A circumstance which influenced my whole career more than any other … was my friendship with Professor Henslow … a man who knew every branch of science…. During the latter half of my time at Cambridge [I] took long walks with him on most days; so that I was called by some of the dons “the man who walks with Henslow.”

A good deal of scepticism in a scientific man is advisable to avoid much loss of time, for I have met with not a few men, who, I feel sure, have often thus been deterred from experiment or observations, which would have proved directly or indirectly serviceable.

A man who dares to waste one hour of time has not discovered the value of life.

A scientific man ought to have no wishes, no affections, a mere heart of stone.

A young man once asked [Erasmus Darwin] in, as he thought, an offensive manner, whether he did not find stammering very inconvenient. He answered, 'No, Sir, it gives me time for reflection, and saves me from asking impertinent questions.'

About thirty years ago there was much talk that geologists ought only to observe and not theorise; and I well remember some one saying that at this rate a man might as well go into a gravel-pit and count the pebbles and describe the colours. How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!

Among the scenes which are deeply impressed on my mind, none exceed in sublimity the primeval [tropical] forests, ... temples filled with the varied productions of the God of Nature. No one can stand in these solitudes unmoved, and not feel that there is more in man than the mere breath of his body.

Among the scenes which are deeply impressed on my mind, none exceed in sublimity the primeval forests undefaced by the hand of man; whether those of Brazil, where the powers of Life are predominant, or those of Tierra del Fuego, where Death and Decay prevail. Both are temples filled with the varied productions of the God of Nature: no one can stand in these solitudes unmoved, and not feel that there is more in man than the mere breath of his body.

Animals manifestly enjoy excitement, and suffer from annul and may exhibit curiosity.

As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.

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

As man advances in civilisation, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all the members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races.

At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate, and replace the savage races throughout the world.

Blushing is the most peculiar and most human of all expressions. Monkeys redden from passion but it would take an overwhelming amount of evidence to make us believe that any animal can blush.

By considering the embryological structure of man - the homologies which he presents with the lower animals - the rudiments which he retains - and the reversions to which he is liable, we can partly recall in imagination the former condition of our early progenitors; and we can approximately place them in their proper position in the zoological series. We thus learnt that man is descended from a hairy quadruped, furnished with a tail and pointed ears, probably arboreal in its habit, and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed among the Quadrumana, as surely as would be the common and still more ancient progenitor of the Old and New World monkeys.

I cannot anyhow be contented to view this wonderful universe, and especially the nature of man, and to conclude that everything is the result of brute force. I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we call chance. Not that this notion at all satisfies me. I feel most deeply that the whole subject is too profound for the human intellect. A dog might as well speculate on the mind of Newton. Let each man hope and believe what he can.

I conclude that the musical notes and rhythms were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex.

I had … during many years, followed a golden rule, namely, that whenever a published fact, a new observation or thought came across me, which was opposed by my general results, to make a memorandum of it without fail and at once; for I had found by experience that such facts and thoughts were far more apt to escape from memory than favorable ones.

I have been speculating last night what makes a man a discoverer of undiscovered things; and a most perplexing problem it is. Many men who are very clever - much cleverer than the discoverers - never originate anything.

I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection, in order to mark its relation to man's power of selection. But the expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.

I see no good reason why the views given this volume [The Origin of Species] should shock the religious feelings of any one. It is satisfactory, as showing how transient such impressions are, to remember that the greatest discovery ever made by man, namely, the law of attraction of gravity, was also attacked by Leibnitz, “as subversive of natural, and inferentially of revealed, religion.”

If we thus go very far back to the source of the Mammalian type of organisation; it is extremely improbable that any of [his relatives shall likewise] the successors of his relations now exist,—In same manner, if we take [a man from] any large family of 12 brothers & sisters [in a state which does not increase] it will be chances against anyone [of them] having progeny living ten thousand years hence; because at present day many are relatives so that tracing back the [descen] fathers would be reduced to small percentage.—& [in] therefore the chances are excessively great against, any two of the 12, having progeny, after that distant period.

If worms have the power of acquiring some notion, however rude, of the shape of an object and over their burrows, as seems the case, they deserve to be called intelligent; for they act in nearly the same manner as would man under similar circumstances.

In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation. Light will be thrown on the origin of man and his history.

It has sometimes been said that the success of the Origin proved “that the subject was in the air,” or “that men's minds were prepared for it.” I do not think that this is strictly true, for I occasionally sounded not a few naturalists, and never happened to come across a single one who seemed to doubt about the permanence of species.

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms.

