Monday, August 20, 2012
Richard Dawkins
I would mind more if I could claim that The Selfish Gene had become severely outmoded and superseded. Unfortunately (from one point of view) I cannot. Details have changed and factual examples burgeoned mightily. But, with an exception that I shall discuss in a moment, there is little in the book that I would rush to take back now, or apologise for. Arthur Cain, late Professor of Zoology at Liverpool and one of my inspiring tutors at Oxford in the sixties, described The Selfish Gene in 1976 as a ‘young man's book’. He was deliberately quoting a commentator on A. J. Ayer's Language Truth and Logic. I was flattered by the comparison, although I knew that Ayer had recanted much of his first book and I could hardly miss Cain's pointed implication that I should, in the fullness of time, do the same.
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The Selfish Gene
ReplyDeleteby Richard Dawkins
Introduction to 30th anniversary edition
ReplyDeleteIt is sobering to realise that I have lived nearly half my life with The Selfish Gene — for better, for worse. Over the years, as each of my seven subsequent books has appeared, publishers have sent me on tour to promote it. Audiences respond to the new book, whichever one it is, with gratifying enthusiasm, applaud politely and ask intelligent questions. Then they line up to buy, and have me sign . . . The Selfish Gene. That is a bit of an exaggeration. Some of them do buy the new book and, for the rest, my wife consoles me by arguing that people who newly discover an author will naturally tend to go back to his first book: having read The Selfish Gene, surely they’ll work their way through to the latest and (to its fond parent) favourite baby?
I would mind more if I could claim that The Selfish Gene had become severely outmoded and superseded. Unfortunately (from one point of view) I cannot. Details have changed and factual examples burgeoned mightily. But, with an exception that I shall discuss in a moment, there is little in the book that I would rush to take back now, or apologise for. Arthur Cain, late Professor of Zoology at Liverpool and one of my inspiring tutors at Oxford in the sixties, described The Selfish Gene in 1976 as a ‘young man’s book’. He was deliberately quoting a commentator on A. J. Ayer’s Language Truth and Logic. I was flattered by the comparison, although I knew that Ayer had recanted much of his first book and I could hardly miss Cain’s pointed implication that I should, in the fullness of time, do the same.
Let me begin with some second thoughts about the title. In 1975, through the mediation of my friend Desmond Morris I showed the partially completed book to Tom Maschler, doyen of London publishers, and we discussed it in his room at Jonathan Cape. He liked the book but not the title. ‘Selfish’, he said, was a ‘down word’. Why not call it The Immortal Gene? Immortal was an ‘up’ word, the immortality of genetic information was a central theme of the book, and ‘immortal gene’ had almost the same intriguing ring as ‘selfish gene’ (neither of us, I think, noticed the resonance with Oscar Wilde’s The Selfish Giant). I now think Maschler may have been right. Many critics, especially vociferous ones learned in philosophy as I have discovered, prefer to read a book by title only. No doubt this works well {viii} enough for The Tale of Benjamin Bunny or The Decline and Fall of the Roman Empire, but I can readily see that ‘The Selfish Gene’ on its own, without the large footnote of the book itself, might give an inadequate impression of its contents. Nowadays, an American publisher would in any case have insisted on a subtitle.
The best way to explain the title is by locating the emphasis. Emphasize ‘selfish’ and you will think the book is about selfishness, whereas, if anything, it devotes more attention to altruism. The correct word of the title to stress is ‘gene’ and let me explain why. A central debate within Darwinism concerns the unit that is actually selected: what kind of entity is it that survives, or does not survive, as a consequence of natural selection. That unit will become, more or less by definition, ‘selfish’. Altruism might well be favoured at other levels. Does natural selection choose between species? If so, we might expect individual organisms to behave altruistically ‘for the good of the species’. They might limit their birth rates to avoid overpopulation, or restrain their hunting behaviour to conserve the species’ future stocks of prey. It was such widely disseminated misunderstandings of Darwinism that originally provoked me to write the book.
