Scientific research also progressed rapidly outside the world of industry and technology, sometimes putting forth direct challenges to traditional beliefs. In geology, for example, Charles Lyell (1797–1875) effectively discredited the long-standing view that the earth’s surface had been formed by short-lived cataclysms, such as biblical floods and earthquakes. Instead, according to Lyell’s principle of uniformitarianism, the same geological processes that are at work today slowly formed the earth’s surface over an immensely long time. Similarly, the evolutionary view of biological development, first proposed by the Greek Anaximander in the sixth century B.C.E., re-emerged in a more modern form. Charles Darwin (1809–1882) was the most influential of all nineteenth-century evolutionary thinkers. Convinced by fossil evidence and by his friend Lyell that the earth and life on it were immensely ancient, Darwin came to doubt the general belief in a special divine creation of each species of animal. Instead, he concluded, all life had gradually evolved from a common ancestral origin in an unending “struggle for survival.” After long hesitation, Darwin published his research, which immediately attracted wide attention.

Darwin’s great originality lay in suggesting precisely how biological evolution might have occurred. His theory of evolution is summarized in the title of his work On the Origin of Species by the Means of Natural Selection (1859). Darwin argued that chance differences among the members of a given species help some survive while others die. Thus the variations that prove useful in the struggle for survival are selected naturally, and they gradually spread to the entire species through reproduction.

Some thinkers applied Darwin’s theory of biological evolution to human affairs. English philosopher Herbert Spencer (1820–1903) saw the human race as driven forward to ever-greater specialization and progress by a brutal economic struggle that determined the “survival of the fittest.” The poor were the ill-fated weak; the prosperous were the chosen strong. Social Darwinism gained adherents among nationalists, who viewed global competition between countries as a grand struggle for survival, as well as among imperialists, who used Social Darwinist ideas to justify the rule of the “advanced” West over their colonial subjects and territories.