Science in the Soul Page 7

  *3 I like Steve Gould’s way of putting it. ‘In science, “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional assent.” I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms’ (‘Evolution as fact and theory’, in Hen’s Teeth and Horse’s Toes).

  *4 Professors of ‘Women’s Studies’ are occasionally given to lauding ‘women’s ways of knowing’ as if these were different from, even superior to, logical or scientific ways of knowing. As Steven Pinker rightly said, such talk is an insult to women.

  *5 Quoted in Carl Sagan, The Demon-Haunted World, p. 234. See also Paul R. Gross and Norman Levitt, Higher Superstition, for a chilling collection and justifiably savage indictment of similar drivel including ‘Cultural Constructivism’, ‘Afrocentric Science’, ‘Feminist Algebra’ and ‘Science Studies’, not forgetting Sandra Harding’s ‘stirring assertion that Newton’s Principia Mathematica Philosophae Naturalis is a “rape manual” ’.

  *6 Winston Churchill, of course.

  *7 I co-opted his phrase, together with Shakespeare’s famous words from Macbeth, in the title of my second memoir, Brief Candle in the Dark.

  *8 The following experience is commonplace. I was once talking to a barrister, a young woman of high ideals specializing in criminal law defence. She expressed satisfaction that a private investigator whom she had employed had found evidence exonerating her client, who was accused of murder. I congratulated her, and asked the obvious question: what would she have done if he had found evidence proving unequivocally that her client was guilty? Without hesitation she said that she would have quietly suppressed the evidence. Let the prosecution find their own evidence. If they failed, more fool them. My outraged reaction to this story was one that she had obviously met many times when talking to non-lawyers, and I didn’t blame her for wearily changing the subject rather than pursuing the argument.

  *9 I felt it necessary to begin The Extended Phenotype by admitting that it was a work of ‘unabashed advocacy’. The fact that I needed to use a word like ‘unabashed’ speaks to my point about the values of science. What lawyer would apologize to the jury for his ‘unabashed advocacy’? Advocacy, partisan advocacy, is precisely what lawyers are trained – and handsomely paid – for. Politicians, too, and advertising or marketing professionals. Science is perhaps the most stringently honest of all professions.

  *10 I heard of a London physicist who went to the lengths of refusing to pay his local government tax as long as the area’s adult education college advertised a course in astrology. An Australian professor of geology is in the process of suing a creationist for making money under false pretences by claiming to have found Noah’s Ark. See commentary by Peter Pockley, Daily Telegraph, 23 April 1997.

  *11 I’d find it hard to justify funding research on alleged correlations between race and IQ. I’m not one of those who thinks that intelligence is unmeasurable or that race is ‘non-biological’, a ‘social construct’ (see the distinguished geneticist A. W. F. Edwards’ splendid take-down of this claim in ‘Human genetic diversity: Lewontin’s fallacy’). But what could possibly be the point of investigating alleged correlations between intelligence and race? Certainly no policy decisions should ever be based on such research. That, I suspect, was the point Lewontin really intended to make and I unreservedly agree. However, as so often with ideologically motivated scientists, he chose to misrepresent his point as a (false) scientific one rather than as a (laudable) political one.

  *12 Bovine spongiform encephalopathy, commonly known as ‘mad cow disease’. An epidemic in Britain starting in 1986 caused widespread alarm, partly because of its affinity to the dangerous human malady CJD or Creutzfeldt–Jakob Disease.

  *13 My favourite moral philosopher, and an excellent example of how valuable philosophers can be when they aim for clarity without pretentious languaging-up, is Jonathan Glover. See, for example, his Causing Death and Saving Lives, a book so far-sighted that it was allowed to go out of print before scientific advances started to make it really topical; or his Humanity, which turns out to be a searing indictment of the opposite. In Choosing Children, which ventures into the near-taboo subject of eugenics, Glover demonstrates the intellectual courage that goes with the territory of honest moral philosophy.

  *14 Julian Huxley edited a compilation of his own and his grandfather’s views on the subject, entitled Touchstone for Ethics.

