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Charles Darwin Quotes
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Charles Robert Darwin, was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. He established that all species of life have descended over time from common ancestors and, in a joint publication with Alfred Russel Wallace, introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.

Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s, the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.

Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. Studies at the University of Cambridge encouraged his passion for natural science. His five-year voyage on HMS Beagle established him as an eminent geologist whose observations and theories supported Charles Lyell's uniformitarian ideas, and publication of his journal of the voyage made him famous as a popular author.

Puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations and in 1838 conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research and his geological work had priority. He was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting immediate joint publication of both of their theories. Darwin's work established evolutionary descent with modification as the dominant scientific explanation of diversification in nature. In 1871 he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex, followed by The Expression of the Emotions in Man and Animals . His research on plants was published in a series of books, and in his final book, The Formation of Vegetable Mould, through the Actions of Worms , he examined earthworms and their effect on soil.

Darwin has been described as one of the most influential figures in human history, and he was honoured by burial in Westminster Abbey.

✵ 12. February 1809 – 19. April 1882   •   Other names Charles Robert Darwin
Charles Darwin photo
Charles Darwin: 161   quotes 18   likes

Charles Darwin Quotes

“I also attended on two occasions the operating theatre in the hospital at Edinburgh, and saw two very bad operations, one on a child, but I rushed away before they were completed. Nor did I ever attend again, for hardly any inducement would have been strong enough to make me do so; this being long before the blessed days of chloroform. The two cases fairly haunted me for many a long year.”

Charles Darwin

page 48 http://darwin-online.org.uk/content/frameset?pageseq=88&itemID=F1497&viewtype=image
Autobiography (1958)

Strong

“It is a curious little world within itself”

Charles Darwin book The Voyage of the Beagle

About the island of Saint Helena
The Voyage of the Beagle (1839)
Source: http://www.darwinproject.ac.uk/letter/entry-305

World

“[T]he young and the old of widely different races, both with man and animals, express the same state of mind by the same movements.”

Charles Darwin book The Expression of the Emotions in Man and Animals

Source: The Expression of the Emotions in Man and Animals (1872), chapter XIV: "Concluding Remarks and Summary", page 352 http://darwin-online.org.uk/content/frameset?pageseq=380&itemID=F1142&viewtype=image

Animals

“It is impossible to answer your question briefly; and I am not sure that I could do so, even if I wrote at some length. But I may say that the impossibility of conceiving that this grand and wondrous universe, with our conscious selves, arose through chance, seems to me the chief argument for the existence of God; but whether this is an argument of real value, I have never been able to decide. I am aware that if we admit a first cause, the mind still craves to know whence it came, and how it arose. Nor can I overlook the difficulty from the immense amount of suffering through the world. I am, also, induced to defer to a certain extent to the judgment of the many able men who have fully believed in God; but here again I see how poor an argument this is. The safest conclusion seems to me that the whole subject is beyond the scope of man's intellect; but man can do his duty.”

Charles Darwin

volume I, chapter VIII: "Religion", pages 306-307 http://darwin-online.org.uk/content/frameset?pageseq=324&itemID=F1452.1&viewtype=image; letter http://www.darwinproject.ac.uk/entry-8837 to Dutch student N.D. Doedes (2 April 1873)
The Life and Letters of Charles Darwin (1887)

Men , God , World , Question

“I would suggest to you the advantage, at present, of being very sparing in introducing theory in your papers (I formerly erred much in Geology in that way): let theory guide your observations, but till your reputation is well established be sparing in publishing theory. It makes persons doubt your observations. How rarely R. Brown ever indulged in theory: too seldom perhaps! Do not work too hard, and do not be discouraged because your work is not appreciated by the majority.”

