The ethical implications of evolution are considerable and require much study. Darwin himself was very interested in ethics and recognized that to make human evolution plausible, he would have to provide an account of the origins of ethics, since most people considered morality a uniquely human trait.

Darwin explained that human moral sentiments differed only in degree, not in kind, from phenomena observable in other animals. These moral sentiments arose from "social instincts" similar to the instincts of ants, bees, wolves, apes, and other animals that live in societies. The social instincts evolved primarily through natural selection, since cooperation aided groups in their struggle for existence against other groups.

In human society, this meant that tribes and societies that had moral virtues, such as loyalty, self-sacrifice, or other altruistic characteristics, would prevail over those without such values. They would then pass on these moral qualities to their offspring.

In summary, Darwin’s theory of evolution poses three distinct challenges to certain religious or ethical beliefs:

Challenge to Biblical Literalism

In Darwin’s day, some defended biblical inerrancy (for example, the seven days of creation in Genesis), and rejected the theory of evolution. But most theologians today accept symbolic rather than literal interpretations of the Bible, although many also insist on the special creation of the human soul. If evolution is God’s way of creating life, does human nature also evolve or is it constant throughout time?

Challenge to Design

Within a static universe, the complex functioning of organisms and their harmonious adaptation to their environments offered a persuasive argument for an intelligent Designer. But Darwin showed that adaptation could be explained by an impersonal process of variation and natural selection. Darwin himself believed that God had designed the whole evolutionary process, but he also believed that morality was based on social instincts that evolved primarily through natural selection. If evolution is God’s way of creating humans, does human morality also evolve or is it constant throughout time?

Challenge to Human Dignity

In classical Jewish, Christian, and Islamic thought, human beings were set apart from all other creatures—a unique status based on belief in the immortality of the human soul and the evidence for human rationality. For some, the idea of descent from the apes is a denial of the value of persons. The “survival of the fittest” concept seems to undercut human ethics—especially considered in a social context. Is human dignity still possible if human beings simply biologically descended from the apes?