But the
diversity
itself is expunged from the record.
Richard-Dawkins-The-Devil-s-Chaplain
In Britain these are clearly distinct species, quite different in colour.
Anybody can tell them apart.
But if you follow the population of Herring Gulls westward round the North Pole to North America, then via Alaska across Siberia and back to Europe again, you notice a curious fact.
The 'Herring Gulls' gradually become less and less like Herring Gulls and more and more like Lesser Black-backed Gulls until it turns out that our European Lesser Black-backed Gulls actually are the other end of a ring that started out as Herring Gulls.
At every stage around the ring, the birds are sufficiently similar to their neighbours to interbreed with them.
Until, that is, the ends of the continuum are reached, in Europe.
At this point the Herring Gull and the Lesser Black-backed Gull never interbreed, although they are linked by a continuous series of interbreeding colleagues all the way round the world.
The only thing that is special about ring species like these gulls is that the intermediates are still alive.
All pairs of related species are potentially ring species.
The intermediates must have lived once.
It is just that in most cases they are now dead.
The lawyer, with his trained discontinuous mind, insists on placing individuals firmly in this species or that. He does not allow for the possibility that an individual might lie halfway between two species, or a tenth of the way from species A to species B. Self-styled 'pro-lifers', and others that indulge in footling debates about exactly when in its development a foetus 'becomes human', exhibit the same discon- tinuous mentality. It is no use telling these people that, depending upon the human characteristics that interest you, a foetus can be 'half human' or 'a hundredth human'. 'Human', to the discontinuous mind, is an absolutist concept. There can be no half measures. And from this flows much evil.
The word 'apes' usually means chimpanzees, gorillas, orang utans, gibbons and siamangs. We admit that we are like apes, but we seldom realize that we are apes. Our common ancestor with the chimpanzees and gorillas is much more recent than their common ancestor with the Asian apes - the gibbons and orang utans. There is no natural category that includes chimpanzees, gorillas and orangs but excludes humans. The artificiality of the category 'apes', as conventionally taken to exclude humans, is demonstrated by the following diagram. The family tree shows humans to be in the thick of the ape cluster; the artificiality of the conventional category 'ape' is shown by the stippling.
22
? Gibbon
Siamang
Gorilla
Pigmy Chimpanzee Chimpanzee Human
I Orang Utan
- 'APES'
In truth, not only are we apes, we are African apes. The category 'African apes', if you don't arbitrarily exclude humans, is a natural category. The stippled area doesn't have any artificial 'bites' taken out of it:
Gibbon
Siamang
Gorilla
Pigmy Chimpanzee Chimpanzee Human
i Orang Utan
- AFRICAN APES
All the African apes that have ever lived, including ourselves, are linked to one another by an unbroken chain of parent-child bonds. The same is true of all animals and plants that have ever lived, but there the distances involved are much greater. Molecular evidence suggests that our common ancestor with chimpanzees lived, in Africa, between 5 and 7 million years ago, say half a million generations ago. This is not long by evolutionary standards.
Happenings are sometimes organized at which thousands of people hold hands and form a human chain, say from coast to coast of the United States, in aid of some cause or charity. Let us imagine setting one up along the equator, across the width of our home continent of Africa. It is a special kind of chain, involving parents and children, and we'll have to play tricks with time in order to imagine it. You stand on the shore of the Indian Ocean in southern Somalia, facing north, and in
GAPS IN THE MIND
23
? SCIENCE AND SENSIBILITY
your left hand you hold the right hand of your mother. In turn she holds the hand of her mother, your grandmother. Your grandmother holds her mother's hand, and so on. The chain wends its way up the beach, into the arid scrubland and westwards on towards the Kenya border.
How far do we have to go until we reach our common ancestor with the chimpanzees? It's a surprisingly short way. Allowing one yard per person, we arrive at the ancestor we share with chimpanzees in under 300 miles. We've hardly started to cross the continent; we're still not half way to the great Rift Valley. The ancestor is standing well to the east of Mount Kenya, and holding in her hand an entire chain of her lineal descendants, culminating in you standing on the Somali beach.