Charles Darwin book More Letters of Charles Darwin

Letter to John Scott, quoted in More Letters of Charles Darwin: A Record of His Work in a Series of Hitherto Unpublished Letters http://books.google.com/books?id=8FXwAAAAMAAJ&, volume 2, page 323 (1903)
Other letters, notebooks, journal articles, recollected statements

Way , Personality

“I have watched how steadily the general feeling, as shown at elections, has been rising against Slavery. What a proud thing for England if she is the first European nation which utterly abolishes it! I was told before leaving England that after living in slave countries all my opinions would be altered; the only alteration I am aware of is forming a much higher estimate of the negro character. It is impossible to see a negro and not feel kindly towards him; such cheerful, open, honest expressions and such fine muscular bodies. I never saw any of the diminutive Portuguese, with their murderous countenances, without almost wishing for Brazil to follow the example of Hayti; and, considering the enormous healthy-looking black population, it will be wonderful if, at some future day, it does not take place.”

Charles Darwin

volume I, chapter VI: "The Voyage", page 246 http://darwin-online.org.uk/content/frameset?pageseq=264&itemID=F1452.1&viewtype=image; letter to sister Caroline Sarah Darwin (22 May 1833)
The Life and Letters of Charles Darwin (1887)

Feeling , Future , Country

“My wife has just finished reading aloud your 'Life with a Black Regiment,' and you must allow me to thank you heartily for the very great pleasure which it has in many ways given us. I always thought well of the negroes, from the little which I have seen of them; and I have been delighted to have my vague impressions confirmed, and their character and mental powers so ably discussed. When you were here I did not know of the noble position which you had filled. I had formerly read about the black regiments, but failed to connect your name with your admirable undertaking. Although we enjoyed greatly your visit to Down, my wife and myself have over and over again regretted that we did not know about the black regiment, as we should have greatly liked to have heard a little about the South from your own lips.”

Charles Darwin

volume III, chapter IV: "The Publication of the 'Descent of Man', page 176 http://darwin-online.org.uk/content/frameset?pageseq=188&itemID=F1452.3&viewtype=image; letter to Thomas Higginson (27 February 1873)
The Life and Letters of Charles Darwin (1887)

Life , Pleasure , Way , Reading

“It seems to me absurd to doubt that a man may be an ardent Theist & an evolutionist. … I have never been an atheist in the sense of denying the existence of a God.”

Charles Darwin

Letter http://www.darwinproject.ac.uk/letter/entry-12041 to John Fordyce, 7 May 1879
Other letters, notebooks, journal articles, recollected statements

God , Sense

“There can be little doubt that the greater size and strength of man, in comparison with woman, together with his broader shoulders, more developed muscles, rugged outline of body, his greater courage and pugnacity, are all due in chief part to inheritance from his half-human male ancestors. These characters would, however, have been preserved or even augmented during the long ages of man's savagery, by the success of the strongest and boldest men, both in the general struggle for life and in their contests for wives; a success which would have ensured their leaving a more numerous progeny than their less favoured brethren.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

second edition (1874), chapter XIX: "Secondary Sexual Characters of Man", page 563 http://darwin-online.org.uk/content/frameset?pageseq=586&itemID=F944&viewtype=image
The Descent of Man (1871)

Life , Men , Age , Courage

“I am quite conscious that my speculations run quite beyond the bounds of true science. … I inferred that genera & Families with very few species (i. e. from Extinction) would be apt (not necessarily always) to have narrow ranges & disjoined ranges. You will not perceive, perhaps, what I am driving at & it is not worth enlarging on, — but I look at Extinction as common cause of small genera & disjoined ranges & therefore they ought, if they behaved properly & as nature does not lie to go together!”

Charles Darwin

The first sentence is often quoted in isolation http://www.conservapedia.com/Charles_Darwin, with the suggestion that Darwin is saying that his speculations concerning evolution "run quite beyond the bounds of true science." In fact, as the context makes clear, Darwin is referring to his speculations concerning the geographical ranges of genera with few species.
Other letters, notebooks, journal articles, recollected statements
Source: Letter http://www.darwinproject.ac.uk/letter/entry-2109 to Asa Gray, 18 June 1857

Lie , Family , Nature , Science

“I am almost convinced (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable.”

