The Descent of Man, and Selection in Relation to Sex

London: John Murray, 1871. First edition. THE EVOLUTION OF MAN.

First edition, second issue, presentation copy from the printer William Clowes the younger. The word 'evolution' appears here for the first time in any of Darwin's works, on page 2 of the first volume, 'that is to say before its appearance in the sixth edition of the Origin of species in the following year' (Freeman p 129). Darwin's second most important work, his seminal treatise on the evolution of man; this is a fine copy in original state, rare in this condition. "This is really two works. The first demolished the theory that the universe was created for Man, while in the second Darwin presented a mass of evidence in support of his earlier hypothesis regarding sexual selection ... In the Origin, Darwin had avoided discussing the place occupied by homo sapiens in the scheme of natural selection, stating only that 'light will be thrown on the origin of man and his history.' Twelve years later he made good his promise with The Descent of Man, in which he compared man's physical and psychological characteristics to similar traits in apes and other animals, showing how even man's mind and moral sense could have developed through evolutionary processes. In discussing man's ancestry, Darwin did not claim that man was directly descended from apes as we know them today, but stated simply that the extant ancestors of homo sapiens would have to be classified among the primates; however, this statement, as misinterpreted by the popular press, caused a furor second only to that raised by the Origin" (Norman). Darwin argues for the common origins of all mankind, placing humans in the evolutionary scheme he had outlined for the rest of the animal kingdom in the Origin. However, not all evolutionists shared this view - many, including Alfred Russel Wallace and Ernst Haeckel, argued for multiple origins of different human species. Science writer Richard Dawkins has noted that Darwin's supposition that the human species arose in Africa was "typically ahead of its time," and despite the strong social pressures to think otherwise, "he carefully considered and decisively rejected the idea ... that different human races should be regarded as separate species." "The book, in its first edition, contains two parts, the descent of man itself, and selection in relation to sex. The word 'evolution' occurs, for the first time in any of Darwin's works, on page 2 of the first volume of the first edition, that is to say before its appearance in the sixth edition of The Origin of Species in the following year. The last chapter is about sexual selection in relation to man, and it ends with the famous peroration about man's lowly origin, the wording of which differs slightly in the first edition from that which is usually quoted" (Freeman, p. 129). Part One of the work marshals behavioural and morphological evidence to argue that humans evolved from other animals. Darwin shows that human mental and emotional capacities, far from making human beings unique, are evidence of an animal origin and evolutionary development. Part Two is an extended discussion of the differences between the sexes of many species and how they arose as a result of selection. Here Darwin lays the foundation for much contemporary research by arguing that many characteristics of animals have evolved not in response to the selective pressures exerted by their physical and biological environment, but rather to confer an advantage in sexual competition. These two themes are drawn together in two final chapters on the role of sexual selection in humans.

Provenance: Inscribed by the recipient 'Given to me by William Clowes, Marden 1871' on half title. William Clowes the younger (1807-1883) was head of the printing firm William Clowes Ltd; bookplate 'Hurrell' with coat-of-arms (three crossbows and chevron).

"Darwin had retained his own conclusions on human evolution quietly in the background while the defense of his general theory was conducted by advocates as diverse as Thomas Henry Huxley (1825-95) in England, Asa Gray (1810-88) in the United States, and Ernst Haeckel (1834-1919) in Germany. Darwin's own position on the 'human question' remained unclear ...

"It was in February of 1867 that Darwin decided to remove material from his massive manuscript of the Variation of Plants and Animals Under Domestication and create a 'very small volume, 'an essay on the origin of mankind'' (Darwin to Hooker, 8 February 1867). At this time he also sent to several correspondents a questionnaire asking for information on human emotional expression. This expanded into a major enterprise in which he became deeply engaged with the issue of the implications of his theory for ethics, writing to Asa Gray that 'the difficulties of the Moral sense has [sic] caused me much labor'. This was expanded into a two-volume work by the time it was sent to the printer in June of 1870. By this date he had also pulled out a separate section from the Variation manuscript that was to become the Expression of the Emotions in Man and the Animals, published in 1872.

"The dual publication of the Descent of Man, and Selection in Relation to Sex (1871) and the Expression of the Emotions (1872) created a watershed in the public reception of Darwin's views. Although Darwin had first worked out many of his views on human evolution in the early 'M' and 'N' Notebooks of 1838-40, public knowledge of Darwin's own conclusions on human evolution rested on the one vague sentence on the issue in the Origin itself. The Descent, however, made public his more radical conclusions, and seemed to many of his readers, even those previously sympathetic to the Origin, to throw Darwin's weight behind materialist and anti-religious forces" (Stanford Encyclopedia of Philosophy).

