Saturday, June 27, 2009

David Hume's influence on Charles Darwin

As a result of helping my son Charlie with his homework, I have just (re-)read David Hume's Dialogues Concerning Natural Religion, which is a superb examination of the arguments for and against the existence of God. 

I was surprised to see how similar some parts of the Dialogues are to some parts of Darwin's own writings. I spent a bit of time Googling away to see if anyone else had noticed this, but can't find much evidence that anyone has. I found this one paper:
  • David Hume and Charles Darwin, William B. Huntley, Journal of the History of Ideas, Vol. 33, No. 3, Festschrift for Philip P. Wiener (Jul. - Sep., 1972), pp. 457-470 http://www.jstor.org/stable/2709046
But this is concerned with the influence on Darwin of Hume's Treatise of Human Nature and An Enquiry Concerning Human Understanding and does not even mention Dialogues Concerning Natural Religion!

Daniel Dennett in Darwin's Dangerous Idea: Evolution and the Meanings of Life does describe some connections between Hume's thinking in the Dialogues and Darwin's evolution by natural selection. But in a chapter is entitled "Hume's Close Encounter", Dennett's point is "look how close Hume got to Darwin". Interpreting Hume in the light of Darwin strikes me as a cart-before-horse argument, reminiscent of David Lodge's fictional thesis on the influence of T. S. Eliot on Shakespeare. Instead, we should be looking for Hume's influence on Darwin!

So, is there any evidence that Darwin was familiar with Hume? The answer is yes, in abundance! Darwin kept a list of books to be read and Hume's works feature several times:
  • Hume's Essay on Human understanding {(Sometime)}
  • Hume's Essay
  • Life of David Hume — (new Edit) by Bell recommended by Erasmus
  • Hume's life of himself with corres: with Rousseau
  • Humes dialogues & Nat. Hist of Religion
  • Hume Hist. Engl. Vol 5 & 6. 
  • 7th & 8th Vol of Hume's England — Admirable
  • Hume's Essays. 2 Vol.
  • 2. vols of Hume's History
  • Hume's Hist of England. to end of the beginning of Elizabeth.
Plus Darwin lists Burton's Life of David Hume twice in his list, the second time with the verdict "poor". In fact, although I haven't totted up all of the books Darwin read, it seems likely that Hume is among the most common authors, if not the most common author, in Darwin's list!

So it is clear that Darwin read Hume's Dialogues, but was his later writing influenced by them? Well Dennett is right to point out how close Hume got to some of Darwin's key ideas:

Hume on the Struggle for Existence and War of Nature
"And why should man, added he, pretend to an exemption from the lot of all other animals? The whole earth, believe me, PHILO, is cursed and polluted. A perpetual war is kindled amongst all living creatures. Necessity, hunger, want, stimulate the strong and courageous: Fear, anxiety, terror, agitate the weak and infirm. The first entrance into life gives anguish to the new-born infant and to its wretched parent: Weakness, impotence, distress, attend each stage of that life: and it is at last finished in agony and horror."

"Observe too, says PHILO, the curious artifices of Nature, in order to embitter the life of every living being. The stronger prey upon the weaker, and keep them in perpetual terror and anxiety. The weaker too, in their turn, often prey upon the stronger, and vex and molest them without relaxation. Consider that innumerable race of insects, which either are bred on the body of each animal, or, flying about, infix their stings in him. These insects have others still less than themselves, which torment them. And thus on each hand, before and behind, above and below, every animal is surrounded with enemies, which incessantly seek his misery and destruction. "

And Hume gets close to Natural Selection
"And this very consideration too, continued PHILO, which we have stumbled on in the course of the argument, suggests a new hypothesis of cosmogony, that is not absolutely absurd and improbable. Is there a system, an order, an economy of things, by which matter can preserve that perpetual agitation which seems essential to it, and yet maintain a constancy in the forms which it produces? There certainly is such an economy; for this is actually the case with the present world. The continual motion of matter, therefore, in less than infinite transpositions, must produce this economy or order; and by its very nature, that order, when once established, supports itself, for many ages, if not to eternity. But wherever matter is so poised, arranged, and adjusted, as to continue in perpetual motion, and yet preserve a constancy in the forms, its situation must, of necessity, have all the same appearance of art and contrivance which we observe at present. All the parts of each form must have a relation to each other, and to the whole; and the whole itself must have a relation to the other parts of the universe; to the element in which the form subsists; to the materials with which it repairs its waste and decay; and to every other form which is hostile or friendly. A defect in any of these particulars destroys the form; and the matter of which it is composed is again set loose, and is thrown into irregular motions and fermentations, till it unite itself to some other regular form."