The daughter that she is holding in her right hand is the one from whom we are descended. Now the arch-ancestress turns eastward to face the coast, and with her left hand grasps her other daughter, the one from whom the chimpanzees are descended (or son, of course, but let's stick to females for convenience). The two sisters are facing one another, and each holding their mother by the hand. Now the second daughter, the chimpanzee ancestress, holds her daughter's hand, and a new chain is formed, proceeding back towards the coast. First cousin faces first cousin, second cousin faces second cousin, and so on. By the time the folded-back chain has reached the coast again, it consists of modern chimpanzees. You are face to face with your chimpanzee cousin, and you are joined to her by an unbroken chain of mothers holding hands with daughters. If you walked up the line like an inspecting general - past Homo erectus, Homo habilis, perhaps Australopithecus afarensis - and down again the other side (the intermediates on the chimpanzee side are unnamed because, as it happens, no fossils have been found), you would nowhere find any sharp discontinuity. Daughters would resemble mothers just as much (or as little) as they always do. Mothers would love daughters, and feel affinity with them, just as they always do. And this hand-in-hand continuum, joining us seamlessly to chimpanzees, is so short that it barely makes it past the hinterland of Africa, the mother continent.
Our chain of African apes in time, doubling back on itself, is in miniature like the ring of gulls in space, except that the intermediates happen to be dead. The point I want to make is that, as far as morality is concerned, it should be incidental that the intermediates are dead. What if they were not? What if a clutch of intermediate types had survived, enough to link us to modern chimpanzees by a chain, not just of hand-holders, but of interbreeders? Remember the song, 'I've danced
24
? with a man, who's danced with a girl, who's danced with the Prince of Wales'? We can't (quite) interbreed with modern chimpanzees, but we'd need only a handful of intermediate types to be able to sing: 'I've bred with a man, who's bred with a woman, who's bred with a chimpanzee. '
It is sheer luck that this handful of intermediates no longer exists. (Good luck from some points of view: for myself, I should love to meet them. ) But for this chance, our laws and our morals would be very different. We need only discover a single survivor, say a relict Austra- lopithecus in the Budongo Forest, and our precious system of norms and ethics would come crashing about our ears. The boundaries with which we segregate our world would be all shot to pieces. Racism would blur with speciesism in obdurate and vicious confusion. Apartheid, for those that believe in it, would assume a new and perhaps a more urgent import.
But why, a moral philosopher might ask, should this matter to us? Isn't it only the discontinuous mind that wants to erect barriers anyway? So what if, in the continuum of all apes that have lived in Africa, the survivors happen to leave a convenient gap between Homo and Pan? Surely we should, in any case, not base our treatment of animals on whether or not we can interbreed with them. If we want to justify double standards - if society agrees that people should be treated better than, say, cows (cows may be cooked and eaten, people may not) - there must be better reasons than cousinship. Humans may be taxonomically distant from cows, but isn't it more important that we are brainier? Or [better], following Jeremy Bentham, that humans can suffer more. Or that cows, even if they hate pain as much as humans do (and why on earth should we suppose otherwise? ), do not know what is coming to them? Suppose that the octopus lineage had happened to evolve brains and feelings to rival ours. They easily might have done. The mere possibility shows the incidental nature of cousinship. So, the moral philosopher asks, why emphasize the human/chimp continuity?
Yes, in an ideal world we probably should come up with a better reason than cousinship for, say, preferring carnivory to cannibalism. But the melancholy fact is that, at present, society's moral attitudes rest almost entirely on the discontinuous, speciesist imperative.
If somebody succeeded in breeding a chimpanzee/human hybrid, the news would be earth-shattering. Bishops would bleat, lawyers would gloat in anticipation, conservative politicians would thunder, socialists wouldn't know where to put their barricades. The scientist that achieved the feat would be drummed out of common-rooms; denounced in pulpit and gutter press; condemned, perhaps, by an Ayatollah's fatwah. Politics
GAPS IN THE MIND
25
? SCIENCE AND SENSIBILITY
would never be the same again, nor would theology, sociology, psychology or most branches of philosophy. The world that would be so shaken, by such an incidental event as a hybridization, is a speciesist world indeed, dominated by the discontinuous mind.
I have argued that the discontinuous gap between humans and 'apes' that we erect in our minds is regrettable. I have also argued that, in any case, the present position of the hallowed gap is arbitrary, the result of evolutionary accident. If the contingencies of survival and extinction had been different, the gap would be in a different place. Ethical principles that are based upon accidental caprice should not be respected as if cast in stone.
26
? 1.
Science, Genetics and Ethics:
Memo for Tony Blair
Senior Ministers could be forgiven for seeing scientists as little more than alternate igniters and quenchers of public panic. If a scientist appears in a newspaper today, it will usually be to pronounce on the dangers of food additives, mobile phones, sunbathing or electricity pylons. I suppose this is inevitable, given the equally forgivable preoc- cupation of citizens with their own personal safety, and their tendency to hold governments responsible for it. But it casts scientists in a sadly negative role. And it fosters the unfortunate impression that their credentials flow from factual knowledge. What really makes scientists special is less their knowledge than their method of acquiring it - a method that anybody could adopt with advantage.
