And bear in mind, that fools are not always merely imbecile and obstructive; they are at times ferocious, dangerous, mad. There is in human nature what Goethe used to call a demoniac element, defying all law, and all induction; and we can, I fear, from that one cause, as easily calculate the progress of the human race, as we can calculate that of the vines upon the slopes of AEtna, with the lava ready to boil up and overwhelm them at any and every moment. Let us learn, in God's name, all we can, from the short intervals of average peace and common sense: let us, or rather our grandchildren, get precious lessons from them for the next period of sanity. But let us not be surprised, much less disheartened, if after learning a very little, some unexpected and truly demoniac factor, Anabaptist war, French revolution, or other, should toss all our calculations to the winds, and set us to begin afresh, sadder and wiser men. We may learn, doubtless, even more of the real facts of human nature, the real laws of human history, from these critical periods, when the root-fibres of the human heart are laid bare, for good and evil, than from any smooth and respectable periods of peace and plenty: nevertheless their lessons are not statistical, but moral. But if human folly has been a disturbing force for evil, surely human reason has been a disturbing force for good. Man can not only disobey the laws of his being, he can also choose between them, to an extent which science widens every day, and so become, what he was meant to be, an artificial being; artificial in his manufactures, habits, society, polity--what not? All day long he has a free choice between even physical laws, which mere things have not, and which make the laws of mere things inapplicable to him. Take the simplest case. If he falls into the water, he has his choice whether he will obey the laws of gravity and sink, or by other laws perform the (to him) artificial process of swimming, and get ashore. True, both would happen by law: but he has his choice which law shall conquer, sink or swim. We have yet to learn why whole nations, why all mankind may not use the same prudential power as to which law they shall obey,--which, without breaking it, they shall conquer and repress, as long as seems good to them.