"It is in vain, therefore, to insist upon the uses of the parts in animals or vegetables, and their curious adjustment to each other. I would fain know, how an animal could subsist, unless its parts were so adjusted? Do we not find, that it immediately perishes whenever this adjustment ceases, and that its matter corrupting tries some new form?"
And here are a few parallel passages that suggest to me that Darwin might have been influenced by the Dialogues.

The ship and botched trials analogy
Hume in the Dialogues: "But were this world ever so perfect a production, it must still remain uncertain, whether all the excellences of the work can justly be ascribed to the workman. If we survey a ship, what an exalted idea must we form of the ingenuity of the carpenter who framed so complicated, useful, and beautiful a machine? And what surprise must we feel, when we find him a stupid mechanic, who imitated others, and copied an art, which, through a long succession of ages, after multiplied trials, mistakes, corrections, deliberations, and controversies, had been gradually improving? Many worlds might have been botched and bungled, throughout an eternity, ere this system was struck out; much labour lost, many fruitless trials made; and a slow, but continued improvement carried on during infinite ages in the art of world-making."

Darwin in the Origin of Species: "When we no longer look at an organic being as a savage looks at a ship, as at something wholly beyond his comprehension; when we regard every production of nature as one which has had a history; when we contemplate every complex structure and instinct as the summing up of many contrivances, each useful to the possessor, nearly in the same way as when we look at any great mechanical invention as 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, will the study of natural history become!"
The house/architect analogy
Hume: "If we see a house, CLEANTHES, we conclude, with the greatest certainty, that it had an architect or builder; because this is precisely that species of effect which we have experienced to proceed from that species of cause."

Darwin: "Throughout this chapter and elsewhere I have spoken of selection as the paramount power, yet its action absolutely depends on what we in our ignorance call spontaneous or accidental variability. Let an architect be compelled to build an edifice with uncut stones, fallen from a precipice. The shape of each fragment may be called accidental; yet the shape of each has been determined by the force of gravity, the nature of the rock, and the slope of the precipice,—events and circumstances, all of which depend on natural laws; but there is no relation between these laws and the purpose for which each fragment is used by the builder. In the same manner the variations of each creature are determined by fixed and immutable laws; but these bear no relation to the living structure which is slowly built up through the power of selection, whether this be natural or artificial selection."
The observation that introduced species thrive in new environments, even though they have not originated there.
Hume in the Dialogues: "LUCULLUS was the first that brought cherry-trees from ASIA to EUROPE; though that tree thrives so well in many EUROPEAN climates, that it grows in the woods without any culture. Is it possible, that throughout a whole eternity, no EUROPEAN had ever passed into ASIA, and thought of transplanting so delicious a fruit into his own country? Or if the tree was once transplanted and propagated, how could it ever afterwards perish? Empires may rise and fall, liberty and slavery succeed alternately, ignorance and knowledge give place to each other; but the cherry-tree will still remain in the woods of GREECE, SPAIN, and ITALY, and will never be affected by the revolutions of human society. It is not two thousand years since vines were transplanted into FRANCE, though there is no climate in the world more favourable to them.

It is not three centuries since horses, cows, sheep, swine, dogs, corn, were known in AMERICA. Is it possible, that during the revolutions of a whole eternity, there never arose a COLUMBUS, who might open the communication between EUROPE and that continent?... Nothing less than a total convulsion of the elements will ever destroy all the EUROPEAN animals and vegetables which are now to be found in the Western world."

