Main currents in American thought

Then a film of haze slowly gathered upon the face of the brilliant sun and the light of men’s hopes grew dimmer. As physics encroached upon the interest in biology, and leadership in speculation based on scientific findings passed from Spencer to Ernst Haeckel, young Americans of the next generation found the membership of the current philosophical trinity changed for them, and instead of unity, growth, purpose, they discovered unity, flux, chance. Purpose had disappeared from the grim face of the material universe, and they found themselves in the coils of a determinism that was more likely to prove malignant than benevolent. The idea of progress slipped quietly from their minds, and in its stead was only a meaningless and purposeless flux of things. But unity remained to bind the individual upon the whole and dwarf him to a pin-point in a vast macrocosm. The intellectual history of the last quarter of the nineteenth century—in America as well as elsewhere—in its teleological aspects is the history of the shift from the benevolent evolutionism of Spencer to the mechanistic materialism of Haeckel, with all the dislocations and readjustments involved in the cataclysmic change; and The Education of Henry Adams, that curiously suggestive study in disillusion, is saturated with the pessimism that followed upon the transition—a pessimism exuding from the contemplation of the bleak unity of a mechanistic universe. Of the earlier period before hope was gone, he wrote thus:

Was there purpose in it all? To this Adams and the younger men more and more declined to make answer. Yet this much is clear, for them the end of the theological age had come, and the end also of the great hopes of the Enlightenment. The idea of progress was given over henceforth to the middle class to become the plaything of material expansion.