ReplyDeleteOr does natural selection, as I urge instead here, choose between genes? In this case, we should not be surprised to find individual organisms behaving altruistically ‘for the good of the genes’, for example by feeding and protecting kin who are likely to share copies of the same genes. Such kin altruism is only one way in which gene selfishness can translate itself into individual altruism. This book explains how it works, together with reciprocation, Darwinian theory’s other main generator of altruism. If I were ever to rewrite the book, as a late convert to the Zahavi/Grafen ‘handicap principle’ (see pages 309–313) I should also give some space to Amotz Zahavi’s idea that altruistic donation might be a ‘Potlatch’ style of dominance signal: see how superior to you I am, I can afford to make a donation to you!
Let me repeat and expand the rationale for the word ‘selfish’ in the title. The critical question is which level in the hierarchy of life will turn out to be the inevitably ‘selfish’ level, at which natural selection acts? The Selfish Species? The Selfish Group? The Selfish Organism? The Selfish Ecosystem? Most of these could be argued, and most have been uncritically assumed by one or another author, but all of them are wrong. Given that the Darwinian message is going to be pithily encapsulated as The Selfish Something, that something turns out to be the gene, for cogent reasons which this book argues. Whether or not {ix} you end up buying the argument itself, that is the explanation for the title.
I hope that takes care of the more serious misunderstandings. Nevertheless, I do with hindsight notice lapses of my own on the very same subject. These are to be found especially in Chapter 1, epitomised by the sentence ‘Let us try to teach generosity and altruism because we are born selfish’. There is nothing wrong with teaching generosity and altruism, but ‘born selfish’ is misleading. In partial explanation, it was not until 1978 that I began to think clearly about the distinction between ‘vehicles’ (usually organisms) and the ‘replicators’ that ride inside them (in practice genes: the whole matter is explained in Chapter 13, which was added in the Second Edition). Please mentally delete that rogue sentence and others like it, and substitute something along the lines of this paragraph.
Given the dangers of that style of error, I can readily see how the title could be misunderstood, and this is one reason why I should perhaps have gone for The Immortal Gene. The Altruistic Vehicle would have been another possibility. Perhaps it would have been too enigmatic but, at all events, the apparent dispute between the gene and the organism as rival units of natural selection (a dispute that exercised the late Ernst Mayr to the end) is resolved. There are two kinds of unit of natural selection, and there is no dispute between them. The gene is the unit in the sense of replicator. The organism is the unit in the sense of vehicle. Both are important. Neither should be denigrated. They represent two completely distinct kinds of unit and we shall be hopelessly confused unless we recognize the distinction.
ReplyDeleteAnother good alternative to The Selfish Gene would have been The Cooperative Gene. It sounds paradoxically opposite, but a central part of the book argues for a form of cooperation among self-interested genes. This emphatically does not mean that groups of genes prosper at the expense of their members, or at the expense of other groups. Rather, each gene is seen as pursuing its own self-interested agenda against the background of the other genes in the gene pool — the set of candidates for sexual shuffling within a species. Those other genes are part of the environment in which each gene survives, in the same way as the weather, predators and prey, supporting vegetation and soil bacteria are parts of the environment. From each gene’s point of view, the ‘background’ genes are those with which it shares bodies in its journey down the generations. In the short term, that means the other members of the genome. In the long term, it means the other genes in {x} the gene pool of the species. Natural selection therefore sees to it that gangs of mutually compatible — which is almost to say cooperating — genes are favoured in the presence of each other. At no time does this evolution of the ‘cooperative gene’ violate the fundamental principle of the selfish gene. Chapter 5 develops the idea, using the analogy of a rowing crew, and Chapter 13 takes it further.
Now, given that natural selection for selfish genes tends to favour cooperation among genes, it has to be admitted that there are some genes that do no such thing and work against the interests of the rest of the genome. Some authors have called them outlaw genes, others ultra-selfish genes, yet others just ‘selfish genes’ — misunderstanding the subtle difference from genes that cooperate in self-interested cartels. Examples of ultra-selfish genes are the meiotic drive genes described on pages 235–237, and the ‘parasitic DNA’ originally proposed on pages 44–45 and developed further by various authors under the catch phrase ‘Selfish DNA’. The uncovering of new and ever more bizarre examples of ultra-selfish genes has become a feature of the years since this book was first published.