Darwin in the Origin of Species: "Still more striking is the evidence from our domestic animals of many kinds which have run wild in several parts of the world: if the statements of the rate of increase of slow-breeding cattle and horses in South-America, and latterly in Australia, had not been well authenticated, they would have been quite incredible. So it is with plants: cases could be given of introduced plants which have become common throughout whole islands in a period of less than ten years. Several of the plants now most numerous over the wide plains of La Plata, clothing square leagues of surface almost to the exclusion of all other plants, have been introduced from Europe; and there are plants which now range in India, as I hear from Dr. Falconer, from Cape Comorin to the Himalaya, which have been imported from America since its discovery."
Superiority of the contrivances of nature to those of art
Hume: "Look round the world: contemplate the whole and every part of it: You will find it to be nothing but one great machine, subdivided into an infinite number of lesser machines, which again admit of subdivisions to a degree beyond what human senses and faculties can trace and explain. All these various machines, and even their most minute parts, are adjusted to each other with an accuracy which ravishes into admiration all men who have ever contemplated them. The curious adapting of means to ends, throughout all nature, resembles exactly, though it much exceeds, the productions of human contrivance; of human designs, thought, wisdom, and intelligence. Since, therefore, the effects resemble each other, we are led to infer, by all the rules of analogy, that the causes also resemble; and that the Author of Nature is somewhat similar to the mind of man, though possessed of much larger faculties, proportioned to the grandeur of the work which he has executed."

Darwin in the Origin: "We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses, through the accumulation of slight but useful variations, given to him by the hand of Nature. But Natural Selection, as we shall hereafter see, is a power incessantly ready for action, and is as immeasurably superior to man's feeble efforts, as the works of Nature are to those of Art."
On the inability of finite minds to grasp an infinite deity
Hume in the Dialogues: "The question is not concerning the being, but the nature of God. This, I affirm, from the infirmities of human understanding, to be altogether incomprehensible and unknown to us. The essence of that supreme Mind, his attributes, the manner of his existence, the very nature of his duration; these, and every particular which regards so divine a Being, are mysterious to men. Finite, weak, and blind creatures, we ought to humble ourselves in his august presence; and, conscious of our frailties, adore in silence his infinite perfections, which eye hath not seen, ear hath not heard, neither hath it entered into the heart of man to conceive."

Darwin in his Autobiography:"But then arises the doubt—can the mind of man, which has, as I fully believe, been developed from a mind as low as that possessed by the lowest animal, be trusted when it draws such grand conclusions*? May not these be the result of the connection between cause and effect which strikes us as a necessary one, but probably depends merely on inherited experience? Nor must we overlook the probability of the constant inculcation in a belief in God on the minds of children producing so strong and perhaps an inherited effect on their brains not yet fully developed, that it would be as difficult for them to throw off their belief in God, as for a monkey to throw off its instinctive fear and hatred of a snake."

*Note the nice evolutionary twist added by Darwin here!
The balance of happiness/misery and pain/pleasure
Hume: "The only method of supporting Divine benevolence, and it is what I willingly embrace, is to deny absolutely the misery and wickedness of man. Your representations are exaggerated; your melancholy views mostly fictitious; your inferences contrary to fact and experience. Health is more common than sickness; pleasure than pain; happiness than misery. And for one vexation which we meet with, we attain, upon computation, a hundred enjoyments."

Darwin:"if we look to all sentient beings, whether there is more of misery or of happiness;—whether the world as a whole is a good or a bad one. According to my judgment happiness decidedly prevails, though this would be very difficult to prove. If the truth of this conclusion be granted, it harmonises well with the effects which we might expect from natural selection. If all the individuals of any species were habitually to suffer to an extreme degree they would neglect to propagate their kind; but we have no reason to believe that this has ever or at least often occurred. Some other considerations, moreover, lead to the belief that all sentient beings have been formed so as to enjoy, as a general rule, happiness."

Hume: "Admitting your position, replied PHILO, which yet is extremely doubtful, you must at the same time allow, that if pain be less frequent than pleasure, it is infinitely more violent and durable. One hour of it is often able to outweigh a day, a week, a month of our common insipid enjoyments; and how many days, weeks, and months, are passed by several in the most acute torments? Pleasure, scarcely in one instance, is ever able to reach ecstasy and rapture; and in no one instance can it continue for any time at its highest pitch and altitude. The spirits evaporate, the nerves relax, the fabric is disordered, and the enjoyment quickly degenerates into fatigue and uneasiness. But pain often, good God, how often! rises to torture and agony; and the longer it continues, it becomes still more genuine agony and torture. Patience is exhausted, courage languishes, melancholy seizes us, and nothing terminates our misery but the removal of its cause, or another event, which is the sole cure of all evil, but which, from our natural folly, we regard with still greater horror and consternation."

