Dawkins and evolution
River out of Eden
Whenever I take down one of Richard Dawkins' books from the shelf, I am always pleased by the happy coincidence that through an accident of alphabetical synchronicity they sit next to the works of Charles Darwin. For Dawkins is, of course, the spiritual heir of Thomas Henry Huxley, "Darwin's Bulldog", who championed the theory of evolution by natural selection and was not averse to entering into debate with Bishops on the subject, once famously besting "Soapy Sam" Wilberforce (according to legend) in a discussion about the desirability of having an ape as an ancestor.
Thanks to modern mass communications, as well as to his own skill as a debater and his commitment to Darwinian ideas, Dawkins must have persuaded even more people than Huxley ever did of the validity of those ideas. There are other biologists who are as committed to the theory of evolution as Dawkins, and some of them may be as able as him at communicating Darwinian ideas; but if you are a TV or radio producer and you need a scientist to enter the lists against a Bishop or a creationist, then Dawkins is the man you can rely on to take up the Darwinian case in public.
It all began, of course, nearly twenty years ago, in 1976, when his book The Selfish Gene first appeared. The idea of living things -- including people -- as "gene machines", driven to follow certain patterns of behaviour by the imperative need of genes to survive and make copies of themselves, helped many people to a better understanding of Darwinian evolution, led some people to misappropriate the idea and misuse it, and enraged yet other people, who saw this as mechanistic reductionism, completely counter to their own beliefs in some mystic, imaginary property of human beings that is supposed to make the whole greater than the sum of its parts. There is no room in Dawkins' world for an immortal soul -- and no need in Darwin's world for the guiding hand of God.
Dawkins has since gained great experience arguing this case, in his role as Darwin's new bulldog. Two decades of debate have shaped River out of Eden, which is far more than the basic "instant guide" to its subject that its appearance in the Science Masters series would suggest. The author not only explains the basics of evolution, but anticipates the kind of criticism likely to be made of these ideas, and gets in a pre-emptive strike by answering the criticisms before they are made. He must have gained the greatest satisfaction from being able to nail, once and for all, one of the favourite arguments of the creationists.
What Dawkins calls "the creationist's favourite conundrum" is the question inevitably raised at any public meeting about evolution: What use is half an eye? This is usually linked to the claim that there has not been sufficient time since the world began (a mere 4.5 thousand million years) for an organ so sophisticated as the eye to have evolved. Both questions, says Dawkins, stem from "the Argument from Personal Incredulity", based on nothing more than the feeling that if I can't understand it, it must be impossible.
Deliciously, Dawkins refutes both aspects of the argument. He explains how useful any kind of light-sensing organ would be, and how it could be formed by successive evolutionary steps. And then he describes recent work in Sweden which shows that a fully functioning "modern" eye could evolve from a patch of light sensitive skin in less than four hundred thousand generations -- less than half a million years in the case of small animals with an annual generation cycle. "It is no wonder," he emphasises, that "'the' eye has evolved at least forty times independently around the animal kingdom. There has been enough time for it to evolve from scratch fifteen hundred times in succession". Rather than requiring an immortal soul to act as the ghost driving the human machine, modern genetics can explain all the workings of the human body, and the way it has evolved, in terms of the coded message carried in the DNA in every living cell. The code consists of no more, and no less, than long chains made up of four chemical compounds, known (from the initial letters of their chemical names) as A, C, G and T. We are all familiar, these days, with the ability of computers to code huge masses of complex data in the form of a binary code, an alphabet with just two letters; in principle, all of Shakespeare (or the Encyclopedia Britannica) could be communicated on an Aldiss lamp, using another binary system, the Morse code. How much easier, then, for genes to convey information coded in a quaternary system, with the luxury of a four-letter alphabet.
The information is conveyed from generation to generation by the genes being copied and handed on from parent to offspring. This provides the metaphorical "river" of Dawkins' title, a stream of genes stretching back from all of us to the original ancestor, the first DNA replicator. All of life on Earth shares the same genetic code, and the odds against this particular code arising twice by chance are one in a million million million million million -- so we are, surely, all descended from a single ancestor, the same ancestor that we share with termites and trees, bacteria and blowfish. Human beings are also all much more closely related than you might think. and in tracing our ancestry (the ancestry of every person alive on Earth today) back to the "African Eve" who lived less than a quarter of a million years ago Dawkins also spells out how closely related you are likely to be to casual acquaintances and strangers you pass on the street. This explains why even selfishness among genes can encourage the bodies those genes inhabit to cooperate with one another -- a delightfully ironic tale, since one of the abuses of the idea of "selfish" genes was the way in which it was used by economists of an extreme Thatcherite persuasion to justify the most excessive workings of the competitive free market. In fact, if most of the people you meet are likely to be quite close relations, cousins who carry copies of many of your own genes, being nice to them and helping them to survive and pass on copies of their genes to the next generation is a good thing, as far as the selfish interest of your own genes is concerned. Genetic selfishness is a good argument in favour of the welfare state. Dawkins packs all this and more into just 172 pages of entertaining, clear prose. It is said that one of the reasons for the phenomenal success of A Brief History of Time is its mystic, semi-religious tone. River out of Eden is better written, on a more important subject, and easy to understand. But if there is one thing it lacks, it is mysticism. It deserves to sell even more copies than Stephen Hawking's book; but I doubt if it will. There are, alas, no million-dollar prizes available for writers who show that there is no evidence that God exists.