"In introducing his Descent of Man and Selection in Relation to Sex (1871), Darwin apologizes for his late contribution to the subject, as many other naturalists had developed the matter since he published his Origin of Species by Means of Natural Selection in 1859. He also apologizes for writing on a single species, as though evolutionary mechanisms were not universal. Finally, he also admits that he deliberately avoided referring to man in his Origin: 'I thought that I should thus only add to the prejudices against my view', pretending to ignore that most of his readers have read it as though the whole book were a demonstration of the descent of man from the apes. However, it would be erroneous to believe that nothing new was left to Darwin to write on man. His book is truly original. For instance, Huxley's book [Evidence as to man's place in nature, 1863] was a presentation of pure facts showing that the chimpanzee and the gorilla are closer to humans than are any other species. It is famous for its illustrations presenting series of skulls, hands and feet, placed side by side to allow readers to determine for themselves which species is closer to which. It contains the oft-imitated figure presenting the complete skeletons a gibbon, an orang-outang, a chimpanzee, and a gorilla standing in a queue with dangling arms following the skeleton of a man facing the same direction. Similarly, what has survived of Haeckel's Natural History of Creation is a genealogical tree stemming from the primeval 'monere' to races of man, with lateral branchings leading to the other organisms: a tree loaded with meanings, quite the opposite of Huxley's devotion to pure facts.

"The difference between Darwin's book and the former two is a matter of mechanisms. Already, the Origin was nowhere devoted to comparing species according to their homologous parts (as in Huxley) or in trying to visualize the tree of life (as in Haeckel). The Origin was actually not interested in the origin of life. Its sole illustration showed the simplest of all diagrams: a schematic tree so designed as to link intraspecific variation to interspecific divergence (the basis of natural selection), and which could represent any organic form. Like the Origin, Darwin's Descent is based on mechanisms. This is why it has survived. Huxley's and Haeckel's books are known nowadays mostly by historians, while Darwin's book is still inspiring for contemporary research, as some ideas in it can be experimentally tested ...

"[The Descent] contains two definitions of mechanisms. Firstly, Darwin summarizes his 'pangenesis hypothesis' straightforwardly:

'According to this hypothesis, every unit or cell of the body throws off gemmules or undeveloped atoms, which are transmitted to the offspring of both sexes, and are multiplied by self-division.'

"This mode of inheritance belongs to what tradition has called 'Lamarckian inheritance', even though it was never so precisely discussed and cautiously presented as by Darwin himself ...

"The second definition in the book concerns sexual selection, which is more concisely presented in the conclusion:

'Sexual selection depends on the success of certain individuals over others of the same sex, in relation to the propagation of the species; whilst natural selection depends on the success of both sexes, at all ages, in relation to the general conditions of life. The sexual struggle is of two kinds; in the one it is between individuals of the same sex, generally the males, in order to drive away or kill their rivals, the females remaining passive; whilst in the other, the struggle is likewise between the individuals of the same sex, in order to excite or charm those of the opposite sex, generally the females, which no longer remain passive, but select the more agreeable partners. This latter kind of selection is closely analogous to that which man unintentionally, yet effectually, brings to bear on his domesticated productions, when he preserves during a long period the most pleasing or useful individuals, without any wish to modify the breed' ...

"Mechanisms matter in evolutionary theory, since different mechanisms can lead to different outcomes. But here we meet a controversial point: should we conclude that, for Darwin, humans deserve a special law of evolution? In his introduction, he comments:

'I have been led to put together my notes, so as to see how far the general conclusions arrived at in my former works were applicable to man. This seemed all the more desirable, as I had never deliberately applied these views to a species taken singly.'

"But further:

'During many years, it has seemed to me highly probable that sexual selection has played an important part in differentiating the races of man; but in my Origin of Species, I contended myself by merely alluding to this belief. When I came to apply this view to man, I found it indispensable to treat the whole subject in full details. Consequently the second part of the present work, treating of sexual selection, has extended to an inordinate length, compared with the first part; but this could not be avoided.'

"It is, however, doubtful that in 1871 he wrote the book he intended to write in 1859, since in the meantime he greatly increased the contribution of use and disuse to his theory. In definitively adopting the pangenesis hypothesis in his Variation, he also accepted the view that many new variations originate as useful adaptations of individuals. At first they emerge through use and disuse, then they become hereditary. In this, the Descent is not so much the continuation of the Origin, as it is of the Variation. Darwin's inspiration for his Descent owes much to his Variation, both for the mechanism of inheritance, and for the similarity between artificial selection and mate choice. Thus, in the Descent, there is an intermingling of the fact that Darwin eventually extends the subject of the Origin to mankind, with the fact that he is defending a substantially different view of the contribution of hereditary mechanisms to evolutionary mechanisms ...