Darwin: "Now an animal may be led to pursue that course of action which is the most beneficial to the species by suffering, such as pain, hunger, thirst, and fear,—or by pleasure, as in eating and drinking and in the propagation of the species, &c. or by both means combined, as in the search for food. But pain or suffering of any kind, if long continued, causes depression and lessens the power of action; yet is well adapted to make a creature guard itself against any great or sudden evil. Pleasurable sensations, on the other hand, may be long continued without any depressing effect; on the contrary they stimulate the whole system to increased action. Hence it has come to pass that most or all sentient beings have been developed in such a manner through natural selection, that pleasurable sensations serve as their habitual guides. We see this in the pleasure from exertion, even occasionally from great exertion of the body or mind,—in the pleasure of our daily meals, and especially in the pleasure derived from sociability and from loving our families. The sum of such pleasures as these, which are habitual or frequently recurrent, give, as I can hardly doubt, to most sentient beings an excess of happiness over misery, although many occasionally suffer much."
Well, what does all this mean? It is uncertain to me whether these parallels reflect a direct influence of Hume's Dialogues on Darwin and if so, if there was a conscious or unconscious decision on Darwin's behalf to exploit them. 

Alternatively, Darwin may have encountered these arguments in a third source that used, or was used by, Hume (e.g. Paley). 

Or the resemblance could be purely coincidental. 

But, in conclusion, it is intriguing to see how far great minds think alike!

Monday, June 22, 2009

Emma Darwin's poignant diary entry

I am still slowly but surely working away on a paper debunking the myth that Annie Darwin's death had anything to do with Charles Darwin's loss of faith in Christianity. And in preparing the paper, I have been looking at the diaries of Charles Darwin and of Emma Darwin, his wife.

There has been quite a bit of publicity about the recent publication of Emma's diaries, but I didn't realise until recently that Charles Darwin also kept a journal of his life (see the Introduction by John van Wyhe). Darwin started keeping the journal in 1838, but backdated the entries to his birth, and made the last entry just four months before his death.

In researching the background to Annie's final illness and death, I took a look at both diaries. Annie Darwin fell ill in the summer of 1850, as is evidenced by this entry from Emma's diary for 27th June:
"Annie first failed about this time"
She was taken to Malvern by Charles on March 24th 1851, in the hope that she would benefit from Dr Gully's water cure. Charles records this and the subsequent tragic events on a single poignant page in his diary:
"March 24th to Malvern with Annie & Etty. returned home 31st.— April 16th. started for Malvern. April 23d our dear child expired. 24th. I returned to Emma. Our darling was born March 2d. 1841.—"
Emma in her diary maintains a progress report on Annie,  gleaned from the letters sent by Dr Gully and by Charles. Unlike most of her diary entries, which tend to be rather terse, her entries on Annie are more informative than usual. On 7th April she writes "Annie's sickup"; on 13th April: "Annie very weak"; on April 14th "Better, Dr G. said she had turned the corner"; on April 15th: "Dr G alarmed, wrote for Ch./ began urine". 

I will leave it to you the reader to follow Emma's records of Annie's illness through these links to individual pages for each week:

But for me Emma's entry on Annie's death is the most poignant of all these diary entries, whether from Charles or Emma. After writing "much better" on April 21st and "diarrhea came on" on April 22nd, for April 23rd, she writes simply:
"12 o'clock"
the time of Annie's death. This reminds me of Auden's poem, Funeral Blues: "Stop all the clocks..." and, for me, nothing in any of the accounts of Annie's illness and death could be more arresting.

Wednesday, June 17, 2009

Please help Darwin's medical students URGENTLY! #2

This week for the second time (see earlier posting) I have been supervising a student-selected activity entitled "The Darwins, Evolution and Medicine". The rationale for these SSAs is to stimulate curiosity and critical thinking among medical students, who are otherwise burdened with a great deal of rote learning. There are fourteen students on the course and I offered them a selection of topics, which ranged from the matter-of-fact to the highly controversial. Here are the topics they chose:
  • The illness of Charles Darwin: a retrospective diagnosis
  • Charles and Emma- Benefits and Hazards of First Cousin Marriages
  • The Pleistocene diet: a recipe for diet and health?
  • Why do Europeans, North Asians and Native American have pale skins
  • How can we explain the course of the recurrent laryngeal nerve
  • Tay-Sachs disease in Ashkenazi Jews: Origins and Prevention
  • Darwin and slavery
The students have been given the option of delivering a conventional powerpoint presentation tomorrow morning or posting on a purpose-built blog Darwin's students, by 7 pm tonight. I offered this latter option as an incentive for them to explore and evaluate the blogosphere as a tool for academic research. 

