The history of evolution, or “transmutation,” as it was often termed before Charles Darwin's time, covered a lot of ground between the close of the eighteenth century and the dawning of the twentieth. When the first printed works began to touch on the topic of biological change over time in the natural world, the term “scientist” did not exist. People working on the subject, and writing about the mechanisms of nature more generally, were known as natural philosophers—a term reflective of the widespread belief that the study of nature was a philosophical or religious pursuit, done most meaningfully when its key goal was to reveal the intricate plan of an all-powerful, conscious deity.

At the start of the eighteenth century, understandings of the natural world relied largely upon an ancient concept, the “great chain of being,” which aligned all living creatures into a linear and progressive hierarchy. The chain of being held sway for centuries, and although a number of its conceptual aspects did not match what natural philosophers saw in the world of plants, animals, fossils, and rocks, it retained its sway over people's reasoning about the natural world, leading to a conviction that the various species were fixed and unchanging. Extinction appeared impossible, for God would not allow a creature to disappear from the long, carefully forged chain of being that linked all organisms. A number of Enlightenment thinkers challenged the chain of being, but the fixity of species found a powerful champion in Carl Linnaeus, who catalogued and organized the animal kingdom. However, in the last years of the century, a number of naturalists began to find fault with Linnaeus' system and to argue for biological change over time.

The French mathematician and philosopher Pierre Maupertuis wrote in 1751 about the accumulation of natural modifications over numerous generations, leading to change over time in the form of new species. Georges-Louis Leclerc, Comte de Buffon, treated evolution in a scientific spirit, but his allied investigations helped to reinforce elements necessary to later conceptions of evolution, such as positing an old Earth. Species change required very long periods of time, and Buffon carefully demonstrated the existence of an Earth much older than that put forth in biblical dogma. His Histoire naturelle, générale et particulière (1749–1788) influenced several generations of late eighteenth- and early nineteenth-century scientists. In the opening volumes of the Histoire, Buffon criticized Linnaeus' taxonomic approach to natural history, described a history of the Earth that bore little resemblance to the biblical account, and proposed a theory of reproduction that ran counter to the prevailing theory of preformationism, which held that organisms developed from miniature, fully formed versions of themselves. The fixity of species came under sustained scientific scrutiny at the opening of the nineteenth century, most significantly with the work of Georges Cuvier, who established the certainty of species extinction and argued for a more open-ended view of natural relationships.

In 1844 the Scottish journalist Robert Chambers anonymously published a book titled Vestiges of the Natural History of Creation. A rambling and speculative natural history, the book probed various ideas about transmutation and claimed that everything, including the stars, had evolved from earlier systems. Chambers' book was read by Queen Victoria, Abraham Lincoln, Charles Darwin and members of Darwin's circle, and many others in social, scientific, and political spheres worldwide. It went through a total of twelve editions, but not until the final edition in 1884—fully forty years after the first— was Chambers' identity revealed. Chambers paved the way for Darwin's 1859 Origin of Species and persuaded Alfred Russel Wallace of the transformation of species. While it is possible that criticisms of Chambers' work contributed to Darwin's reluctance to publish his own book quickly, Darwin later wrote that Vestiges “has done excellent service in this country in calling attention to the subject, in removing prejudice, and in thus preparing the ground for the reception of analogous views” (Origin, 3rd ed., 1861, p. xvi).

Charles Darwin began writing obliquely on evolution as early as 1837, less than a year after returning from his five-year voyage around the world on HMS Beagle. He only revealed his ideas about how one species could and did change into another species to close friends such as the geologist Charles Lyell and the botanist Joseph Hooker, preferring to wait until he had amassed a wider body of evidence to support the theory. His grandfather Erasmus Darwin had produced proto-evolutionary writing at the end of the eighteenth century with his book Zoonomia, in which he speculated that the world was millions of years old and argued “that all warm-blooded animals have arisen from one living filament, which the great First Cause endued with animality, with the power of acquiring new parts, attended with new propensities, … and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end!” (vol. 1, p. 505). This statement, of obvious interest to young Charles Darwin, anticipated modern notions of descent from a common ancestor.

The first explicit publication by Darwin on the theory of evolution appeared in brief in the Journal of the Linnean Society of London in early July 1858, accompanied by a piece by the British naturalist Alfred Russel Wallace, which reflected Wallace's similar, but not identical, views on transmutation. The publication of this piece spurred a longer work, and the first edition of Darwin's book On the Origin of Species appeared in 1859. Anticipating public outcry and debate, Darwin carefully avoided explaining the ultimate origin of species, despite the claim to that effect in the title of the book, focusing instead on building a case for the evolution of nonhuman species. The word “evolution” or any variant of it does not appear in the book until the final word: “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved” (Origin, 1859, p. 490). A cautious writer, Darwin buttressed his scientific theory with hundreds of examples culled from correspondence with naturalists from around the world, as well as from many dozens of published works. The book immediately received considerable attention.

Some of the early translations of On the Origin of Species were confounding. For instance, the translator of the first German edition, Heinrich Bronn, had intellectual preoccupations of his own, and felt, for instance, that any discussion of evolution should go hand in hand with spontaneous generation, a topic Darwin had avoided because of its controversial nature. The French translator Clémence Royer, did much the same, adding a long anticlerical preface exploring eugenics and the perils of marriage, and including footnotes that overruled Darwin's caution. Despite these missteps, Darwin knew that foreign-language translations of his works would hasten the spread of his ideas. On the Origin of Species went through six English editions in Darwin's lifetime between 1859 and 1882 and was translated into at least twenty-eight languages.

