P a u l B. S e a r s (Y ale University): A t the outset we must make the assumption that rational and humane individuals want to see the human adventure continue without being throttled by a lack of the materials and energy. But beyond this point there arises a serious difference of opinion. On the one hand there are biologists, geographers, demogra­ phers, and doubtless some historians who take it for granted that the present increase in world population and rise in the standard of living with consequent pressure upon natural resources cannot continue without disaster. On the other hand, there is an impressive group which holds that we have, in human resourcefulness itself, an unlimited resource which, by exploration, invention, and organ­ ization, will be able to meet any emergency that may arise.