Even more important, it leaves out the cultural and aesthetic value of science. It is as though one met Picasso and devoted the whole convers- ation to the dangers of licking one's brush. Or met Bradman* and talked only of the best box protector to put down one's trousers. Science, like painting (and some would say like cricket), has a higher aesthetic. Science can be poetry. Science can be spiritual, even religious in a non- supernatural sense of the word.
In a short memo it is obviously unrealistic to attempt comprehensive coverage of the kind that you will anyway get from civil service briefings. Instead, I thought I would pick out a few isolated topics, vignettes almost, that I find interesting and I hope that you might too. Given more space, I would have mentioned other vignettes (such as nanotechnology, which I suspect we shall be hearing a lot about in the twenty-first century).
Genetics
It is hard to exaggerate the sheer intellectual excitement of post- Watson/Crick genetics. What has happened is that genetics has become
*Note to American readers: Sir Donald Bradman (1908-2001) was a cricketer widely regarded, even outside Australia, as the best batsman ever.
27
? SCIENCE AND SENSIBILITY
a branch of Information Technology. The genetic code is truly digital, in exactly the same sense as computer codes. This is not some vague analogy, it is the literal truth. Moreover, unlike computer codes, the genetic code is universal. Modern computers are built around a number of mutually incompatible machine languages, determined by their processor chips. The genetic code, on the other hand, with a few very minor exceptions, is identical in every living creature on this planet, from sulphur bacteria to giant redwood trees, from mushrooms to men. All living creatures, on this planet at least, are the same 'make'.
The consequences are amazing. It means that a software subroutine (that's exactly what a gene is) can be Copied from one species and Pasted into another species, where it will work exactly as it did in the original species. This is why the famous 'antifreeze' gene, originally evolved by Arctic fish, can save a tomato from frost damage. In the same way, a NASA programmer who wants a neat square root routine for his rocket guidance system might import one from a financial spreadsheet. A square root is a square root is a square root. A program to compute it will serve as well in a space rocket as in a financial projection.
What, then, of the widespread gut hostility, amounting to revulsion, against all such 'transgenic' imports? I suspect that it comes from a pre- Watson/Crick misconception. Surely, the appealing but erroneous reasoning goes, an antifreeze gene from a fish must come with a fishy 'flavour'. Surely some of its fishiness must rub off? Surely it is 'unnatural' to splice a fish gene, which was only ever 'meant' to work in a fish, into the alien environment of a tomato cell? Yet nobody thinks that a square root subroutine carries a 'financial flavour' with it when you paste it into a rocket guidance system. The very idea of 'flavour' in this sense is not just wrong but profoundly and interestingly wrong. It is a cheerful thought, by the way, that most young people today understand computer software far better than their elders, and they should grasp the point instantly. The present Luddism over genetic engineering may die a natural death as the computer-illiterate generation is superseded.
Is there nothing, then, absolutely nothing, in the misgivings of Prince Charles, Lord Melchett and their friends? I wouldn't go that far, although they are certainly muddleheaded. * The square root analogy might be unfair in the following respect. What if it isn't a square root that the rocket guidance program needs, but another function which is
*I explained why in an Open Letter to Prince Charles, The Observer, 21 May 2000, http://www. guardian. co. uk/Archive/Article/0,4273,4020558,00. html. See also my article on Lord Melchett's vandalizing of scientific trials of GM crops, The Observer, 24 September 2000, http://www. guardian. co. uk/gmdebate/Story/0,2763,372528,00. html.
28
? not literally identical to the financial equivalent? Suppose it is sufficiently similar that the main routine can indeed be borrowed, but it still needs tweaking in detail. In that case, it is possible that the rocket could misfire if we naively import the subroutine raw. Switching back to biology, although genes really are watertight subroutines of digital software, they are not watertight in their effects on the development of the organism, for here they interact with their environment, including importantly the environment furnished by other genes. The antifreeze gene might depend, for optimal effect, on an interaction with other genes in the fish. Plonk it down in the foreign genetic climate of a tomato, and it might not work properly unless tweaked (which can be done) to mesh with the existing tomato genes.
What this means is that there is a case to be made on both sides of the argument, and we need to exercise subtle judgement. The genetic engineers are right that we can save time and trouble by climbing on the back of the millions of years of R & D that Darwinian natural selection has put into developing biological antifreeze (or whatever we are seeking). But the doomsayers would also have a point if they softened their stance from emotional gut rejection to a rational plea for rigorous safety testing. No reputable scientist would oppose such a plea. It is rightly routine for all new products, not just genetically engineered ones.