It is not the conscience which raises a blush, for a man may sincerely regret some slight fault committed in solitude, or he may suffer the deepest remorse for an undetected crime, but he will not blush... It is not the sense of guilt, but the thought that others think or know us to be guilty which crimsons the face.

It must not be forgotten that although a high standard of morality gives a slight or no advantage to each individual man and his children over the other men of the same tribe, yet an advancement in the standard of morality will certainly give an immense advantage to one tribe over another.

Jealousy was plainly exhibited when I fondled a large doll, and when I weighed his infant sister, he being then 15? months old. Seeing how strong a feeling of jealousy is in dogs, it would probably be exhibited by infants at any earlier age than just specified if they were tried in a fitting manner

Man is developed from an ovule, about 125th of an inch in diameter, which differs in no respect from the ovules of other animals.

Man may be excused for feeling some pride at having risen, though not through his own exertions, to the very summit of the organic scale; and the fact of his having thus risen, instead of having been aboriginally placed there, may give him hopes for a still higher destiny in the distant future. But we are not here concerned with hopes or fears, only with the truth as far as our reason allows us to discover it. I have given the evidence to the best of my ability; and we must acknowledge, as it seems to me, that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system—with all these exalted powers—Man still bears in his bodily frame the indelible stamp of his lowly origin.

Many kinds of monkeys have a strong taste for tea, coffee and spirituous liqueurs.

My books have sold largely in England, have been translated into many languages, and passed through several editions in foreign countries. I have heard it said that the success of a work abroad is the best test of its enduring value. I doubt whether this is at all trustworthy; but judged by this standard my name ought to last for a few years.

My mind seems to have become a kind of machine for grinding general laws out of large collections of facts, but why this should have caused the atrophy of that part of the brain that alone on which the higher tastes depend, I cannot conceive. A man with a mind more highly organised or better constituted than mine would not, I suppose, have thus suffered, and if I had to live my life over again, I would have made a rule to read some poetry and listen to some music at least once every week; for perhaps the parts of my brain now atrophied would thus have been kept alive through use.

Not one man in a thousand has accuracy of eye and judgment sufficient to become an eminent breeder. If gifted with these qualities, and he studies his subject for years, and devotes his lifetime to it with indomitable perseverance, he will succeed, and may make great improvements; if he wants any of these qualities, he will assuredly fail.

Nothing could have been worse for the development of my mind than Dr. Butler's school, as it was strictly classical, nothing else being taught, except a little ancient geography and history. The school as a means of education to me was simply a blank. During my whole life I have been singularly incapable of mastering any language. Especial attention was paid to versemaking, and this I could never do well. I had many friends, and got together a good collection of old verses, which by patching together, sometimes aided by other boys, I could work into any subject.

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 they 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.

On becoming very intimate with Fitz-Roy, I heard that I had run a very narrow risk of being rejected, on account of the shape of my nose! He was an ardent disciple of Lavater, and was convinced that he could judge a man's character by the outline of his features. He doubted whether anyone with my nose could possess sufficient energy and determination for the voyage. I think he was well-satisfied that my nose had spoken falsely.

One more word on “designed laws” and “undesigned results.” - I see a bird which I want for food, take my gun and kill it, I do this designedly.—An innocent and good man stands under a tree and is killed by a flash of lightning. Do you believe (& I really should like to hear) that God designedly killed this man? Many or most persons do believe this; I can’t and don’t.—If you believe so, do you believe that when a swallow snaps up a gnat that God designed that that particular swallow should snap up that particular gnat at that particular instant? I believe that the man and the gnat are in the same predicament. If the death of neither man nor gnat are designed, I see no good reason to believe that their first birth or production should be necessarily designed.

Origin of man now proved.— Metaphysics must flourish.—He who understands baboon would do more towards metaphysics than Locke.

Our ancestor was an animal which breathed water, had a swim-bladder, a great swimming tail, an imperfect skull & undoubtedly was an hermaphrodite! Here is a pleasant genealogy for mankind.

Recollections [his autobiographical work] might possibly interest my children or their children. I know that it would have interested me greatly to have read even so short and dull a sketch of the mind of my grandfather, written by himself, and what he thought and did, and how he worked. 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.

So in regard to mental qualities, their transmission is manifest in our dogs, horses and other domestic animals. Besides special tastes and habits, general intelligence, courage, bad and good tempers. etc., are certainly transmitted.

Some few, & I am one, even wish to God, though at the loss of millions of lives, that the North would proclaim a crusade against Slavery. In the long run, a million horrid deaths would be amply repaid in the cause of humanity. ... Great God how I sh^d like to see that greatest curse on Earth Slavery abolished.

