CHARLES DARWIN: THE MAKING OF A NATURALIST

Charles Darwin was born on 12 February 1809, in Shrewsbury, a pleasant market town in the English West Midlands. He was the fifth child, and second son, of Robert Waring Darwin (1766–1848) and Susannah Wedgwood Darwin (1765–1817). His father was a successful physician in Shrewsbury and was himself the son of Erasmus Darwin (1731–1802), physician, inventor, poet and theorist of evolution. His mother was the daughter of Josiah Wedgwood I (1730–95), founder of the famous pottery to which his name is still attached. Darwin thus had a very solid pedigree, intellectually, socially and financially. His mother died when he was eight years old, and historians have sometimes attributed Darwin’s later health problems to the maternal deprivation he suffered as a child. There is no direct evidence for this, however; his mother was forty-three when he was born, and his elder sisters took on the role of mothering him after her death. More important for his future career was the financial security that Darwin always enjoyed. His father’s lucrative medical practice and shrewd investments added to the family fortunes; his father watched his pennies and pounds, as did Charles.

Save for his mother’s death, Darwin enjoyed a pretty uneventful childhood. He enjoyed country pursuits, shared a chemistry set with his elder brother, and was from an early age an avid collector of natural objects. He was, as he himself put it, ‘born a naturalist’, and with the collector’s passion for the objects that he acquired. That passion always meant trying to understand, and not just admire, the specimens in his possession. He was described as an ordinary student at Shrewsbury School, and his father famously once rebuked him with the remark, ‘You care for nothing but shooting, dogs, and rat-catching, and you will be a disgrace to yourself and all your family.’⁵ Despite the comfortable finances that the family enjoyed, boys were expected to have a career, and Darwin was packed off to the University of Edinburgh in 1825, aged sixteen, to follow his father and grandfather into medicine. He lived with his brother (another Erasmus), also a student at the university, but the mediocre lectures and his experience in an operating theatre convinced him that he did not want to become a doctor. His two years in Edinburgh did, however, provide him the opportunity to extend his interests in natural history, as much through his own reading, collecting and participation in a student natural history society as through the formal lectures, which he rarely attended. Instead, he spent hours collecting sea creatures on the shores and in the rock pools of the Forth of Firth. He also made friends with the biologist Robert Grant (1793–1874), then obsessed with sponges and already persuaded by the transmutationist ideas espoused by the French naturalist Jean-Baptiste de Lamarck (1744–1829). Lamarck’s influence on Darwin’s later thinking was not especially great and Grant himself remains a shadowy figure in Darwin’s life. They briefly moved in similar circles in London from the late 1830s, but only one letter survives, and Darwin certainly left Edinburgh with traditional beliefs about the fixity of biological species.

If natural history was Darwin’s passion, the only thing for it was a career as a country clergyman, a profession that would offer him the leisure time to follow in the footsteps of many previous parson-naturalists. Consequently, Darwin was sent to Cambridge University in 1828. His life there was undistinguished academically, but he was able to continue his real love for studying the earth and its creatures. Sea creatures in Edinburgh gave way to beetles in Cambridge. In addition, J. S. Henslow (1796–1861), the professor of botany (and a clergyman), treated him like a son and reminded him that plants as well as animals were worthy of investigation. Darwin made several lifelong friends in Cambridge, and the professor of geology, Adam Sedgwick (1785–1873), also a clergyman, taught him about geology, particularly during a trip they took together to Wales, a country rich in land forms and fossils.

We can only surmise that Darwin would have unwillingly obtained a living in the Church of England after graduating from Cambridge in 1831, save for a fortuitous turn of events. Captain Robert Fitzroy (1805–65) was about to leave on a voyage on HMS Beagle, to map and chart South American and Pacific waters, among other aims. He invited Henslow to be his travelling companion, as a gentleman naturalist on board (there was already an official naturalist). Henslow, a married man with a family, reluctantly declined but recommended Darwin instead. Darwin was ecstatic at the prospect but his sober father objected that such a voyage was dangerous and would further delay his son’s settling-down into a career. The young Darwin convinced his father to let his uncle, Josiah Wedgwood II, cast the deciding vote and the uncle prevailed on Dr Darwin to let his son accompany Fitzroy.