A largely unrecognized danger of the obsessive hysteria surrounding genetically modified foods is crying wolf. I fear that, if the green move- ment's high-amplitude warnings over GMOs turn out to be empty, people will be dangerously disinclined to listen to other and more serious warnings. The evolution of antibiotic resistance among bacteria is a vicious wolf of proven danger. Yet the menacing footfalls of this certain peril are all but drowned out in the caterwauling shrieks over genetically modified foods, whose dangers are speculative at most. To be more precise, genetic modification, like any other kind of modification, is good if you modify in a good direction, bad if you modify in a bad direction. Like domestic breeding, and like natural selection itself, the trick is to introduce the right new DNA software. The realization that software is all it is, written in exactly the same language as the organism's 'own' DNA, should go a long way towards dispelling the gut fears that rule most discussions of GMOs.
I can't leave the subject of gut feelings without a favourite quote from the lamented Carl Sagan. When asked a futurological question, he said that not enough was known to answer it. The questioner pressed him on what he really thought. 'What is your gut feeling? ' Sagan's reply is
SCIENCE, GENETICS A N D ETHICS
29
? SCIENCE AND SENSIBILITY
immortal: 'But I try not to think with my gut. ' Gut thinking is one of the main problems we have to contend with in public attitudes to science. I shall return to the point under Ethics. Meanwhile, some more remarks on the future of genetics in the twenty-first century, especially in the wake of the Human Genome Project (HGP).
The HGP, which will be completed any time now, is really a twentieth-century accomplishment. It is an outstanding success story, but it has limited scope. We have taken the human hard disk and transcribed every jot and tittle of the 11000101000010000111-style bits of information on it, regardless of what they mean in the software as a whole. The HGP needs to be followed up by a twenty-first-century Human Embryology Project (HEP) which, in effect, deciphers all the high-level software routines in which the machine-code instructions are embedded. An easier task will be a series of genome projects for different species (like the Arabidopsis plant genome project, whose completion is announced on the day that I write). These would be quicker and easier than the HGP, not because the other genomes are smaller or simpler than ours, but because the collective expertise of scientists increases cumulatively and rapidly with experience.
There is a frustrating aspect of this cumulative improvement. Given the rate of technological advance, with hindsight, when we started the Human Genome Project it wasn't worth starting. It would have been better to do nothing until the last two years and start then! Indeed, that is pretty much what the rival firm of Dr Craig Venter did. The fallacy in the 'never bother to start' maxim is that later technologies cannot get into a position to 'overtake' without the experience gained in developing the earlier ones. *
The HGP implicitly plays down the differences between individuals. But, with the intriguing exception of identical twins, everybody's genome is unique, and you might wonder whose genome is being sequenced in the HGP. Has some dignitary been singled out for the honour, is it a random person pulled off the street, or even an anonymous clone of cells in a tissue culture lab? It makes a difference. I have brown eyes while you have blue. I can't curl my tongue into a tube, whereas it's 50/50 that you can. Which version of the tongue-curling gene makes it into the published Human Genome? Which is the canonical eye colour? The answer is that, for the few 'letters' of the DNA text that vary, the canonical genome is the majority 'vote' among a sample of
*I have discussed the implications of the rapid growth of our understanding of genetics in more detail in 'Son of Moore's Law' (see pp. 107-15).
30
? people carefully chosen to give a good spread of human diversity.
But the diversity itself is expunged from the record.
By contrast the Human Genome Diversity Project (HGDP), now under way, builds on the foundation of the HGP but focuses on those relatively few nucleotide sites that vary from person to person, and from group to group. Incidentally, a surprisingly small proportion of that variance consists of between-race variance, a fact that has sadly failed to reassure spokesmen for various ethnic groups, especially in America. They have dreamed up influential political objections to the project which they see as exploitative and tarred with the brush of eugenics.
The medical benefits of studying human variation could be immense. Hitherto, almost all medical prescribing has assumed that patients are pretty much the same, and that every disease has an optimal recom- mended cure. Doctors of tomorrow will be more like vets in this respect. Doctors have only one species of patient, but in future they will subdivide that species by genotype, as a vet subdivides his patients by species. For the special needs of blood transfusions, doctors already recognize a few genetic typings (OAB, Rh) etc. In the future, every patient's personal record will include the results of numerous genetic tests: not their entire genome (that will be too expensive for the foreseeable future) but, as the century goes on, an increasing sampling of the variable regions of the genome, and far more than the present 'blood group' typings. The point is that for some diseases there may be as many different optimal treatments as there are different genotypes at a locus - more even, because genetic loci may interact to affect susceptibility to disease.
