Inception of Darwin's theory
The inception of Darwin's theory began with his search to explain contradictions in contemporary theories of organic development as well as religious explanations of the appearance of design in the natural world.  His fascination as a young man with these questions culminated in the formulation his theory of natural selection, which was eventually published in his book On the Origin of Species.
This article covers Charles Darwin's biography during the period in which he conceived of his theory, and puts his life and work at the time into a broader context.  It begins after Charles Darwin's education and his voyage on the Beagle. See the development of Darwin's theory, the publication of Darwin's theory and the reaction to Darwin's theory for the periods that followed.

# Summary - outline of inception of theory
At Darwin's Geological debut, species related to places were shown when the ornithologist John Gould noticed that specimens from the Galapagos Islands formed "a series of ground finches which are so peculiar" as to form "an entirely new group." The anatomist Richard Owen found that Darwin's fossils showed that extinct species were related to current species in the same locality.
Transmutation ideas convinced Darwin that original immigrants had been altered somehow to become an array of new species, and he began to look at fossils in an evolutionary light.
In notebooks Darwin's speculations included an "irregularly branched" genealogical tree, life as arising only once, and possible experiments. He developed an essentially materialist and deterministic view of human beings and began writing of "my theory".
Animal observations of an orangutan at the zoo showed how human its expressions looked, and made him think that there was little gulf between man and animals. He investigated animal breeding and found parallels to nature removing runts and keeping the fit, with farmers deliberately selecting breeding animals so that through "a thousand intermediate forms" their descendants were significantly changed.
His speculations considered instincts and mental traits, with habits, beliefs, facial expressions and even the "love of deity" having evolved. He thought of the social implications of evolution, suggesting female education to improve mankind which had been "created from animals."
Malthus and Natural Law led him to apply to his search for the Creator's laws the Whig social thinking of struggle for survival with no handouts.
In his Theory he compared breeders selecting traits to a Malthusian Nature selecting from variants thrown up by "chance", then continued to look to the countryside for supporting information.

# Background: influences
After his early life in a Unitarian family, Charles Darwin's education developed his interest in natural history. At Edinburgh University his work as a student of Robert Edmund Grant involved him in pioneering investigations of the ideas of Jean-Baptiste Lamarck and Erasmus Darwin on homology showing common descent, but he also saw how controversial and troubling such theories were. Robert Jameson's course taught Darwin stratigraphic geology, and closed with lectures on the "Origin of the Species of Animals". At Christ's College, Cambridge to qualify as an Anglican clergyman, Darwin became passionate about beetle collecting, then shone in John Stevens Henslow's botany course. He  was convinced by Paley's Natural Theology which set out the Teleological argument that complexity of "design" in nature proved God's role as Creator. The geology course of Adam Sedgwick and summer work mapping strata in Wales emphasised that life on earth went back over eons of time.
Then on his voyage on the Beagle Darwin became convinced by Charles Lyell's uniformitarian theory of gradual geological process, and puzzled over how various theories of creation fitted the evidence he saw.
In the third edition of On the Origin of Species Darwin provided a Historical Sketch of his predecessors in writing of descent with modification or natural selection, including those who he had only learnt of after the 1859 publication of The Origin. His account essentially deals with 19th century authors; "Passing over authors from the classical period to that of Buffon, with whose writings I am not familiar, Lamarck was the first man whose conclusions on this subject excited much attention." However, in a footnote he remarks on how his grandfather, Dr. Erasmus Darwin, Goethe and Geoffroy Saint Hilaire came to the same conclusion on the origin of species in the years 1794-5, anticipating Lamarck.
Various claims have been made of other influences on Darwin, including Ibn Miskawayh's al-Fawz al-Asghar and the Brethren of Purity's Encyclopedia of the Brethren of Purity, which expressed evolutionary ideas on how species evolved from matter, into plants, and then animals, then apes, and then humans. These claims have not been supported by Darwin's biographers.

