ternal forces, which reverse the process of evolution, integrating motion and dissipating matter in the form of gas, again to evolve motion by its condensation; so, it may be said, does the aggregation of individuals in a community evolve a force which produces the light and warmth of civilization, but when this process ceases and the individual components are brought into a state of equilibrium, assuming their fixed places, petrifaction ensues, and the breaking up and diffusion caused by an incursion of barbarians is necessary to the recommencement of the process and a new growth of civilization.
But analogies are the most dangerous modes of thought. They may connect resemblances and yet disguise or cover up the truth. And all such analogies are superficial. While its members are constantly reproduced in all the fresh vigor of childhood, a community cannot grow old, as does a man, by the decay of its powers. While its aggregate force must be the sum of the forces of its individual components, a community cannot lose vital power unless the vital powers of its components are lessened.
Yet in both the common analogy which likens the life power of a nation to that of an individual, and in the one I have supposed, lurks the recognition of an obvious truth—the truth that the obstacles which finally bring progress to a halt are raised by the course of progress; that what has destroyed all previous civilizations has been the conditions produced by the growth of civilization itself.
This is a truth which in the current philosophy is ignored; but it is a truth most pregnant. Any valid theory of human progress must account for it.
