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A Lunatic Idea: British Science and Evolution on the Eve of Darwin’s Origin of Species

Paper presented by Professor Iain McCalman, University of Sydney
Darwin symposium, National Museum of Australia, 26 February 2009

NICHOLAS DRAYSON: As Robyn has said, this morning we will be hearing about some of the background to the story of the publication of On the Origin of Species. Iain McCalman will be telling us what was happening in British science when Darwin’s book was published. Then Tom Frame will give us some information about Darwin the man: was he really as nice as Robyn thinks he was? And finally in this session Frank Nicholas will give us an account of Darwin’s time here in Australia, which I think was more important to his subsequent thinking that has generally been appreciated. First I would like to ask Professor Iain McCalman to present his paper ‘Evolution, a lunatic idea?’

Prof. IAIN McCALMAN: Towards the end of April 1856 Charles Darwin asked botanist Joseph Hooker, biologist Thomas Huxley and three other younger generation naturalists to stay for a weekend at his Kent residence Downe House. Being crippled with a chronic stomach ailment, the 47-year-old Darwin didn’t issue such invitations lightly. Emma, his devout Anglican wife, believed that Darwin’s mind and stomach were intimately connected and she knew that his mind was at that moment in an agony of indecision.

Darwin’s agenda for the proposed April weekend visit could not have been more serious. After 18 years of secrecy, he was on the brink of deciding whether to lay before the world a version of his theory on the origin of species by the evolutionary mechanism of natural selection. The 1850s had brought a marked improvement in the British political environment since he had first penned a rough draft of his theory during the turbulent ‘hungry forties’. Even someone as nervous of notoriety as himself could appreciate that prosperous, peaceable, mid-Victorian Britain was not the combustible place of popular uprisings and mass marches that had faced him when he disembarked from the Beagle in 1836.

Another more immediate reason for considering publishing had been presented recently to him by the distinguished geologist Sir Charles Lyell, a friend now of some 20 years. Lyell had just come upon a paper written from Sarawak in the Malay Archipelago by an obscure insect and butterfly collector Alfred Russell Wallace that seemed to be sniffing down a similar trail to Darwin’s. Lyell’s urgent concern had encouraged Darwin to invite his old mentor to Downe House a few weeks before the weekend for a private explanation of what he called ‘the formation of species by natural selection’.

Lyell’s notebook afterwards telegraphed what he had learnt:

When the conditions alter, those individuals which vary so as to adapt them to new circumstances flourish and survive while the others are cut off.

In other words, naturally-generated varieties among organic beings would, over time, transmute into new species by successfully exploiting their chance physical advantages in a fierce and perpetual struggle against rivals for food and reproductive success. Though still a firm creationist himself, Lyell recognised the theory’s stunning importance. Returning home, he scribbled Darwin a warning: he must publish. ‘Out with the theory and let it take date - and be cited and understood.’

To publish or not? This was the dilemma Darwin hoped to resolve at the weekend party by taking intellectual soundings and exercising his subtlest arts of persuasion. Hooker and Huxley, both in their early 30s, were the crucial targets. Before plunging into the riskiest action of his life, Darwin had to test and if necessary change their opinions. His decision would be determined largely by their response. They were close personal friends, fellow Southern Ocean voyagers and rising scientific stars with a following of reformist-minded friends cast in their own meritocratic mould. They would be the true barometers of whether the intellectual climate was ready for his explosive theory. The other invitees, botanist Hewett Cottrell, entomologist Thomas Wollaston and biologist John Lubbock, were smaller fry and less important. They had been chosen because they represented a cross-section of younger scientists who might be predisposed to have some sympathy with a heretical theory of evolution.

This moment in 1856 when Darwin chose deliberately to feel the pulse of English science as well as the sample he selected for his experiment together offer us a snapshot of the outlook of the most progressive elements of British science on the eve of the Origin. Above all, they give an indication of how far and in what form evolutionary ideas had penetrated into the minds of Darwin’s younger contemporaries before he had published. The intellectual baggage that these rising young scientists brought to the weekend suggests both what Charles Darwin was up against and what he could count on by way of potential sympathy for his heretical theory, should he take the plunge and publish.

