Darwin spells out in his introduction his three-fold purpose. He will first consider whether man, like all other species, is descended from an earlier form. Then he will discuss the way man has developed. Finally, he will evaluate the differences among the human races.

Darwin develops his arguments through many examples from a wide range of sources. The first two chapters describe physical correspondences between man and the other vertebrates, concluding that to deny a common descent would be unreasonable. Only prejudice and arrogance, he says, would explain a rejection of this evidence.

Man’s mental powers are compared at length with those of the other animals. Darwin finds many animals capable of some reasoning, and he also finds parallels between man’s use of language and the cries of animals. Most significant, perhaps, are his tentative remarks about man’s religious instincts and the instincts of animals.

Darwin devotes eleven chapters to the principles of sexual selection among animals and to their secondary sexual characteristics. The four chapters on birds give much information on the sexual functions of their plumage, their calls, and their behavior patterns.

The last three chapters are a special section on “Sexual Selection in Relation to Man.” Much of the discussion in this part treats the role of beauty in determining marriages. Darwin also studies marriage customs among primitive people.

In conclusion, Darwin emphasizes that humans are descended from “barbarians.” He compares our ancestors to the natives he had seen on Tierra del Fuego. Rather than being distressed by his findings, Darwin insists that man should feel pride at having ascended from lowly origins.

For Further Review

Clark, Ronald W. The Survival of Charles Darwin: A Biography of a Man and an Idea. New York: Random House, 1984. Comprehensive (more than 400-page) but very readable biography that gives background on the conception, composition, and publication of The Descent of Man. Notes, bibliography, and index.

Desmond, Adrian, and James Moore. Darwin. New York: Warner Books, 1991. Chronicles Darwin’s controversial life; focuses on the critical reception of The Descent of Man within his circle of friends and colleagues and on the business concerns of publishing the book.

Ghiselin, Michael T. The Triumph of the Darwinian Method. Berkeley: University of California Press, 1969. Explores the centrality of The Descent of Man to Darwin’s thought, and in turn, the centrality of the book’s chief theory, sexual selection, to the theory of evolution. Also examines Darwin’s methodology.

Gruber, Howard E. Darwin on Man: A Psychological Study of Scientific Creativity. 2d ed. Chicago: University of Chicago Press, 1981. Gruber traces the development of Darwin’s thinking and his intentionally delayed application of his theories to humanity. Analyzes the central ideas of The Descent of Man.

Hull, David L. Darwin and His Critics: The Reception of Darwin’s Theory of Evolution by the Scientific Community. Cambridge, Mass.: Harvard University Press, 1973. Introductory discussion of Darwin’s inductive methods and such arcane topics as teleology and the empiricist/ rationalist dichotomy. Hull includes letters and reviews from Darwin’s contemporaries.