ABSTRACT
Human beings have always been migratory. Sometime between 100,000 and 400,000 years ago man's predecessor Homo erectus had spread from China and Java to Britain and southern Africa Since this propensity to migrate has persisted in every epoch, its explanation requires a theory independent of any particular epoch. For the underdeveloped country emigration appears to be a stopgap allowing postponement of internal economic and demographic changes that would make emigration unnecessary. It is like borrowing money at high interest to pay off debts that one's income could not support in the first place. In the future the failure of international migration to solve problems will not necessarily prevent its happening. The present wave of voluntary movement from underdeveloped nations to developed ones may reach a maximum and be reduced, but if so, it will be replaced by other waves.