Please feel free to look at what they have written and provide constructive comments on their postings, links to other postings or literature etc etc just as if they were regular bloggers! As I explained to them, in a real sense, blogging is more peer-reviewed than the regular scientific literature, as dozens or even hundreds of people can comment. BUT be gentle with them—this is their first foray into the blogosphere!

Tuesday, June 16, 2009

The amazing power of Darwinite

You remember Superman and how he suddenly lost all his powers in the presence of the element kryptonite? Well, I am beginning to wonder if there isn't an element called Darwinite out there that means people lose their critical faculties and say and write and believe any old rubbish when face to face with Darwin, his life and his theory of evolution. 

I have already pointed out some of the many myths surrounding this topic, but the more I read about the myth of Annie's-death-caused-Darwin's-loss-of-faith, the more I am driven to believe in this powerful but hidden element, Darwinite.

Before I start on the Annie myths, let me point out that Darwinite is clearly inherited, as proven by this piece written by CD's great-great-grand-daughter Emma Darwin, where the diluted Darwinite in her veins is still able to induce hyperventilation in a healthy human male:

Let me give just two examples from the Annie mythos:

1. In his Autobiography, Darwin admits that 
"later in life I wholly lost, to my great regret, all pleasure from poetry of any kind, including Shakespeare".
Well, lot's of people go off poetry in later life or get cheesed off with Shakespeare-it's part of becoming a grumpy old man. But exposure to Darwinite ensures that American English professor, George Levine, comes up with an explanation custom-built for Darwin in his book Darwin Loves You. It goes like this: 
  • Annie Darwin died on April 23rd 1851. 
  • Which happens to be Shakespeare's birthday
  • So the memory of her death meant that Darwin developed a life-long downer on Shakespeare! 
It has just got to be true (not)!

2. Without Darwinite poisoning, how else could anyone write the kind of twaddle that ends Jim Moore's publication (Of Love and Death: Why Darwin 'gave up Christianity'’ in Jim Moore ed., History, Humanity and Evolution. pp. 195-229, Cambridge, 1989) that kicked off the Annie myth? As opium was to Coleridge's poetry, so it seems Darwinite is to Moore's prose. Be warned this is strong stuff!
"He ends the chapter in search of a palliative: 'We may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt, that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply.' But the words ring hollow. Why should consolation be sought unless some one has been bereaved? And can bereavement be so readily assuaged? Nature is the victim in Darwin's figure, but nature is also given a 'face', a face 'bright with gladness', to which death comes promptly without fear. Only one face in Darwin's experience ever did that. He could recall it 'with much distinctness' - 'her eyes sparkled brightly; she often smiled' - and he had the imaginative ability with bygone faces to make them 'do anything I like' Here, then, nature may be tortured that health and happiness should prevail, but the face is also sacrificed for the redemption of the world. The bereavement is finally his own; the real victim, tragically, a child already perfect. Annie, who died at Easter, became the paschal lamb of Darwin's post-Christian evolutionary soteriology."
And how many of you didn't have to look up that last word!!

Monday, June 15, 2009

In The Light of Evolution III

The current early edition of the Proceedings of the National Academies of Sciences of the USA has just been released and is chock full of articles on evolution from a recent colloquium:

Sunday, June 14, 2009

New review of The Rough Guide to Evolution

Fyrefly has just posted a review of The Rough Guide to Evolution  here. Generally highly positive, although Fyrefly doesn't like the way people are highlighted in bold, e.g Charles Darwin (1809-1882), but this is Rough Guides house style, I'm afraid.