Another important use of the genetics of human diversity is forensic. Precisely because DNA is digital like computer bytes, genetic finger- printing is potentially many many orders of magnitude more accurate and reliable than any other means of individual identification, including direct facial recognition (despite the unshakeable gut feeling of jurors that eyewitness identification trumps everything). Moreover, identity can be established from a tiny trace of blood, sweat or tears (or spit, semen or hairs).
DNA evidence is widely regarded as controversial, and I need to say a little about why. Firstly, human error can obviously vitiate the accuracy of the method. But that is true of all evidence. Courts are already accustomed to taking precautions to avoid the muddling up of specimens, and such precautions now become even more important. DNA finger- printing can establish, almost infinitely far beyond all reasonable doubt, whether a smear of blood came from a particular individual. But
SCIENCE, GENETICS AND ETHICS
31
? SCIENCE AND SENSIBILITY
obviously you must test the right smear.
Secondly, astronomical though the odds against mistaken identity by
DNA fingerprinting theoretically are, it is possible for geneticists and statisticians to come up with what seem like widely different estimates
19
of the precise odds. I quote from Unweaving the Rainbow (Chapter 5,
which is devoted to explain DNA fingerprinting in lay terms).
Lawyers are accustomed to pouncing when expert witnesses seem to disagree. If two geneticists are summoned to the stand and are asked to estimate the probability of a misidentification with DNA evidence, the first may say 1,000,000 to one while the second may say only 100,000 to one. Pounce. 'Aha! AHA! The experts disagree! Ladies and gentlemen of the jury, what confidence can we place in a scientific method, if the experts themselves can't get within a factor of ten of one another? Obviously the only thing to do is throw the entire evidence out, lock, stock and barrel. '
But. . . any disagreement. . . is only over whether the odds against a wrongful identification are hyper-mega-astronomical, or just plain astronomical. The odds cannot normally be lower than thousands to one, and they may well be up in the billions. Even on the most conservative estimate, the odds against wrongful identification are hugely greater than they are in an ordinary identity parade. 'M'lud, an identity parade of only 20 men is grossly unfair on my client. I demand a line-up of at least a million men! '
The idea of a nationwide database, in which all citizens' DNA finger- prints would be held, is now being discussed (only a sample of genes, of course: doing the whole genome would be overkill, far too expensive). I don't see this as a sinister, Big Brotherish idea (and I have written to my doctor volunteering to be a guinea pig in the pilot study of 500,000 now being prepared). But there are potential problems, of a civil liberties character. If your house is burgled, the police will routinely look for (traditional, old-fashioned) fingerprints of the burglar. They need to fingerprint the householder's family too, for elimination purposes, and most people are happy to oblige. Obviously the same principle will apply to DNA fingerprinting, but many people would want to stop well short of a nationwide database. Presumably they would also object to a nationwide database of conventional, old-fashioned fingerprints, but perhaps that is not a practical issue because it would take too long to search through it for a match. DNA fingerprinting doesn't suffer from this difficulty. Computer searches of huge DNA databases could be accomplished swiftly.
What, then, are the civil liberties problems? Surely, those with nothing to hide will have nothing to fear? Perhaps not, but some
32
? people do have legitimate reasons to hide information, not from the law but from each other. A surprisingly large number of people, of all ages, are genetically unrelated to the man they think is their father. To put it mildly, it is not clear that to disillusion them, with conclusive DNA evidence, would increase the sum of human happiness. If a national DNA database were in place, it might be hard to control unauthorized access to it. If a tabloid newspaper were to discover that the official heir to a Dukedom was actually sired by the gamekeeper, the consternation in the College of Heralds might be mildly amusing. But in the population at large it doesn't take much to imagine the family recriminations and sheer private misery that could flow from freely available information of true paternity. Nevertheless, the existence of a national DNA database wouldn't alter the situation much. It is already perfectly feasible for a jealous husband, say, to take a saliva or blood sample from one of his supposed children and compare it with his own, in order to confirm his suspicion that he is not the real father. What the national database could add is a swift computer search to find out who, out of all the males in the entire country, is\
More generally, the study of human diversity is one of very few areas where a good (though in my opinion not overwhelming) case can be made against the pure disinterested search for knowledge: one of very few areas where we might actually be better off ignorant. It is possible that, by the end of the twenty-first century, doctors will be able accurately to predict the manner and time of death of everybody, from the day they are conceived. At present this kind of deterministic prognostica- tion can be achieved only for possessors of genes such as Huntington's Chorea. * For the rest of us, all that is possible is the vague statistical forecast of the life insurance actuary, based on our smoking and drink- ing habits, and a quick listen through a stethoscope. The whole life insurance business depends upon such forecasts being vague and statistical. Those who die old subsidize (the heirs of) those who die young. If the day comes when deterministic forecasting (along Huntington's Chorea lines) becomes universal, life insurance as we know it will collapse. That problem is soluble (presumably by universal compulsory life insurance with no individual medical risk assessment). What will be
*The folk singer Woody Guthrie died of Huntington's Chorea, a horrible disease that waits till early middle age before killing you. It's a dominant gene, so each of Woody's children knows that he has an exactly 50 per cent chance of suffering the same horrible fate. Some people, given these odds, prefer not to be tested. They'd rather not know until they have to. IVF doctors can now push the test back to the newly fertilized zygote, and choose to implant only those that lack the fatal gene. This is obviously a huge boon, but it is attacked by ignorant lobbies fearful of 'scientists playing God'.