Charles Darwin

volume II, chapter II: "The Growth of the 'Origin of Species' — 1843-1856", page 23 http://darwin-online.org.uk/content/frameset?pageseq=39&itemID=F1452.2&viewtype=image; letter http://www.darwinproject.ac.uk/letter/entry-729 to J.D. Hooker (11 January 1844)
The Life and Letters of Charles Darwin (1887)

“In this case, therefore, the worms judged with a considerable degree of correctness how best to draw the withered leaves of this foreign plant into their burrows; notwithstanding that they had to depart from their usual habit of avoiding the foot-stalk.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 2: Habits of Worms, p. 70. http://darwin-online.org.uk/content/frameset?pageseq=85&itemID=F1357&viewtype=image

Drawing

“Lastly, isolation, by checking immigration and consequently competition, will give time for any new variety to be slowly improved; and this may sometimes be of importance in the production of new species. If, however, an isolated area be very small, either from being surrounded by barriers, or from having very peculiar physical conditions, the total number of the individuals supported on it will necessarily be very small; and fewness of individuals will greatly retard the production of new species through natural selection, by decreasing the chance of the appearance of favourable variations.”

Charles Darwin book On the Origin of Species (1859)

This passage has been cited as an anticipation of the idea of punctuated equilibrium.
Source: On the Origin of Species (1859), chapter IV: "Natural Selection", page 105 http://darwin-online.org.uk/content/frameset?pageseq=120&itemID=F373&viewtype=image

Support , Nature , Appearance , Chance

“Even insects express anger, terror, jealousy, and love by their stridulation.”

Charles Darwin book The Expression of the Emotions in Man and Animals

Source: The Expression of the Emotions in Man and Animals (1872), chapter XIV: "Concluding Remarks and Summary", page 350

Love , Jealousy , Anger

“He remarks that "considering their weakness and their size, the work they are represented to have accomplished is stupendous." Here we have an instance of that inability to sum up the effects of a continually recurrent cause, which has often retarded the progress of science, as formerly in the case of geology, and more recently in that of the principle of evolution.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Introduction, p. 6. http://darwin-online.org.uk/content/frameset?pageseq=21&itemID=F1357&viewtype=image
The Formation of Vegetable Mould through the Action of Worms (1881)

Science

“Now when naturalists observe a close agreement in numerous small details of habits, tastes and dispositions between two or more domestic races, or between nearly-allied natural forms, they use this fact as an argument that all are descended from a common progenitor who was thus endowed; and consequently that all should be classed under the same species. The same argument may be applied with much force to the races of man.

As it is improbable that the numerous and unimportant points of resemblance between the several races of man in bodily structure and mental faculties (I do not here refer to similar customs) should all have been independently acquired, they must have been inherited from progenitors who were thus characterised.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter VII: "On the Races of Man", page 233 http://darwin-online.org.uk/content/frameset?pageseq=246&itemID=F937.1&viewtype=image
The Descent of Man (1871)

Nature

“As dogs, cats, horses, and probably all the higher animals, even birds, as is stated on good authority, have vivid dreams, and this is shewn by their movements and voice, we must admit that they possess some power of imagination. … Few persons any longer dispute that animals possess some power of reasoning. Animals may constantly be seen to pause, deliberate, and resolve. It is a significant fact, that the more the habits of any particular animal are studied by a naturalist, the more he attributes to reason and the less to unlearnt instincts.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter II: "Comparison of the Mental Powers of Man and the Lower Animals", page 46 http://darwin-online.org.uk/content/frameset?pageseq=59&itemID=F937.1&viewtype=image
The Descent of Man (1871)

