Evolutionary concepts had a great impact upon American thought during the Gilded Age and afterwards. Because Darwinian theory was one of the primary products of nineteenth century science, it could hardly have been otherwise. A response to evolutionary ideas spread throughout the intellectual community from those in the sciences. Prominent American academics, especially biologists and theologians, felt bound to defend or attack evolutionary concepts. As the interest in evolution grew, theories bearing the influence of Herbert Spencer as well as Charles Darwin appeared in economics, anthropology, sociology, and psychology. During a time of transition, American thought assumed a character consistent with the predominance of change, adapting the dynamism of European naturalism to the American climate.
From the end of the Civil War until the end of the Spanish American war, a period called the Gilded Age, the United States changed from a largely agrarian nation to a largely industrial one. At the beginning of the period, Americans typically lived in scattered rural communities. By the turn of the century, the trend toward industrialization had established itself. In a great movement that continued through the World Wars, the center of American life moved toward the cities. A new orientation toward technology accompanied that great social and physical shift. The secularity of science was replacing the values long maintained by the traditional religious institutions.
In The Gilded Age, the novel that gave its name to the era, Mark Twain and Charles Dudley Warner described the turbulence of the time. They identified the revolution that had gripped social and political institutions, bringing changes that Americans would feel for several generations. According to Paul Boller, the developments in intellectual that occurred during that time "went far deeper than a response to economic development." A world vie...