For the most part modern theories of economic growth assume population change to be a determining factor of human welfare. A central tenet of the dominant theory is that although population growth doesn’t affect the long-run rate of change in living standards in any way, it affects the long-run standard of living adversely (Solow, 1956). Recent models of economic growth have been more assertive. They lay stress on new ideas as a source of progress. It is mostly supposed that the growth of ideas is capable of circumventing any constraint the natural-resource base may impose on the ability of economies to grow indefinitely. It is noted too.
