The Darwinian Revolution
The Origin of Species was published in 1859. The date is important: from that date commenced the rapid change which made the values and beliefs of the twentieth century so different from those of any earlier period. Now that the twentieth century also has passed into history, we can perhaps begin see the Darwin's revolution more objectively than has previously been possible.
Darwinism, as it very soon came to be called, had three components: the theory of evolution, which claimed that all living things have developed from common origins; the theory of natural selection, which suggested an automatic mechanism to explain this development of life; and a new conception of man, as an animal related to other animals, and particularly to the apes, which followed from evolution but had a special significance of its own. From all these developments, and particularly from the theory of natural selection and the concept of man as an animal, emerged a new system of values. And from this change, came profound social and political changes in which science and medicine inherited much of the previous influence of the Church.
The events of the 1860's and later were dominated by two remarkable men: Charles Darwin and T H Huxley. Darwin provided the theory and the book, but played little part in the subsequent controversy. Huxley led the battle for acceptance of the new ideas, and his political influence did much to establish in Britain the new scientific and educational intelligentsia which increasingly displaced the Church in the moral leadership of society.
There was also a third man - Alfred Russell Wallace - who arrived at the theory of natural selection independently of Darwin, who thus precipitated the writing of the Origin of Species, and whose brilliant later writings might just (with Huxley's aid) have achieved similar effects, if there had been no Darwin at all. But if Wallace had been invested with the influence which Darwin attained, things might have turned out differently. For Wallace quite soon became convinced that natural selection could not account for the origin of the human mind, and that divine intervention was necessary to explain both sentient consciousness and the origin of life itself.
But we need to begin at the beginning. To understand the impact of the Origin of Species, we must see the world as it appeared to the early nineteenth century.
Evolution over time
The astronomical discoveries which we associate with Copernicus, Galileo and Newton had revolutionised European man's perception of his position in space. It had become clear that the earth was not the centre of creation, but a small planet circling one among many stars, situated at immense distances from each other in a virtually limitless universe.
But the change in perception of space had brought no corresponding change in the perception of time. The universe was still assumed to have been created at a fixed date, certainly not more than 10,000 years ago. All the species of animals and plants now in existence were thought to have been created in their final form at the time of the Creation. The dates that were suggested for the beginning of the world (on the basis of the Book of Genesis) correspond approximately to what we now know to be the dates of the first settled civilizations in Egypt and Mesopotamia.
Historical evidence was absent before that date. But increasingly, scientific observers were becoming aware of the existence of fossils. Fossilised bones - of unknown and presumably extinct animals, some of them of colossal size - had been discovered. Fossil sea-creatures had been found in apparently sedimentary rocks high on mountains. For the collectors and scientific observers of the eighteenth century, fossils (though increasingly studied) were an enigma. Only vast and incalculable forces - whether of flood or of earthquake and eruption - could, it seemed, account for such momentous changes as the rise of mountains from the bed of the sea. When had these appalling events occurred, why had we no other record of them, and why had the fossils been deposited in layers, with different types or species commonly found in specific strata?
The eighteenth-century geologist James Hutton (see link ) belonged to the sceptical Scottish circle of Hume and Adam Smith. Hutton was the first to suggest the principle that the past development of the earth must be explained only by the same kind of changes that are still in progress today. ‘No powers' he wrote ‘are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principle'. He studied the effects of erosion and normal volcanic activity and explained the events of the past on the same slow-acting principles. This led him to demand an immense time-scale. In the economy of the world' he wrote 'I can discover no trace of a beginning, no prospect of an end.'
The theories of Hutton were regarded as atheistical, but caused little stir, partly because they were obscurely presented. But by the early nineteenth century, the now accepted series of strata was approximately understood and William Smith had suggested a 'Law of faunal succession (which) holds that different strata contain particular types of fossilised flora and fauna, and that these fossil forms succeed each other in a specific and predictable order that can be identified over wide distances.' (see link ). Nevertheless the full implications in terms of time scale were not established.
By this time biological research among living species had been increasingly professionalised, developing most strongly in France. Cuvier's classification of the species of the natural world was not far from what became established later. The structure of the living world clearly divided into related groups of species: genera, families and orders of animals. Cuvier suggested that old forms had become extinct as a result of successive floods and new forms had each time taken their places. The possibility that similar species and groups had simply developed from common ancestors was explicitly suggested by Darwin's grandfather Erasmus Darwin and by Cuvier's French rival Lamarck. The theory, which as yet had no accepted scientific basis, became known initially as transmutationism.