"The introduction quoted above suggests that the first and the second halves of the Descent are very different. The first half actually includes an interesting review of whatever had been published in the few years before on the subject of the 'Darwinian teaching' by other people. It examines the development of vertebrate embryos, the morphology, the physiology, and the five senses of man; the diverse adaptations and intellectual specificities of humans, including imagination, superstition, belief in God, moral sense and altruism. There is some tendency to categorize these advances into steps. Darwin seems to examine mankind as though he was 'a zoologist from another planet'. This encyclopaedia mentions several doctrines on mankind, such as utilitarianism, eugenism and Spencerianism. It conveys a number of prejudices of the time about the rise and fall of nations: a nice example is the idea that the differential economic success of English and French Canadians demonstrates their different hereditary potential in the framework of the same environment; another one is the idea that the Inquisition counterselected the best endowed class of the Spanish people, allowing other peoples to rule America. Nowhere does this review turn into a synthesis. Its departure from Darwin's personal style culminates in including in the second edition an appendix by Huxley himself, responding to one of his critics in comparative anatomy, a domain which was not Darwin's firmest field. This first part terminates abruptly, as Darwin moves on to say that in order to tell how and why humanity evolved to its current state, he will now have to consider the whole animal kingdom and substantiate his theory of sexual selection. In the rest of the book, he will no longer elaborate on the views of others, except to cite here and there Bagehot, Spencer and Galton, and will exclusively present his own views.

"Then another book begins, a pure marvel, as Darwin stops reviewing the writings of his contemporaries to review the sexual habits of the whole animal kingdom, from molluscs to primates. From an enormous collection and elaboration of scanty second-hand information on behaviour, and using magnificent figures of birds of Paradise or strange illustrations of sexually dimorphic heads of chameleons or beetle horns, Darwin writes one of the most influential books of the 19th century on sexuality. For instance, Freud's Totem and Taboo imagined it to be a foundation of psycho-analysis. This masterpiece of natural history establishes his authority on the subject, but the really important two sections in it are the introduction, presenting the mechanisms, and the conclusion, presenting his conclusions on man, after a brief and final summary of mechanisms.

"Of the conclusions, let us say that they present mankind as a mosaic of traits caused by a mosaic of evolutionary forces. In short, they posit that moral sense developed in individuals through social interactions and have become hereditary through usage. Pride and courage developed through the habit of fighting between members of the same sex (in this case, human males) over access to the other sex; artistic sense, musical skills, the sense of beauty, and the morphological differences between human populations developed through mate choice. The mechanisms leading to these adaptations are presented in the opening of the second part of the book, where Darwin really uncovers his purpose. Interestingly, this means that to interpret the evolution of moral sense through the law of use and disuse, Darwin depicts this trait in the first part of the book, then presents his law of inheritance at the beginning of the second part, and eventually combines the two in the general conclusion. Likewise, the morphological differences among humans are presented in the first part, sexual selection at the beginning of the second part, and the two are combined by the end of the book. All of this contributes to make the beginning of the second part the cornerstone of the book ...

"Darwin never confused the evolutionary mechanisms based on selection with the hereditary mechanism, pangenesis, which he merely thought to be 'provisionally' the most likely hypothesis to explain known facts of heredity. The overlap of the two mechanisms in explaining a single process may have looked confusing, but he maintained their distinctness throughout, and the selective explanation always prevailed in his writing. The re-evaluation of Lamarckian inheritance in Darwin's late works preluded a weakening of his theory which lasted until the rediscovery of natural selection around 1930. These dark ages were presented by Julian Huxley as the 'eclipse of Darwinism', an expression that became a reference in history of science. The eclipse was actually not so much that of 'Darwinism' itself, as this evasive word was used by a variety of doctrines. It was the eclipse of natural selection theory. But the maintenance of the concept in Darwin's works allowed it to be rediscovered by contemporary science" (Veuille).

"The first edition is in two volumes and occurs in two issues ... The first issue can be recognized by the errata on the verso of the title leaf of Volume II, seventeen errata for Volume I and eight for Volume II. The verso of the title leaf of Volume II of the second issue has a list of nine other works by Darwin and no errata. The verso of the half title leaf of Volume II of the first issue bears the printer's note, but it is blank in the second. The first issue has a note on a tipped in leaf (pp. [ix-x]) in Volume II which refers to 'a serious and unfortunate error' which affects pages 297-299 in Volume I, and pages 161 and 237 in Volume II. In the second issue this leaf is absent and the relevant pages have been entirely reset. The easiest way to distinguish the two issues of Volume I alone is to look at the first word on page 297. It is 'transmitted' in the first issue and 'When' in the second. Both issues have sixteen pages of inserted advertisements for Murray's popular works in Volume I, and sixteen pages of Murray's standard works in Volume II, all dated January 1871. The first issue, of 2,500 copies, was published on February 24, and the second, of 2,000 copies, in March" (Freeman).

Freeman 937; Garrison & Morton 170; Norman 599. Veuille, 'Darwin and sexual selection: One hundred years of misunderstanding,' Comptes Rendus Biologies 333 (2010), pp. 145-156.

2 vols, 8vo (190 x 125 mm), [i-v], vi-viii, [1], 2-423, [1], [16, Murray's advertisements, dated January 1871]; [i-v], vi-viii, [2], [1], 2-475, [1], [16, Murray's advertisements, dated January 1871], including half-titles, with 76 woodcut illustrations in text. Original green publisher's cloth, blind-stamped boards, spine lettered and decorated in gilt. A fine copy.