# Return to celebrity and science
When the Beagle returned, Darwin was quick to take the coach home and arrived at the family home of The Mount House in Shrewsbury, Shropshire late at night on 4 October 1836. He went straight to bed, then greeted his family at breakfast and began catching up with news of his family and of the country: "all England appears changed". The Reform Bill had brought  what the Tory Duke of Wellington described as a shift in power from decent Tory Anglicans to Whig manufacturers, shopkeepers and atheists. Everyone was discussing the writings of Thomas Malthus on population outstripping resources as the New Poor Law described by opponents as "a Malthusian bill designed to force the poor to emigrate, to work for lower wages, to live on a coarser sort of food" brought the construction of workhouses in the southern counties despite riots and arson. The government had not yet dared introduce these measures to London and the industrial north, and recession was bringing threats of mass unemployment.
Darwin wrote to Henslow that he was still "giddy with joy & confusion... I want your advice on so many points, indeed I am in the clouds" and on 15 October went on to Cambridge to get advice from Henslow and Sedgwick on the task of organising the description and cataloguing of his collections accumulated from the Beagle expedition. Henslow took on the plants, and Darwin was given introductions to the best London naturalists with a warning that they would already be busy with other work.
Charles went on to stay with his brother Erasmus in London, near the scientific institutions which were in the throes of renovation, while the city itself was being torn up to install new sewers and gas lighting. He went round the British Museum, the Royal College of Surgeons, the Linnean, the Zoological Society and  Geological Society, trying to get the experts to take on his collections. Henslow had already established his former pupil's reputation during the Beagle expedition by giving selected naturalists access to fossil specimens sent back as well as having Darwin's geological writings privately printed for distribution. Darwin went "in most exciting dissipation amongst the Dons in science", and as Charles Bunbury reported, " seems to be a universal collector" finding new species "to the surprise of all the big wigs". While geologists were quick to take on the rock samples, zoologists already had more specimens arriving than they could deal with. Their institutions were in turmoil as democrats argued for reforms replacing the aristocratic amateurs with professional salaried scientists as in the French research institutes. At the Zoological Society the reformers were led by Darwin's tutor from Edinburgh days, Robert Edmund Grant. Darwin now had an allowance plus stocks from his father, bringing him around 400 per year, and his sympathies were with the amateur clerical "Dons in science" of Cambridge.

## Owen and fossils
The geologist Charles Lyell invited Darwin to dinner on 29 October 1836. Over dinner Lyell listened eagerly to Darwin's stories (which supported Lyell's uniformitarianism) and introduced him to Richard Owen and William Broderip, Tories who had just been involved in voting Grant out of a position at the Zoological Society. Owen was rapidly ousting Grant as the country's leading anatomist. Darwin went to visit him at his Royal College of Surgeons, and Owen agreed to work on some animal specimens in spirits and the fossil bones. Owen shared Darwin's enthusiasm. He was a proponent of German ideas of "organising energy" and vehemently opposed to Grant's evolution. At around this time Grant was one the few to volunteer his help with cataloguing the collection. Darwin turned down the offer, not wanting to be associated with a disreputable radical who denounced his Cambridge friends.
On 12 November Darwin visited his Wedgwood relatives at Maer Hall and they encouraged him to publish a book of his travels based on his diary, an idea his sisters picked up when he visited his home.
On 2 December he returned to London and began finding takers for his specimens, with Thomas Bell (naturalist) and the Revd. William Buckland interested in the reptiles. Darwin's reputation was being made by the giant mammal fossils. Owen's first surprising revelation was that a hippopotamus sized fossil skull 2 feet 4 inches (710 mm) long which Darwin had bought for eighteen pence while on a "galloping" trip 120 miles (190 km) from Montevideo was of an extinct giant capybara, a rodent which Owen named Toxodon. Darwin wrote to his sister Caroline that " are turning out great treasures" and of the rodent, "what famous cats they ought to have had in those days!" The College of Surgeons distributed casts of the fossils to the major scientific institutions.
Darwin paid a visit to his brother Eras's lady friend the literary Whig Miss Harriet Martineau who had strong views on egalitarianism and whose writings had popularised the ideas of Thomas Malthus. "She was very agreeable" and they discussed the "process of world making" that she had seen on her visit to the Niagara Falls. While he later remarked on "how ugly" she was, she described Charles as "simple, childlike, painstaking, effective".