Then in his Principles of Geology (1830-33), Darwin's contemporary Charles Lyell revived Hutton's principle of slow geological change, and presented a classic explanation of development over millions of years. Among scientists at least, his account soon came to be widely accepted. Darwin took Lyell's book with him on his trip to South America on the Beagle.
Despite his perception of geological time, Lyell at first explicitly dissociated himself from the theory of the "transmutation" of life. But his theory of long-term, gradual geological change inevitably made the theory of common descent seem much more likely. If species had appeared and become extinct at different times over an immense period of time, surely God had not continually intervened with new batches of creation?
But if life had developed in this gradual way, why had it done so? The challenge was to present some convincing scientific hypothesis which would explain the development of life - and the ability of nature to produce new species each so marvellously adapted to its environment. There was a very strong psychological pressure to come up with the missing piece in the jigsaw - a theory which might explain how and why new species have developed to fit new environmental conditions.
At the same time, there were attempts to trace the emergence of higher species over time on the analogy of the development of embryos. The Industrial Revolution and increasing European world dominance were producing a sense of confidence in the future, which was reflected in theories of progressive historical development. Evolution was in the air. But though "transmutationism" was attractive, it was also dangerous; it inevitably encountered the active hostility of churchmen, yet it could not count on the support of the scientists.
Nevertheless the extent to which the public would respond to the idea, when it came, was revealed by the immense success (a succès de scandale) of the Vestiges of the Natural History of Creation , published in 1844. This book, the anonymous work of a successful Scottish publisher, Robert Chambers, presented a broad popular view of science and the universe, in which Lyell's time-scale of geological development was combined with ideas of evolutionary change, up to and including man, derived from Lamarck.
Chambers' book was exciting and imaginative but it contained many scientific inaccuracies and it provided no explanation for evolution which would stand up in scientific terms; it was furiously condemned by both church and science, in chorus. This made no difference to its popularity: Chambers brought out successive new editions in which he adapted his theory to the criticisms that were expressed of it. By the time the Origin of Species was published, the intelligent reading public had been well prepared for the idea of evolution.
However much he tidied up his details in the light of current scientific knowledge, Chambers could never command the respect of the scientific community, because his book offered no acceptable explanation of why evolution had taken place. The Church taught explicitly that the marvellous complexity of the living world was a proof of the existence and omnipotence of a divine Designer. No evolutionary theory could be scientifically respectable, or could effectively challenge this doctrine, until a hypothesis could be found - it need only be a hypothesis - which could provide a scientific explanation for the complexity and diversity of nature and explain not merely how but why life had gradually evolved into its present forms.
Darwin
Darwin had spent five years on an extended voyage as ship's naturalist on HMS Beagle , studying in particular the the animals, plants and geology of South America. What he had seen influenced him greatly:
During the voyage of the Beagle I had been deeply impressed by discovering in the Pampean formation great fossil animals covered with armour like that on existing armadillos; secondly by the manner in which closely allied animals replace one another in proceeding southwards over the Continent; and thirdly, by the South American character of most of the productions of the Galapagos archpelago, and more especially by the manner in which they differ on each island of the group; none of the islands appearing to be very ancient in a geological sense.
It was evident that such facts as these, as well as many others, could only be explained on the supposition that species gradually became modified; and the subject haunted me. But it was equally evident that neither the action of surrounding conditions, nor the will of the organisms (especially in the case of plants) could account for the innumerable cases in which organisms of every kinds are beautifully adapted to their habits of life....I had always been struck by such adaptations, and until these could be explained it seemed to me almost useless to endeavour to prove by direct evidence that species have been modified..
Darwin: Autobiography
He set to work, following the example of Lyell in geology, to collect material which seemed relevant to a theory of the development of life over time. In 1838, he thought he had found the basis for his theory:
In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement 'Malthus on Population' and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of a new species. Here then I had at last got a theory by which to work..
(Autobiography)
A very large part of Darwin's work, subsequently summarised in his Variation of Animals and Plants under Domestication, related to artificial rather than natural selection. He studied in detail and relative to many species the art by which the breeder or the horticulturist is able to produce new varieties by selection, choosing as parents for the next generation only those individuals which show a small variation in the desired direction; the effect of their selection thus builds up cumulatively in successive generations, resulting in major changes.
I collected facts on a wholesale scale, more especially with respect to domesticated productions, by printed enquiries, by conversation with skilful breeders and gardeners, and by extensive reading..