The Selfish Gene has been criticized for anthropomorphic personification and this too needs an explanation, if not an apology. I employ two levels of personification: of genes, and of organisms. Personification of genes really ought not to be a problem, because no sane person thinks DNA molecules have conscious personalities, and no sensible reader would impute such a delusion to an author. I once had the honour of hearing the great molecular biologist Jacques Monod talking about creativity in science. I have forgotten his exact words, but he said approximately that, when trying to think through a chemical problem, he would ask himself what he would do if he were an electron. Peter Atkins, in his wonderful book Creation Revisited, uses a similar personification when considering the refraction of a light beam, passing into a medium of higher refractive index which slows it down. The beam behaves as if trying to minimize the time taken to travel to an end point. Atkins imagines it as a lifeguard on a beach racing to rescue a drowning swimmer. Should he head straight for the swimmer? No, because he can run faster than he can swim and would be wise to increase the dry-land proportion of his travel time. Should he run to a point on the beach directly opposite his target, thereby minimizing his swimming time? Better, but still not the best. Calculation (if he had time to do it) would disclose to the lifeguard an optimum intermediate angle, {xi} yielding the ideal combination of fast running followed by inevitably slower swimming. Atkins concludes:
ReplyDeleteThat is exactly the behaviour of light passing into a denser medium. But how does light know, apparently in advance, which is the briefest path? And, anyway, why should it care?
He develops these questions in a fascinating exposition, inspired by quantum theory.
Personification of this kind is not just a quaint didactic device. It can also help a professional scientist to get the right answer, in the face of tricky temptations to error. Such is the case with Darwinian calculations of altruism and selfishness, cooperation and spite. It is very easy to get the wrong answer. Personifying genes, if done with due care and caution, often turns out to be the shortest route to rescuing a Darwinian theorist drowning in muddle. While trying to exercise that caution. I was encouraged by the masterful precedent of W. D. Hamilton, one of the four named heroes of the book. In a paper of 1972 (the year in which I began to write The Selfish Gene) Hamilton wrote:
A gene is being favoured in natural selection if the aggregate of its replicas forms an increasing fraction of the total gene pool. We are going to be concerned with genes supposed to affect the social behaviour of their bearers, so let us try to make the argument more vivid by attributing to the genes, temporarily, intelligence and a certain freedom of choice. Imagine that a gene is considering the problem of increasing the number of its replicas, and imagine that it can choose between . . .
That is exactly the right spirit in which to read much of The Selfish Gene.
Personifying an organism could be more problematical. This is because organisms, unlike genes, have brains and therefore really might have selfish or altruistic motives in something like the subjective sense we would recognize. A book called The Selfish Lion might actually confuse, in a way that The Selfish Gene should not. Just as one can put oneself in the position of an imaginary light beam, intelligently choosing the optimal route through a cascade of lenses and prisms, or an imaginary gene choosing an optimal route through the generations, so one can postulate an individual lioness, calculating an optimal behavioural strategy for the long term future survival of her genes. Hamilton’s first gift to biology was the precise mathematics that a truly Darwinian individual such as a lion would, in effect, have to employ, {xii} when taking decisions calculated to maximize the long term survival of its genes. In this book I used informal verbal equivalents of such calculations — on the two levels.
ReplyDeleteOn page 130 we switch rapidly from one level to the other:
We have considered the conditions under which it would actually pay a mother to let a runt die. We might suppose intuitively that the runt himself should go on struggling to the last, but the theory does not necessarily predict this. As soon as a runt becomes so small and weak that his expectation of life is reduced to the point where benefit to him due to parental investment is less than half the benefit that the same investment could potentially confer on the other babies, the runt should die gracefully and willingly. He can benefit his genes most by doing so.
That is all individual-level introspection. The assumption is not that the runt chooses what gives him pleasure, or what feels good. Rather, individuals in a Darwinian world are assumed to be making an as-if calculation of what would be best for their genes. This particular paragraph goes on to make it explicit by a quick change to gene-level personification:
That is to say, a gene that gives the instruction ‘Body, if you are very much smaller than your litter-mates, give up the struggle and die’ could be successful in the gene pool, because it has a 50 per cent chance of being in the body of each brother and sister saved, and its chances of surviving in the body of the runt are very small anyway.