It was the defining moment of Darwin’s whole life, and a turning point in the history of biology. We cannot of course know whether Darwin would have become an evolutionist without the Beagle voyage (although he probably would), but the Origin would not have been the same book. These five years, from 27 December 1831 to 2 October 1836, provided Darwin with experiences and insights that would stay with him all his life. That voyage was ‘by far the most important event of my life and has determined my whole career’.⁶

It was not all plain sailing, however. Waiting for weather suitable for embarkation from Plymouth, Darwin suffered from heart palpitations and thought he was about to die. He never acquired his sea legs and suffered from seasickness for much of the time. Darwin was tall and the ceilings of the Beagle low; although he was given special considerations (dining with the captain, for instance), his living and working conditions were cramped. The daily life among sailors would have been novel for a man of Darwin’s social and economic circumstances. For their part, the crew treated Darwin with ironic affection, dubbing him ‘Philos’, the Philosopher, or the Flycatcher.

Despite the uncomfortable aspects of his voyage, Darwin had approached it systematically, taking with him equipment for collecting, studying, preserving and shipping back to England specimens that he expected to find on his adventure. In addition, he acquired a copy of the first volume of Lyell’s Principles of Geology, just published in 1830. The later volumes came to him during the voyage, and he always looked geologically through Lyell’s eyes. Sedgwick had approached the geological history of the earth as a ‘catastrophist’, following the dominant geological doctrine of the 1820s, in which earth history was conceived as consisting of long periods of stability punctuated by short periods of violent geological and biological change. In the 1820s, most geologists still assumed that the last great catastrophe was the biblical flood of Noah, following which the present relatively stable era had begun. These periodic catastrophes had destroyed life wholesale, and then had been followed by the wholesale creations of plants and animals.

This vision of earth history was providential, postulating that God’s design had gradually prepared the earth for human beings; it explained the sharp breaks in fossils as one went back through the strata, and the fact that fossils from younger strata possessed forms more like those of existing species. This powerful theory had much to recommend it. It accepted that the earth was of great antiquity, made sense of the breaks in the fossil record, allowed for the emergence of the major biological groups (invertebrates, fish, reptiles, birds, mammals), and kept a central place for special creations by a deity who saw the whole scheme in advance. It made the appearance of man the central event in earth history. It incorporated the most up-to-date palaeontology and geology of the 1820s, and could (with an allegorical reading of Scripture) reconcile Genesis and geology. It was the geology that the Reverend Adam Sedgwick would have taught Darwin both at Cambridge and when they were exploring the Welsh mountains together.

Lyell challenged this reading of earth history. Adopting what was called the ‘principle of uniformitarianism’, he argued that the geological forces now observed (earthquakes, volcanic upheaval, erosion by wind and water, and so forth) were sufficient to explain the past geological history of the earth. He depicted an active present, not a dead present and a catastrophic past. He also argued that there was no real progress in the geological record. Countering the view of biological history that the catastrophists adopted, that the fossil record revealed a steady progression to the present era of mankind, Lyell believed that the overall message of fossils was that all major groups (fish, reptiles, birds, mammals) had always been present, for all we can say. Older fossil-rich strata were subjected to degradation by heat, pressure and other forces. Thus, the fossil record is very fragmentary, but the occasional unexpected finding, like that of a fossil mammal (akin to the opossum) in an old secondary stratum in Stonesfield, Oxfordshire, meant that mammals had long inhabited the earth. This second aspect of Lyell’s ‘steady-state’ notion of the ancient earth was even more controversial than his insistence that present geological forces had always been present, in their same intensity. Nevertheless, his discussions of the paucity of the fossil record, when compared to the richness of life in geological time, were mined by Darwin in Origin.

For the young Darwin aboard the Beagle, however, Lyell offered a way of viewing the exotic parts of the world that Darwin saw. Not all of it was water, although the sea provided much material for his microscope and collecting jars. Fortunately for his seasickness, in South America, both the east and the west, Darwin went ashore for long periods, where he was able to observe geological features and collect fossils and living plants and animals. He felt he was walking in the footsteps of Alexander von Humboldt (1769–1859), whose Personal Narrative of travels to the Equinoctial Regions of the New Continent during the years 1799–1804 had been presented to Darwin by Henslow just before he left on the Beagle. Humboldt remained one of Darwin’s heroes and, in a wonderful act of mutual admiration, Humboldt sent Darwin a letter full of insight and praise after the young naturalist presented him with a copy of his own Journal of Researches (1839), the published volume describing his Beagle years.