Dogs , Dreams , Imagination , Cats

“Amongst the half-human progenitors of man, and amongst savages, there have been struggles between the males during many generations for the possession of the females. But mere bodily strength and size would do little for victory, unless associated with courage, perseverance, and determined energy. With social animals, the young males have to pass through many a contest before they win a female, and the older males have to retain their females by renewed battles. They have, also, in the case of mankind, to defend their females, as well as their young, from enemies of all kinds, and to hunt for their joint subsistence. But to avoid enemies or to attack them with success, to capture wild animals, and to fashion weapons, requires the aid of the higher mental faculties, namely, observation, reason, invention, or imagination. These various faculties will thus have been continually put to the test and selected during manhood; they will, moreover, have been strengthened by use during this same period of life. Consequently, in accordance with the principle often alluded to, we might expect that they would at least tend to be transmitted chiefly to the male offspring at the corresponding period of manhood.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

second edition (1874), chapter XIX: "Secondary Sexual Characters of Man", page 564 http://darwin-online.org.uk/content/frameset?pageseq=587&itemID=F944&viewtype=image
The Descent of Man (1871)

Life , Imagination , Fashion , Courage

“The expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.”

Charles Darwin book On the Origin of Species (1859)

Compare: "This survival of the fittest, which I have here sought to express in mechanical terms, is that which Mr Darwin has called 'natural selection, or the preservation of favoured races in the struggle for life.' ", Herbert Spencer, The Principles of Biology (1864) volume 1, part III: "The Evolution of Life", chapter XII, "Indirect Equilibration", pages 444-445.
Source: On the Origin of Species (1859), chapter III: "Struggle For Existence", page 72 http://darwin-online.org.uk/content/frameset?pageseq=101&itemID=F387&viewtype=image, in the fifth (1869) and sixth (1872) editions

“But just in proportion as this process of extermination has acted on an enormous scale, so must the number of intermediate varieties, which have formerly existed on the earth, be truly enormous. Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.”

Charles Darwin book On the Origin of Species (1859)

Source: On the Origin of Species (1859), chapter IX: "On the Imperfection of the Geological Record", page 280 http://darwin-online.org.uk/content/frameset?pageseq=298&itemID=F373&viewtype=image

“With mankind the differences between the sexes are greater than in most species of Quadrumana, but not so great as in some, for instance, the mandrill. Man on an average is considerably taller, heavier, and stronger than woman, with squarer shoulders and more plainly-pronounced muscles. … Man is more courageous, pugnacious, and energetic than woman, and has a more inventive genius. His brain is absolutely larger, but whether relatively to the larger size of his body, in comparison with that of woman, has not, I believe been fully ascertained. In woman the face is rounder; the jaws and the base of the skull smaller; the outlines of her body rounder, in parts more prominent; and her pelvis is broader than in man; but this latter character may perhaps be considered rather as a primary than a secondary sexual character. She comes to maturity at an earlier age than man.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume II, chapter XIX: "Secondary Sexual Characters of Man", pages 316-317 http://darwin-online.org.uk/content/frameset?pageseq=333&itemID=F937.2&viewtype=image
The Descent of Man (1871)

Age , Sex , Courage , Parting

“In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.”

Charles Darwin

This related misquote http://www.darwinproject.ac.uk/six-things-darwin-never-said appeared in The Living Clocks (1971) by Ritchie R. Ward.
Misattributed

“It is easy to specify the individual objects of admiration in these grand scenes; but it is not possible to give an adequate idea of the higher feelings of wonder, astonishment, and devotion, which fill and elevate the mind.”