The aid which we feel impelled to give to the helpless is mainly an incidental result of the instinct of sympathy, which was originally acquired as part of the social instincts, but subsequently rendered, in the manner previously indicated, more tender and more widely diffused. Nor could we check our sympathy, even at the urging of hard reason, without deterioration in the noblest part of our nature.

The main conclusion arrived at in this work, namely that man is descended from some lowly-organised form, will, I regret to think, be highly distasteful to many persons. But there can hardly be a doubt that we are descended from barbarians.

The moral faculties are generally and justly esteemed as of higher value than the intellectual powers. But we should bear in mind that the activity of the mind in vividly recalling past impressions is one of the fundamental though secondary bases of conscience. This affords the strongest argument for educating and stimulating in all possible ways the intellectual faculties of every human being.

The number of humble-bees in any district depends in a great degree on the number of field-mice, which destroy their combs and nests; and Mr. H. Newman, who has long attended to the habits of humble-bees, ... says “Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice.” Hence it is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!

The science of geology is enormously indebted to Lyell—more so, as I believe, than to any other man who has lived.

The Simiadae then branched off into two great stems, the New World and Old World monkeys; and from the latter at a remote period, Man, the wonder and the glory of the universe, proceeded.

The Struggle for Existence amongst all organic beings throughout the world, which inevitably follows from their high geometrical powers of increase ... This is the doctrine of Malthus, applied to the whole animal and vegetable kingdoms. 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.

There is no fundamental difference between man and the higher animals in their mental faculties ... The lower animals, like man, manifestly feel pleasure and pain, happiness, and misery.

This is the question
Marry
Children—(if it Please God)—Constant companion (& friend in old age) who will feel interested in one—object to be beloved and played with—better than a dog anyhow. Home, & someone to take care of house—Charms of music and female chit-chat.—These things good for one’s health.—but terrible loss of time.—
My God, it is Intolerable to think of spending ones whole life, like a neuter bee, working, working—& nothing after all.—No, no, won’t do. 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-—Compare this vision with the dingy reality of Grt. Marlbro’ Street.
Not Marry
Freedom to go where one liked—choice of Society and little of it. —Conversation of clever men at clubs—Not forced to visit relatives, & to bend in every trifle. —to have the expense and anxiety of children—perhaps quarreling—Loss of time. —cannot read in the Evenings—fatness & idleness—Anxiety & responsibility—less money for books &c—if many children forced to gain one’s bread. —(but then it is very bad for ones health to work too much)
Perhaps my wife won’t like London; then the sentence is banishment & degradation into indolent, idle fool.
Marry—Marry—Marry Q.E.D.
It being proved necessary to Marry When? Soon or late?

Thus we have given to man a pedigree of prodigious length, but not, it may be said, of noble quality.

To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree. When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei, as every philosopher knows, cannot be trusted in science. Reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real.

We thus learn that man is descended from a hairy quadruped, furnished with a tail and pointed ears, probably arboreal in its habits, and an inhabitant of the Old World.

What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern?

When I was a little over eight years old,… I was sent to a day-school…. [By this time] my taste for natural history, and more especially for collecting, was well developed. I tried to make out the names of plants, and collected all sorts of things, shells, seals, franks, coins, and minerals. The passion for collecting which leads a man to be a systematic naturalist, a virtuoso, or a miser, was very strong in me.

When the principles of breeding and of inheritance are better understood, we shall not hear ignorant members of our legislature rejecting with scorn a plan for ascertaining by an easy method whether or not consanguineous marriages are injurious to man.

When we no longer look at an organic being as a savage looks at a ship, as something wholly beyond his comprehension; when we regard every production of nature as one which has had a long history; when we contemplate every complex structure and instinct as the summing up of many contrivances, each useful to the possessor, in the same way as any great mechanical invention is the summing up of the labour, the experience, the reason, and even the blunders of numerous workmen; when we thus view each organic being, how far more interesting, I speak from experience, does the study of natural history become!

Why does man regret, even though he may endeavour to banish any such regret, that he has followed the one natural impulse, rather than the other; and why does he further feel that he ought to regret his conduct? Man in this respect differs profoundly from the lower animals.

With me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind.

Zorrillos, or skunks…, … are far from uncommon. … Conscious of its power, it roams by day about the open plain, and fears neither dog nor man. If a dog is urged to the attack, its courage is instantly checked by a few drops of the fetid oil, which brings on violent sickness and running at the nose. Whatever is once polluted by it, is for ever useless. Azara says the smell can be perceived at a league distant; more than once, when entering the harbour of Monte Video, the wind being off shore, we have perceived the odour on board the Beagle. Certain it is, that every animal most willingly makes room for the Zorrillo.