Experience constitutes almost the only effective process by which a truth may be solidly established in the mind of the masses, and illusions grown too dangerous be destroyed. To this end, however, it is necessary that the experience should take place on a very large scale, and be very frequently repeated. The experiences undergone by one generation are useless, as a rule, for the generation that follows, which is the reason why historical facts, cited with a view to demonstration, serve no purpose. Their only utility is to prove to what an extent experiences need to be repeated from age to age to exert any influence, or to be successful in merely shaking an erroneous opinion when it is solidly implanted in the mind of the masses.
Our century and that which preceded it will doubtless be alluded to by historians as an era of curious experiments, which in no other age have been tried in such number.
The most gigantic of these experiments was the French Revolution. To find out that a society is not to be refashioned from top to bottom in accordance with the dictates of pure reason, it was necessary that several millions of men should be massacred and that Europe should be profoundly disturbed for a period of twenty years. To prove to us experimentally that dictators cost the nations who acclaim them dear, two ruinous experiences have been required in fifty years, and in spite of their clearness they do not seem to have been sufficiently convincing. The first, nevertheless, cost three millions of men and an invasion, the second involved a loss of territory, and carried in its wake the necessity for permanent armies. A third was almost attempted not long since, and will assuredly be attempted one day. To bring an entire nation to admit that the huge German army was not, as was currently alleged thirty years ago, a sort of harmless national guard, the terrible war which cost us so dear had to take place. To bring about the recognition that Protection ruins the nations who adopt it, at least twenty years of disastrous experience will be needful. These examples might be indefinitely multiplied.