DARWIN, CHARLES (1809–82)

DARWIN, CHARLES (1809–82)

Charles Darwin, the English natural historian, revolutionized biological theory in the nineteenth century, although—following the general prejudice of the period—he always presented himself as a thoroughgoing empiricist. Darwin did not invent ‘evolution’—the theory that simple life-forms were once the ancestors of modern, complex organisms— but he did explain the mechanism of evolution in terms of a hypothesis—‘natural selection’, or the preservation of well-adapted, variant organisms in an ongoing ‘struggle for existence’—that has remained central to biological science ever since. The following paragraphs outline Darwin’s intellectual life, the content of his theory of natural selection, some historical issues raised by the ongoing popularity of alternative theories of evolution during the period (despite Darwin’s fame) and the impact of his work on social science. Particular reference is made to his most famous books, The Origin of Species (1859) and The Descent of Man (1871).

Charles Darwin was born in Shrewsbury in 1809 and first educated at the local public school (Shrewsbury School) from 1815 to 1825. His father, Robert, was a physician and, as a youth, Charles intended to join this profession until he failed to make a success of medical school in Edinburgh (1825–7). He moved to Cambridge University (1827–31) with the intention of becoming a clergyman, but, apart from the works of William Paley, Darwin disliked academic theology, and devoted more time to his hobby of natural history—both through reading and through collecting insects and fossils. His interest in the subject had been aroused in Scotland and later made more rigorous through an association with an Edinburgh physician, Robert Edmund Grant. His paternal grandfather, Erasmus Darwin (1731–1802), had also been a naturalist and was the author of Zoonomia (1794–6). (Scholars differ regarding the extent to which Erasmus Darwin’s ideas about evolution anticipated Charles Darwin’s theory of natural selection, given that the main thrust of the earlier theory followed the path outlined by the radical biologists of the French Enlightenment—see below—and stressed ‘acquired characteristics’.)

On graduation, Darwin accepted the unpaid post of naturalist aboard the geographical survey ship, HMS Beagle. The most famous episodes in this 5-year voyage (1831–6) were his visits to South America and to the Galapagos Islands in the Pacific Ocean, where he observed many unusual plants and animals. Already sceptical of the ‘creationist’ account of the origins of life, the voyage inspired Darwin to invent his own theory of biological evolution, but 23 years elapsed between his return to England and his decision to make his ideas public. Darwin’s mother, Susannah (who died in 1817), was a daughter of Josiah Wedgwood, the potter, and in 1839 Charles married another

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Wedgwood, his cousin Emma. This family wealth helped to sustain Darwin’s lengthy research programme for many years prior to the commercial success of The Origin of Species .

In 1838 Charles became Secretary of the Geological Society and in 1839 he published

a Journal of Researches from his voyage to the southern hemisphere. He subsequently published monographs on coral reefs, on volcanic islands and on South America. From 1846 to 1851, he worked on a significant problem of biological classification and this led to the publication of a four-volume study of both fossil and living barnacles (1851–4). Thus, Darwin became known as an accurate and thorough descriptive naturalist, although

he had already begun a programme of breeding experiments on domestic animals, designed to investigate the transmission of inherited characteristics.

Fifteen years earlier (between 1837 and 1839) Darwin had organized his evidence and drafted his theory of evolution in roughly 900 pages of private notes (The Notebooks on Transmutation of Species) and much of his subsequent work involved seeking to verify the central hypotheses of natural selection. In 1844 he completed a lengthy essay expounding the theory (which was never published in his lifetime) and this gained the support of two notable scientific friends, the botanist, Joseph Hooker (1817–1911), and the geologist, Charles Lyell (1797–1875). The deeply hostile public reaction to a popular work on evolution by Robert Chambers—Vestiges of the Natural History of Creation (1844)—discouraged Darwin from publishing his ideas, but in 1856 he started work on a fully fledged exposition of the theory of natural selection. However, this work was cut short in 1858 by the discovery that another British naturalist, ALFRED RUSSEL WALLACE, had reached the same conclusions regarding the mechanism of evolution and intended to publish the theory—which he did, shortly afterwards. This challenge encouraged Darwin to publish an abstract of his fully fledged theory as The Origin of Species by Means of Natural Selection .

