"On the other hand, after observing how the processes that have brought things to their present stage are still going on, not with a decreasing rapidity indicating approach to cessation, but with an increasing rapidity that implies long continuance and immense transformations; there follows the conviction that the remote future has in store, forms of social life higher than any we have imagined: there comes a faith transcending that of the Radical, whose aim is some re-organisation admitting of comparison to organisations which exist. And while this conception of societies has naturally evolved, beginning with small and simple types which have their short existences and disappear, advancing to higher types that are larger, more complex, and longer-lived, coming to still-higher types like our own, great in size, complexity, and duration, and promising types transcending these in times after existing societies have died away--while this conception of societies implies that in the slow course of things changes almost immeasurable in amount are possible, it also implies that but small amounts of such changes are possible, within "short periods"--Herbert Spencer: The Study of Sociology, Chapter XVI. It has repeatedly been necessary, in the course of this survey, to stimulate the indulgence of the reader by a reminder, based upon the speed of our progress in the past and its steady acceleration in recent decades, that there is much more danger of underestimating than of exaggerating the advances likely to have been achieved a hundred years hence. In order to guard against misconception of the manner in which these advances will be brought about, it is now advisable to mention specifically what has been once or twice hinted parenthetically, namely, the fact that the progress of the Future is certain to be produced in a way perfectly capable of being deduced from the manner of our progress in the past. One of the most fruitful causes of error in existing prognostications has been the tacit assumption that, at some vague moment in the spacious middle-distance of the coming time, sudden and cataclysmal movements of society, and also unexpected and revolutionary discoveries in science, will occur: and it is as a precaution against one aspect of this mistake that a weighty quotation from the writings of one of the sanest and most perspicuous thinkers who have ever written upon that science of society which he may almost be said to have created has been recalled to the memory of the reader at the head of this chapter.