Autobiography
He wrote two short summaries of his theory and in 1856 was advised by Lyell to "write out my views pretty fully" and he at once began to do so, in great detail. It seems likely that a very large part of this work would actually have dealt with variation under domestication. But he was interrupted by the arrival of a letter from Alfred Russell Wallace, enclosing his paper On The Tendency of Varieties to Depart Indefinitely from the Original Type. Wallace was in what is now Indonesia, studying the natural history of the tropical islands and collecting specimins for taxidermy to pay his way. Wallace's paper outlined (entirely independently of Darwin) the principle of natural selection.
It was impracticable to discuss the situation with Wallace, who would not be able to reply to a letter for many months. After consulting his friends Lyell and Hooker, Darwin published Wallace's paper, along with some notes of his own on the same subject. Then he immediately set to work. The Origin of Species, a summary of Darwin's work over the previous twenty years, was published the year after. It caused an immediate sensation.
The Impact of the Origin of Species
Darwin had arrived at the hypothesis of natural selection long before he received Wallace's paper, and his slowness in publishing his conclusions must be explained by an awareness of the dramatic effect likely to be produced by a serious presentation of "transmutationism" implying a scientific endorsement of man's animal descent. As a former disciple of Paley, Darwin must also have known that (in England at least) the faith of many if not most sincere Christians was based to a large degree on "natural theology" - the belief that best possible proof of the existence, wisdom and goodness of God is to be found in the structures and functions of living things. Darwin had himself shared this belief. Natural selection, he now realized, might appear to make this belief unnecessary, because it could provide an alternative and more truly scientific explanation for the perfect adaptations of nature (see link ).
It could also be said that Darwin had a superb sense of timing. Because in fact the blow he inflicted came with much more force than it would have done twenty years' earlier.
Darwin knew that it was vital that he should have a hypothesis which would provide a new and rational explanation of the reason why living things have evolved as they have; but he was reluctant to rely upon the natural selection theory too heavily, and his presentation of a supplementary theory of ‘sexual selection', which he was to develop later, shows that he was aware of one of the most obvious objections to it.
His omission of the connection to man was tactical. He knew that the implication would be understood by most readers, but he also knew that an explicit statement of man's origins would immediately increase the anticipated level of opposition:
It would have been useless and injurious to the success of the book to have paraded, without giving any evidence, my conviction with respect to (man's) origin.
Autobiography
The 1860's was a decade of intense controversy, in which Darwin himself took little part, his principal champion being T H Huxley. Huxley read the Origin just before publication and was immediately convinced. He immediately went to work and contrived to review the book anonymously, at length and very favourably in The Times.
This was an extraordinary coup. The Times - then at the height of its power - was at that time the almost universal morning reading of the British educated class. The Times, in that period, made and unmade governments. Throughout the world, the newspaper was regarded as the authoritative voice of Britain; at a time when Britain was the richest, most powerful and most scientifically advanced country in the world. No new idea has ever been launched with more thorough preparation, or with greater immediate impact, than Darwin's theory of evolution.
Huxley's Times review was a clever piece of journalism which helps us to place Darwin's book in its historical context. Note the superior and dismissive tone in which he refers to the Vestiges:
Since Lamarck's time, almost all competent naturalists have left speculations on the origins of species to such dreamers as the author of the Vestiges, by whose well intentioned efforts the Lamarckian theory received its final condemnation in the minds of all sound thinkers. Notwithstanding this silence, however, the transmutation theory, as it has been called, has been a "skeleton in the closet" to many an honest zoologist and botanist who had a soul above the mere naming of dried plants and skins. Surely, has one such thought, nature is a mighty and consistent whole, and the providential order established in the world of life must, if only we could see it rightly, be consistent with that dominant over the multiform shapes of brute matter. What is the history of astronomy, of all the branches of physics, of chemistry, of medicine, but a narration of the steps by which the human mind has been compelled, often sorely against its will, to recognise the operation of secondary causes in events where ignorance beheld only an immediate intervention of higher power? And when we know that living beings are formed of the same elements as the inorganic world, that they act and react on it, bound by a thousand ties of natural piety, is it probable, nay is it possible, that they and they alone, should have no order in their seeming multiplicity, should suffer no explanation by the discovery of some central and sublime law of mutual connexion?
Questions of this kind have assuredly often arisen, but it might have been long before they received such expression as would have commanded the respect and attention of the scientific world, had it not been for the publication of the work which prompted this article..
The Times Dec 26th 1859
For Huxley, evolution was his opportunity. He was a younger man, established as a scientist, but with his public reputation still to be made. He wrote to Darwin:
‘I trust you will not allow yourself to be in any way disgusted or annoyed by the considerable abuse and misrepresentation which, unless I greatly mistake, is in store for you. You must remember that some of your friends, at any rate, are endowed with an amount of combativeness which (though you have often and justly rebuked it) may stand you in good stead.