Charles Darwin book The Voyage of the Beagle

Source: The Voyage of the Beagle (1839), chapter II, "Rio de Janeiro", 18 April 1832, page 29 http://darwin-online.org.uk/content/frameset?viewtype=image&itemID=F11&pageseq=48

Feeling , Idea

“Man bears in his bodily structure clear traces of his descent from some lower form; but it may be urged that, as man differs so greatly in his mental power from all other animals, there must be some error in this conclusion. No doubt the difference in this respect is enormous, even if we compare the mind of one of the lowest savages, who has no words to express any number higher than four, and who uses no abstract terms for the commonest objects or affections, with that of the most highly organised ape.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter II: "Comparison of the Mental Powers of Man and the Lower Animals", page 34 http://darwin-online.org.uk/content/frameset?pageseq=47&itemID=F937.1&viewtype=image
The Descent of Man (1871)

Error , Animals

“Worms seize leaves and other objects, not only to serve as food, but for plugging up the mouths of their burrows; and this is one of their strongest instincts.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 2: Habits of Worms, p. 58. http://darwin-online.org.uk/content/frameset?pageseq=73&itemID=F1357&viewtype=image

Food

“The great break in the organic chain between man and his nearest allies, which cannot be bridged over by any extinct or living species, has often been advanced as a grave objection to the belief that man is descended from some lower form; but this objection will not appear of much weight to those who, convinced by general reasons, believe in the general principle of evolution. Breaks incessantly occur in all parts of the series, some being wide, sharp and defined, others less so in various degrees; as between the orang and its nearest allies—between the Tarsius and the other Lemuridæ—between the elephant and in a more striking manner between the Ornithorhynchus or Echidna, and other mammals. But all these breaks depend merely on the number of related forms which have become extinct. At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate and replace throughout the world the savage races. At the same time the anthropomorphous apes, as Professor Schaaffhausen has remarked, will no doubt be exterminated. The break will then be rendered wider, for it will intervene between man in a more civilised state, as we may hope, than the Caucasian, and some ape as low as a baboon, instead of as at present between the negro or Australian and the gorilla.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter VI: "On the Affinities and Genealogy of Man", pages 200-201 http://darwin-online.org.uk/content/frameset?pageseq=213&itemID=F937.1&viewtype=image
The sentence "At some future period … the savage races" is often quoted out of context to suggest that Darwin desired this outcome, whereas in fact Darwin simply held that it would occur.
The Descent of Man (1871)

World , Hope , Distant , Appearance

“I love fools' experiments. I am always making them.”

Charles Darwin

recollection http://darwin-online.org.uk/content/frameset?itemID=F2113&viewtype=text&pageseq=7 by E. Ray Lankester, from his essay "Charles Robert Darwin" in C.D. Warner, editor, Library of the World's Best Literature: Ancient and Modern (R.S. Peale & J.A. Hill, New York, 1896) volume 2, pages 4835-4393, at page 4391
Other letters, notebooks, journal articles, recollected statements

Love , Fools

“[Y]ou have expressed my inward conviction, though far more vividly and clearly than I could have done, that the Universe is not the result of chance. … Lastly, I could show fight on natural selection having done and doing more for the progress of civilization than you seem inclined to admit. Remember what risk the nations of Europe ran, not so many centuries ago of being overwhelmed by the Turks, and how ridiculous such an idea now is! The more civilized so-called Caucasian races have beaten the Turkish hollow in the struggle for existence. Looking to the world at no very distant date, what an endless number of the lower races will have been eliminated by the higher civilized races throughout the world.”

Charles Darwin

volume I, chapter VIII: "Religion", page 316 http://darwin-online.org.uk/content/frameset?pageseq=334&itemID=F1452.1&viewtype=image; letter to William Graham (3 July 1881)
The Life and Letters of Charles Darwin (1887)

World , Idea , Nature , Universe

“As for a future life, every man must judge for himself between conflicting vague probabilities.”