That was in the future. For the days and months of 1832 and beyond, the Beagle was home. From the multitude of experiences, four stand out in retrospect. First, there were the three natives of Tierra del Fuego on board, being transported back in triumph from a previous visit to that desolate coast of South America. Two men and one woman, they had been brought to England to be taught English, how to wear clothes and become Christians. They were to become the seeds of a new civilization in their native land and were accompanied by a young, earnest missionary. Darwin was a man of his time and class, and we should not sentimentalize his reactions to the Fuegians on board. Nevertheless, he always loathed both slavery and cruelty, and was in for a shock at what happened when the Beagle deposited their charges in Tierra del Fuego. ‘The sight of a naked savage in his native land is an event which can never be forgotten.’⁷ The off-loading completed, the Beagle sailed on to chart coastal waters. It returned four weeks later to check on Matthews, the missionary. He was miserably bedraggled and desperate to rejoin the ship; the three Fuegians had all returned to their natural life, the refinements they had had painted on them in England gone. Darwin never forgot how close ‘civilization’ and ‘savagery’ are; the ‘natural’ human beings he observed on Tierra del Fuego remained an image he often recalled, and would be integrated into his later works on human evolution.

A second major source of inspiration for his later work was the remarkable congruencies between the fossils that he collected on the South American mainland and the living species that he found there. In Patagonia, the armadillo especially impressed him, both in its characteristics and its relationship to similar-looking fossils he uncovered that clearly were not of the same species. The extant armadillo was prized as a game animal and Darwin appreciated its flesh. He found many other fossil bones there, commenting that ‘the Pampas is one wide sepulchre of these extinct quadrupeds’.⁸ They were as strange as the living species, and seemed to be somehow related.

A third incident made Darwin appreciate the cogency of Lyell’s vision of a world that was still active geologically. His very first geological encounter on the Beagle voyage, a copy of Lyell at hand, was at Saint Jago, in the Cape Verde islands; two years later, off the coast of Chile, he witnessed a massive earthquake that visibly raised the coastline. Here, indeed, was evidence of major formative forces still at work.

A fourth series of observations acquired crucial significance only later, when Darwin was back in England sorting out the thousands of specimens he had dispatched back during his voyage. In 1835, the Beagle sailed to the Galapagos archipelago, 500 miles off the west coast of South America. Darwin explored the islands, full of giant turtles, lizards and birds. He met a man who could identify the island from which a turtle came merely by its markings. The wildlife was very tame and easily collected, but Darwin failed to label the particular island from which he took his specimens. Nevertheless, he noted that each island seemed to have its particular flora and fauna, even though the islands were obviously recent geological formations. The individual islands seemed so many little Edens, albeit desolate and inhospitable ones. Even then, Darwin was amazed: ‘Here,’ he wrote, ‘both in time and in space, we seem to be brought somewhat near to that great fact – that mystery of mysteries – the first appearance of new beings on the earth.’⁹ The Galapagos still occupy a special place in evolutionary history, even if the problem the islands now face is one of conservation.

The Beagle continued westward after the Galapagos stopover, visiting New Zealand and Australia, and returned via the Cocos (Keeling) Islands, where Darwin consolidated a theory that had long been in his mind: how coral reefs are formed. After a brief stop at the Cape of Good Hope, the compulsive Fitzroy insisted on a detour to South America again. At last, the Beagle headed for home: ‘never was a ship so full of homesick heroes…’; ‘I loathe, I abhor the sea, and all ships which sail on it. But I believe we shall reach England the latter half of October,’ Darwin wrote to his sisters.¹⁰ They were early, and on 2 October 1836 Darwin left his home for almost five years at Falmouth and made straight for Shrewsbury. He returned to England at the dawn of the railway age.

