The year Lewis and Clark left on their expedition, a British scientist named Erasmus Darwin published his ideas on evolution. Half a century later, his grandson Charles would embark on a journey to the Galápagos Islands and emerge with a theory that would overturn the world.
Charles Darwin was twenty-two years old when he was presented with the opportunity of a lifetime: the captain of the HMS Beagle sought a naturalist for a sea voyage around South America, and Darwin was recommended for the post.
The Beagle, a ten-gun brig refitted as a three-masted bark, sailed from Plymouth, England, in 1831, for a voyage of two years. The journey would in fact last five years, during which time Darwin explored the South American continent and the Galápagos islands, riding with gauchos in Argentina, making his way through political rebellions, and embarking on shooting expeditions. He once saved the expedition by rescuing a boat from a tidal wave. For the young Victorian gentleman with scientific aspirations, it was, as he had written Captain FitzRoy in his letter of acceptance, a “second birth.”
Darwin collected nearly ten thousand specimens of plants, animals, rocks, and fossils while traveling on the Beagle, and sent them back to England in box after box. The information he recorded in a detailed log of his discoveries would sustain years of study and publication, and prove seminal to his theory of evolution.
“The result of it all is published in The Origin of Species and his other works,” says Frederick Burkhardt, founder and general editor of the Correspondence of Charles Darwin project. “But you don’t know how he got there, except through his correspondence.”
The project is making available for the first time the complete, authoritative texts of Darwin’s correspondence--a total of fifteen thousand letters, five thousand of which he penned, and the remainder, which he received.
“Darwin’s letters are not incidental to his life by any means,” says Alison Pearn, an editor at the project’s site in Cambridge. “They were actually the primary tool for gathering the information that he was using to back up his theories, to develop new theories, and to refine theories.”
When Darwin commenced his first notebook “for facts in relation to The Origin of Species” upon his return from the Beagle voyage, he began collecting observations on natural and domestic variation, and geographical distribution and isolation. His 1859 volume The Origin of Species would draw heavily from the previous two decades of recorded data. Darwin revised his book repeatedly, taking into account criticisms and further discoveries, and it eventually reached six editions.
From horse-breeders to society ladies, gardeners to army officers, and from Welsh hill-farmers to his own sons and daughters, Darwin kept in contact with anyone who could aid his research on natural selection.
“Once he got the notion of natural selection, he knew he was going to have to have a great deal of evidence for it and he would have to get it from all sorts of people, all sorts of experts,” says Burkhardt.
Mail was fast and reliable, and Darwin wrote letters as a matter of course. He maintained a constant dialog with other scientists, recounting in great detail how he pursued his research, formulated hypotheses and arrived at conclusions, and the problems he encountered. The letters show Darwin to be a questioner, an observer, and a synthesizer, and reveal his doubts and false starts as he formulated his theories.
Darwin was the son of a distinguished medical doctor and the grandson of the physician Erasmus Darwin, who set out his own theories concerning evolution in his book Zoonomia, or the Laws of Organic Life. While Charles Darwin was studying medicine--a discipline for which he had little enthusiasm--he befriended a zoologist and a geologist and was introduced to their fields. When medicine did not prove to be his forte, his father sent him to study divinity at Cambridge instead. There, his cousin William Darwin Fox, an entomologist, opened scientific circles to him and arranged for him to meet botanist John Stevens Henslow, who encouraged Darwin’s interests and eventually recommended him to the captain of the Beagle.
Fox also imparted to his cousin a lifelong interest in beetles. Darwin once wrote to him of the frustrations of the lone collector: “I am dying by inches, from not having any body to talk to about insects.”
The year he left Cambridge, Darwin set sail on the Beagle, bringing a copy of Charles Lyell’s Principles of Geology with him. The book influenced him greatly and Darwin became convinced of Lyell’s view that changes in the earth were the result of an accumulation of events such as volcanic eruptions, earthquakes, and erosion.
While on the Beagle voyage, Darwin witnessed volcanoes, earthquakes, and coral reefs firsthand and interpreted his observations as evidence for Lyell’s theories. He wrote to his cousin William Fox, “Everything in America is on such a grand scale. The same formations extend for 5 or 600 miles without the slightest change--for such geology one requires 6 league boots.”
At first Darwin was insecure about his lack of experience and worried that his travels were wasted on him. In 1834 he wrote to Henslow back at Cambridge, disparaging his own theories: “I have not one clear idea about cleavage, stratification, lines of upheaval.--I have no books, which tell me much & what they do I cannot apply to what I see. In consequence I draw my own conclusions, & most gloriously ridiculous ones they are.”
