology offers of phenomena which are often obscure, we may note the world-wide effects of the advances in the arts and sciences which have been made during the last hundred years. These improvements have especially affected transportation and communication; that is, they have lessened the obstacles of time and space which separate the groups of mankind from each other and have tended to make the whole human race a single unit. The distinction between over-populated and under-populated countries loses its sharpness, and all are brought to an average. Every person who migrates from Europe to America affects the comparative status of the two continents. He lessens the pressure in the country he