  *15 His ‘Progress, biological and other’, the first of his Essays of a Biologist, contains passages that read almost like a call to arms under evolution’s banner: ‘[man’s] face is set in the same direction as the main tide of evolving life, and his highest destiny, the end towards which he has so long perceived that he must strive, is to extend to new possibilities the process with which, for all these millions of years, nature has already been busy, to introduce less and less wasteful methods, to accelerate by means of his consciousness what in the past has been the work of blind unconscious forces’ (page 41). That passage exemplifies what I shall disparage, on this page, as ‘poetic science’ – poetic in the bad sense, not the good sense implied by my title Science in the Soul. Huxley’s book of essays influenced me deeply when I read it as an undergraduate. I am now less impressed, and rather subscribe to the view which I once heard Peter Medawar utter in an audaciously unguarded moment: ‘The trouble with Julian is that he just doesn’t understand evolution!’

  *16 Stephen J. Gould, in Full House, rightly attacked ‘progress’ where it is taken to mean progress towards the lofty evolutionary peak of humanity. But in my critical review of his book, published in Evolution (1997), I defend ‘progress’ where it means evolutionary movement in consistently the same direction towards the build-up of adaptive complexity, the drive often being powered by ‘evolutionary arms races’.

  *17 I made the same point with reference to Rose’s Marxist co-author Richard Lewontin in an earlier footnote to this essay (see above).

  *18 Twin studies constitute a powerful and easily understood technique for estimating the contribution of genes to variance. Measure something (anything you like) in pairs of monozygotic twins (who are known to be genetically identical). Compare their similarity (to each other) with the similarity (to each other) of dizygotic twins (who are no more likely to share genes than ordinary siblings). If the pairs of monozygotic twins resemble each other significantly more than the pairs of dizygotic twins in, for example, intelligence, you can conclude that genes are responsible. The twin-study technique is especially persuasive in those rare – and much studied – cases where monozygotic twins happen to be separated at birth and brought up apart.

  *19 Any kind of government-imposed eugenic policy, breeding positively for some nationally sought-after characteristic such as running speed or intelligence, would be a lot harder to justify than a voluntary version. In vitro fertilization (IVF) techniques hormonally stimulate women to super-ovulate, producing as many as a dozen eggs. Of those that are successfully fertilized in the petri dish, only two or perhaps three are reinserted in the woman, in the hope that one of them will ‘take’. The choice is normally made at random. However, it is possible for one cell from an eight-cell conceptus to be extracted without damage, and the genes assayed. This means that the choice of which ones are reinserted, which ones discarded, can be non-random with respect to genes. Few people would object to this technique being used to select against a condition such as haemophilia or Huntington’s disease – ‘negative eugenics’. However, many recoil from using the same technique in ‘positive eugenics’: selecting, in the petri dish, for musical ability, say, if that were one day to become possible. Yet the same people don’t object to ambitious parents imposing music lessons and piano practice on their children. There may be good reasons for this double standard, but they need to be discussed. It is at the very least important to distinguish voluntary eugenics practised by individual parents from state-imposed eugenics such as the Nazis b
rutally implemented.

  *20 S. Rose, L. J. Kamin and R. C. Lewontin, Not in Our Genes. The order of authors, weirdly, is different from that in the American edition, in which Rose and Lewontin change places. My review of the book in New Scientist, vol. 105, 1985, pp. 59–60, gives a full critique which briefly earned me, and New Scientist, the threat of a lawsuit. I stand by every word of it.

  *21 Edward O. Wilson, author of Sociobiology.

  *22 For a view of this topic which many scientists will find congenial, see Daniel C. Dennett’s Elbow Room. Dennett has returned to the question in later books such as Freedom Evolves and From Bacteria to Bach and Back. Not all scientists and philosophers agree with Dennett’s version of ‘compatibilism’, however. Jerry Coyne and Sam Harris are among those who do not. After my public speeches I have come to dread the near-inevitable ‘Do you believe in free will?’ question, and sometimes resort to quoting Christopher Hitchens’ characteristically witty answer: ‘I have no choice.’ What I will more confidently say, in reply to Rose and Lewontin, is that the addition of the word ‘genetic’ before ‘determinism’ doesn’t make it any more deterministic.

