Science and Religion_A Very Short Introduction

by Thomas Dixon

  9. An ichneumon wasp injecting its eggs into the caterpillar that will play host to the wasp larvae and, in due course, provide their first meal

  Darwin never became an atheist. At the time he wrote On the Origin of Species he was still a theist, although not a Christian. By the end of his life he preferred to adopt the label ‘agnostic’, which had been coined by his friend Thomas Huxley in 1869. Darwin, for the most part, kept his religious doubts to himself. He had many reasons to do so, not least his desire for a quiet life and social respectability. The most important reason, though, was his wife Emma. In the early years of their marriage, Emma, a pious evangelical Christian, wrote a letter to Charles of her fears about his loss of faith in Christianity and the consequences for his salvation. She could not bear the thought that his doubts would mean they were not reunited after death in heaven. The death of their beloved young daughter Annie in 1851 brought home again the need for the consolation of an afterlife. The difference between Charles and Emma on this question was a painful one. Among Darwin’s papers after his death, Emma found the letter she had written to him on the subject 40 years earlier. On it her husband had added a short note of his own: ‘When I am dead, know that many times, I have kissed and cryed over this.’

  The theory of evolution by natural selection

  The observations made by Darwin during his Beagle voyage proved crucial to his later theoretical speculations. As with all scientific observations, these only made sense with reference to existing theoretical frameworks, in this case to William Paley’s natural theology and Charles Lyell’s geology. On his return to England, reading a work of political economy by the Reverend Thomas Malthus would provide Darwin with a further and critically important idea, which would become the linchpin of his theory.

  Like all Cambridge students at the time, Darwin was well versed in the works of William Paley. An Anglican clergyman, philosopher, and theologian, Paley was one of the most popular religious writers of the 18th and 19th centuries. His 1802 book Natural Theology, or Evidence of the Existence and Attributes of the Deity, Collected from the Appearances of Nature compared plants and animals to a pocket watch. Any structure with many intricately crafted parts working together to achieve a specified end – telling the time in the one case, gathering pollen, flying, or seeing, in the other – must have had a designer. Just as a watch has a human watchmaker, Paley reasoned, to the satisfaction of the young Darwin and tens of thousands of other readers, so the works of nature – its flowers and its bees, its birds’ wings and its human eyes – must have had a supremely powerful and intelligent designer, namely God. Unlike Thomas Paine and the Deists, who took this argument as the main basis for their religion, Paley thought that this kind of natural theology was of use largely as a supplementary argument confirming what was already known from the Bible, and from the inner voice of one’s conscience. What Darwin specifically took from Paley was the tendency to find everywhere in nature extraordinary evidence of design, of contrivance, of adaptation.

  A second key component of Darwin’s world view was provided by a book he read during the Beagle voyage, Sir Charles Lyell’s Principles of Geology, published in three volumes between 1830 and 1833. Lyell’s book argued that the history of the earth was one of gradual changes operating over long periods of time rather than one of regular violent catastrophes. His was a reformist rather than a revolutionary view of geology – time was to replace violence as the principal agent of change. Darwin came to see geological phenomena through Lyell’s eyes. He witnessed an earthquake, for example, in Chile in 1835. After the quake he noticed that the shoreline had risen slightly. He also observed similar elevated beaches at much higher levels up in the Andes. If geological change could be explained by such gradual modifications over time, perhaps biological change could too. Darwin later confessed, ‘I always feel as if my books came half out of Lyell’s brains.’

  When Darwin got back to England and started to try to make sense of the numerous specimens of plants and animals he had collected during the voyage, he began to focus on the ‘species question’. This was the ‘mystery of mysteries’ for those seeking a naturalistic explanation of the origins of the different forms of life. In the 1830s, Darwin was confronted with two alternative explanations which were both equally unpalatable to him. Either each species had been created at a particular time and place by God, as most other naturalists believed, or else all life had started, perhaps spontaneously, in a simple form and had gradually climbed the ladder of life in the direction of greater complexity and perfection. The first option was unattractive because it posited a whole series of miraculous interventions by God in the history of life. What Darwin wanted to find was an explanation in terms of natural laws. The second option, the French naturalist Jean-Baptiste Lamarck’s theory of ‘transmutation’, developed in his Philosophie Zoologique (1809), involved too many unacceptable theoretical assumptions for Darwin, such as the idea that life was continuously being spontaneously generated and starting its ascent up the ladder of life, that all life was climbing in the same direction up this single ladder, and that a creature’s own voluntary efforts could alter its physical structure. Lamarck’s theory was also widely believed to be connected to religiously unacceptable ideas of materialism and determinism – in other words, to the view that all phenomena, both mental and physical, could ultimately be explained in terms of causal interactions between particles of matter.

