According to Heraclitus of old, the world moves by opposites; the law of contradiction is a law of the universe. And many writers of history assert that human progress does not proceed in the path of a straight line, but rather in cycles, or with a to-and-fro movement like the swings of a pendulum. Thus, some 2500 years ago, after the Old, the Middle, and the New Empires of Egypt, each lasting for about a thousand years, had passed away, the world was roused by a new twofold force - the genius of the Greek and the power of the Roman. The Greek-Roman day lasted for about a thousand years also. Then the world went to sleep for another thousand years; the spirit of progress, like the apocalyptic dragon, seemed to be bound in the bottomless pit. But when the required number of days were fulfilled, some five hundred years ago, the world awoke again, perhaps to fall into another slumber five hundred years from now. - American Journal of Sociology, Vol. 13, p. 541, Elkin.

. . . The conception of "progress" is a useful conception in so far as it binds together those who are working for common ends, and stimulates that perpetual slight movement in which life consists. But there is no general progress in Nature, nor any unqualified progress; that is to say, that there is no progress for all groups along the line, and that even those groups which progress pay the price of their progress. It was so even when our anthropoid ancestors rose to the erect position; that was "progress" and it gained us the use of hands. But it lost us our tails, and much else that is more regrettable than we are always able to realize. There is no general and ever increasing evolution towards perfection. "Existence is realized in its perfection under whatever aspect it is manifested," says Jules de Gaultier. Or, as Whitman put it, "There will never be any more perfection than there is now." We cannot expect an increased power of growth and realization in existence, as a whole, leading to any general perfection; we can only expect to see the triumph of individuals, or of groups of individuals, carrying out their own conceptions along special lines, every perfection so attained involving, on its reverse side, the acquirement of an imperfection. It is in this sense, and in this sense only, that progress is possible. We need not fear that we shall ever achieve the stagnant immobility of a general perfection. - Ellis, Task of Social Hygiene, pp. vii, viii.

Of course this principle of cycles means that progress toward any goal or ideal which we may set up will be intermittent, swerving now this way and now that, with times of positive loss instead of gain. Even telic progress cannot go far in a straight line. The railroad winds its way to avoid natural obstacles and touch important centers of population.

Of more profound import is the way in which the longer cycles contribute to, or permit, the flow of human energy. Somewhat as the short cycles permit strength to accumulate for large undertakings, or more closely, perhaps, as the short cycles give fresh outlook and new spirit to prosecute large undertakings, so each long cycle has a new set of ideals and gives progress in some new direction. The spirit of the age possesses men's hearts so fully that they are sure the world is now on the right track at last. The leaders see ahead of them, through a long vista of improvements, the perfection of the system in which they are working; that perfection is their goal; each man strives mightily to attain it, or at least to bring the world somewhat nearer toward it. But there is a limit to the progress that is possible in a given direction; it is not perfection, but only an approximation to the ideal, for human capacity is limited. When the limit approaches and it becomes evident that no further progress can be made without exposing fundamental weaknesses in the system, then the downfall or radical reconstruction comes soon, and a new dispensation begins.

The new dispensation, however, is not altogether new. It adapts much from the old. It finds its new ideals in the visions of seers whom the old dispensation condemned to drink poison, nailed to a cross, burned at the stake, starved in garrets. The seed thoughts are old, but they are planted in a new soil, and yield a new human harvest, richer, as the people who gather it think, than any ever seen before, and of its kind perhaps the best the world ever will see.

It is, therefore, by means of the cycles of change that the idea of progress persists. Just as plants and animals grow by short cycles of anabolism and katabolism, action and eating and sleeping, and just as they are able to progress by the variation of each generation from its predecessor, so also civilization itself keeps up its progress through the centuries and the millenniums by long periods of growth following short periods of recession and readjustment. It is the privilege of the people of each generation to see themselves at a unique turn in the human episode with some principle which they exemplify for all time; what they make out of it will always be, as we say in sports, the world's "record."

The question whether, after all, the world really does progress is not one that can be settled by an intellectual demonstration of any kind. . . .

In short, the reality of progress is a matter of faith. We find ourselves in the midst of an onward movement of which our own spirits are a part, and most of us are glad to be in it, and to ascribe to it all the good we can conceive or divine. This seems the brave thing to do, the hopeful, animating thing, the only thing that makes life worth while, but it is an act rather of faith than of mere intelligence. - Cooley, Social Process, pp. 406, 408.