  *23 In Anticipations of the Reaction of Mechanical and Scientific Progress upon Human Life and Thought. My lecture included a longer quotation from Wells’s book.

  *24 This is the highest estimate I have seen for living species. The true figure is unknown and may be substantially lower, but if you include extinct species it is certainly higher. To draw a tree diagram of the complete pedigree of all life you’d need a sheet of paper whose acreage would cover the island of Manhattan six times over. James Rosindell was accordingly moved to write the brilliant ‘OneZoom’ software, which represents the entire tree of life as a fractal. You can fly over it on your computer screen like a sort of taxonomic Google Earth, and ‘drill down’ to any particular species you fancy. OneZoom is now being fleshed out in collaboration with Yan Wong, my co-author of The Ancestor’s Tale, the second edition of which makes extensive use of it. Rosindell and Wong invite enthusiasts (I am one) to sponsor favourite species to defray the costs of adding their details to the tree.

  *25 In nineteenth-century terms without reference to genes, of course.

  *26 Said by whom? Nobody seems to know. The suspicion that the answer might be Nicholas Humphrey himself doesn’t threaten the pertinence of his parable. And Ford himself would probably not have minded. I’ve quoted Humphrey’s tale so often that my friend the enigmatically humorous ichthyologist David Noakes went to the trouble of procuring, and sending to me out of the blue, the kingpin of a Model T, which looks, I must say, in pristine condition and weighty enough to seem overdesigned.

  *27 With his handsomely patrician head of hair and matching white beard, it is said (there we go again; see footnote above) that he exploited his resemblance to God when soliciting charitable donations from rich old ladies.

  *28 Marian Stamp Dawkins, the author of Animal Suffering and our leading investigator of the subject, has discussed with me the possibility that selective breeding of this sort might in theory provide a solution to some of the ethical problems of intensive animal husbandry. For instance, if present-day hens are unhappy in the confined conditions of battery cages, why not breed a race of hens that positively enjoy such conditions? She notes that people tend to greet such suggestions with repugnance (or humour in the case of Douglas Adams’ brilliant The Restaurant at the End of the Universe, in which a large bovine quadruped approaches the table and announces itself as ‘Your dish of the day’, explaining that its kind has been bred to want to be eaten). Perhaps the idea conflicts with some deep-seated human value, possibly some version of what has been called the ‘yuk factor’. It is hard to see that it falls foul of dispassionate utilitarian reasoning, provided we could be sure the selective breeding genuinely changed the animal’s perception of pain, rather than – horrifying thought – changing its method of responding to pain while leaving the perception of pain intact.

  *29 It is in this spirit that I chose ‘The fortyfold path to enlightenment’ as my title for the chapter on the evolution of the eye in Climbing Mount Improbable. A whole chapter was necessary because, from William Paley on, the eye has been such a favourite of creationists seeking to apply what I called ‘the Argument from Personal Incredulity’. Even Darwin confessed that the evolution of the eye seemed at first blush implausible. But his confession was a temporary rhetorical ploy, for he went on to show how easy it is to explain its gradual evolution. It is almost as though life is positively eager to evolve eyes, based on a variety of optical principles. Unlike language, which is the point I am making in this essay.

  *30 This statement might be disputed, depending on the disputant’s definition of language. Honey bees tell each other, with quantitative precision, how far away food is to be found, and in which direction relative to the sun. Vervet monkeys have three different ‘words’ for danger, depending on whether the threat is a snake, a bird or a leopard. I wouldn’t call this language because it doesn’t have the recursive, hierarchical embedding that gives human language its indefinite flexibility. Only humans can say things like: ‘The leopard who has cubs, and who normally sits in the tree by the river in the direction of the mountain, is now crouching in the long grass beyond the hut belonging to the father of the chief.’ Theoretically there is no limit to the depth of embedding of relative and prepositional clauses within one another, although keeping track of deep, multiple embedding makes demands on the brain’s computational machinery. Steven Pinker’s The Language Instinct is a beautifully written, evolutionarily slanted introduction to such matters.