  The animal life of the Galapagos islands – its finches and giant tortoises, its iguanas and mocking birds – was later to provide one of the keys to unlocking the ‘mystery of mysteries’. During his five weeks on the island in 1835, Darwin became aware that these creatures differed in form from one island to the next, and also between the islands and the South American mainland. Subsequently, back in England, Darwin started to see these differences as useful evidence for evolution. At the time, he did not take great care to mark which finches had been collected from which island. And in the case of the giant tortoises, he even ate some of the evidence, recording in his diary: ‘Eating tortoise meat. By the way delicious in soup.’

  The Galapagos finches have become a popular example with which to explain Darwin’s theory since they nicely illustrate the dilemma he faced as he thought about the history of life in the 1830s. Each island had its own species of finch, with differences in the sizes and shapes of their beaks. Did this require Darwin to believe that there had been a separate act of creation by God on each island, and another one on the mainland too? This seemed scientifically and theologically inelegant, to say the least. A unidirectional transmutationist model would not work either, since there was no obvious way to arrange these different species in a single line with one developing into the other. From the late 1830s, Darwin filled his notebooks with arguments and counter-arguments trying to solve these sorts of problems. He thought about the way that breeders of pigeons selected particular individuals among each generation when trying to produce unusual new varieties. The analogy with artificial selection would be central to his argument. Even more central, though, was an idea he took from An Essay on the Principle of Population (1798) by Thomas Malthus.

  10. A giant Galapagos tortoise of the kind Darwin enjoyed eating during his visit to the islands in 1835

  Darwin read Malthus’s Essay in 1838 and saw how it could be applied to the species question. Malthus’s concern was with human populations. He believed that these had a natural tendency to increase at an exponential rate from one generation to the next (1, 2, 4, 8 ...), while the amount of food that a society could produce increased only arithmetically (1, 2, 3, 4 ...). This led, in each generation, to a struggle for resources. The strong would survive but the weak would perish. Looking at the entangled creepers of the South American jungle, the parasitic and murderous instincts of insects, and even at the plants and weeds in his own back garden, Darwin could see something similar going on – a competition for resources which those creatures with even a slight advantage over their competitors
would win. This struggle for existence and the resulting ‘survival of the fittest’, as the evolutionary philosopher Herbert Spencer would call it, became the central idea of Darwin’s theory. Alfred Russel Wallace, who came up with the idea of natural selection in the 1850s, 20 years later than Darwin but before Darwin had published his theory, also gave credit to Malthus as a source of inspiration.

  11. An illustration from Darwin’s Journal of Researches into the Natural History and Geology of the Countries Visited During the Voyage of H.M.S. Beagle (1845), showing a selection of the different species of finch collected during the voyage

  Darwin now had his solution. The adaptation of organisms to their environment, and the origins of separate species, should be explained not in terms of the creative acts of Paley’s designer, but by geographical distribution, random heritable variation, competition for resources, and the survival of the fittest over vast aeons of time. Natural selection could come in many different guises – as a disease, a predator, a drought, a shortage of your favourite food, a sudden change in the weather – but those individuals in each generation who happened by good luck to be the best equipped to cope with these natural assaults would flourish and leave offspring, while the less well adapted would perish without issue. Repeat that process for hundreds of millions of years and the whole panoply of species now observed could evolve from the simplest forms of life.

  So, according to this theory, the species of Galapagos finches were not separately created, nor were they on the successive rungs of a single ladder of life; instead, they were at the ends of different branches of a huge family tree – the tree of life. The differences in the kinds of food that had been available on the different islands – seeds, insects, or cactuses – meant that different sizes and shapes of beak would have bestowed a greater advantage in the struggle for existence depending on geographical location. These species had diverged from a common ancestor species, originally blown across from the mainland. Nature had then acted like the pigeon-fancier, selecting those individuals with the desired characteristics, and allowing them to breed.

  When, in 1858, Darwin received a letter from Wallace outlining a theory virtually identical to his, he was spurred into a more rapid publication of his ideas than he had planned. At a hurriedly arranged meeting of the Linnaean Society, an announcement was made of Darwin’s and Wallace’s theories. The following year saw the publication by John Murray of Albemarle Street, London, of On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life. The author’s credentials were prominently displayed on the title page: ‘Charles Darwin, M.A., Fellow of the Royal, Geological, Linnaean, etc., Societies; Author of Journal of Researches During H.M.S. Beagle’s Voyage Round the World’. Hopefully this impressive potted curriculum vitae would make the book’s revolutionary contents more palatable to its Victorian readers.

  12. One of Darwin’s first sketches, in his notebooks of the late 1830s, of his idea of a branching tree of life connecting all organisms through a shared ancestry

  ‘Our unsuspected cousinship with the mushrooms’

  Those first readers of On the Origin of Species were presented with a view of nature in which God had been pushed to the margins rather than banished completely. God was no longer needed to create each individual species but Darwin, whether for the sake of convention or out of his own remaining religious convictions, presented his argument as favouring a kind of theistic evolution. On opening their copy of the book in 1859, the first words that a reader would have come across were two theological epigraphs – one a quotation from the Anglican divine and polymath, William Whewell, the other from Francis Bacon, one of the leading lights of the scientific revolution of the 17th century. Whewell stated that in the material world ‘events are brought about not by insulated interpositions of Divine power, exerted in each particular case, but by the establishment of general laws’. According to Bacon, one could never have too much knowledge of either the book of God’s word or the book of God’s works, divinity or philosophy, ‘rather let men endeavour an endless progress or proficience in both’.