Let’s begin with looking at Charles Darwin’s own intellectual baggage. How far had theories of evolution penetrated into his own consciousness as a young man prior to the discovery of natural selection in 1838? Some biographers like to give the impression that Darwin was predestined to become an evolutionary theorist because his celebrated doctor-poet grandfather Erasmus Darwin had expounded evolutionary ideas in his famous vitalist poems of the 1790s, The Economy of Vegetation and The Loves of the Plants, and to a lesser degree in two medical works. These were exuberant, sensual and quasi-materialist hymns of praise to progressive laws of nature that had advanced species towards greater complexity and perfection over geological time.

However, Erasmus Darwin’s writings belonged to an historical moment - the French-influenced late Enlightenment - that had long been superseded in Britain by an intense and pervasive phase of counter-revolutionary conservatism and religious revivalism. Charles read his grandfather’s poems with enjoyment but he saw them as literary period pieces whose science was not to be taken seriously.

It is also true that Charles Darwin had, while a lacklustre medical student at Edinburgh University in 1825-27, associated for a time with the radical physician and sponge expert, Robert Edmond Grant, who was a deist and an exponent of evolution. Grant had been influenced by the great French transmutationist Jean-Baptiste Lamarck, well known in 1790s British naturalist circles for his theory that animals could will useful physiological changes and transmit them to their descendants.

However, Lamarck’s ideas explaining the development of new species by purely material laws had suffered similarly from the widespread British revulsion against revolutionary France, and most British scientists regarded his ideas as discredited. Grant represented a tiny sprinkling of avant-garde naturalists who defied orthodox British opinion during the early nineteenth century by continuing to favour the evolutionary ideas of Lamarck. Here again, however, there is no evidence that any of these heretical theories made a lasting impact on Charles Darwin who seems to have been more attracted by Grant’s enthusiasm for sponge collecting than for evolution. Darwin subsequently wrote off his entire medical education at Edinburgh as the most sterile and wasted period of his life - lots of our students probably say that.

Anyone who attended the Downe weekend would have found Charles Darwin to be no Lamarckian. Indeed the single most formative intellectual influence on Darwin’s naturalism came from one of Lamarck’s fiercest critics. Charles Lyell’s Principles of Geology (1831-33) had been written explicitly to refute Lamarckian transmutation and the book quickly became Darwin’s bible. Lyell saw geological change as perpetual and gradual, a process he claimed misunderstood by most previous thinkers who, even when discounting the biblical time span, still assumed that the earth’s continents had been shaped over a few millennia by cataclysmic supernatural events like the flood. Lyell argued rather that slow, everyday forces of wind, rain, ice and sun had sculpted the earth’s rivers, lakes, plains, valleys and mountains over eons of time. His simple subtitle for the principles said it all: ‘an attempt to explain the former changes of the Earth’s surface, by reference to causes now in operation’ - not back in creation time. Lyell believed that divine creation had set the machinery of geological change in motion, perhaps through several creationist interventions separated by a long hiatus. But he insisted that modern geologists must use only observable natural forces as tools for explaining how the process of change ordinarily operated in the world.

He argued that this process of change, a type of ceaseless geological flux, revealed no particular direction or purpose. There was insufficient evidence, he argued, to draw firm conclusions as to whether species were more complex and developed in the present time than in the past. As a firm creationist he stressed that nothing could alter the fixed biological character of species. These had originally been created at a variety of geographical centres in exact conformity within their environments and they had remained essentially immutable. However, he conceded that changes in geological and geographical circumstances could alter the habitats and environments of some species, and make them become extinct while others could develop slight but temporary variations as they adapted to these new habitats. Such variations would disappear over time, however, as interbreeding among wild populations occurred. Species would then go back to their original immutable form.

This divinely triggered but naturalistic model of the historical origins and adaptations of species within the geological and geographical framework of the earth was approved by a large percentage of British scientists on the eve of the Origin. In short, I think we have to stress that creationist science was not idiotic; it was a plausible theory in its time. It had been Darwin’s own position until his ruminations during the last weeks of the Beagle voyage, shortly afterwards followed by the revelations of the Galapagos species diversity and then the inspirational re-reading of [Thomas] Malthus in 1838. At that point Darwin had essentially worked out the evolutionary mechanism of natural selection through the struggle for existence, though his settled thoughts on the associated process of species divergence, which is a second and crucial dimension of the theory, had not even been completed by April 1856.