Thursday, June 11, 2009

Clarence Darrow (1857-1938): greatest trial lawyer of all time

The Guardian today features a piece by Donald McRae entitled The Great Defender, which details the remarkable courtroom skills of Clarence Darrow. Those interested in evolution will be familiar with Darrow's pivotal role in the Scopes Monkey—here is the relevant section from The Rough Guide to Evolution:

The trial ran for less than a fortnight, but attracted unprecedented media attention with over two hundred reporters and the first ever radio broadcast of judicial proceedings. Acerbic Baltimore Sun reporter H.L. Mencken presented the trial to the public in colourful turns of phrase such as “the infidel Scopes” or “the monkey trial” [NOTE added to blog: the discerning reader will note another link here between the show, The Wire, and Darwin's legacy]. The prosecution called just four witnesses to establish that Scopes had broken the law. The defence tried to field eight expert witnesses to establish that there was no conflict between evolution and the Bible. However, the prosecution argued – and Judge John Raulston accepted – that such expert opinion was irrelevant to the question of whether Scopes had actually taught about evolution. After Bryan snuck in a jibe that humans were descended “not even from American monkeys, but from old world monkeys” defence lawyer Malone delivered a dramatic speech, seen as the highpoint of the trial, passionately arguing that the Bible belonged to the realm of theology and morality rather than to science.

Towards the end, the trial took a bizarre twist as Darrow questioned Bryan as a witness to the authenticity of the Bible. Sparks flew in the resulting exchange, with Darrow using phrases like “your fool religion” and declaring (presciently, given later history): “We have the purpose of preventing bigots and ignoramuses from controlling the education of the United States.” To prevent Bryan from summing up, Darrow waived his own right to a closing statement. Instead, Darrow asked the judge to bring the jury in and instruct them to return a guilty verdict, which they did after just nine minutes deliberation. The judge fined Scopes the minimum allowed: just $100.

What I didn't know before I read the Guardian article was Darrow's role in two other high-profile court cases, the Leopold and Loeb trial (Darrow's summation, an eloquent attack on anti-capital punshment, which moved the judge to tears, can be found here) and the trial of African-American physician Dr Ossian Sweet (read Darrow's account of it here).

The author of the Guardian article, has a book out on Darrow: The Old Devil: Clarence Darrow: The World's Greatest Trial Lawyer, while the Clarence Darrow home page is stuffed full of information and links about Darrow.

Oh and here is a question for you: what's the link between Clarence Darrow and Claire Bennet from the cult show Heroes?

Wednesday, June 10, 2009

Darwin podcasts from the Fitzwilliam Museum

The Fitzwilliam Museum in Cambridge (which Darwin frequented), is next week launching an exhibition, Endless Forms, to celebrate the Darwin bicentennial. 

To accompany the exhibition, the Fitzwilliam has produced a series of fascinating podcasts, including most recently an account of Darwin's time in Cambridge from my friend John van Wyhe. Note the sly reference in John's talk to the myth of Annie Darwin and Darwin's loss of faith: watch this space for more on this issue!

Tuesday, June 9, 2009

Latest news from Simon Singh

For those of you interested in Simon Singh's struggle with the British Chiropractic Association and the English legal system, Simon has written a nice summary of the history of the case, the issues involved and his determination to continue here:

Thursday, June 4, 2009

Darwin, the "Missing Link" and raucous students

There has been much talk in the blogosphere about the hyping up of Darwinius as a "missing link" (summarised here by Carl Zimmer). And Harry Gee has been delving into the history of the term, as has Carl's brother Ben

On reading all this, my curiosity was piqued as to whether Darwin ever used the term "missing link"....?