## Geological debut, species related to places
Unhappy with life in a dirty odious London he returned to Cambridge on 13 December then presented a talk to the Cambridge Philosophical Society on glassy tubes he had found amongst Maldonado sand dunes, explained by lightning having fused the sand. He then wrote his first paper, showing that the Chilean coast and the South American land-mass was rising slowly, and discussed his ideas with Lyell. To Lyell's delight, Darwin went further in balancing the rising continent with sinking mountains forming the basis of coral atolls.  Darwin then returned to London to read his paper to the Geological Society on 4 January 1837. Despite Darwin's nerves about his debut, the talk was so well received that he felt like a peacock admiring his tail.
On the same day Darwin presented 80 mammal and 450 bird specimens to the Zoological Society. The Mammalia were ably taken on by George R. Waterhouse. While the birds seemed almost an afterthought the ornithologist John Gould was quick to notice the significance of specimens from the Galapagos Islands and startlingly revealed at the next meeting on 10 January that what Darwin had taken to be wrens, blackbirds and slightly differing finches were "a series of ground finches which are so peculiar" as to form "an entirely new group, containing 12 species." The story of what we now call "Darwin's finches" was covered by the daily newspapers.
Owen was finding unexpected relationships from the fossils: a horse sized anteater, a gigantic ground sloth and an ox-sized armoured armadillo which he called Glyptodon. The Patagonian spine and leg bones which Darwin had thought might be from a Mastodon were from a gigantic Llama. Lyell saw a "law of succession" with mammals being replaced by their own kind on each continent, and on 17 February 1837 used his presidential address at the Geographical Society to present Owen's findings to date on Darwin's fossils, pointing out this inference that extinct species were related to current species in the same locality. He invited Darwin to come along, and the speech drew Darwin's attention to the question of why past and present species in one place should be so closely related. At the same meeting Darwin was elected to the Council of the Society. For Lyell this was "a glorious addition to my society of geologists", gentlemen (and amateurs of independent means) with duty only to scientific integrity, social stability and responsible religion, for Darwin it meant joining the respectable elite of eminent geologists developing a science dealing with the age of the earth and the Days of Creation.
Darwin had already been invited by FitzRoy to contribute his Journal, based on his field notes, as the natural history section of the captain's account of the Beagle's voyage. He now also plunged into writing a book on South American Geology, putting his and Lyell's ideas forward against the cataclysmic explanation of mountain formation Alcide d'Orbigny was promoting in a multi-volume account of the continent begun two years previously.
To supervise his collections Darwin had to return to London, and on Lyell's advice he arrived on 6 March 1837, in time for one of Charles Babbage's Saturday soirees, talking shops about the latest developments "brilliantly attended by fashionable ladies, as well as literary and scientific gents", bankers and politicians, where Babbage promoted such projects as his mechanical computer. Lyell had been impressed by Babbage's unofficial Ninth Bridgewater Treatise, A Fragment which suggested that God acted as a divine programmer rather than miraculously producing new species on a Creative whim. At first Darwin stayed with Eras, then moved to nearby lodgings, joining Eras's circle of friends including Martineau and Hensleigh and enjoying his intimate dinner parties with guests such as Lyell, Babbage and Thomas Carlyle.