Nonetheless, Henslow took Darwin’s theories seriously, and went so far as to read passages of the young man’s letters aloud to the Cambridge Philosophical Society and the Geological Society of London. When he returned to England, Darwin would find that his fame had preceded him.
Being given to serious bouts of seasickness, which he combated by lying in a hammock aboard ship, Darwin spent as much time ashore as possible. In his first letter to his father from the Beagle, he writes, “The misery I endured from sea-sickness is far far beyond what I ever guessed at . . . I must especially except your receipt of raisins, which is the only food that the stomach will bear.” But he remained undaunted, and in the same letter extols the beauty of the tropics: “Nobody but a person fond of Nat: history, can imagine the pleasure of strolling under Cocoa nuts in a thicket of Bananas & coffee plants, & an endless number of wild flowers. . . . It would be as profitable to explain to a blind man colors, as to a person, who has not been out of Europe, the total dissimilarity of a Tropical view. . . . So you must excuse raptures & those raptures badly expressed.”
“I cannot express the delight, which I felt at such a famous winding up of all my geology in S.-- America.--I literally could hardly sleep at nights for thinking over my days work,” he wrote his sister from Valparaiso. “The scenery was so new & so majestic: every thing at an elevation of 12000 ft. bears so different an aspect, from that in a lower country.--I have seen many views more beautiful but none with so strongly marked a character.”
By 1835 his earlier tentativeness had nearly vanished. “There is a strong presumption (in my own mind conviction) that the enormous mass of mountains… are so very modern as to be contemporaneous with the plains of Patagonia,” he wrote his sister. “If this result shall be considered as proved it is a very important fact in the theory and formation of the world.”
The South American coral reefs Darwin encountered caused him to challenge some of Lyell’s views on geology, and brought him to a crucial point in the progression of his theories. He examined many fossils, including those of armadillos and even a woolly mammoth, which he believed suggested a similarity between extinct species and living ones. This reflection led him to wonder by what process new species took the place of extinct ones. He began collecting data to answer his questions about “the species problem.”
When Darwin returned to England, he left aside fieldwork and worked on analyzing and evaluating his Beagle discoveries. By virtue of his letters and Henslow’s support, he was warmly welcomed into scientific society. As he set about publishing his discoveries, he made use of this network to gather additional data. He made many of his requests in letters, and was not shy about asking fellow scientists to send him specimens or share their observations.
“People think of Darwin as a man who went around as a youth on the Beagle and this was his great period of discovery and research,” says editor Paul White. “He used correspondence to keep traveling around the world. He had a network of correspondents around the world--China, India, North America--and he drew heavily on the information he got from these correspondents throughout his life. He kept casting his net wide even after he retired to a quiet village in England.”
Although Darwin is best known for his work on evolution, he made advances in a variety of scientific disciplines. “Geology to zoology to botany, and along the way anthropology and cognitive psychology,” says Duncan Porter, project director and professor of botany at Virginia Tech. “He’s a real pioneer in all of these subjects. We biologists think of him as a biologist. Geologists think of him as a geologist. Cognitive psychologists say he influenced their field too.” After publishing books on topics such as the geology of South America and barnacles, Darwin devoted his attention to the question of how species came to exist in their current forms.
In English society at the time, the creation of new species was believed to be an unequivocal demonstration of the spirit of God. Darwin was poignantly aware that his idea of the evolution of species contradicted Christian belief in divine creation and could be considered blasphemous or seditious under current laws. In an 1844 letter to Joseph Dalton Hooker, his lifelong friend and critic, he writes, “I am almost convinced. . .that species are not (it is like confessing a murder) immutable. Heaven forfend me from Lamarck nonsense of a ‘tendency to progression’. . .but the conclusions I am led to are not widely different from his--though the means of change are wholly so.”
Fifty years previously, the French biologist Jean-Baptiste Lamarck had sketched out the first diagram of evolution, in the form of a ladder that ascended from one-celled organism to human being. As Darwin alluded in his letter, Lamarck believed that an “inner feeling” toward perfection caused spontaneous generation in organisms. Darwin’s own diagram of evolution was that of a branching tree, and according to his theory, competition within a species led to the prevalence of individuals with characteristics advantageous to survival.
Darwin had discovered patterns of similarity between animals inhabiting different continents. He had found that the tortoises of the Galápagos Islands were not native to the American continents, and that some birds from the islands, such as mockingbirds and finches, belonged to entirely different species than those of nearby continents. Synthesizing the ideas Thomas Malthus set forth in his Essay on the Principle of Population, which states that population increases geometrically while food supply increases arithmetically, thereby limiting population growth, Darwin arrived at the conclusion that “favourable variations would tend to be preserved, and unfavourable ones to be destroyed….The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work.”