THE UNLIKELY REVOLUTIONARY

Darwin came back from his long adventure a convinced Lyellian in geology. He was probably still a Lyellian in his biology, too. Lyell provided a long critique of Lamarck’s theories in the second volume of his Principles, which Darwin read on board the Beagle. Lyell offered a powerful account of biological extinction, not as some wholesale event but as a piecemeal and ordinary occurrence, which happens when the last members of a species are unable to reproduce, because of changed environmental circumstances or mere attrition of numbers. The logic of Lyell’s position required that the introduction of new species was also a normal, regular event. He recognized this, and argued that it did, indeed, regularly occur, although by some unknown mechanism, and so rare an event that the fact that nobody had ever observed a new species coming into existence was unsurprising. It became apparent later that Lyell refused to close his logical circle because of concern for the special character of mankind as a moral, rational being.

All the evidence suggests that Darwin returned from his journeys still believing in the traditional assumption that biological species are fixed. In any case, there was plenty of work to be done, getting his specimens sorted and described and writing up his journal for publication. After visiting his family, he spent a few months in Cambridge before moving to London. Revelling in the fact that the regular shipments of specimens he had sent back to England were much appreciated, and that he was now acknowledged as a fully fledged man of science, Darwin threw himself into the buzz of scientific London. He made friends with Lyell and other leading figures, joined several scientific societies, including the Geological Society, and in 1839 was received into the inner sanctum of the scientific community, the Royal Society.

In early 1837, too, he began privately to consider that mystery of mysteries, the coming into being of new species. He knew that Grant, Lamarck and his own grandfather, Erasmus Darwin, did not believe that species were eternally fixed. The younger Darwin began to doubt it, too, and in July he opened a series of ‘species notebooks’ in which he put down his thoughts on the subject: reflections on Beagle experiences, notes from his reading, conversations with his father, and frank speculations about the nature of sex, life and religion. They were meant for his eyes only, but they have been much studied in recent times for evidence of the growth of his thinking, as examples of his scientific creativity and as important insights to the inner Darwin. Two special notebooks were devoted to man, proof that from the very beginning Darwin recognized that Homo sapiens was the product of the same forces that had produced the other organisms of the living world.

Along with his work on his Beagle-related publications, Darwin read widely about the species question. In September 1838, he picked up a copy of An Essay on the Principle of Population (1798) by Thomas Malthus (1766–1834). Like Darwin, Malthus has become a part of the English language, through the adjectival form of his name, Malthusian, which is still used to refer to the struggle for resources in all organisms whose capacity to reproduce is always greater than can be sustained. Darwin would have heard his name frequently mentioned in conversations, since his brother Erasmus, whom he saw regularly during this period, was friendly with Harriet Martineau (1802–76), the radical writer on many topics, including history, political economy and improving tracts. Malthus was one of her subjects and Darwin met her a few times at Erasmus’s house. In his Essay, written primarily about the effects of poverty and its relief, Malthus elaborated a general principle about the relationship between reproductive capacity and resources. In a neat reversal of the later structure of the Origin, which was about the biological kingdom but omitted mankind as a referent, Malthus wrote principally about human beings, but generalized his population principle to the world at large. The reproductive capacity of all organisms, human beings as well as elephants, flies and oak trees, is vastly larger than the actual survival of their offspring. Unchecked, any species could produce enough offspring to fill all space, given enough time. The reason for this is that reproduction is geometrical, doubling every so many years. If a single oak tree produces several thousand acorns every year, or a rabbit a brood of half a dozen twice a year, it is easy to see that not all of them can survive. There must be a reason why some of them survive while others do not. Plants and animals certainly vary, and if their variations are in some degree inherited, then Malthusian logic suggests that the survivors have some characteristic – strength, ability to run faster, more fitness – than their comrades. Malthus provided Darwin with the principle of natural selection: ‘Here, then, I had at last got a theory by which to work.’¹¹

Darwin’s private species notebooks changed their character after his reading of Malthus. They became more focused, as he mined books and articles on breeding, pursuing the analogy between artificial selection – by which animal and plant breeders change the nature of organisms by selecting those with desirable characteristics to be their breeding stock, thereby producing dramatic changes in their size, form or ability to survive in differing conditions. He also began to think about breeding in another sense: marriage. Darwin’s bachelor years in London were productive but lonely and, in characteristic fashion, he debated with himself the pros and cons of marriage. It was a male, egocentric view, although he became a loving and caring husband and father. Against the demands that a wife and children would make on his work, he concluded that the companionship and stability were worth the effort: ‘Marry, marry, marry,’ he decided, after totting up the pluses and minuses. And the choice was not far to seek: his cousin and childhood friend, Emma Wedgwood. They married on 29 January 1839: bride and bridegroom were both past the first flush of youth. Darwin was just short of his thirty-first birthday, and his bride was nine months older than him.