  When it came to the concluding section of the book, Darwin reiterated Whewell’s view that God acted in a law-like rather than a miraculous fashion. ‘To my mind,’ Darwin wrote,

  it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes … When I view all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Silurian system was deposited, they seem to me to become ennobled.

  In the famous closing sentences of the book, Darwin marvelled that from ‘the war of nature, from famine and death’, the highest forms of life had been produced. He concluded:

  There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

  From the second edition onwards, in case there was any doubt about his meaning, he changed the phrase ‘breathed into a few forms or into one’ to ‘breathed by the Creator into a few forms or into one’.

  There were some within the Christian churches who were persuaded by Darwin’s new natural theology. There was indeed greater grandeur and nobility, they agreed, as well as more simplicity and order, in a world where God had created through a law-like process of evolution, rather than one in which God periodically intervened to top up the planet’s flora and fauna after particularly destructive catastrophes. We have already seen in Chapter 3 that Henry Drummond was one such individual. The historian, Christian socialist, and novelist Charles Kingsley was another. His famous children’s story The Water Babies, published in 1863, included an allusion to his approval for Darwin’s new theory. The little boy Tom approaches ‘Mother Carey’, a personification of nature, and says ‘I heard, ma’am, that you were always making new beasts out of old.’ Mother Carey replies ‘So people fancy. But I am not going to trouble myself to make things, my little dear. I sit here and make them make themselves.’ A future Archbishop of Canterbury, Frederick Temple, was another Anglican who supported the idea that God might have created through variation and natural selection rather than by a succession of miracles. On the other side of the Atlantic also there were individuals, such as the Harvard botanist and Presbyterian Asa Gray, who were persuaded to adopt a theistic version of Darwinian evolution.

  But there were instances of conflict too, most famously in the form of a dramatic confrontation at the British Association for the Advancement of Science in Oxford in 1860. Darwin himself was not present at the occasion, but his theory was discussed in a paper applying Darwinian ideas to the question of intellectual and social progress. The general issue of Darwinism was then opened up to the floor for further debate. The first speaker was the Bishop of Oxford, Samuel Wilberforce. He spoke at some length about Darwin’s theory. We do not have a record of exactly what he said, but we can make an educated guess based on his review of On the Origin of Species which appeared in the conservative Quarterly Review. In that review, Wilberforce noted that the conclusion implied by Darwin’s book, namely that ‘mosses, grasses, turnips, oaks, worms, and flies, mites and elephants, infusoria and whales, tadpoles of today and venerable saurians, truffles and men, are all equally the lineal descendants of the same aboriginal common ancestor’ was certainly a surprising one, but one which he would have to admit if the scientific reasoning were sound. He was not going to object, he wrote, to Darwin’s inference of ‘our unsuspected cousinship with the mushrooms’ on biblical grounds, since it was most unwise to try to judge the truth of scientific theories with reference to revelation. However, drawing heavily on the work of the country’s leading anatomist, Richard Owen,
Wilberforce found plenty of scientific objections to the theory, focusing especially on the lack of fossil evidence of transitional forms, and on the fact that however many varieties of pigeons and dogs may have been produced under domestication, pigeons had always remained pigeons and dogs always dogs. There had been no hint of a new species.

  Although he did not base his objections on a literal reading of the Bible, Wilberforce’s resistance to evolution, like that of many religious believers since his day, did derive from a commitment to a biblically inspired world view in which human beings were separate from and superior to the rest of the animal world. The Christian teaching that God took on human form in the person of Jesus Christ also gave that human form a particularly special significance. To claim that man was nothing more than an ‘improved ape’ rather than ‘Creation’s crown and perfection’ was, Wilberforce pointed out, therefore demeaning to God as well as to humanity. At the Oxford meeting, at the end of his remarks, Wilberforce is reported to have turned to one of Darwin’s staunchest advocates, Thomas Huxley, who was present among the throng of almost a thousand people, and asked him whether he was descended from an ape on the side of his grandmother or his grandfather. It was intended as a joke, but Huxley was apparently white with anger as he whispered to his neighbour, ‘The Lord hath delivered him into mine hands.’ Huxley rose and replied severely that he would rather be descended from an ape than from a man who used his intellect and influence to introduce ridicule into a grave scientific discussion. As the temperature in the packed auditorium rose, and at least one woman fainted in the excitement, Darwin’s old companion from HMS Beagle, Captain Fitzroy, stood up holding a Bible aloft with both hands and denounced Darwin’s theory. Another of Darwin’s inner circle, the botanist Joseph Hooker, then weighed in with what was, on Hooker’s own account, a decisive intervention on the side of Darwinism.