He did not choose to apply his theory to the evolution of humans, however. “You ask whether I shall discuss ‘man’;--I think I shall avoid whole subject, as so surrounded with prejudices, though I fully admit that it is the highest & most interesting problem for the naturalist,” he wrote in a letter. He did perform extensive experiments on variation, breeding, and geographic transport of organisms, to discover such things as how long seeds in salt water remained capable of germinating, or whether small eggs could be carried in the mud on birds’ feet, or pass through their digestive tracts and still be viable.
Darwin delayed publishing his theories for many years. In 1844 he wrote his wife, “I have just finished my sketch of my species theory. If, as I believe that my theory is true & if it be accepted even by one competent judge, it will be a considerable step in science. I therefore write this, in case of my sudden death, as my most solemn & last request. . .that you will devote 400 £ to its publication & further will yourself, or through Hensleigh, take trouble in promoting it.”
Fourteen years later, as Darwin was still developing his theories for Origin of Species, another British scientist, Alfred Russel Wallace, also came upon the idea of natural selection. He, too, had read Malthus and connected his ideas with what he himself had observed. While in the Malay archipelago, Wallace had noted a similar phenomenon to what Darwin had seen in South America: the fauna of the western islands resembled that of Asia, while population of the eastern islands was related to that of Australia. The border marking this discontinuity would later be named “Wallace’s Line.”
Wallace and Darwin published a joint paper on the topic, and some controversy has persisted regarding the authorship of the idea. The two men had corresponded as colleagues for some time before the publication of their paper. Darwin had written about his development of a theory of natural selection to scores of scientists, including Wallace. Before Darwin could complete his work, Wallace sent him his paper on the same theme.
I never saw a more striking coincidence,” Darwin wrote to Lyell, whom he had befriended. “if Wallace had my M.S. sketch written out in 1842 he could not have made a better short abstract! Even his terms now stand as Heads of my Chapters. So all my originality, whatever it may amount to, will be smashed.”
Darwin offered to help Wallace get his paper published. “It’s always been a mystery why Wallace sent this to Darwin and not to a journal for publication,” says Porter.
New evidence regarding this controversy has come to light through the Darwin correspondence project. Three years ago, Wallace’s grandson invited Porter to read some of Wallace’s remaining letters and manuscripts. Porter found a letter from Wallace addressed to a colleague, which said, “I just heard from Charles Darwin that he is working on transmutation but won’t publish for two or three more years. We can send him the information we’ve gathered in South America on this subject.”
“The letter was published in 1905, but people just haven’t picked up on it,” says Porter. “Now we can see why Wallace sent Darwin his material.”
Wallace himself deferred to Darwin as the author of their theory, and the world has concurred, largely because Wallace only sketched out the theory, while Darwin collected the evidence to prove it. “Wallace always used to say in correspondence to Darwin: ‘In your theory,’” says Porter. “And Darwin would say it is our theory.”
The first edition of Origin of Species sold out immediately. Darwin received great response to his theory from the press and from learned circles. Prominent scientists wrote to him, criticizing his views for not accounting for phenomena such as beauty; others opposed the potential application of Darwin’s theories to humans. Some wrote to him in praise, such as a teacher named James Shaw: “Newton’s ocean of wonder on whose shore he gathered shells seems no longer a dark unnavigable sea crested with howling breakers. Here and there through its awful bosom the strong vision with which you have supplied us enables us to see at least that there are other islands whose conditions are explicable by our own.”
When one scientist told Darwin he had “stuck up” for The Origin of Species to the Council of the Royal Society of London, Darwin replied, “Your letter is by far the grandest eulogium, which I have ever received, or shall ever receive; and if one half, or one quarter be true and not exaggerated by your great kindness, I may well rest content that I have not laboured in vain.”
Throughout his life, Darwin remained active in upper-class English society and was a member of fiftyseven foreign learned societies at the time of his death in 1882.
The project has delighted Darwin enthusiasts, scientists, and biographers. “It is the greatest store of knowledge of Darwin’s mind and character, of his way of working, of his family and personal relations with hundreds of scientists and friends on whom he drew for information,” says Burkhardt.
Twelve volumes of correspondence have already been published. Volume 13, which appears in November, is comprised of letters from 1865, when Darwin was fifty-six years old and preparing The variation of animals and plants under domestication, a response to criticism of his theory of evolution. The volume includes a supplement containing 106 letters that were written before 1865 but were discovered after the publication of the volumes in which they ought to have been published: a few from Darwin’s adolescence, and more than half from the period before the publication of Origin. The remaining letters, dating from 1865 through Darwin’s death in 1882, will be edited and published through 2024, for a total of thirty-two volumes.
Darwin once jotted in a notebook: “Mention persecution of early astronomers--then add chief good of individual scientific men, is to push their science a few years in advance only of their age.”