And then the paragraph immediately switches back to the introspective runt:
There should be a point of no return in the career of a runt. Before he reaches this point he should go on struggling. As soon as he reaches it he should give up and preferably let himself be eaten by his litter-mates or his parents.
I really believe that these two levels of personification are not confusing if read in context and in full. The two levels of ‘as if calculation’ come to exactly the same conclusion if done correctly: that, indeed, is the criterion for judging their correctness. So, I don’t think personification is something I would undo if I were to write the book again today.
Unwriting a book is one thing. Unreading it is something else. What are we to make of the following verdict, from a reader in Australia? {xiii}
ReplyDeleteFascinating, but at times I wish I could unread it. . . On one level, I can share in the sense of wonder Dawkins so evidently sees in the workings-out of such complex processes . . . But at the same time, I largely blame The Selfish Gene for a series of bouts of depression I suffered from for more than a decade . . . Never sure of my spiritual outlook on life, but trying to find something deeper — trying to believe, but not quite being able to — I found that this book just about blew away any vague ideas I had along these lines, and prevented them from coalescing any further. This created quite a strong personal crisis for me some years ago.
I have previously described a pair of similar responses from readers:
A foreign publisher of my first book confessed that he could not sleep for three nights after reading it, so troubled was he by what he saw as its cold, bleak message. Others have asked me how I can bear to get up in the mornings. A teacher from a distant country wrote to me reproachfully that a pupil had come to him in tears after reading the same book, because it had persuaded her that life was empty and purposeless. He advised her not to show the book to any of her friends, for fear of contaminating them with the same nihilistic pessimism (Unweaving the Rainbow).
If something is true, no amount of wishful thinking can undo it. That is the first thing to say, but the second is almost as important. As I went on to write,
Presumably there is indeed no purpose in the ultimate fate of the cosmos, but do any of us really tie our life’s hopes to the ultimate fate of the cosmos anyway? Of course we don’t; not if we are sane. Our lives are ruled by all sorts of closer, warmer, human ambitions and perceptions. To accuse science of robbing life of the warmth that makes it worth living is so preposterously mistaken, so diametrically opposite to my own feelings and those of most working scientists, I am almost driven to the despair of which I am wrongly suspected.
A similar tendency to shoot the messenger is displayed by other critics who have objected to what they see as the disagreeable social, political or economic implications of The Selfish Gene. Soon after Mrs Thatcher won her first election victory in 1979, my friend Steven Rose wrote the following in New Scientist:
I am not implying that Saatchi and Saatchi engaged a team of sociobiologists to write the Thatcher scripts, nor even that certain Oxford and {xiv} Sussex dons are beginning to rejoice at this practical expression of the simple truths of selfish genery they have been struggling to convey to us. The coincidence of fashionable theory with political events is messier than that. I do believe though, that when the history of the move to the right of the late 1970s comes to be written, from law and order to monetarism and to the (more contradictory) attack on statism, then the switch in scientific fashion, if only from group to kin selection models in evolutionary theory, will come to be seen as part of the tide which has rolled the Thatcherites and their concept of a fixed, 19th century competitive and xenophobic human nature into power.
The ‘Sussex don’ was the late John Maynard Smith, admired by Steven Rose and me alike, and he replied characteristically in a letter to New Scientist: ‘What should we have done, fiddled the equations?’ One of the dominant messages of The Selfish Gene (reinforced by the title essay of A Devil’s Chaplain) is that we should not derive our values from Darwinism, unless it is with a negative sign. Our brains have evolved to the point where we are capable of rebelling against our selfish genes. The fact that we can do so is made obvious by our use of contraceptives. The same principle can and should work on a wider scale.
ReplyDeleteUnlike the Second Edition of 1989, this Anniversary Edition adds no new material except this Introduction, and some extracts from reviews chosen by my three-times Editor and champion, Latha Menon. Nobody but Latha could have filled the shoes of Michael Rodgers, K-selected Editor Extraordinary, whose indomitable belief in this book was the booster rocket of its first edition’s trajectory.
