half of the nineteenth century has been one of the most indefatigable workers in the cause of reason against authority.
Another comprehensive system was worked out by an Englishman, Herbert Spencer. Like Comte's, it was based on science, and attempts to show how, starting with a nebular universe, the whole knowable world, psychical and social as well as physical, can be deduced. His Synthetic Philosophy perhaps did more than anything else to make the idea of evolution familiar in England.
I must mention one other modern explanation of the world, that of Haeckel, the zoologist, professor at Jena, who may be called the prophet of evolution. His Creation of Man (1868) covered the same ground as Darwin's Descent, had an enormous circulation, and was translated, I believe, into fourteen languages. His World-riddles (1899) enjoys the same popularity. He has taught, like Spencer, that the principle of evolution applies not only to the history of nature, but also to human civilization and human thought. He differs from Spencer and Comte in not assuming any unknowable reality behind natural phenomena. His adversaries commonly stigmatize his theory as materialism, but this is a mistake. Like Spinoza he recognizes matter and mind, body and thought, as