Anyway, at that April weekend, there had also been another kind of elephant in the room, if you like - an invisible naturalist presence in the house in the form of the zoological collector Alfred Russell Wallace. Although he was still thousands of miles away in the Malay Archipelago, Wallace’s Sarawak paper of 1855 had given formal shape to a theory he had been pondering for ten years. He believed he had accumulated enough empirical fact to prove the existence of a geological and geographical link between closely similar species. He still didn’t know though the evolutionary mechanism that created this link.

On a first reading of Wallace’s paper, Darwin himself had detected nothing new. ‘It seems all creation with him,’ he scribbled in the margin. Darwin thought the paper to be simply another version of the thesis that had been expounded by an anonymous bestseller Vestiges of Natural Creation in 1844 [1] that attracted much scientific odium when it was published. Darwin was right in guessing the source of Wallace’s evolutionary ideas. When Wallace read the Vestiges, it had been the singlemost important intellectual experience of his life. The book had been written by Robert Chambers, a talented Scottish journalist of radical and free-thinking views who managed to blend wild speculations with an innovative natural history of the earth. As the title hinted, the book rejected a literal version of the biblical creation in favour of a materialist interpretation of the origin of the firmaments, organic life on earth and of global geological change. Chambers carefully hid his subversion. He gave the divine creative responsibility for setting these natural laws in progress. He didn’t use the term ‘evolution’ but he had sketched out an historical theory of the biological interconnection of species and of what he said ‘the progress of organic life upon the globe,’ and it implied an evolutionary law.

Everyone had read the book. Darwin had been less scathing about it than many of his scientific contemporaries but he was angry that its slapdash speculations had worsened his own chances of publishing credibly in the future on the subject of the origin of species. Hooker, his friend, thought Vestiges was a joke. Huxley savaged it as a dangerous fiction. Wallace, a self-educated working-class artisan with no credibility to lose, disagreed with them vehemently. He thought it contained ‘an ingenious hypothesis which remains to be proved by more facts and the additional light which more research might throw on the problem’. Studying the rich biodiversity of the Malay Archipelago had pushed him closer to finding that additional light. So in less than two years after the Downe House weekend of 1856 he would send Darwin from the Malaccas a 20-page paper outlining an almost identical theory of natural selection through the struggle for existence. But this is to jump ahead of our story.

In April 1856 Darwin’s single-most important target for conversion was the biologist Thomas Huxley, a young man who took aggressive public pride in being an active doubter of any form of evolutionary theory. On first meeting Huxley in 1853, Darwin had found the sarcastic and brilIiant young biologist decidedly unnerving. He quickly decided that Huxley was the best talker, the quickest thinker and the most potent controversialist he had ever met. Poor, lovesick for his Australian fiancé, and angry at his inability to obtain a scientific position, Huxley was flaunting his contempt for the Anglican and the aristocratic clerical privilege that still seemed to monopolise British science. He wanted to impress his peers but it had to be on his own terms, ‘I shall make my mark somewhere and it shall be clear and distinct and free from the abominable blur of cant, humbug and self-seeking which surrounds everything in the present world.’ An angry young man, this radical young biologist associated existing evolutionary theories with a Christian-based transcendental belief in the divinely ordained perfection of species through special creations.

Here is the irony: Huxley thinks of evolution as a creationist theory. He was adamant that nature’s laws had no inherent direction. He hated the Vestiges of Natural Creation because it predicated a divine creator triggering laws that developed species and made them more perfect over time. He despised all such theories as metaphysical nonsense. His own scientific interests centred on the structures and relations of marine species. His stellar reputation had come from redefining major categories of open water sea creatures found in the Pacific and Coral seas around Australia. He had reconfigured [Georges] Cuvier’s work by proving an underlying structural kinship between wholly dissimilar types of jellyfish, sea squirts, stingers and polypi, bluebottles - all those things familiar to us when we go swimming in Australia. But his theoretical model came actually from the creationist anatomist Sir Richard Owen, who would later become both his and Darwin’s most inveterate enemy.