SCIENCE, GENETICS AND ETHICS
33
? SCIENCE AND SENSIBILITY
less easy to solve is the angst which will hang over everyone's psychology. As things are now, we all know we are going to die, but most of us don't know when, so it doesn't feel like a death sentence. That may change, and society should be prepared for difficulties as people struggle to adjust their psychologies to it.
Ethics
I have already touched on some ethical issues. Science has no methods for deciding what is ethical. That is a matter for individuals and for society. But science can clarify the questions being asked, and can clear up obfuscating misunderstandings. This usually amounts to the useful 'You cannot have it both ways' style of arguing. I'll give five examples, before turning to a more unusual interpretation of the phrase 'science and ethics'.
Science cannot tell you whether abortion is wrong, but it can point out that the (embryological) continuum that seamlessly joins a non- sentient foetus to a sentient adult is analogous to the (evolutionary) continuum that joins humans to other species. If the embryological continuum appears to be more seamless, this is only because the evolutionary continuum is divided by the accident of extinction. Fundamental principles of ethics should not depend on the accidental contingencies of extinction. * To repeat, science cannot tell you whether abortion is murder, but it can warn you that you may be being inconsistent if you think abortion is murder but killing chimpanzees is not. You cannot have it both ways.
Science cannot tell you whether it is wrong to clone a whole human being. But it can tell you that a Dolly-style clone is just an identical twin, though of a different age. It can tell you that, if you want to object to cloning humans, you must not appeal to arguments such as 'The clone wouldn't be a full person' or 'The clone wouldn't have a soul'. Science cannot tell you whether anybody has a soul, but it can tell you that, if ordinary identical twins have souls, so do Dolly-style clones. f You cannot have it both ways.
Science cannot tell you whether stem cell cloning for 'spare parts' is wrong. But it can challenge you to explain how stem cell cloning differs morally from something that has long been accepted: tissue culture. Tissue culture has been a mainstay of cancer research for decades. The famous HeLa cell line, which originated in the late Henrietta Lacks in
? See 'Gaps in the Mind' (pp. 20-6) for a fuller discussion. tSee 'Dolly and the Cloth Heads' (pp. 152-5).
34
? 1951, is now being grown in labs all over the world. A typical lab, at the University of California, grows 48 litres of HeLa cells per day, as a routine service to researchers in the university. The total daily worldwide production of HeLa cells must be measured in tons - all a gigantic clone of Henrietta Lacks. In the half century since this mass production began, nobody seems to have objected to it. Those who agitate to stop stem cell research today have to explain why they do not object to the mass cultivation of HeLa cells. You cannot have it both ways.
Science cannot tell you whether it is right to kill 'Mary' to save her conjoined twin 'Jodie' (or whether both twins should be allowed to die). * But science can tell you that a placenta is a true clone of the baby it nourishes. You could legitimately 'spin' the story of any placenta as a 'twin' of the baby that it nourishes, to be discarded when its role is completed. Admittedly, nobody is tempted to call their placenta Mary, but one might equally question the emotional wisdom of bestowing such a name on a Siamese twin with no heart or lungs, and only a primitive brain. And if anybody wishes to invoke 'slippery slopes' and 'thin ends of wedges' here, let them think on the following.
In 1998, a television gastronome served on screen a new gourmet dish: human placenta. He
flash-fried strips of the placenta with shallots and blended two thirds into a puree. The rest was flambeed in brandy, and then sage and lime juice were added. The family of the baby concerned ate it, with twenty of their friends. The father thought it so delicious that he had fourteen helpings.