# Transmutation
Scientific circles were buzzing with ideas of Transmutation of species with most medical men talking of a legislated "process of change", overturning the Creation biology doctrine of "Created kinds". Darwin came to accept that "the Creator creates by... laws". A few days after arriving in London he met Gould again. He learnt that his Galapagos "wren" was yet another species of finch, making 13 in all. Although Darwin had not bothered to label these birds by island, he had labeled four mockingbirds, speculating later on the return voyage that if they turned out to be true varieties it "would undermine the stability of Species". Now Gould told him that they were not just varieties, but distinct species, related to but different from other species on the American mainland. Thomas Bell confirmed that the giant Galapagos tortoises were native, not brought in by buccaneers for food as Darwin had thought, giving credibility to the Vice-Governor's story that each island had its own tortoise.
By mid March Darwin realised that original immigrants had been altered somehow to become an array of new species. These were the ideas of what his Cambridge tutor Adam Sedgwick called "infidel naturalists.. false theories", and even for Lyell this heretically implied ape ancestry, destroying mankind's "high estate". Darwin was more open to new speculation. He had seen the bestial life of the natives of Tierra del Fuego, apparently happy in their harsh environment, and Jemmy Button's reversion to savagery. To him the need was to explain how both Fuegians and civilised Europeans could be "essentially the same creatures" from the hand of the same Creator. At the Geographical Society meeting on 2 May 1837, when Darwin read his next paper on the Pampas, the first discoveries of ancient fossil monkeys were announced. Lyell uncomfortably joked that from "Lamarck's view" this gave a long time "for their tails to wear off", but Darwin was beginning to look at these "wonderful" fossils in an evolutionary light.
At their frequent meetings Owen argued that intrinsic "organising energy" in the "embryonic germ" set the lifespan of the species and precluded transmutation. The botanist Robert Brown showed Darwin a different concept, of "swarming atoms" inside the germ, allowing nature's self development. Darwin began speculating on transmutation in his Red Notebook which he had begun on the Beagle. Gould confirmed that the southern Rhea was indeed a separate species, and Darwin speculated as to why their territories overlapped without intermediate species, wondering if mutations (known then as "monsters" or "freaks") "present an analogy to production of species". Embarrassed by his lack of labels for his finch specimens, he examined FitzRoy's in the British Museum and contacted seamen including Syms Covington for their collections. From this he was able to relate the finches to separate islands, with distinct species on each island. As well as pressing on with his Journal, he started an ambitious project to get the expert reports on his collection published as a multi-volume Zoology of the Voyage of H.M.S. Beagle. A search for sponsorship was answered when Henslow used his contacts with the Chancellor of the Exchequer Thomas Spring Rice to arrange a Treasury grant of 1,000. Darwin finished writing his Journal around 20 June when King William IV died and the Victorian era began.

## Secret notebooks
In mid July 1837 Darwin began a secret notebook on transmutation, his "B" notebook, with a title page headed Zoonomia, scribbling down a framework for his speculations. Considering Owen's idea that complexity of a species was inversely related to its life span, he sketched an "irregularly branched" genealogical tree and began thinking of life as arising only once. Still influenced by Paley, he assumed that variants emerged perfect, but he rejected Grant's idea of progress upwards to higher forms, writing "It is absurd to talk of one animal being higher than another". He developed the hypothesis that, for example, where every island in the Galapagos Archipelago had its own kind of tortoise, these had originated from a single tortoise species and had adapted to life on the different islands in different ways. Thinking of how ancestors could have spread to islands, he noted possible experiments.
Under pressure with organising Zoology and correcting proofs of his Journal which had to have the introduction revised when FitzRoy complained that he was "astonished at the total omission of any notice of the officers" for their help, Darwin's health suffered. On 20 September 1837 he suffered "an uncomfortable palpitation of the heart". His doctors advised him "strongly to knock off all work" and leave for the country. Two days later he went to Maer Hall, the Wedgwood's home, for a month of recuperation. His relations wore him out with questions about gaucho life. His invalid aunt was being cared for by the as yet unmarried Emma, and his uncle Jos pointed out an area of ground where cinders had disappeared under loam which Jos though might have been the work of earthworms. Darwin returned to London on 21 October and on 1 November gave a talk on worm casts to the Geological Society, a mundane subject which to them seemed eccentric.
His notebooks developed an essentially materialist and deterministic view of human beings, with the conclusions that freewill was an illusion and the brain was mechanistic. He had avoided taking on official posts which would take valuable time, turning down William Whewell's request that he become Secretary of the Geological Society with excuses including "anything which flurries me completely knocks me up afterwards and brings on a bad palpitation of the heart", but by March 1838 he accepted the post. On 7 March he read to the Society his longest paper yet, which explained the earthquake he had witnessed at Concepcion, Chile, in terms of gradual crustal movements, to the delight of Lyell. Despite hours of practice "I was so nervous at first, I somehow could see nothing all around me, & felt as if my body was gone, & only my head left." At the same time Darwin was privately scorning Whewell's faith in a human-centred universe being perfectly adapted to man and writing of "my theory" which he thought "would give zest to recent & Fossil Comparative Anatomy", transforming the "whole metaphysics".
Darwin's ideas fitted with the radical Unitarianism of his brother Erasmus's circle including Harriet Martineau, but were heretical to his Anglican friends in the scientific establishment. Despite stomach upsets Darwin explored in his notebooks the metaphysical implications of a consistent positivist creed, arguing that a person can be congratulated for doing good but the act is actually purely conditioned and deserves no credit. Indeed, wickedness is no more a mans fault than bodily disease!. His Anglican friends would have found this deterministic materialism more shocking than his ideas of evolution. Such materialist ideas had been seized on by socialist agitators, red Lamarckians who stirred the mob to overthrow the social order and Chartists who even demanded the vote for working men! The establishment and the Tory press were quick to crush such ideas, using the full force of the law at a time when blasphemy was a criminal offence. Many were denounced and overthrown for such scandalous ideas, including the surgeon William Lawrence who was forced to resign his post and lost copyright on his book Lectures on Man. This book was promptly pirated by the notorious agitator and pornography publisher William Benbow, and then published in cheap editions such as the copy that Darwin now read.  As a result Darwin was secretive and very cautious in even hinting about his ideas to the friends he was bursting to share discussions with.
Dissenters such as John Wesley abhorred slavery and privilege, and had a bleaker view of nature than Paley. Darwin reflected these ideas in his notes, writing "Animals  whom we have made our slaves we do not like to consider our equals.  Do not slave holders wish to make the black man other kind? Animals with affections, imitation, fear, pain, sorrow for the dead." and "if we choose to let conjecture run wild then animals our fellow brethren in pain, disease death & suffering & famine; our slaves in the most laborious work, our companion in our amusements, they may partake, from our origin in one common ancestor we may all be netted together."