Darwin held back from stating directly in The Origin that not only the animal kingdom, but also mankind itself, must be a product of natural selection and biological evolution—and this view was only made explicit in one of his later works, The Descent of Man . Nevertheless, The Origin was bitterly contested in public controversy as a blasphemous, anti-Christian work, and took more than a decade to acquire general acceptance. In the 1860s, he continued his scientific work in relative seclusion in Kent, while a colleague, THOMAS HUXLEY, took the lead in ‘the Darwin debate’. In later life, Darwin published several further works that elaborated various aspects of his theory, such as The Variation of Animals and Plants under Domestication (1868), The Expression of the Emotions in Man and Animals (1872) and The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom (1876). Having suffered poor personal health since the 1840s, Darwin finally died at Down House in Kent in 1882.

Why was Charles Darwin’s theory so contentious? In the eighteenth century, educated Europeans had generally assumed that the earth was only a few thousand years old and that the natural world was divided into a large, but finite, number of independently created species. Biblical authority was usually cited to justify such a perspective and this world-view remained common-place in the mid-nineteenth century. Darwin’s theory relied upon recent geological ideas about the great antiquity of the earth in order to provide time for long sequences of minor variations between parents and offspring to produce the great variety of observable flora and fauna, and the prior succession of

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species shown by the fossil record. Darwin applied Malthusian ideas about competition for scarce resources to explain the extinction of certain variations and even of whole species, but he did not invent the general idea of evolution—the theory that simple life- forms were once the ancestors of modern, complex organisms was as old as the Greeks. The credibility of his theory was assisted by the fact that, during the Enlightenment, evolutionist ideas had acquired limited acceptance amongst professional scientists, thanks to the work of figures such as Georges-Louis Buffon (1707–88) and Jean-Baptiste Lamarck (1744–1829) on the ‘transmutation’ of species through the acquisition of functionally useful characteristics.

Darwin was sceptical whether the biological category of ‘species’ was ontologically different from that of ‘variety’—such categories were imposed on data by naturalists for the sake of convenience—and so his research focused upon behavioural and physiological change within ‘breeding populations’. The theory of natural selection assumed that a multitude of chance variations were always present in the behaviour and, more importantly, the physiology of such breeding populations, and that these variations were transmitted across generations by a mechanism of inheritance. Without a workable theory of genetics, Darwin assumed that most variations were randomly distributed, although some took the form of ‘acquired characteristics’. Each breeding population was subject to ‘selection pressures’ (e.g. changes in habitat, climate, the presence/absence of predators and internal competition within the population for scarce resources) and these pressures had differential effects favouring some variations at the expense of others. Darwin concluded that environmental change tended to favour the survival of variants (within a breeding population/species) that were well adapted to hostile changes, while other, less well-adapted variants died out over the generations. The long-term consequence of this process was the complete transformation of biological life from simple to complex forms, otherwise known as ‘evolution’. In the revised, fifth edition of The Origin (1869), Darwin referred to the medium-term survival of species (of those that were more or less satisfactorily adapted to both their old and new environments) as ‘the survival of the fittest’—thereby adopting a phrase coined by SPENCER and creating additional controversy regarding the morality of his doctrine.

As noted earlier, Darwin addressed the question of ‘whether man, like every other species, is descended from some pre-existing form’ in The Descent of Man and Selection in Relation to Sex —the second topic being highlighted on the grounds that it was ‘highly probable that sexual selection has played an important part in differentiating the races of man’. Following earlier work by Huxley, Darwin argued that the resemblance between the bodily structures of adult humans and primates, the resemblance between human and primate embryos and the presence of common rudimentary organs that served no modern purpose all pointed towards descent from common ancestors. By stressing the role of ‘sexual selection’ (mating according to an implicit standard of beauty) in enhancing the physiological differences between the ‘so-called races of man’, Darwin was able to confute the theories of ‘polygenists’, such as James Hunt (1833–69), who had considered the different races to be separate species—descended from a number of ‘original pairs’. Although The Descent is often criticized today for unreflectively assuming the activity of males, and the passivity of females, in courtship and for accepting at face value a variety of ‘travellers’ tales’ regarding non-European cultures, it is no more (and no less) subliminally ‘sexist’ or ‘racist’ than many other notable Victorian texts.