The whole thing was presented in the papers as a bit of a lark. Yet those who worry about slippery slopes need to ask themselves why that television dinner should not be called cannibalism. Cannibalism is one of our oldest and deepest taboos, and a devotee of the 'slippery slope' or 'thin end of the wedge' style of argument might do well to worry at the slightest breach of that taboo. I suspect that, if the television executives had known enough science to understand that a placenta is
? These were widely publicized pseudonyms given to a pair of conjoined 'Siamese' twins who came to Britain for medical treatment around this time. The authorities wanted, against the parents' wishes, to separate the twins, in a mammoth operation which could have given Jodie (some sort of) life but would certainly result in Mary's death. Without the operation both twins would die, because Mary, who lacked most vital organs including a functioning brain, subsisted parasitically on Jodie. Many liberal people thought it right to over-rule the parents' religiously-based reluctance to 'kill' Mary to save Jodie. I thought the parents were right to reject the operation, although for the wrong reasons, and that in any case their wishes should have been respected because it was they whose lives were likely to be profoundly affected by the demands of the severely handicapped surviving twin.
SCIENCE, GENETICS AND ETHICS
35
? SCIENCE AND SENSIBILITY
a true clone of a baby, the dinner would never have gone ahead, especially at the height of the Dolly-inspired cloning controversy. You cannot have it both ways.
I want to conclude with a rather idiosyncratic approach to the matter of science and ethics: ethical treatment of scientific truth itself. I want to suggest that objective truth sometimes needs the same kind of protection as the libel laws now give to individuals. Or at least to suggest that the Trades Descriptions Act might be more imaginatively invoked. I'll say a little about this first, in the light of Prince Charles's recent plea for public money to do research into 'alternative medicine'.
If a pharmaceutical company advertises its pills as curing headaches, it must be able to demonstrate, in double-blind controlled trials, that its pills do indeed cure headaches. Double-blind means, of course, that neither the patients, nor the testers, know until afterwards which patients received the dose, and which the placebo control. If the pills cannot pass this test - if numerous strenuous efforts fail to distinguish them from a neutral placebo - I presume the company might be in danger of prosecution under the Trades Descriptions Act.
Homeopathic remedies are big business, they are advertised as efficacious in various ways, yet they have never been demonstrated to have any effect at all. Personal testimony is ubiquitous, but it is useless evidence because of the notorious power of the placebo effect. This is exactly why 'orthodox' medicines are obliged to prove themselves in double-blind trials. *
I do not want to imply that all so-called 'alternative medicines' are as useless as homeopathy. For all I know, some of them may work. But they must be demonstrated to work, by double-blind placebo-control trials or some equivalent experimental design. And if they pass that test, there is then no longer any reason to call them 'alternative'. Mainstream medicine would simply adopt them. As the distinguished journalist John Diamond wrote movingly (like many patients dying of cancer, he had false hopes cruelly raised by a succession of plausible quacks) in The Independent recently:
There is really no such thing as alternative medicine, just medicine that works and medicine that doesn't. . . There isn't an 'alternative' physiology or anatomy or nervous system any more than there's an alternative map of London which lets you get to Battersea from Chelsea without crossing the Thames.
? Homeopathy has special problems with double-blind control testing. I discuss this in my Foreword to John Diamond's Snake Oil (see pp. 181-4).
36
? But I began this final section in more radical terms. I wanted to extend the concept of libel to include lies that may not damage particular people but damage truth itself. Some twenty years ago, long before Dolly showed it was plausible, a book was published claiming, in great detail, that a rich man in South America had had himself cloned, by a scientist code-named Darwin. As a work of science fiction it would have been unexceptionable, but it was sold as sober fact. The author and publishers were sued, by Dr Derek Bromhall, who claimed that his reputation as a scientist was damaged by his being quoted in the book. My point is that whatever damage may or may not have been done to Dr Bromhall, far more important was the damage done to scientific truth itself.
That book has faded from memory and I bring it up only as an example. Obviously I want to generalize the principle to all deliberate falsifications, misrepresentations, of scientific truth. Why should a Derek Bromhall have to prove himself personally damaged, before we can prosecute a book which wantonly publishes lies about the universe? As will be obvious I'm no lawyer but, if I was, rather than constantly feel the need to drag things down to the question of whether particular humans have been damaged, I think I would like to stand up and defend truth itself. No doubt I shall be told - and convinced - that a court of law is not the right place for this. But in the wider world, if I am asked for a single phrase to characterize my role as Professor of Public Understanding of Science, I think I would choose Advocate for Disinterested Truth.