On The Shelf
John Gribbin on Charles Darwin's Origin of Species
How many of the original publications describing a revolution in science can be recommended as a good read for non-scientists? Isaac Newton's epic, the Principia, hardly qualifies (even if you do read Latin); Albert Einstein's papers on general relativity may look beautiful to mathematicians, but leave the rest of us less than enthralled. And the writings of the quantum pioneers are not something you would take to while away a train journey. True, James Watson did write a highly enjoyable book about the discovery of DNA; but that was long after the event, and dealt more with personalities than the science. No, there is only one candidate -- Charles Darwin's On the Origin of Species by Means of Natural Selection, first published in 1859 and still in print in a Penguin volume that, significantly, reprints the first edition of Darwin's great work.
Darwin didn't just have the genius to make major scientific discoveries; he was also a superb writer, in the great Victorian tradition. He loved literature (one of the highlights of his social life was a meeting with George Eliot), and he agonised over his own prose, constantly rewriting his books, even at the proof stage, and driving printers and publishers to distraction with his last minute changes. And yet, for all the frantic revisions, the result is a clear voice, talking to the reader in straightforward terms, describing the trials and tribulations of the research that led Darwin to his revolutionary conclusions, as well as explaining those conclusions as clearly as anyone has ever been able to do. I have to confess that I came late to Darwin. Trained as a physicist and astronomer, it was only when I became a science journalist, and began writing stories about exciting topics such as selfish genes, that a colleague gently suggested that it might be no bad thing to read the Origin. I approached the task out of a sense of duty, accepting the wisdom of his advice but wishing there was some way out. But I was gripped from the opening passage of the book, and although I didn't quite devour it in the proverbial single sitting (it is, after all, a substantial work), my family saw little of me for the rest of that weekend. Why on Earth, I wondered, had nobody told me about this before?
The introduction itself id bound to hook anybody reared on a diet of Coral Island and Swallows and Amazons. "When on board H.M.S. 'Beagle' as a naturalist," writes Darwin, "I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species -- that mystery of mysteries, as it has been called by one of our greatest philosophers." By the second paragraph, we learn that there is some urgency about Darwin's work, and that he lives under the threat of death. "My work is now nearly finished; but as it will take me two or three more years to complete it, and as my health is far from strong, I have been urged to publish this Abstract."
The "abstract" ran to nearly five hundred printed pages in its original form, carefully setting out the story of variation among domesticated species and in the wild, ranging from pigeon breeding in London to the birds of the Galapagos islands, before coming on to the heart of the matter, the struggle for existence. "In looking at Nature, it is most necessary to keep the foregoing considerations always in mind -- never to forget that every single organic being around us may be said to be striving to the utmost to increase in numbers; that each lives by a struggle at some period of its life; that heavy destruction inevitably falls either on the young or old, during each generation or at recurrent intervals." By the time you reach the discussion of Natural Selection (Darwin always used the capitals) itself, you are well prepared. As you read about the "preservation of favourable variations and the rejection of injurious variations, [which] I call Natural Selection," you feel like the character in C. P. Snow's The Search, who "saw a medley of haphazard facts fall into line and order . . . 'But it's true,' I said to myself. 'It's very beautiful. And it's true.'" (Macmillan edition, 1963.) In spite of the beauty and clarity of Darwin's original version, there are still debates about the nature of evolution. It is, perhaps, no surprise to find that many of the critics of the very idea of evolution have not, in fact, read the Origin; it is more of a surprise to find that even among biologists who debate exactly how evolution works there are reprobates who have somehow overlooked the importance of checking out what Darwin actually said. But someone must be reading the book. According to The Portable Darwin (edited by Duncan Porter and Peter Graham, Penguin, 1993), there were six editions, 35 printings and translations into 11 languages in Darwin's lifetime, the book has been continuously in print since, and the reprints now exceed 400 while the translations number at least 29 languages.
