|Table of contents|
2 Journey on the Beagle
3 First writings
4 The Origin of Species
5 Before Darwin
6 Darwin's theory of evolution
7 Views on religion
8 See also
9 External links
After finishing school, Darwin studied medicine in Edinburgh in 1825. His dislike for dissection and the brutality of surgery at the time led him to leave the medical school in 1827. Whilst there, however, he was influenced by the Lamarckian Robert Edmund Grant.
His father, unhappy that his younger son had not become a physician and fearing that he would become a "ne'er do well", enrolled him at Cambridge University, with the hopes of Charles' eventually becoming a parson. While at Cambridge, he came under the intellectual influence of scientific minds such as William Whewell and John Stevens Henslow which (combined with his interest in collecting beetles, which was encouraged by his cousin, William Darwin Fox) resulted in him pursuing natural history.
After taking his degree with honors, Darwin stayed at Cambridge for further studies in geology, where he proved particularly adept. In the summer of 1831, Darwin worked with the great geologist Adam Sedgwick mapping strata in Wales.
Darwin had planned to visit Madeira with some class-mates upon graduation in 1831. These plans, however, fell through. After Darwin finished his studies, Henslow recommended him for the position of gentleman's companion to Robert Fitzroy, the captain of the HMS Beagle, which was departing on a five-year expedition to chart the coastline of South America.
Journey on the Beagle
Darwin's work during the Beagle expedition allowed him to study both the geological properties of continents and isles and a multitude of living organisms and fossils. He collected an enormous number of specimens new to science in a very methodical way, and his specimens sent back to the British Museum were by themselves a significant contribution to science, and made him one of the precursors of ecology. No other collector has rivalled his work since.
During his voyage, he visited the Cape Verde Archipelago, the Falkland Islands, the South American coast, the Galapagos Islands, New Zealand and Australia, collecting considerable quantities of specimens.
After returning from the voyage on October 2, 1836, Darwin analyzed the specimens he collected, and noticed similarities between fossils and living species within the same geographic area. In particular, he noticed that every island in the Galapagos Archipelago had its own kind of tortoises and birds that were all slightly different in appearance, favored food etc., but otherwise similar.
In the spring of 1837 ornithologists at the British Museum informed Darwin that the several very different species of birds he had taken in the Galapagos were all finches. This, coupled with a re-reading of Thomas Malthus' 1798 essay on populations, triggered a chain of thought that would culminate in the theory of evolution by natural and sexual selection. He developed the hypothesis that, for example, all the different turtles had originated from a single turtle species, and had adapted to life on the different islands in different ways.
Based on these thoughts, he formulated his ideas about the changes and developments of species in his Notebook on the Transmutation of Species, which was in accordance with Lyell's Principles of Geology and Thomas Malthus' Essay on the Principle of Population, which stated that the size of a population is limited by the food resources available. Realizing the potential of this understanding, Darwin undertook extensive experiments with pigeons and plants, and extensive consultation with pig breeders and other animal husbanders, in an attempt to discover holes in the hypothesis.
In 1842, Darwin formulated a short "Pencil Sketch" of his theory and by 1844 had written a 240 page "Essay" which provides an expanded version of his early ideas on natural selection. Between 1844 and 1858, when he would present his theory to the Linnean Society of London, Darwin would modify his theory in a number of ways.
Darwin published other treatises in science, including an explanation for the creation of coral atolls in the South Pacific, and the story of his voyage aboard the Beagle.
Darwin married his cousin Emma Wedgwood in 1839. After living for a number of years in London, the couple eventually moved to Down House, in Downe, Kent (which is now open to public visits, south of Orpington). Darwin and his wife had ten children, three of whom died early. Between 1839 and 1843, Darwin's Zoology of the Voyage of H.M.S. Beagle was published in five volumes.
The Origin of Species
Darwin's work brought him a correspondence relationship with Alfred Russel Wallace, working in the islands of the South Pacific. In June, 1858, Wallace sought Darwin's ideas on a theory Wallace had developed which exactly mirrored Darwin's own work. Scientist friends persuaded Darwin to go public with the theory, now independently confirmed. On 1 July, 1858, Darwin's paper about The Origin of Species by Means of Natural Selection was read to the Linnean Society in London, jointly with Wallace's paper.
Darwin's book On the Origin of Species by Means of Natural Selection was published one year later, and was of sufficient interest to have the publisher's stocks completely sold to bookstores on the first day.
It provoked an outraged response from the Church. A large meeting was organised in Oxford where 'Soapy Sam' Wilberforce, the Bishop of Oxford, numerous Clergy and Robert Fitzroy (the Captain of HMS Beagle) argued against Darwin, Thomas Huxley and their Evolutionist supporters. On being asked by Wilberforce, whether he was descended from monkeys on his grandfather's side or his grandmother's side, Huxley, recognizing the stupidity of the question, apparently muttered to himself: "The lord has delivered him into my hands", and then replied that he "would rather be descended from an ape than from a cultivated man who used his gifts of culture and eloquence in the service of prejudice and falsehood" [several alternative versions of this supposed quote exist, see Wilberforce and Huxley: A Legendary Encounter.