# Animal observations
By February 1838 Darwin was on to a new pocketbook, the maroon C notebook, and was investigating the breeding of domestic animals. He found the newspaper wholesaler William Yarrell at the Zoological museum a fund of knowledge, and questioned if breeders weren't going against nature in "picking varieties". He was now writing of "Descent" rather than transmutation, and hinting at ideas of "adaptation" to climate.
At the zoo on 28 March he had his first sight of an ape, and was impressed at the orang-utan's antics "just like a naughty child" when the keeper held back an apple. In his notes he wrote "Let man visit Ourang-outang in domestication, hear expressive whine, see its intelligence.... let him look at savage...naked, artless, not improving yet improvable & let him dare to boast of his proud preeminence." Here Darwin was drawing on his experience of the natives of Tierra del Fuego and daring to think that there was little gulf between man and animals despite the theological doctrine that only humanity possessed a soul.
He sent his parents the gossip that Miss Martineau had been "as frisky lately as the Rhinoceros.  Erasmus has been with her noon, morning & night:  if her character is not as secure, as a mountain in the polar regions she would certainly lose it". He began thinking about marriage himself, listing the pros and cons on the back of an old letter and noting that rather than being "a man tied down in London" going over information, "I have so much more pleasure in direct observation... In country, experiment & observation on lower animals,  more space."
Darwin found a pamphlet by Yarrell's friend Sir John Sebright with a passage reading:
A severe winter, or a scarcity of food, by destroying the weak and the unhealthy, has all the good effects of the most skilful selection. In cold or barren countries no animals can live to the age of maturity, but those who have strong constitutions; the weak and the unhealthy do not live to propagate their infirmities.
After reading the pamphlet, Darwin commented "excellent observations of sickly offspring being cut off". Sebright talked of females falling to "the most vigorous males" and of how "the strongest individuals of both sexes, by driving away the weakest, will enjoy the best food, and the most favourable positions, for themselves and their offspring." To Darwin, while nature removed runts and thrust the fit forward, "the whole art of making  varieties" by selecting mates to breed an ornamental duck produced "a mere monstrosity propagated by art". Quizzing his cousin William Darwin Fox about crossing domestic breeds, he admitted for the first time that "It is my prime hobby & I really think some day, I shall be able to do something on that most intricate subject species & varieties." Pondering likely opposition to his ideas, he noted that there must have been "a thousand intermediate forms" between the otter and its land ancestor. "Opponents will say, show me them. I will answer yes, if you will show me every step between bull Dog & Greyhound." 