A few minutes searching on Darwin Online and on the Darwin Correspondence Project reveals that he did not. But interestingly, the term does feature in several letters written to Darwin, but not always in the sense of an intermediate between humans and apes:
  • Librarian Mary Boole wrote to Darwin in Dec 1866: "I felt that you had supplied one of the missing links,—not to say the missing link,—between the facts of Science & the promises of religion." 
  • In a letter dated 12 July 1871, Otto Kratz sent Darwin photographs of very hairy Burmese natives and suggested that they may be the "missing link".
  • Geologist  Frederic William Harmer quotes an opponent of Darwin, Frederick Bateman of Norwich in 1872: "I was unwise enough to reply to the latter, that a theory was not disproved by a mere objection being urged against it, & also to attempt to explain that an argument which he rested great weight upon, viz. the non production of the missing link, was valueless, owing to the imperfection of the geological record"
  •  In 1877, one of Darwin's shipmates on the Beagle, Arthur Mellersh writes to ask Darwin whether "the missing link" been found in New Guinea, as he read in the newspaper.
  • Also in 1877 comes perhaps the first sinister racist use of the term in  a letter from W. B. Bowles, who tells Darwin he 'believes "missing link" between higher mammals and man consists of a race of "speaking monkeys" – akin to Africans – who pollute blood of better race and impede civilisation'.
A search on Darwin Online also pulls up an interesting use of the term in recollections of Darwin  collecting an honorary LLD degree from the University of Cambridge in 1877. The first is from John Neville Keynes, the economist father of John Maynard Keynes:
"The honorary degree of LLD was conferred upon Darwin in the Senate House amidst a scene of some disorder. The building was crammed, floor and galleries, the undergraduates being chiefly in the galleries; and it was of course an occasion on wh. undegraduate wit felt bound to distinguish itself. The chief pleasantry consisted of a monkey swung across by strings from gallery to gallery, which monkey was in the course of the proceedings to have been changed into a man. Before however this desirable consummation was reached, the representative of the original ancestor, (than whom he was less fortunate), was seized by one of the proctors, & thus prevented from fulfilling his high destiny. The perpetrators of the joke were very wrath, & vented their fury chiefly in groans for Humphreys, the most unpopular of the proctors. He was also made the butt of such remarks as this, Would Dr. Darwin kindly afford us some information regarding the ancestors of Mr. Humphreys? — a sally which took amazingly. Sandys, the public orator, introduced Darwin, according to custom, in a rather long Latin oration, wh. was delivered amidst a ceaseless fire of interruptions, (chiefly feeble), from the wittiest of the undergraduates. Sandys (I imagine inadvertently) made use of the word apes, & then the cheering was enormous. Darwin bore himself in a rather trying position with remarkable dignity; but I heard afterwards that his hand shook so much while he was signing the registry, that his signature was scarcely legible. Another emblem swung from the galleries was a large ring of iron, adorned with ribbons, supposed to represent the missing link. It was ultimately swung down into the lap of one of the lady visitors, who pluckily cut it down and appropriated it, amidst tremendous applause. I afterwards found that this courageous lady was Miss Borchardt."
A second account of the same event is recorded in a letter from Emma Darwin to her son William

CAMBRIDGE, Sunday mg., Nov. 17th, 1877.

MY DEAR WILLIAM,

It was a great disappointment your not coming yesterday to witness the honours to F., and so I will tell you all about it.

Bessy and I and the two youngest brothers went first to the Senate House and got in by a side door, and a most striking sight it was. The gallery crammed to overflowing with undergraduates, and the floor crammed too with undergraduates climbing on the statues and standing up in the windows. There seemed to be periodical cheering in answer to jokes which sounded deafening; but when F. came in, in his red cloak, ushered in by some authorities, it was perfectly deafening for some minutes. I thought he would be overcome, but he was quite stout and smiling and sat for a considerable time waiting for the Vice-Chancellor. The time was filled up with shouts and jokes, and groans for an unpopular Proctor, Mr ———, which were quite awful, and he looked up at them with a stern angry face, which was very bad policy. 

We had been watching some cords stretched across from one gallery to another wondering what was to happen, but were not surprised to see a monkey dangling down which caused shouts and jokes about our ancestors, etc. A Proctor was foolish enough to go up to capture it and at last it disappeared I don't know how. Then came a sort of ring tied with ribbons which we conjectured to be the "Missing Link." At last the Vice-Chancellor appeared, more bowing and hand-shaking, and then F. was marched down the aisle behind two men with silver maces, and the unfortunate Public Orator came and stood by him and got thro' his very tedious harangue as he could, constantly interrupted by the most unmannerly shouts and jeers; and when he had continued what seemed an enormous time, some one called out in a cheerful tone "Thank you kindly." At last he got to the end with admirable nerve and temper, and then they all marched back to the Vice-Chancellor in scarlet and white fur, and F. joined his hands and did not kneel but the Vice-Chancellor put his hands outside and said a few Latin words, and then it was over, and everybody came up and shook hands."

It's nice to see that students at Cambridge were just as raucous back then as they are today!