I am sharpening my claws and beak in readiness.' ( see link )
Throughout the 1860's, evolution was a subject of intense controversy. Alvar Ellegard compares the reaction towards Chambers' Vestiges of Creation, in 1844, with that towards Darwin's Origin of Species, fifteen years later. In many ways, the reaction of press and public to the two books was similar. But if the Vestiges was more widely read, the Origin was taken more seriously:
In a sense, the Vestiges acted more strongly on the popular mind than the Origin. The book was quite as much talked about in the press in the first few years, and had undoubtedly a much wider readership. It appealed to the imagination by treating Evolution as concerning the whole of nature, and not just the organic world. Yet in spite of this, "Vestigianism" never reached the proportions of Darwinism as a matter of public concern. The Vestiges was a popular success, but no more. No scientific authority ever came forward to support its thesis. The Origin was sometimes taken as a more learned and less comprehensive imitation of the Vestiges - it was in fact described as such by the Daily News reviewer in 1859 - yet since it was perforce taken seriously by the intellectual elite of the country, the questions which it raised, whether great or small, soon took on a much deeper significance than had ever been granted to the speculations of the Vestiges. The broad public perhaps did not realize precisely in what way Darwin was more significant than Chambers, but the stir he caused in the intellectual world showed that he was. Darwinism concerned, as one popular commentator put it, 'the tremendous isues of life."
Alvar Ellegard : Darwin and the General Reader, p333.
By the end of the 1860's, the battle, as far as Britain was concerned, was largely won. Most of the younger scientists had accepted it at once; the older scientists mostly came over gradually, or were themselves discredited; the educated public and most of the press, already prepared by Chambers' Vestiges, came over also: some but not all churchmen fought on, but did themselves no good by it. The controversy increasingly resolved itself into a battle between the traditional authority of the Church and the new and growing authority of the scientists; and the scientists won.
Nevertheless Darwin's victory was at that stage an incomplete one. Darwin had persuaded most people of the validity of "transmutationism" but he had not necessarily persuaded them that natural selection was the cause of it:
It is clear that Darwin's contemporaries were, in a way, prepared for an evolution theory. But they were not at all prepared for the sort of evolution theory which Darwin actually propounded. This contradiction explains one of the paradoxes of the subsequent development of opinion: though it is practically certain that the evolution theory would not have been established at all if Darwin had not been able to support it by means of the naturalistic theory of Natural Selection, yet the majority of the general public, and a good many scientists, refused to accept the Natural Selection theory, while allowing themselves to be converted to evolutionism.
Ellegard p.17
From this point of view Darwin may be compared with Columbus. In believing that the world could in principle be circumnavigated, Columbus was in no way original. But he produced a major change in our perception of the world as a result of his mistaken confidence in the ease of circumnavigating it. In rather the same way, Darwin's belief in evolution was not new. But the route he found to it - his theory of natural selection - made it accessible to science as a serious hypothesis.
Man's Animal Origin: Images and Emotions
In the popular debate, the issue of man's animal origin was always the difficult part: it aroused very strong emotions. The Times reviewer of Darwin's Descent of Man, quoted by Ellegard, probably came near to the truth:
There are certain instincts, which so far as we can see, are ultimate facts, and an instinct of this nature, except where it is obscured by the prejudices of speculation, impels us to a profound conviction of the essential difference between man and the rest of the animal creation. We are intimately sensible of a difference which is not one of degree, but of kind.
Ellegard , P297, quoting The Times, April 7 1871.
The borderline between man and other animals has a strange fascination, but it also induces a sense akin to horror which may well have an instinctive origin. If man is an animal, the operation of the species-recognition principle must be as important to him as it is to all other animals. All animals behave quite differently when they encounter members of their own species, from the way in which they behave with other species, no matter how closely related. Many of the emotions which were aroused in the debate over man's animal ancestry may have drawn some of their strength from a deep and unacceptable sense that the special identity of man as a species was being challenged ( see link ).
The period during which Darwin's work was having its impact was also the period during which Africa was first being opened up to European contact. Africa was the home of chimpanzees and gorillas - and also of human societies very different from those of Europe, with many uncivilized practices, including (it was believed) cannibalism. Black men with dark, satanic practices - might they be not so distantly related to the great apes with whom they shared the "Dark Continent"?
Three books were published not long after the Origin of Species , which set the tone of the discussion, particularly in the press. All of them tended to invest the animal origin of man with disturbing emotional associations.