While On the Origin of Species remains the touchstone for the theory of natural selection, Darwin published many more works on the subject. His works were consistently based on careful methods that were both inductive and deductive, some working from specific examples to form generalized conclusions, and some taking general observations and deriving specific principles of reasoning. Among his other writings was a two-volume work on living and fossil Cirripedia, which ran to more than a thousand pages and established Darwin as the world's leading expert on barnacles. Writing on topics as diverse as orchids and their fertilization, climbing plants, and variation under domestication, Darwin steered a careful course that supplemented his theory of evolution with highly detailed examples in the natural world.

For twelve years Darwin avoided the controversy that he knew would accompany the discussion of evolution in humans. Then, in 1871, he released his two-volume work The Descent of Man, and Selection in Relation to Sex. By then his ideas had gained wider acceptance. “Everybody is talking about it without being shocked,” he noted, which he found to be proof of the increasing liberality of England (Hague, p. 760). The book was the first to explicitly apply evolutionary theory to human evolution, while also extending his writings on sexual selection. In addition, Darwin delved into evolutionary psychology and ethics, differences between human races and the sexes, and the dominant role of women in mate selection. In 1872 Darwin published The Expression of the Emotions in Man and Animals, which further extended some of the ideas put forth in The Descent of Man. This book focused on the inheritance of human characteristics, both genetically from other humans but also in an evolutionary sense from animal predecessors. Public acceptance of evolutionary theory was assisted by the work of Darwin's colleague Thomas Henry Huxley, whose Evidence as to Man's Place in Nature (1863) made the case for the evolution of apes and humans from a common ancestor. While Darwin was a field naturalist, Huxley was an anatomist, and both brought their divergent experiences and scientific knowledge to bear in their writings on evolution.

Darwin's ideas provoked controversy, leading to the publication of numerous opposing books, many polemical and some based on scientific reasoning. For instance, George Jackson Mivart's On the Genesis of Species (1871) laid out a detailed rebuttal to Darwin's claims about natural selection. Darwin's arguments were extended into different spheres by other writers, such as the British physicist John Tyndall, whose Fragments of Science for Unscientific People (1871) argued against the efficacy of prayer. Like many proponents of evolution in debates between scientific reason and religion Tyndall was not broadly antireligious. In fact, many of Darwin's supporters had strong religious beliefs, despite their support of specific evolutionary ideas. For instance, Asa Gray, the most important botanist of the nineteenth century and a close friend of Darwin's, tried to convince Darwin that design in nature stemmed from a higher power, insisting that there was no contradiction between theism and rational scientific investigation. In 1876 Gray published Darwiniana, which sought to reconcile Darwinian evolution and theistic thought.

Evolutionary theory continued to develop after Darwin's death in 1882. Some of these post-Darwinian ideas remain controversial, such as Ernst Haeckel's recapitulation theory, which stated that an individual organism's biological development, or ontogeny, provided evidence of its entire species' evolutionary development, or phylogeny. Haeckel also wrote the popular Natürliche Schöpfungsgeschichte (1868), translated into English in 1876 as The History of Creation. In this work Haeckel argued that evolution consisted of exactly twenty-two stages. But the most significant change in evolutionary theory at the dawn of the twentieth century was the introduction of genetics into the mix of evolutionary theory, and with rapidly increasing sophistication and precision. The question of just how information was passed from person to person and from generation to generation remained a mystery until Gregor Mendel, writing in an obscure natural history publication in 1865, argued that inherited traits were passed along through an assortment of separate elements now known as genes. Mendel's work fell into obscurity but was resurrected by William Bateson in the 1890s. Bateson's seminal Materials for the Study of Variation (1894) triggered the modern study of genetics and led to Mendel's laws of inheritance replacing Darwin's speculative and poorly supported theories about the mechanisms of transfer, which he had called “pangenesis.” Integrated with Darwin's theory of natural selection, genetics led to a much wider acceptance of evolution and made previously held notions, such as orthogenesis and linear progress, obsolete.

The large, vibrant circle of thinkers, supporters, detractors, rationalists, scientists, and rationalizers of religious thought preceding, simultaneous with, and following Darwin created one of the most important bodies of writing on what is perhaps the most significant topic in the history of biology: the evolution of life.

Sources:

• Browne, Janet. Charles Darwin: A Biography. 2 vols. Princeton, NJ: Princeton University Press, 1996, 2002.
• Darwin, Charles. On the Origin of Species by Means of Natural Selection. London: J. Murray, 1859; 3rd ed., with additions and corrections, 1861.
• Darwin, Erasmus. Zoonomia; or, The Laws of Organic Life. 2 vols. London: J. Johnson, 1794, 1796.
• Desmond, Adrian, and James Moore. Darwin: The Life of a Tormented Evolutionist. New York: Norton, 1994.
• Hague, James D. “A Reminiscence of Mr. Darwin.” Harper's New Monthly Magazine 69, no. 413:759–763 (October 1884).
• Mayr, Ernst. The Growth of Biological Thought: Diversity, Evolution, and Inheritance. Cambridge, MA: Belknap Press, 1985.
• Quammen, David. The Reluctant Mr. Darwin: An Intimate Portrait of Charles Darwin and the Making of His Theory of Evolution. New York: Norton, 2007.

—Daniel Lewis, Dibner Senior Curator of the History of Science & Technology, The Huntington Library