constitution of the world. They have indeed altered it for us, for they have given us the means of applying forces previously dormant, and therefore for practical purposes non-existent. Such beliefs have an immediate bearing upon the practices of ordinary human beings. But if we are to set down all philosophies as at once untenable and as absolutely unknown to the enormous majority of mankind, it becomes difficult to understand by what process they come to influence, or apparently to influence, the position of the race. A philosopher frames his scheme of the universe to his own satisfaction; but you and I hear nothing about it, and do not trouble ourselves to understand it, and go on working with our good old common-sense conceptions of things, leaving it to the philosopher to construct or destroy the fanciful system which he somehow supposes to lie beneath them. One answer is of course obvious. Religious and ethical systems, it is said, presuppose a philosophy: no one denies that men are profoundly affected by the gods whom they worship and the rules of conduct which they adopt; and therefore the sceptic who is burrowing at the base may be ruining the whole superstructure, although his operations are no more obvious upon the surface than those of some minute parasite. Accordingly, we are often told that revolutions are ultimately produced by speculation; and that old systems fall with a crash because some shrewd witness has been boring into the foundations upon which they really repose. The French Revolution, according to one familiar statement, was due to the freethinkers who had set about prying into the ultimate grounds of the old faith, and had succeeded in shaking the convictions necessary to social welfare.