## Secret speculations
Darwin's secret speculations in his notebooks deepened as he wondered how instincts and mental traits were passed on to offspring, finding it "difficult to imagine  anything but structure of the brain". He wrote of habits, beliefs and even the "love of deity" having evolved, adding to himself "oh you Materialist!". In private discussions with his cousin, "Hensleigh says the love of the deity & thought of him or eternity, only difference the mind of man & animals" which conflicted with Darwin's own experience with the "savages" of Tierra del Fuego. He struggled on with the Beagle geology, overworked, worried and suffering stomach upsets and headaches which laid him up for days on end. Privately he thought of the social implications of evolution, writing "Educate all classes, improve the women. (double influence) & mankind must improve." This was similar to the position of the radical Lamarckians, but female education was already supported by the whole Wedgwood-Darwin family, and strongly advocated by Martineau.
Darwin wrote "Man in his arrogance thinks himself a great work, worthy the interposition of a deity, more humble & I believe true to consider him created from animals." He thought grinning was "no doubt a habit gained by formerly being a baboon with giant canine teeth... Laughing modified barking, smiling modified laughing. Barking to tell  good news. discovery of prey.  arising no doubt from want of assistance.  crying is a puzzler."
In June as he worried at these ideas and the Beagle Geology his illness intensified, with stomach upsets, headaches and heart troubles, so that he became overworked and laid up for days on end. "I hope I may be able to work on right hard the next three years... but I find the noddle & the stomach are antagonistic powers, and that it is a great deal more easy to think too much in a day, than to think too little  What thought has to do with digesting roast beef,I cannot say."
At the same time Darwin was gaining public position, and on 21 June 1838 was elected to the establishment Athenaeum Club, along with Charles Dickens. He would dine there daily, feeling " like a gentleman, or rather like a Lord... I enjoy it the more, because I fully expected to detest it... one meets so many people there that one likes to see."

# Thoughts of marriage
The Hensleigh Wedgwoods were now living next door to Erasmus and were visited for a week by Catherine Darwin and Emma Wedgwood. Charles visited and found them "a very pleasant merry company", particularly noticing Emma's remarkably pleasant manners.
Illness prompted Darwin to take a break from the pressure of work and on 23 June 1838 he took the steamboat to Edinburgh to go "geologising" in Scotland. After revisiting Edinburgh on 28 June (the day that Queen Victoria had her coronation in London) he went on to Fort William. At Glen Roy in glorious weather he was convinced that he had solved the riddle of the "parallel roads" around the glen, which he identified as raised beaches, though later geologists would support the ideas of Louis Agassiz that these had been formed by glaciation.
Fully recuperated and optimistic, he returned home to  The Mount, Shrewsbury. He discussed his ideas with his father and asked for advice about Emma. Speaking from experience, Doctor Robert Waring Darwin told his son to conceal religious doubts which could cause "extreme misery... Things went on pretty well until the husband or wife became out of health, and then some women suffered miserably by doubting about the salvation of their husbands, thus making them likewise to suffer." Charles drew up a list with two columns on a scrap of paper. Under Marry he listed benefits, "Childrenif it please GodConstant companion & friend in old age will feel interested in one,object to be beloved and played with, better than a dog anyhow.....Imagine living all one's day solitary in smoky dirty London House.only picture to yourself a nice soft wife on a sofa with good fire, & books & music perhaps...", while Not Marry headed "Freedom to go where one liked... Not forced to visit relatives..to have the expense and anxiety of children.. fatness & idleness... if many children forced to earn one's bread..". He concluded "MarryMarryMarry Q.E.D."
Then he spent his fortnight being "Very idle at Shrewsbury" which meant starting his "D" notebook on the transmutation sequence and his "M" notebook on the evolutionary basis of moral and social behaviour, filling sixty pages with notes and anecdotes from his father about experiences with patients.
Having come down in favour, he went to visit his cousin Emma on 29 July. He did not get around to proposing, but failed to conceal his ideas on transmutation. Emma noted "he is the most open, transparent man I ever saw, and every word expresses his real thoughts." When she asked about ultimate origins he steered clear of the subject, aware that "it will become necessary to show how the first eye is formed" which he could not yet do.