Charles Darwin

volume I, chapter VIII: "Religion", page 307 http://darwin-online.org.uk/content/frameset?pageseq=325&itemID=F1452.1&viewtype=image; letter to an unidentified German student (1879)
The Life and Letters of Charles Darwin (1887)

Life , Future

“There should be open competition for all men; and the most able should not be prevented by laws or customs from succeeding best and rearing the largest number of offspring. Important as the struggle for existence has been and even still is, yet as far as the highest part of man's nature is concerned there are other agencies more important. For the moral qualities are advanced, either directly or indirectly, much more through the effects of habit, the reasoning powers, instruction, religion, &c., than through natural selection; though to this latter agency the social instincts, which afforded the basis for the development of the moral sense, may be safely attributed.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume II, chapter XXI: "General Summary and Conclusion", pages 403-404 http://darwin-online.org.uk/content/frameset?pageseq=420&itemID=F937.2&viewtype=image
The Descent of Man (1871)

Men , Religion , Law , Nature

“Believing as I do that man in the distant future will be a far more perfect creature than he now is, it is an intolerable thought that he and all other sentient beings are doomed to complete annihilation after such long-continued slow progress. To those who fully admit the immortality of the human soul, the destruction of our world will not appear so dreadful.”

Charles Darwin

volume I, chapter VIII: "Religion", page 312 http://darwin-online.org.uk/content/frameset?pageseq=330&itemID=F1452.1&viewtype=image
The Life and Letters of Charles Darwin (1887)

World , Soul , Distant , Appearance

“I believe that animals have descended from at most only four or five progenitors, and plants from an equal or lesser number.

Analogy would lead me one step further, namely, to the belief that all animals and plants have descended from some one prototype. But analogy may be a deceitful guide. Nevertheless all living things have much in common, in their chemical composition, their germinal vesicles, their cellular structure, and their laws of growth and reproduction. We see this even in so trifling a circumstance as that the same poison often similarly affects plants and animals; or that the poison secreted by the gall-fly produces monstrous growths on the wild rose or oak-tree. Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed by the Creator.”

Charles Darwin book On the Origin of Species (1859)

Source: On the Origin of Species (1859), chapter XIV: "Recapitulation and Conclusion", page 484 http://darwin-online.org.uk/content/frameset?pageseq=505&itemID=F376&viewtype=side, in the second (1860) edition

Life , Secret , Law , Tree

“I think it can be shown that there is such an unerring power at work in Natural Selection (the title of my book), which selects exclusively for the good of each organic being.”

Charles Darwin

Darwin's first published expression of the concept of natural selection.
"On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection" Journal of the Proceedings of the Linnean Society of London: Zoology (read 1 July 1853; published 20 August 1858) volume 3, pages 45-62, at page 51 http://darwin-online.org.uk/content/frameset?pageseq=7&itemID=F350&viewtype=image
Other letters, notebooks, journal articles, recollected statements

Books , Nature , Thinking

“The subject may appear an insignificant one, but we shall see that it possesses some interest; and the maxim "de minimis lex non curat," does not apply to science.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Introduction, p. 2. http://darwin-online.org.uk/content/frameset?pageseq=17&itemID=F1357&viewtype=image
de minimis non curat lex - The law does not concern itself with trifles.
The Formation of Vegetable Mould through the Action of Worms (1881)

Appearance , Science

“We will now discuss in a little more detail the struggle for existence.”

Charles Darwin book On the Origin of Species (1859)

Compare: "this perpetual struggle for room and food", The Reverend Thomas Malthus, An Essay on the Principle of Population (1798) section III.7 http://www.econlib.org/library/Malthus/malPop2.html#III.7.
Source: On the Origin of Species (1859), chapter III: "Struggle For Existence", page 62 http://darwin-online.org.uk/content/frameset?pageseq=77&itemID=F373&viewtype=image

“As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.”