But one word of caution. Many of those reprints and translations are from later editions of the work, especially the sixth, revised by Darwin in the light of criticisms provoked by the first edition. Much of that criticism later proved to be ill-founded, and Darwin's accessible prose did, for once, suffer from his attempts to buttress his arguments. It is the first edition which strikes the reader with such clarity and force that it provokes the "but it's true" reaction, and it is, happily, the first edition which most closely matches the way biologists today think that evolution really does work. It is a sumptuous delight of a book, the only science book that I can recommend, hand on heart, as a good read to anybody who likes books, regardless of their attitude to science. It is also one I would recommend to all scientists (including astrophysicists) as an example both of the meticulous way in which scientific research ought to be carried out, and of the way in which even the most complex scientific arguments really can be presented with full force to an educated, interested, but not necessarily scientifically literate audience.
The Moral Animal:
Why we are the way we are
Sociobiology, it seems, is now The Science That Dare Not Speak Its Name. Particularly in the United States, the idea of investigating the way people behave by applying the same criteria used to study the behaviour of other animals, and in particular the idea of explaining our present day behaviour in terms of the survival of genes that made our ancestors successful, has caused such a backlash that authors such as Robert Wright now seek to hide behind the smokescreen of a new name, "Evolutionary Psychology". This is rather like replacing the emotive term "genocide" by the smokescreen term "ethnic cleansing"; it works for about half a millisecond, and then you realise that this is the same reality wearing a different hat.
Worse, by using a smokescreen name the author gives the impression that sociobiology is, like genocide, something to be ashamed about. In reality, whatever the name it goes under, this is one of the most exciting developments in the life sciences in recent decades, with implications for all of us -- not least, the prospect of understanding why some groups of people go in for genocide, and by understanding the problem finding ways to avert it.
Wright tends not to go into these broader issues, but chooses to focus on the relationship between the sexes and within the family. This is familiar ground -- are men more inclined to be philanderers than women, and if so, why? do children always want more from their parents than their parents want to give? and so on. But Wright adds yeast to the mix with a delightfully whimsical idea, using the story of Charles Darwin's marriage to illustrate the main points he wishes to put across. As he tells us, "even Charles Darwin was an animal", and as such ripe for study -- a sentiment Darwin himself, who made detailed studies of his own children, would surely have endorsed.
Since evolution is all about the transmission of genes from one generation to the next, there is a great deal here about sex, Victorian morality, and possible lessons that might be drawn from the way Victorian society handled these matters. Wright clearly brings out the way in which genetically influenced patterns of behaviour that evolved because they were advantageous in a hunter- gatherer society influenced what seems superficially to be a very different society in 19th century England. And he suggests that the Victorian response to those genetic imperatives -- institutionalised monogamy in the form of marriage, with divorce made difficult -- was in many respects a better one than the modern response, where easy divorce provides men, in particular, with the opportunity for serial monogamy that in some cases amounts to polygyny.
"Johnny Carson," Wright points out, "like many wealthy, high-status males, spent his career monopolizing long stretches of the reproductive years of a series of young women", to the detriment and frustration of other men who might have married those women. Repeat the pattern often enough and you have (perhaps) one explanation for the behaviour of lower-status males in American society today. Darwin's marriage was certainly a shining example of how well the Victorian system could work. He moved from a cold-blooded assessment of the pros and cons of marriage, written down in July 1838 and including the comment that a wife would be "better than a dog, anyway" to persuading himself to fall in love with his cousin Emma (in many ways the only suitable candidate) and to spend many happy and devoted years with her raising a large number of children. A complete success, in evolutionary terms -- although it wouldn't take much ingenuity to come up with counter-examples demonstrating the problems caused by Victorian marriage rules.
The snag with Wright's approach, though, is that he manages to give us both too much about Darwin and not enough. A more concise description of key events in Darwin's life and times would have done a better job of making the sociobiological points, without disrupting the flow of the scientific argument. As it is, the flow is disturbed, while the reader is also left wanting to know more about Darwin. There are also some dubious aspects of the biographical passages, as when we are told that Darwin's move from London to Kent was "testament to his physical decline"; it was much more a testament to the fact that there were riots in the streets of London at the time, and it was no place to bring up children!
The Moral Animal starts well, peaks in the middle, and rambles on for rather too long. It is best where the author (a science writer, not a scientist) reports the work of the pioneering sociobiologists, and weakest where he feels bold enough to offer his own interpretations, as with the assessment of Darwin's profound grief at the death of his daughter Annie. This is cast in purely sociobiological terms, as the expected response of a parent to the loss of a daughter close to child-bearing age, and contrasted with the lack of comparable grief the Darwins showed at the deaths of two infant children. It would at least have been worth considering the possibility that Annie's death was a bigger blow because the Darwins had known and loved her for ten years, not merely a few weeks or months.
That, of course, is the problem with sociobiology. Its successes encourage proponents to apply it to excess, failing, on occasion, to take due account of other factors. Which is what stimulates the backlash that leads to the change of name. But as sociobiology books go, this is a good one, well worth reading, and sure to stimulate further debate. What we have here is by and large the truth, but it is surely not the whole truth.