In several of his later books The Variation of Animals and Plants Under Domestication (1868), The Descent of Man, and Selection in Relation to Sex (1871) and The Expression of Emotions in Animals and Man (1872), Darwin expanded on many topics introduced in Origin of Species.
The value of Darwin's work was appreciated throughout the scientific community. He became a member of the Royal Society of London in 1839 (on the basis of his collecting during his voyages) and of the French Academy of Sciences (l'Académie des Sciences) in 1878
Darwin was given particular recognition in 2000 when his image appeared on the Bank of England ten pound note, replacing Charles Dickens. His impressive and supposedly hard-to-forge beard was reportedly a contributing factor in this choice.
Before the nineteenth century, the accepted theory for the extinction of species was called Catastrophism, which stated that species went extinct due to catastrophes that were often followed by the formation of new species ex nihilo (out of nothing). The extinct species can then be found as fossils. The new species were considered unchangeable. This theory was in accordance with the story of the Flood in the Bible. In the early nineteenth century, several new theories started to compete with Catastrophism. One of the most important ones was developed by Jean-Baptiste Lamarck (1744-1829). He observed that every new generation inherits the traits of its ancestors. He suggested that traits or organs become enhanced with repeated use and weakened or removed by disuse in each individual, who will pass these improvements or losses directly to their offspring. In 1830, the British geologist Sir Charles Lyell disproved the Catastrophism Theory, but held on to the theory of species staying unchanged during time. Lyell founded uniformitarianism, a theory stating that the surface of earth changed slowly through eons by constant forces.
Darwin's theory of evolution
Darwin's theory of evolution is based on five key observations and inferences drawn from them. These observations and inferences have been summarized by the great biologist Ernst Mayr as follows: First, species have great fertility. They make more offspring than can grow to adulthood. Second, populations remain roughly the same size, with modest fluctuations. Third, food resources are limited, but are relatively constant most of the time. From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals. Fourth, in sexually reproducing species, generally no two individuals are identical. Variation is rampant. And fifth, much of this variation is heritable. From this it may be inferred: In a world of stable populations where each individual must struggle to survive, those with the "best" characteristics will be more likely to survive, and those desirable traits will be passed to their offspring. These advantageous characteristics are inherited by following generations, becoming dominant among the population through time (Fig. 2). This is natural selection. It may be further inferred that natural selection, if carried far enough, makes changes in a population, eventually leading to new species. These observations have been amply demonstrated in biology, and even fossils demonstrate the veracity of these observations.
Darwin imagined it might be possible that all life is descended from an original species from ancient times. DNA evidence supports this idea.
Figure 2 : Schematic drawing of the evolution process.
(1) Natural selection. (2) Reproduction. (3) Mutation.
Response to Darwin's theory
After the publication of Darwin's book, evolution as the means of natural selection was widely discussed (Fig. 3), particularly by the religious and the scientific communities. Though Darwin was supported by some scientists (e.g., T.H. Huxley), others hesitated to accept the theory due to the unexplained ability of individuals to pass their special abilities to their offspring. The last point remained a mystery until the existence of genes was discovered. In 1902 Peter Kropotkin published the book Mutual Aid: A Factor of Evolution, challenging Darwin's Theory as too narrow. In 1874, the theologian Charles Hodge accused Darwin of denying the existence of God by defining humans to be a result of a natural process rather than a creation designed by God. Darwin's theory is now backed up by the comparison of DNA from different organisms which shows the closeness of their relationship.
Today, whilst the overwhelming majority of biologists consider Darwin's basic theory correct, a significant fraction of the general population, particularly in the United States amongst Western countries, do not do so on religious grounds. See Pseudoscience creationism.
Contrary to popular opinion, Darwin did not "discover" evolution as it was accepted by many since the beginning of the 1800s.
Instead, he and Wallace discovered the first really coherent mechanism that explains how evolution occurs (natural selection).
Other important aspects of Darwin's overall theory were: common descent, sexual selection, gradualism, and pangenesis. It is important to remember that Darwin's version of natural selection was different from that presented by Wallace in that he held that natural selection was continuously operating, whereas Wallace argued that selection only occurred when the environment changed.
Figure 3 : Caricature of Darwin as an ape in the Hornet magazine. (Image in the PD)
Views on religion
It has been falsely claimed that Darwin converted to Christianity on his deathbed. The claim can be dismissed by his never having renounced the church. This claim is discussed in The Survival of Charles Darwin: A Biography of a Man and an Idea, by Ronald W. Clark (Weidenfeld & Nicholson 1985), p. 199:
- "Shortly after his death, Lady Hope addressed a gathering of young men and women at the educational establishment founded by the evangelist Dwight Lyman Moody at Northfield, Massachusetts. She had, she maintained, visited Darwin on his deathbed. He had been reading the Epistle to the Hebrews, had asked for the local Sunday school to sing in a summerhouse on the grounds, and had confessed: 'How I wish I had not expressed my theory of evolution as I have done.' He went on, she said, to say that he would like her to gather a congregation since he 'would like to speak to them of Christ Jesus and His salvation, being in a state where he was eagerly savouring the heavenly anticipation of bliss.'