Huxley had worked out the link between these wildly and weirdly different creatures by using the contemporary zoological idea of the archetype, a kind of basic blueprint or ground plan to which outwardly diverse animals supposedly conformed. For Richard Owen, this archetype was the idea in God’s mind when the creatures had been created. For rational Thomas Huxley however, whatever the archetype was, it was not God’s thought. Whether an archetype actually existed he didn’t know, but he found it an invaluable tool for analysing and comparing anatomical structures. The best way for us to think about it might be like a sort of lowest common denominator between similar types of creatures. It would be easy to assume that Huxley is here hypothesising the existence of some ancestral animal from which the marine species had evolved, but this is to jump the historical gun. Like most respectable English scientists at the time, he regarded evolution as a crackpot idea, whether in its Lamarckian materialist or its divine Christian form.

So when the April weekend arrived, Darwin concentrated his attention on Huxley. Joseph Hooker had been working with him very closely and was already showing signs of coming round to the idea of evolution as a way of explaining the distribution of species of plants that he had been studying in Australia, New Zealand and the Antarctic islands. He and Darwin had been working together on this as Darwin wrote his book. So Darwin concentrates on Huxley. On the Saturday morning after a provocative set of questions about species had circulated during the dinner the evening before, Darwin leads his guests on a tour of the garden. It is craftily designed to instil doubts about the fixity of species. He genially shows Huxley his 90 types of domestic pigeons, pointing out that their vast differences had been skilfully produced by breeders who had selected and exploited tiny chance variations in pigeon offspring. Nature, he implied, worked in exactly the same way.

Later in the afternoon Huxley got a genial grilling. Why was he so resistant, Darwin asked, to the idea that the modern horse might be descended from the small three-toed Eocene fossil. Did he really think there was no connection between South American llamas and armadillos and the similar fossil beasts that Darwin had found in South America? Why did he hold such sharp distinctions between varieties and species, even in the case of Darwin’s barnacle evidence?

Later, after Huxley left the study, Darwin jotted down some of the fallacies in the young man’s answers. Very likely he raised these again at dinner that evening. We don’t know what was said. Something at any rate shook Huxley’s certainty. A week after the weekend, someone told Lyell that the group had got carried away with wild discussions about evolution.

When Huxley, Hooker and Wollaston were at Darwin’s last week they (all four of them) ran full tilt against species ...

Cautious though he was, Darwin saw the weekend as a vindication. He was encouraged by his Downe soundings to announce three weeks later, on 14 May, that he had decided to write and publish a book on natural selection. True, he remained anxious about how far he had managed to convince Huxley. With some trepidation he sent the acerbic young biologist his conclusions about embryology in early 1859. His provocative description of the embryo as ‘a picture more or less obscured of the common parent form of each class of animals’ brought Huxley’s warm approval. Here in the ancestry of the past, Huxley conceded, was the real source of the archetype; in other words, an evolutionary ancestral system.

In his bluntest admission yet, Huxley reported back to Hooker that ‘the facts seem to me to come very strong for the mutability of species’. Even so, when Huxley pointed out to Darwin that natural selection would remain open to doubt until breeders managed to produce a sterile cross, as in natural species, Darwin could only agree and wrote back to Huxley:

It is mere rag of a hypothesis with as many flaws and holes as sound parts My question is whether the rag is worth anything.

Darwin need not have worried. Huxley, Hooker, Wallace and their circles of young, reformist-minded scientific friends were itching to run Darwin’s red rag up the masthead and, still more, to roll out the heavy cannon so that they could knock over the clerical and aristocratic establishment that monopolised British science. These self-made outsiders were proud to see themselves as evolutionists and disciples of Darwin’s meticulous empirical methods. Darwin’s theory gave them the ‘Whitworth gun’ they needed to instigate ‘a new reformation’, as Huxley put it. Whatever remaining doubts any of them might have had about the particularities of Darwin’s theory of natural selection vanished in the thunder and smoke of engagement as Darwin’s Armada went to war. Thank you very much.

Footnote

1 Full title: anonymous, Vestiges of the Natural History of Creation, England, 1844

Date published: 30 April 2009