  *31 The seminal book on evolutionary psychology, with chapters by many of its leading practitioners, is the volume edited by J. H. Barkow, L. Cosmides and J. Tooby, The Adapted Mind. Not long after this lecture was given, Steven Pinker’s masterly How the Mind Works appeared. Evolutionary psychology, for reasons I don’t understand, arouses incandescent hostility in quarters where I wouldn’t expect it. The complaints seem to centre on particular studies that are poorly conceived or executed. But the existence of particular bad examples is no reason to dismiss an entire scientific discipline. The best practitioners of evolutionary psychology, Leda Cosmides, John Tooby, Steven Pinker, David Buss, Martin Daly, the late Margot Wilson and others, are good scientists by any standards.

  *32 Current thinking favours several excursions out of Africa, and genetic evidence suggests a bottleneck, that is, a temporary, dramatic reduction in the population from which all non-Africans are descended, some time under one hundred thousand years ago. Yan Wong, in the second edition of The Ancestor’s Tale which he co-authored with me, managed to use my genome (which happened to have been fully sequenced for a different purpose concerned with a television documentary) to estimate the population size at various times in the past. He did it by comparing my maternal genes and my paternal genes, estimating, for each pair, the time elapsed since they ‘coalesced’, i.e. since they split off from a common ancestral gene. A significant majority of my pairs of genes coalesced about sixty thousand years ago. This suggests that the population was briefly very small about sixty thousand years ago – hence a ‘bottleneck’. It is probable that this bottleneck represents a particular out-of-Africa migration event.

  *33 And sanctioned by the ultimate role model: ‘…for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me’ (Exodus 20: 5).

  *34 I didn’t have time to spell out in the lecture why it is too simple. The reason is that fellow villagers are not only likely to be your closest relatives; they are also your closest rivals for food, mates and other resources. For purposes of kin selection calculation, relatedness is computed not as an absolute number, but as the increment over and above a baseline of relatedness to random members of the population. In a close-knit, inbred village everybody you meet is likely to be a cousin. Kin selection theory predicts altruism towards individuals
who are closer than the average, even when the average is already pretty close. In these circumstances, where a village consists of cousins, kin selection theory predicts xenophobia towards strangers from outside the village. My colleague Alan Grafen, in Oxford Surveys in Evolutionary Biology (1985), developed a beautiful geometric model, in my opinion by far the best way to explain the true meaning of r, the coefficient of relatedness which lies at the heart of kin selection theory. Many people who rely on popular accounts of Hamilton’s theory are confused by the apparent mismatch between the values for r (0.5 for full siblings, 0.125 for first cousins) and the fact that all of us share more than 90 per cent of our genes with each other. I give an example of this below in the article ‘Twelve misunderstandings of kin selection’ (this page). Grafen’s geometric model really gets across the point, in an intuitively vivid way, that r is the extra closeness over and above the baseline sharing among the whole population.

  *35 In my foreword to the 2006 Penguin edition of The Evolution of Cooperation, I explained how I introduced Axelrod to Hamilton. I am quite proud to have instigated their fruitful collaboration, combining evolutionary with social science theory.

  *36 I’m fond of quoting Sydney Brenner, the eminent molecular geneticist, on the point. He satirically imagines a naive biologist speculating about a particular gene being favoured in the Cambrian era because ‘it might come in handy in the Cretaceous’ (hear it in a sardonically witty South African accent and accompanied by a wicked twinkle in the eye).

  *37 An expanded version of this list of unpleasant adjectives formed the opening paragraph of chapter 2 of The God Delusion, where it has become somewhat infamous for giving ‘offence’. Every one of those adjectives can be justified from scripture, as was demonstrated by my colleague Dan Barker. His splendid book, God: the most unpleasant character in all fiction, takes each one of my distasteful adjectives in order and documents them meticulously with quotations from the Bible – which he knows very well, as a sometime preacher who has now seen the light.