Charles Darwin book On the Origin of Species (1859)

"Introduction", page 5 http://darwin-online.org.uk/content/frameset?pageseq=20&itemID=F373&viewtype=image
On the Origin of Species (1859)

Life , Nature , Strong , Chance

“In conclusion, it appears to me that nothing can be more improving to a young naturalist, than a journey in distant countries. It both sharpens, and partly likewise allays that want and craving, which, as Sir J. Herschel remarks, a man experiences although every corporeal sense is fully satisfied. The excitement from the novelty of objects, and the chance of success, stimulate him to increased activity. Moreover as a number of isolated facts soon become uninteresting, the habit of comparison leads to generalization. On the other hand, as the traveller stays but a short space of time in each place, his descriptions must generally consist of mere sketches, instead of detailed observation. Hence arises, as I have found to my cost, a constant tendency to fill up the wide gaps of knowledge, by inaccurate and superficial hypotheses.”

Charles Darwin book The Voyage of the Beagle

Source: The Voyage of the Beagle (1839), chapter XXIII: "Mauritius To England", pages 607-608 http://darwin-online.org.uk/content/frameset?pageseq=626&itemID=F10.3&viewtype=image

Travel , Knowledge , Sense , Distant

“Looking not to any one time, but to all time, if my theory be true, numberless intermediate varieties, linking most closely all the species of the same group together, must assuredly have existed; but the very process of natural selection constantly tends, as has been so often remarked, to exterminate the parent forms and the intermediate links. Consequently evidence of their former existence could be found only amongst fossil remains”

Charles Darwin book On the Origin of Species (1859)

.
Source: On the Origin of Species (1859), chapter VI: "Difficulties on Theory", page 179 http://darwin-online.org.uk/content/frameset?pageseq=197&itemID=F373&viewtype=side

Nature , Parent , Time

“With respect to the function of the calciferous glands, it is probable that they primarily serve as organs of excretion, and secondarily as an aid to digestion.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 1: Habits of Worms, p. 49. http://darwin-online.org.uk/content/frameset?pageseq=64&itemID=F1357&viewtype=image

“The comparison here implied between the actions of one of the higher animals and of one so low in the scale as an earth-worm, may appear far-fetched; for we thus attribute to the worm attention and some mental power, nevertheless I can see no reason to doubt the justice of the comparison.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 1: Habits of Worms, pp. 24-25. http://darwin-online.org.uk/content/frameset?pageseq=39&itemID=F1357&viewtype=image

Justice , Appearance , Animals

“I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including dependence of one being on another, and including (which is more important) not only the life of the individual, but success in leaving progeny.”

Charles Darwin book On the Origin of Species (1859)

Source: On the Origin of Species (1859), chapter III: "Struggle For Existence", page 62 http://darwin-online.org.uk/content/frameset?pageseq=77&itemID=F373&viewtype=image

Life , Sense , Success , Dependency

“Fitz-Roy's temper was a most unfortunate one. It was usually worst in the early morning, and with his eagle eye he could generally detect something amiss about the ship, and was then unsparing in his blame. He was very kind to me, but was a man very difficult to live with on the intimate terms which necessarily followed from our messing by ourselves in the same cabin. We had several quarrels; for instance, early in the voyage at Bahia, in Brazil, he defended and praised slavery, which I abominated, and told me that he had just visited a great slave-owner, who had called up many of his slaves and asked them whether they were happy, and whether they wished to be free, and all answered "No." I then asked him, perhaps with a sneer, whether he thought that the answer of slaves in the presence of their master was worth anything? This made him excessively angry, and he said that as I doubted his word we could not live any longer together. I thought that I should have been compelled to leave the ship; but as soon as the news spread, which it did quickly, as the captain sent for the first lieutenant to assuage his anger by abusing me, I was deeply gratified by receiving an invitation from all the gun-room officers to mess with them. But after a few hours Fitz-Roy showed his usual magnanimity by sending an officer to me with an apology and a request that I would continue to live with him.”