# Malthus and Natural Law
After returning to London on 1 August 1838 Darwin read a review of Auguste Comte's Positive Philosophy at the Athenaeum Club. It bolstered his pantheist ideas of natural laws, making him remark "What a magnificent view one can take of the world" with everything synchronised "by certain laws of harmony", a vision "far grander" than the Almighty individually creating "a long succession of vile Molluscous animals  How beneath the dignity of Him"! Only a "cramped imagination" saw God "warring against those very laws he established in all organic nature." His work on Coral Reefs and a paper theorising that Glen Roy had been an arm of the sea soldiered on. He visited the zoo to experiment, observing the reactions of the apes and seeing emotions like "revenge and anger", implying that "Our descent, then,  of our evil passions." He needed an ally, and hinted to Lyell that his work was "bearing on the question of species", amassing "facts, which begin to group themselves clearly under sub-laws."
On 21 September he had a vivid dream "that a person was hung & came to life, & then made many jokes, about not having run away &c having faced death like a hero...  showing  scar behind  that he had honourable wounds."
Then in late September he began reading "for amusement" the 6th edition of Malthus's An Essay on the Principle of Population which reminded him of Malthus's statistical proof that human populations breed beyond their means and compete to survive, at a time when he was primed to apply these ideas to animal species. Malthus had softened from the bleakness of the earlier editions, now allowing that the population crush could be mitigated by education, celibacy and emigration. Already Radical crowds were demonstrating against the harsh imposition of Malthusian ideas in the Poor Laws, and a slump was resulting in mass emigration. Lyell was convinced that animals were also driven to spread their territory by overpopulation, but Darwin went further in applying to his search for the Creator's laws the Whig social thinking of struggle for survival with no handouts.
Malthus's essay calculates from the birth rate that human population could double every 25 years, but in practice growth is kept in check by death, disease, wars and famine. Darwin was well prepared to see at once that this related to de Candolle's concept of "nature's war" and also applies to the struggle for existence amongst wildlife, so that when there is more population than resources can maintain, favourable variations that allow the organism to better use the limited resources available tend to be preserved, and unfavourable ones destroyed by being unable to get the means for existence, resulting in the formation of new species. On 28 September 1838 he noted this insight, describing it as a kind of wedging, forcing adapted structures into gaps in the economy of nature formed as weaker ones were thrust out. He now had a theory by which to work.

# Proposal
Darwin's thoughts and work continued and he suffered repeated bouts of illness. On 11 November he returned to Maer Hall and proposed to Emma.
Again he discussed his ideas, and she subsequently wrote telling him of her "fear that our opinions on the most important subject should differ widely. My reason tells me that honest & conscientious doubts cannot be a sin, but I feel it would be a painful void between us. I thank you from my heart for your openness with me & I should dread the feeling that you were concealing your opinions from the fear of giving me pain.... my own dear Charley, we now do belong to each other & I cannot help being open with you... Will you..read our Saviour's farewell discourse to his disciples . It is so full of love & devotion & every beautiful feeling". As well as "love one another" it also includes "If a man abide not in me...they are burned". He sent her a warm reply which gave her the comfort that he had entered into her heart's concern "a little more", but this tension would remain.
Emma's father promised a dowry of 5,000 plus 400 a year, while Doctor Darwin added 10,000 for Charles, to be invested. They decided to move to London until Charles had "wearied the geological public" with his itch to write, then they would "decide, whether the pleasures of retirement & country... are preferable to society."

