Arnold’s central message is this: Challenges to the validity of long-standing theological and moral precepts have shaken the faith of people in God and religion. In Arnold’s world of the mid-1800's, the pillar of faith supporting society was perceived as crumbling under the weight of scientific postulates, such as the evolutionary theory of English physician Erasmus Darwin and French naturalist Jean-Baptiste Lamarck. Consequently, the existence of God and the whole Christian scheme of things was cast in doubt. Arnold, who was deeply religious, lamented the dying of the light of faith, as symbolized by the light he sees in “Dover Beach” on the coast of France, which gleams one moment and is gone the next. He remained a believer in God and religion, although he was open to—and advocated—an overhaul of traditional religious thinking. In God and the Bible, he wrote: "At the present moment two things about the Christian religion must surely be clear to anybody with eyes in his head. One is, that men cannot do without it; the other, that they cannot do with it as it is."