- "With Moody's encouragement, Lady Hope's story was printed in the Boston Watchman Examiner. The story spread, and the claims were republished as late as October 1955 in the Reformation Review and in the Monthly Record of the Free Church of Scotland in February 1957. These attempts to fudge Darwin's story had already been exposed for what they were, first by his daughter Henrietta after they had been revived in 1922. 'I was present at his deathbed,' she wrote in the Christian for February 23, 1922. 'Lady Hope was not present during his last illness, or any illness. I believe he never even saw her, but in any case she had no influence over him in any department of thought or belief. He never recanted any of his scientific views, either then or earlier. We think the story of his conversion was fabricated in the U.S.A. . . . The whole story has no foundation whatever.'" (Ellipsis original.)
- "Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science."
- "Belief in God- Religion.- There is no evidence that man was aboriginally endowed with the ennobling belief in the existence of an Omnipotent God. On the contrary there is ample evidence, derived not from hasty travellers, but from men who have long resided with savages, that numerous races have existed, and still exist, who have no idea of one or more gods, and who have no words in their languages to express such an idea. The question is of course wholly distinct from that higher one, whether there exists a Creator and Ruler of the universe; and this has been answered in the affirmative by some of the highest intellects that have ever existed."
- "The belief in God has often been advanced as not only the greatest, but the most complete of all the distinctions between man and the lower animals. It is however impossible, as we have seen, to maintain that this belief is innate or instinctive in man. On the other hand a belief in all-pervading spiritual agencies seems to be universal; and apparently follows from a considerable advance in man's reason, and from a still greater advance in his faculties of imagination, curiosity and wonder. I am aware that the assumed instinctive belief in God has been used by many persons as an argument for His existence. But this is a rash argument, as we should thus be compelled to believe in the existence of many cruel and malignant spirits, only a little more powerful than man; for the belief in them is far more general than in a beneficent Deity. The idea of a universal and beneficent Creator does not seem to arise in the mind of man, until he has been elevated by long-continued culture."
- "Whilst on board the Beagle (October 1836-January 1839) I was quite orthodox, and I remember being heartily laughed at by several of the officers (though themselves orthodox) for quoting the Bible as an unanswerable authority on some point of morality. I suppose it was the novelty of the argument that amused them. But I had gradually come, by this time, to see that the Old Testament; from its manifestly false history of the world, with the Tower of Babel, the rainbow as a sign, etc., etc., and from its attributing to God the feelings of a revengeful tyrant, was no more to be trusted than the sacred books of the Hindoos, or the beliefs of any barbarian." (Charles Darwin: The Autobiography of Charles Darwin with original omissions restored. New York, Norton, 1969. p.85)
- "By further reflecting that the clearest evidence would be requisite to make any sane man believe in the miracles by which Christianity is supported, --that the more we know of the fixed laws of nature the more incredible, do miracles become, --that the men at that time were ignorant and credulous to a degree almost incomprehensible by us, --that the Gospels cannot be proved to have been written simultaneously with the events, --that they differ in many important details, far too important as it seemed to me to be admitted as the usual inaccuracies of eyewitness; --by such reflections as these, which I give not as having the least novelty or value, but as they influenced me, I gradually came to disbelieve in Christianity as a divine revelation. The fact that many false religions have spread over large portions of the earth like wild-fire had some weight with me. Beautiful as is the morality of the New Testament, it can hardly be denied that its perfection depends in part on the interpretation which we now put on metaphors and allegories." (p.86)
- "Thus disbelief crept over me at a very slow rate, but at last was complete. The rate was so slow that I felt no distress, and have never since doubted even for a single second that my conclusion was correct." (p.87)
- "I can indeed hardly see how anyone ought to wish Christianity to be true; for if so the plain language of the text seems to show that the men who do not believe, and this would include my Father, Brother and almost all my best friends, will be everlastingly punished. And this is a damnable doctrine." (p. 87)
- "The old argument of design in nature, as given by Paley, which formerly seemed to me so conclusive, fails, now that the law of natural selection had been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows. Everything in nature is the result of fixed laws." (p.87)
- "At the present day (ca. 1872) the most usual argument for the existence of an intelligent God is drawn from the deep inward conviction and feelings which are experienced by moat persons. But it cannot be doubted that Hindoos, Mahomadans and others might argue in the same manner and with equal force in favor of the existence of one God, or of many Gods, or as with the Buddists of no God...This argument would be a valid one if all men of all races had the same inward conviction of the existence of one God: but we know that this is very far from being the case. Therefore I cannot see that such inward convictions and feelings are of any weight as evidence of what really exists." (p.91)
- "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 as 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." (p.93)
- Darwin Literature, Chapter-indexed, searchable versions of Darwin's works.
- Note: The comprehensive and authoritative web source for Darwin texts (essentially all of them, in a consistent and citable format) is here: http://pages.britishlibrary.net/charles.darwin/
- See also: http://textbook.wikipedia.org/wiki/Charles_Darwin