This edition does, however — and it is a source of particular joy to me — restore the original Foreword by Robert Trivers. I have mentioned Bill Hamilton as one of the four intellectual heroes of the book. Bob Trivers is another. His ideas dominate large parts of Chapters 9, 10 and 12, and the whole of Chapter 8. Not only is his Foreword a beautifully crafted introduction to the book: unusually, he chose the medium to announce to the world a brilliant new idea, his theory of the evolution of self-deception. I am most grateful to him for giving permission for the original Foreword to grace this Anniversary Edition.
RICHARD DAWKINS
Oxford, October 2005
The Selfish Gene is a book on evolution by Richard Dawkins, published in 1976. It builds upon the principal theory of George C. Williams’s first book Adaptation and Natural Selection. Dawkins coined the term “selfish gene” as a way of expressing the gene-centred view of evolution as opposed to the views focused on the organism and the group, popularizing ideas developed during the 1960s by W. D. Hamilton and others. From the gene-centred view follows that the more two individuals are genetically related, the more sense (at the level of the genes) it makes for them to behave selflessly with each other. Therefore the concept is especially good at explaining many forms of altruism, regardless of a common misuse of the term along the lines of a selfishness gene.
ReplyDeleteAn organism is expected to evolve to maximize its inclusive fitness—the number of copies of its genes passed on globally (rather than by a particular individual). As a result, populations will tend towards an evolutionarily stable strategy. The book also coins the term meme for a unit of human cultural evolution analogous to the gene, suggesting that such “selfish” replication may also model human culture, in a different sense. Memetics has become the subject of many studies since the publication of the book.
So, the question is: if greenflies and elm trees don’t do it, why do the rest of us go to such lengths to mix our genes up with somebody else’s before we make a baby? It does seem an odd way to proceed. Why did sex, that bizarre perversion of straightforward replication, ever arise in the first place? What is the good of sex?
ReplyDeleteThis is an extremely difficult question for the evolutionist to answer. Most serious attempts to answer it involve sophisticated mathematical reasoning. 1 am frankly going to evade it except to say one thing. This is that at least some of the difficulty that theorists have with explaining the evolution of sex results from the fact that they habitually think of the individual as trying to maximize the number of his genes that survive. In these terms, sex appears paradoxical because it is an ‘inefficient’ way for an individual to propagate her genes: each child has only 50 per cent of the individual’s genes, the other 50 per cent being provided by the sexual partner. If only, like a greenfly, she would bud-off children who were {44} exact replicas of herself, she would pass 100 per cent of her genes on to the next generation in the body of every child. This apparent paradox has driven some theorists to embrace group-selectionism, since it is relatively easy to think of group-level advantages for sex. As W. F. Bodmer has succinctly put it, sex ‘facilitates the accumulation in a single individual of advantageous mutations which arose separately in different individuals.’
But the paradox seems less paradoxical if we follow the argument of this book, and treat the individual as a survival machine built by a short-lived confederation of long-lived genes. ‘Efficiency’ from the whole individual’s point of view is then seen to be irrelevant. Sexuality versus non-sexuality will be regarded as an attribute under single-gene control, just like blue eyes versus brown eyes. A gene ‘for’ sexuality manipulates all the other genes for its own selfish ends. So does a gene for crossing-over. There are even genes — called mutators — that manipulate the rates of copying-errors in other genes. By definition, a copying error is to the disadvantage of the gene which is miscopied. But if it is to the advantage of the selfish mutator gene that induces it, the mutator can spread through the gene pool. Similarly, if crossing-over benefits a gene for crossing-over, that is a sufficient explanation for the existence of crossing-over. And if sexual, as opposed to non-sexual, reproduction benefits a gene for sexual reproduction, that is a sufficient explanation for the existence of sexual reproduction. Whether or not it benefits all the rest of an individual’s genes is comparatively irrelevant. Seen from the selfish gene’s point of view, sex is not so bizarre after all.
human being is a selfish being with selfish gene.
ReplyDeletebut wonder if man's gene are more selfish than woman's?