# Theory
Charles went house-hunting by day. At night he thought about "innumerable variations" (which he still thought were acquired in some way) with competitive nature selecting the best leading to step by step change, while vestigial organs like the human coccyx (tail) were not, as commonly thought, God "rounding out his original thought  exhaustion", but ancestral remnants pointing to "the parent of man".
Darwin considered Malthus's argument, that human populations breed beyond their means and compete to survive, in relation to his findings about species relating to localities, earlier enquiries into animal breeding, and ideas of Natural "laws of harmony". Around late November 1838 he compared breeders selecting traits to a Malthusian Nature selecting from random variants, now thrown up by "chance", so that "every part of newly acquired structure is fully practised and perfected", thinking this "the most beautiful part of my theory" of how species originated.
In the inception of his theory Darwin tried to satisfy the methodology of William Whewell's metascience which is now thought to be mistaken in many ways, and in the 1860s this led to him having to debate the merits of the methodology.

## Stress
The Zoology ran into difficulties, with Richard Owen having to halt work on Fossil Mammalia, and John Gould sailing off for Tasmania leaving Darwin to complete the half finished Birds. "What can a man have to say, who works all morning in describing hawks & owls; & then rushes out , & walks in a bewildered manner up one street & down another, looking out for the word To Let'." Emma responded urging him "to leave town at once & get some rest. You have looked so unwell for some time that I fear you will be laid up... nothing could make me so happy as to feel that I could be of any use or comfort to my own dear Charles when he is not well. So don't be ill any more my dear Charley till I can be with you to nurse you".
On 19 December 1838 as secretary of the Geological Society of London Darwin witnessed the vicious interrogation by Owen and his allies including Sedgwick and Buckland of Darwin's old tutor Robert Edmund Grant when they ridiculed Grant's Lamarckian heresy in a clear reminder of establishment hatred of evolutionism.

# Marriage
Emma came to help and they found the gaudily decorated house they nicknamed "Macaw Cottage" in Gower Street, London, and Darwin moved his "museum" in on 1 January 1839, astounding himself, Erasmus and the porters with the weight of his luggage containing geological specimens.
On 24 January 1839 he was honoured by being elected as Fellow of the Royal Society and presented his paper on the Roads of Glen Roy. The next day he took the train home to Shrewsbury, then on the 28th travelled to Maer Hall.
On 29 January 1839, Charles married Emma at Maer, Staffordshire in an Anglican ceremony arranged to also suit the Unitarians, conducted by the vicar, their cousin John Allen Wedgwood. Emma's bedridden mother slept through the service, sparing Emma "the pain of parting". Immediately afterwards Charles and Emma rushed off to the railway station, raising their relative's eyebrows, and ate their sandwiches and toasted their future from a "bottle of water" on the train. Back at Macaw Cottage, Charles noted in his journal "Married at Maer & returned to London 30 years old", and in his secret "E" notebook recorded uncle John Wedgwood's views on turnips.
See the development of Darwin's theory for the ensuing developments, in the context of his life, work and outside influences at the time.

# Citations
-  Darwin 1861, p. xiii.
-  Muhammad Hamidullah and Afzal Iqbal (1993), The Emergence of Islam: Lectures on the Development of Islamic World-view, Intellectual Tradition and Polity, p. 143-144. Islamic Research Institute, Islamabad.
-  Eloise Hart, Pages of Medieval Mideastern History. (cf. Isma'ili, Yezidi, Sufi, The Brethren Of Purity, Ismaili Heritage Society)
-  "Ikhwan as-Safa and their Rasa'il: A Critical Review of a Century and a Half of Research", by A. L. Tibawi, as published in volume 2 of The Islamic Quarterly in 1955; pgs. 28-46
-  Browne 1995
-  Babbage, Charles The Ninth Bridgewater Treatise 2nd edn. 1838, London: John Murray.
-  Charles Darwin (1838). "Notebook B: Transmutation of species (1837-1838) p. 216". Retrieved 2007-09-21..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
-  EconLib-1826: An Essay on the Principle of Population, 6th edition, 1826.  Library of Economics and Liberty
-  Desmond & Moore 1991, p. 264-265.
-  Jump up to: 10.0 10.1 Charles Darwin: gentleman naturalist A biographical sketch by John van Wyhe, 2006
-  Huxley, Thomas, 1897, Evolution and Ethics and Other Essays", D. Appleton and Company, New York. Section IV, CapitalThe Mother of Labour, pp 162-3.
-  Autobiography of Charles Darwin, p.34