Charles Darwin

volume I, chapter II: "Autobiography", pages 60-61 http://darwin-online.org.uk/content/frameset?pageseq=78&itemID=F1452.1&viewtype=image
The Life and Letters of Charles Darwin (1887)

Anger , Happiness

“Earth-worms abound in England in many different stations. Their castings may be seen in extraordinary numbers on commons and chalk-downs, so as almost to cover the whole surface, where the soil is poor and the grass short and thin.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 1: Habits of Worms, p. 9. http://darwin-online.org.uk/content/frameset?pageseq=24&itemID=F1357&viewtype=image

Grass

“My object in this chapter is solely to shew that there is no fundamental difference between man and the higher mammals in their mental faculties.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter II: "Comparison of the Mental Powers of Man and the Lower Animals", page 35 http://darwin-online.org.uk/content/frameset?pageseq=48&itemID=F937.1&viewtype=image
The Descent of Man (1871)

“The lower animals, like man, manifestly feel pleasure and pain, happiness and misery. Happiness is never better exhibited than by young animals, such as puppies, kittens, lambs, &c., when playing together, like our own children. Even insects play together, as has been described by that excellent observer, P. Huber, who saw ants chasing and pretending to bite each other, like so many puppies.
The fact that the lower animals are excited by the same emotions as ourselves is so well established, that it will not be necessary to weary the reader by many details. Terror acts in the same manner on them as on us, causing the muscles to tremble, the heart to palpitate, the sphincters to be relaxed, and the hair to stand on end. Suspicion, the offspring of fear, is eminently characteristic of most wild animals. Courage and timidity are extremely variable qualities in the individuals of the same species, as is plainly seen in our dogs. Some dogs and horses are ill-tempered and easily turn sulky; others are good-tempered; and these qualities are certainly inherited.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter II: "Comparison of the Mental Powers of Man and the Lower Animals", pages 39-40 http://darwin-online.org.uk/content/frameset?pageseq=52&itemID=F937.1&viewtype=image
The Descent of Man (1871)

Pain , Children , Pleasure , Fear

“It may be doubted whether any character can be named which is distinctive of a race and is constant.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter VII: "On the Races of Man", page 225 http://darwin-online.org.uk/content/frameset?pageseq=238&itemID=F937.1&viewtype=image
The Descent of Man (1871)

“When a worm is suddenly illuminated and dashes like a rabbit into its burrow—to use the expression employed by a friend—we are at first led to look at the action as a reflex one.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 1: Habits of Worms, p. 23. http://darwin-online.org.uk/content/frameset?pageseq=38&itemID=F1357&viewtype=image

“I have attempted to write the following account of myself, as if I were a dead man in another world looking back at my own life. Nor have I found this difficult, for life is nearly over with me. I have taken no pains about my style of writing.”

Charles Darwin

volume I, chapter II: "Autobiography", page 27 http://darwin-online.org.uk/content/frameset?pageseq=45&itemID=F1452.1&viewtype=image
The Life and Letters of Charles Darwin (1887)

Life , Pain , World , Dead

“M. Perrier found that their exposure to the dry air of a room for only a single night was fatal to them. On the other hand he kept several large worms alive for nearly four months, completely submerged in water.”

Charles Darwin book The Formation of Vegetable Mould through the Action of Worms

Source: The Formation of Vegetable Mould through the Action of Worms (1881), Chapter 1: Habits of Worms, pp. 12-13 http://darwin-online.org.uk/content/frameset?pageseq=27&itemID=F1357&viewtype=image.

Water , Night

“There is good evidence that the art of shooting with bows and arrows has not been handed down from any common progenitor of mankind, yet the stone arrow-heads, brought from the most distant parts of the world and manufactured at the most remote periods, are, as Nilsson has shewn, almost identical; and this fact can only be accounted for by the various races having similar inventive or mental powers.”

Charles Darwin book The Descent of Man, and Selection in Relation to Sex

volume I, chapter VII: "On the Races of Man", pages 232-233 http://darwin-online.org.uk/content/frameset?pageseq=245&itemID=F937.1&viewtype=image
The Descent of Man (1871)

World , Art , Distant , Parting