A dynamic element asserted itself in American political and social thought that kept inflating the possibilities of the original American creed-though the relative proportion of the elements remained the same: there was a sense of expanding frontiers. By this is meant not merely the narrow thesis of Frederick Jackson Turner, expounded when it could no longer apply and largely mistaking cause for effect, but a wider national feeling of almost limitless possibilities, of living all the time in tomorrow in almost every sphere of life. That the ‘frontiers of knowledge’ about man-in-society would be expanded just as science and technology had expanded man’s knowledge and control of the physical universe was a belief soon to be widely heard in pulpit and press as well as from academic chairs. The ground in popular educated sentiment was being laid for a future science of politics and of society, although the educational leaders of roughly the years 1860 to 1910 rightly did not all believe that to have their ears too close to the ground was always a becoming gesture.