Entries A-Z 151 It should be noted that, like most other theories, Darwin’s theory of evolution was

itself the product of an ‘intellectual evolution’. Perhaps the four most important influences on Darwin’s scientific thought were Paley, Lyell, Lamarck and MALTHUS. Through the study of William Paley’s Natural Theology (1802) while an undergraduate, Darwin came to appreciate the particular significance of the adaptation of animals and plants to their immediate environment; this was a recurring theme in all his works. Before

he met Lyell in person, Darwin read Lyell’s Principles of Geology (1831–3) and was particularly impressed by the book’s uniformitarian theory of geology and its summary of the theory of Lamarckian evolution (although Lyell concluded that the evolutionism was not proven). Darwin certainly acquired much of his knowledge of European ‘nature philosophy’ at second hand, but he considered Lamarck to be a ‘justly-celebrated naturalist’—having been introduced to his evolutionary ideas initially by Grant in the 1820s. In the early stages of his career, Darwin made frequent reference to Lamarck’s System of Invertebrate Animals (1815), which included the (now famous) contention that all modern species are descended from other species.

Originally hesitant to embrace evolution, Darwin moved towards ‘transmutationism’ while reflecting on his Galapagos Islands data. In 1838 he read Malthus’s Essay on the Principle of Population (1798) and drew novel conclusions. The application of Malthusian theory to biological life, in general, led Darwin to deduce that competition for ecological resources could intensify selection pressures to the point where favourable variations might so transform a breeding group that its members could no longer interbreed with other descendants of common ancestors (who had formed another breeding group/‘species’). As noted previously, on further reflection, Darwin concluded that (at least among the higher organisms) the most well-adapted individuals tended to mate with other well-adapted individuals (‘sexual selection’) and this constituted an important causal factor in both the preservation of ‘favoured races’ and in physiological differentiation within races. This paralleled the well-recorded tendency of human horticulturists and farmers to breed from ‘superior’ individuals and to ‘weed out’ less- favoured plants and animals. ‘Selection by nature’ was thus a metaphorical extension of selection by mankind, but Darwin’s works always attributed some causal influence in natural history to ‘the conditions of life’ (the environment) and the ‘use and disuse’ of parts of the organism (as well as to purely inherited variations). Thus, Darwin’s theory of evolution (taken as a whole) combined a major hypothesis—that of Malthusian ‘natural selection’-with several auxiliary hypotheses of a more Lamarckian character.

Although there were a significant number of objections to Darwin’s theory from within the scientific community, the strongest reaction against his work came from all parts of the Christian church (Anglican, Catholic, Non-conformist). This seems to have been mainly due to a long-drawn-out upsurge of biblical literalism after the French Revolution. However, two distinguished Christian critics, Samuel Wilberforce (1805–73) and St George Mivart (1827–1900) also raised scientific objections to The Origin of some value, which adumbrate a variety of possible anti-Darwinisms. More famous for a polemical confrontation with Huxley—‘The Oxford Debate’ of 1860—Wilberforce deployed a most telling anti-Darwinian argument by pointing out the absence of cases where domestic selection had created new species. Mivart, on the other hand, reasserted the case for Lamarckian, saltatory evolution in On the Genesis of Species (1871), and this

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is just one example of the continued popularity of non-Darwinian evolution—further exemplified by figures such as Spencer and Ernst Haeckel (1834–1919).

Twentieth-century commentators (so numerous that their activities are often referred to as ‘the Darwin industry’) have often assumed that there was some connection between the continued popularity of Lamarckian ideas after 1859 and the relative importance to Darwin’s own theory of both natural selection and the maintenance of the idea of acquired characteristics. An example of the latter is Darwin’s hypothesis of ‘pangenesis’—proposed in The Variation of Animals, but now refuted—which suggested that minute ‘gemmule’ cells (from adapted organs) circulated in the body and eventually affected reproduction. Other commentators have placed greater emphasis on Darwin’s original uniformitarian geology (rather than a definite commitment to Lamarckism) and have argued that, during his latter years, he felt obliged to ‘speed up’ evolution, for he was unable to deal with an objection (again now refuted) to his chronology by the physicist, William Thomson (1824–1907). (In 1862, Thomson, later Lord Kelvin, published thermodynamic calculations to the effect that the earth was only about 1 million years old.) Finally, it must be noted that both Darwin and the Lamarckians had a significant impact on the social sciences in the late nineteenth century, although the term ‘SOCIAL DARWINISM’—which has also generated a massive literature—is a catch-all phrase, encompassing many different applications of evolutionary, hereditarian and organicist concepts to human society. In The Descent, Darwin expressed a certain sympathy for the eugenicist ideas being developed by his cousin, FRANCIS GALTON, as well as seeking to demonstrate some (limited) continuity between biological evolution and mechanisms for change in contemporary human society.