On the Origin of Species
On the Origin of Species (or, more completely, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life)[3] is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. It was published on 24 November 1859.[4] Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection although Lamarckism was also included as a mechanism of lesser importance. The book presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had collected on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation.[5]
"Origin of Species" and "Origin of the species" redirect here. For other uses, see Origin of Species (disambiguation).Author
Various evolutionary ideas had already been proposed to explain new findings in biology. There was growing support for such ideas among dissident anatomists and the general public, but during the first half of the 19th century the English scientific establishment was closely tied to the Church of England, while science was part of natural theology. Ideas about the transmutation of species were controversial as they conflicted with the beliefs that species were unchanging parts of a designed hierarchy and that humans were unique, unrelated to other animals. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream.
The book was written for non-specialist readers and attracted widespread interest upon its publication. Darwin was already highly regarded as a scientist, so his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion. The debate over the book contributed to the campaign by T. H. Huxley and his fellow members of the X Club to secularise science by promoting scientific naturalism. Within two decades, there was widespread scientific agreement that evolution, with a branching pattern of common descent, had occurred, but scientists were slow to give natural selection the significance that Darwin thought appropriate. During "the eclipse of Darwinism" from the 1880s to the 1930s, various other mechanisms of evolution were given more credit. With the development of the modern evolutionary synthesis in the 1930s and 1940s, Darwin's concept of evolutionary adaptation through natural selection became central to modern evolutionary theory, and it has now become the unifying concept of the life sciences.
Structure, style, and themes[edit]
Nature and structure of Darwin's argument[edit]
Darwin's aims were twofold: to show that species had not been separately created, and to show that natural selection had been the chief agent of change.[175] He knew that his readers were already familiar with the concept of transmutation of species from Vestiges, and his introduction ridicules that work as failing to provide a viable mechanism.[176] Therefore, the first four chapters lay out his case that selection in nature, caused by the struggle for existence, is analogous to the selection of variations under domestication, and that the accumulation of adaptive variations provides a scientifically testable mechanism for evolutionary speciation.[177][178]
Later chapters provide evidence that evolution has occurred, supporting the idea of branching, adaptive evolution without directly proving that selection is the mechanism. Darwin presents supporting facts drawn from many disciplines, showing that his theory could explain a myriad of observations from many fields of natural history that were inexplicable under the alternative concept that species had been individually created.[178][179][180] The structure of Darwin's argument showed the influence of John Herschel, whose philosophy of science maintained that a mechanism could be called a vera causa (true cause) if three things could be demonstrated: its existence in nature, its ability to produce the effects of interest, and its ability to explain a wide range of observations.[181] This reflected the influence of William Whewell's idea of a consilience of inductions, as explained in his work Philosophy of the Inductive Sciences, where if you could argue that a proposed mechanism successfully explained various phenomena you could then use those arguments as evidence for that mechanism.[182]
Literary style[edit]
The Examiner review of 3 December 1859 commented, "Much of Mr. Darwin's volume is what ordinary readers would call 'tough reading;' that is, writing which to comprehend requires concentrated attention and some preparation for the task. All, however, is by no means of this description, and many parts of the book abound in information, easy to comprehend and both instructive and entertaining."[176][183]
While the book was readable enough to sell, its dryness ensured that it was seen as aimed at specialist scientists and could not be dismissed as mere journalism or imaginative fiction. Though Richard Owen did complain in the Quarterly Review that the style was too easy for a serious work of science.[184] Unlike the still-popular Vestiges, it avoided the narrative style of the historical novel and cosmological speculation, though the closing sentence clearly hinted at cosmic progression. Darwin had long been immersed in the literary forms and practices of specialist science, and made effective use of his skills in structuring arguments.[176] David Quammen has described the book as written in everyday language for a wide audience, but noted that Darwin's literary style was uneven: in some places he used convoluted sentences that are difficult to read, while in other places his writing was beautiful. Quammen advised that later editions were weakened by Darwin making concessions and adding details to address his critics, and recommended the first edition.[185] James T. Costa said that because the book was an abstract produced in haste in response to Wallace's essay, it was more approachable than the big book on natural selection Darwin had been working on, which would have been encumbered by scholarly footnotes and much more technical detail. He added that some parts of Origin are dense, but other parts are almost lyrical, and the case studies and observations are presented in a narrative style unusual in serious scientific books, which broadened its audience.[186]
Human evolution[edit]
From his early transmutation notebooks in the late 1830s onwards, Darwin considered human evolution as part of the natural processes he was investigating,[187] and rejected divine intervention.[188] In 1856, his "big book on species" titled Natural Selection was to include a "note on Man", but when Wallace enquired in December 1857, Darwin replied; "You ask whether I shall discuss 'man';—I think I shall avoid whole subject, as so surrounded with prejudices, though I fully admit that it is the highest & most interesting problem for the naturalist."[189][190]
On 28 March 1859, with his manuscript for the book well under way, Darwin wrote to Lyell offering the suggested publisher John Murray assurances "That I do not discuss origin of man".[64][65]
In the final chapter of On the Origin of Species, "Recapitulation and Conclusion", Darwin briefly highlights the human implications of his theory:
Discussing this in January 1860, Darwin assured Lyell that "by the sentence [Light will be thrown on the origin of man and his history] I show that I believe man is in same predicament with other animals.[192] Many modern writers have seen this sentence as Darwin's only reference to humans in the book;[187] Janet Browne describes it as his only discussion there of human origins, while noting that the book makes other references to humanity.[193]
Some other statements in the book are quietly effective at pointing out the implication that humans are simply another species, evolving through the same processes and principles affecting other organisms. For example,[187] in Chapter III: "Struggle for Existence" Darwin includes "slow-breeding man" among other examples of Malthusian population growth.[194] In his discussions on morphology, Darwin compares and comments on bone structures that are homologous between humans and other mammals.[195]
Darwin's early notebooks discussed how non-adaptive characteristics could be selected when animals or humans chose mates,[196] with races of humans differing over ideas of beauty.[197] In his 1856 notes responding to Robert Knox's The Races of Man: A Fragment, he called this effect sexual selection.[198] He added notes on sexual selection to his "big book on species", and in mid-1857 he added a section heading "Theory applied to Races of Man", but did not add text on this topic.[199]
In On the Origin of Species, Chapter VI: "Difficulties on Theory", Darwin mentions this in the context of "slight and unimportant variations":[200]
When Darwin published The Descent of Man, and Selection in Relation to Sex twelve years later, he said that he had not gone into detail on human evolution in the Origin as he thought that would "only add to the prejudices against my views". He had not completely avoided the topic:[201]
He also said that he had "merely alluded" in that book to sexual selection differentiating human races.[203]