Marriage changed the nature of Darwin’s daily life, but it hardly slowed his productivity. He continued work on the separate volumes of his geological work on the Beagle, published as monographs in 1842 (Coral Reefs), 1844 (Volcanic Islands) and 1846 (Geological Observations), and helped with the descriptions of his zoological specimens, appearing in parts between 1838 and 1843. The most important revelation to Darwin in his dealings with the naturalists actually producing the official volumes of the Beagle’s voyage was John Gould’s conclusion that each of the finches Darwin had collected from the various islands of the Galapagos was actually a different species. This was dramatic grist for his transmutationist mill: evidence that in differing ecological conditions new species emerged. These and other speculations and nuggets from his wide reading found their way into his private notebooks. By 1842, he had enough material and thoughts to allow himself the luxury of a brief sketch of what he increasingly called ‘my theory’. In 1844, he turned this into a substantial ‘essay’, which is in essence the Origin in outline. He wrote it in private and made arrangements in his will for its publication should he die before it saw the light of day. Any desire to burst quickly into print would have been dented by the hostile reaction to the publication, in 1844, of an anonymous work on evolution, Vestiges of the Natural History of Creation. Much of the author’s science (he is now known to have been Robert Chambers, an Edinburgh publisher and naturalist) was shaky, and establishment scientists responded firmly and negatively. Other would-be scientists, such as Herbert Spencer and Alfred Russel Wallace, found it liberating. Darwin sided with the establishment, but, since he was also thinking heretical thoughts about the mutability of species, he turned his attention elsewhere.

By 1844, when Darwin wrote his own essay, he and Emma had moved from London to Down House, in the village of Downe, Kent (the spelling of the village changed from Down to Downe in 1844). His health, which had deteriorated in earnest shortly after his marriage, had come to dominate his life, and Down House, with Emma, the growing family and a troop of servants, provided the bedrock on which he anchored his daily existence. Darwin’s ill health has provided later commentators with much puzzlement. It was certainly real and frequently debilitating. His regular symptoms included dry retching, weakness and skin eruptions. He had periods of relatively good health and periods of serious incapacitation. A number of modern diagnoses have been put forward, including: Chagas’s disease, a parasitical infection he might have picked up in South America; arsenic poisoning from medication; infection with helicobacter, the organism now shown to cause many instances of peptic ulcer; maternal deprivation; and anxiety attacks. The symptoms are certainly compatible with an overactive autonomic nervous system, but the cause or causes will probably never be known.

Darwin’s illness certainly impinged on his life: much of his limited travel after he settled at Down House was to spas, in search of a regime that would cure him. His letters are full of his symptoms and the way they curtailed his work. He even kept an intermittent diary of his daily, even hourly symptoms. His health has to be taken seriously, but it ought to be put in the context of his life and achievements. He married relatively late but fathered ten children, seven of whom survived to adulthood. He worried constantly that he had given them his bad constitution, but they mostly thrived: three of his sons became Fellows of the Royal Society, a fourth a prosperous banker, and a fifth an active man of letters. Only the death of his eldest daughter, Annie, aged ten, interrupted the progress of family life. His description of her short life and death brought forth some of the most heartfelt prose he ever wrote.

In addition to his children, he produced almost twenty separate books (most of which went through multiple editions), dozens of scientific papers, and thousands of letters. For much of his life, doctor’s orders dictated that he could work only two or three hours a day, and Emma was there to enforce them. How remarkable were those hours! Whatever the sources of his illness, he shrewdly turned it to his advantage, living the life he wanted to, with minimal interruptions and deviation from routine. He was utterly devoted to his wife and family; he was equally devoted to his life’s work.

