ABSTRACT
The intellectual life of the nineteenth century was more complex than that of any previous age. This was due to several causes. First: the area concerned was larger than ever before; America and Russia made important contributions, and Europe became more aware than formerly of Indian philosophies, both ancient and modern. Second: science, which had been a chief source of novelty since the seventeenth century, made new conquests, especially in geology, biology, and organic chemistry. Third: machine production profoundly altered the social structure, and gave men a new conception of their powers in relation to the physical environment. Fourth: a profound revolt, both philosophical and political, against traditional systems in thought, in politics, and in economics, gave rise to attacks upon many beliefs and institutions that had hitherto been regarded as unassailable. This revolt had two very different forms, one romantic, the other rationalistic. (I am using these words in a liberal sense.) The romantic revolt passes from Byron, Schopenhauer, and Nietzsche to Mussolini and Hitler; the rationalistic revolt begins with the French philosophers of the Revolution, passes on, somewhat softened, to the philosophical radicals in England, then acquires a deeper form in Marx and issues in Soviet Russia.
