Allowing, as every competent thinker must allow, a full measure of validity to the contention that social developments are matters of slow growth and gradual attainment rather than of sudden and catastrophic change; admitting that even in the sphere of scientific discovery and mechanical invention changes occur much more gradually than a cursory glance at individual achievements would suggest; recognising that many of the most remarkable changes whose arrival in the past is the only possible valid guide to anticipation of similar or kindred changes in the future; it is still a condition of such anticipation that we should take account of causes likely to be operative in altering the rate at which the world will move. To allow that social improvements generally have the air of occurring almost automatically is not to conceive that they are without cause. Neither can it be believed by anyone who has studied the history of such movements in the past, or watched them in current progress, that the rate of development is everywhere and at all periods the same. There have been eras of almost complete moral, and even of almost complete mechanical, stagnation in the history of the world. There have been other eras of almost violent reformation and reconstruction. To reason as if these characteristics were arbitrarily or miraculously imposed upon the physiognomy of society, to be content with laboriously unintelligent estimation of the facts without attempting to learn anything from them of their causes, is to neglect the only important lesson which either history or observation is capable of teaching. When, therefore, an enormous acceleration in a rate of progress already unprecedented in the records of society has been predicted for the next hundred years of human history, it is evident that this anticipation must have been based upon some estimate of forces calculated to be operative in producing acceleration. So far as scientific or material progress is concerned, it is obvious enough that we shall move forward with increasing momentum, because every discovery and every invention tends automatically to facilitate fresh attainment, and the very growth of population must act in the same way, as must also the struggle for existence. As there are every year more men and women working on scientific research and on mechanical invention, the results must be progressively greater every year; and as the rewards of success are increased by the growing demand resulting from a growing population, it is evident that the incentives to industry in this respect are proportionately liable to increase. But the ethical progress of the world is actuated by forces entirely different, and what makes for mechanical improvement may very easily be conceived--in fact has actually been conceived by one rather conspicuous prophet--to operate adversely upon the moral future of the race.