By the mid-1840s, Darwin’s life at Down House had settled into its permanent routine: improvements on the house; the regular birth of children; the coming and going of servants; the constant presence of Parslow, Darwin’s personal servant; letters; work; reading by Emma; and occasional visits from scientific friends and more frequent ones from relatives. It was broken only by occasional trips to London and stays in spas, in search of health. Having circled the globe for five years, Darwin never again left Britain. The work of the Beagle completed, his essay on evolution safely tucked away, and his reputation as a man of considerable scientific standing established, Darwin turned to a strange project: a study of barnacles, both living and fossilized. His old teacher Henslow had always said that a naturalist ought to study some group thoroughly, and Darwin had long been fascinated by barnacles. They come in a variety of forms, have wonderfully different adaptations to their conditions of life, possess an array of reproductive mechanisms, and are well represented in the fossil record. He thought the project would take him three or four years; in the end, it took twice as long, yielded four substantial volumes and drove him almost to despair, so endless was the work. He made new friends with the few barnacle enthusiasts around, borrowed specimens from collections all over the world, and sent old friends to collect new ones for him. Some of these old and trusted friends, especially Joseph Hooker, botanizing in British India, urged him to finish this work quickly and get back to his work on evolution. Hooker, who knew of Darwin’s 1844 essay, saw how powerful an explanatory tool natural selection was, but he was sworn to secrecy. Darwin’s dogged determination took him through, and he was at last free, in 1854, to return to evolution proper. In retrospect, we can see that the barnacle work was actually very important to him, although the volumes themselves have to be read with hindsight to perceive their evolutionary message.

Darwin’s ‘big book’, as he sometimes called it, bore the tentative title of Natural Selection. It was to be a large work, properly referenced within the standards of Victorian convention, and clearly aimed at a specialist audience. Darwin was always concerned with the reaction to his ideas of colleagues and those who had the capacity to judge them on their scientific merits. He never courted popular acclaim even if he actually became the most famous scientist in Britain. Instead, while writing Natural Selection, he reported progress to his closest confidants, especially Lyell and Hooker. He worked slowly and methodically, revising earlier chapters as he completed later ones. By mid-1858, he had completed ten chapters, covering about two-thirds of the topics he would later deal with in Origin. The manuscript stood at about 225,000 words. Then, in mid June 1858, the postman brought him a packet that had been posted almost three months earlier, from halfway around the world. It was from Alfred Russel Wallace, and was sent to Darwin because Wallace knew of his interest in the species question. They had already corresponded about natural history topics, and Darwin had encouraged Wallace in his work in Malaysia, where Wallace had been for four years, collecting and exploring. Wallace had, like Darwin, also spent time in South America, but, coming from a less privileged background, he was self-taught and had been obliged to rely on his own resources to make his way in the world. In his letter, Wallace enclosed a short sketch of how species might change over time through the selective pressures of surviving and reproducing: natural selection, in other words. Wallace’s insight had also come through his reading of Malthus, although the essence of his theory was conceived during a malarial fever fit. It was almost as if Wallace had read Darwin’s earlier sketch and was summarizing it.

It is no exaggeration to say that Darwin’s intellectual world crumbled that day. He had had the insight about the power of natural selection to explain so many things two decades previously; his full essay on the subject was almost fifteen years old. He confided to Hooker at the time that believing species were not immutable was ‘like confessing a murder’.¹² The more he worked on geology, barnacles, plants and pigeons, the more convinced he was that his theory was of fundamental importance to our understanding of the world. Now, even as his big book was actively being written, his main ideas had been duplicated by Wallace. His despair is easy to appreciate. His old friends Lyell and Hooker, in whom he immediately confided, devised what they felt was an equitable solution, although without Wallace’s approval. Wallace’s communication, along with portions of Darwin’s earlier letter to the American botanist Asa Gray (1810–88) describing his ideas and some extracts from his 1844 essay, were hastily arranged to be read at the Linnean Society and then published in the society’s journal. Wallace was thousands of miles away and ignorant of the meeting. Darwin did not attend. This gave credit to both men while establishing Darwin’s priority. All this was done in mid-1858, although the session at the Linnean and the subsequent publication attracted little comment, positive or negative.

His ideas now in the public domain, Darwin abandoned (temporarily, he thought) his big book, and started working on a shorter abstract, aimed at summarizing his arguments. This was On the Origin of Species, published on 24 November 1859. This became the book that helped define the rest of his life; he published a modestly corrected second edition in 1860 and revised it four times to accommodate comments and criticisms, and further research. Natural Selection remained in manuscript form until it was finally transcribed and published in 1975.