The first, Explorations and Adventures in Equatorial Africa, by Du Chaillu, an explorer, gave detailed descriptions of gorillas, as well as of cannibalism in Africa. A review in the Times quoted with approval Du Chaillu's first encounter with a fully grown gorilla:
His eyes began to flash fire as we stood motionless on the defensive, and the crest of short hair which stands on his forhead began to twitch rapidly up and down, while his powerful fangs were shown as he again sent forth a thunderous roar. And now truly he reminded me of nothing but some hellish dream creature - a being of that hideous order, half-man, half-beast, which we find pictured by old artists in some representations of the infernal regions..
(Quoted in Times review of Du Chaillu's book, May 21 1861)
and on cannibalism:
M. Du Chaillu killed this his first gorilla in the country of the Fans, about 150 miles from the coast and about 1 degree north of the Equator. The Fans are an interesting people, for they are real, unmistakeable cannibals, who make no secret of their partiality for human flesh. ...M Du Chaillu is careful to support his statements on this head with corroborative testimony, but we do not doubt for a moment the accuracy of his own observations or his entire trustworthiness. He says that he soon had an opportunity to satisfy himself as to allegations of which he had previously cherished some doubts.."Presently we passed a woman who solved all doubt. She bore with her a piece of the thigh of a human body, just as we should go to market and carry thence a roast or steak"
(Times review, 1861)
In the same year (1861) the first English description of the Neanderthal fossils was published. The Neanderthal possessed the unfortunate combination of a large brain - there appeared to be no doubt of his human identity - with a powerful frame and heavy brow-ridges very suggestive of the gorilla. It seemed that ‘Primitive man' had been discovered - and he was a monster! The images of the gorilla, the "primitive savage" and perhaps the medieval devil were merged in the public mind into the single horrific image of the Neanderthal.
Huxley is now remembered as an impeccable scientist. But he also was capable of sensationalism. His Evidence as to Man's Place in Nature followed in 1862. Huxley combined in a short volume - based on lectures to working men - a scientific analysis of the physical similarities between man and apes, a detailed description of the Neanderthal bones - and a popular account of apes and cannibalism in Africa, with a sensational cannibal illustration (see link )! The close association of the animal origin of man with cannibalism was entirely inappropriate - few non-human species practice cannibalism. With this kind of contribution from a major protagonist, it was difficult for the debate to be conducted with any kind of rational detachment.
The Victory of Darwinism?
What is the situation now? With the exception of small minority of biblical fundamentalists, almost everybody now accepts that the earth is very ancient and that species have evolved over time. Some parts of the evolution story, notably the dinosaurs, have appealed strongly to our imagination. Darwin's victory here is almost complete. But the other two ingredients in the Darwinian mix - natural selection and the animal descent of man - have proved much more difficult to assimilate.
The principle of natural selection is now generally understood and accepted by educated people, but in a somewhat naive and simplified way, which does not attempt to keep up with more recent evolutionary thinking. It is probably generally believed that natural selection has caused a gradual linear development of lower forms of life into higher forms. I am not sure that even some professional biologists have altogether abandoned this perception of evolution. In reality, the fossil record shows that evolution is not linear but jerky: a pattern which has been described as "punctuated equilibrium." Its jerkiness is explained by the process of speciation. It is now realized that new species have typically appeared in isolated micropopulations under the influence not only of natural selection but of changes in the environment and genetic factors. Evolution is part of life; like the rest of life, it is unpredictable and it may be perfectly legitimate to describe it, as the great evolutionary biologist Mayr does, as a "creative" process.
The trouble is that (as the "ism" shows us) Darwinism very quickly became not simply a scientific advance, but a materialistic belief system, supporting a new group of established and (increasingly) salaried scientists and academics. Natural selection had a very important role to play in that belief system: it "proved" that the development of life had been simple and automatic. It became the basis of a new materialism which was thought to have discredited religious belief.
In other sciences, it is generally accepted that nature is complex and no scientific theory is final. In physics, twentieth century thought moved on well beyond the apparent certainties of Newton. In biology, simple and apparently comprehensive materialistic interpretations of complex phenomena might well in the long term prove even less adequate than in physics. It might have been safer to have claimed merely that natural selection was an exciting and useful explanation of many observed events. That is certainly how Darwin and most of his contemporaries regarded it. Scientific practice does not provide any justification for treating natural selection as a dogma. Yet unfortunately, dogma is what it often appears to have become.
This website takes the basic model of evolution (or "transmutationism") for granted. It looks a little more closely at natural selection and speciation, in relation to nineteenth century theology and modern evolutionary theory. And a good part of the site is devoted to summarising our increasing knowledge of how (it now appears) the early bipeds survived in their dangerous environment; and how mankind rapidly came to dominate it.