SCIENCE, GENETICS A N D ETHICS
37
? /
1. 5 Trial By Jury
Trial by jury must be one of the most conspicuously bad good ideas anyone ever had. Its devisers can hardly be blamed. They lived before the principles of statistical sampling and experimental design had been worked out. They weren't scientists. Let me explain using an analogy. And if, at the end, somebody objects to my argument on the grounds that humans aren't herring gulls, I'll have failed to get my point across.
Adult herring gulls have a bright yellow bill with a conspicuous red spot near the tip. Their babies peck at the red spot, which induces the parents to regurgitate food for them. Niko Tinbergen, Nobel Prize- winning zoologist and my old maestro at Oxford, offered naive young chicks a range of cardboard dummy gull heads varying in bill and spot colour, and shape. For each colour, shape or combination, Tinbergen measured the preferences of the baby chicks by counting their pecks in a standard time. The idea was to discover whether naive gull chicks are born with a built-in preference for long yellow things with red spots. If so, this would suggest that genes equip the young birds with detailed prior knowledge of the world in which they are about to hatch - a world in which food comes out of adult herring gull beaks.
Never mind the reason for the research, and never mind the con- clusions. Consider, instead, the methods you must use, and the pitfalls you must avoid, if you want to get a correct result in any such experiment. These turn out to be general principles which apply to human juries as strongly as to gull chicks.
First, you obviously must test more than one chick. It could be that some chicks are red-biased, others blue-biased, with no tendency for herring gull chicks in general to share the same favourite colour. So, by picking out a single chick, you are measuring nothing more than individual bias.
So, we must test more than one chick. How many? Is two enough? No, nor is three, and now we must start to think statistically. To make
38
? it simple, suppose that in a particular experiment we are comparing only red spots versus blue spots, both on a yellow background, and always presented simultaneously. If we test just two chicks separately, suppose the first chick chooses red. It had a 50 per cent chance of doing so, at random. Now the second chick also happens to choose red. Again, the odds were 50 per cent that it would do so at random, even if it were colourblind. There's a 50 per cent chance that two randomly choosing chicks will agree (half of the four possibilities: red red, red blue, blue red, blue blue). Three chicks aren't enough either.
The lawyer, with his trained discontinuous mind, insists on placing individuals firmly in this species or that. He does not allow for the possibility that an individual might lie halfway between two species, or a tenth of the way from species A to species B. Self-styled 'pro-lifers', and others that indulge in footling debates about exactly when in its development a foetus 'becomes human', exhibit the same discon- tinuous mentality. It is no use telling these people that, depending upon the human characteristics that interest you, a foetus can be 'half human' or 'a hundredth human'. 'Human', to the discontinuous mind, is an absolutist concept. There can be no half measures. And from this flows much evil.
The word 'apes' usually means chimpanzees, gorillas, orang utans, gibbons and siamangs. We admit that we are like apes, but we seldom realize that we are apes. Our common ancestor with the chimpanzees and gorillas is much more recent than their common ancestor with the Asian apes - the gibbons and orang utans. There is no natural category that includes chimpanzees, gorillas and orangs but excludes humans. The artificiality of the category 'apes', as conventionally taken to exclude humans, is demonstrated by the following diagram. The family tree shows humans to be in the thick of the ape cluster; the artificiality of the conventional category 'ape' is shown by the stippling.
22
? Gibbon
Siamang
Gorilla
Pigmy Chimpanzee Chimpanzee Human
I Orang Utan
- 'APES'
In truth, not only are we apes, we are African apes. The category 'African apes', if you don't arbitrarily exclude humans, is a natural category. The stippled area doesn't have any artificial 'bites' taken out of it:
Gibbon
Siamang
Gorilla
Pigmy Chimpanzee Chimpanzee Human
i Orang Utan
- AFRICAN APES
All the African apes that have ever lived, including ourselves, are linked to one another by an unbroken chain of parent-child bonds. The same is true of all animals and plants that have ever lived, but there the distances involved are much greater. Molecular evidence suggests that our common ancestor with chimpanzees lived, in Africa, between 5 and 7 million years ago, say half a million generations ago. This is not long by evolutionary standards.
Happenings are sometimes organized at which thousands of people hold hands and form a human chain, say from coast to coast of the United States, in aid of some cause or charity. Let us imagine setting one up along the equator, across the width of our home continent of Africa. It is a special kind of chain, involving parents and children, and we'll have to play tricks with time in order to imagine it. You stand on the shore of the Indian Ocean in southern Somalia, facing north, and in
GAPS IN THE MIND
23
? SCIENCE AND SENSIBILITY
your left hand you hold the right hand of your mother. In turn she holds the hand of her mother, your grandmother. Your grandmother holds her mother's hand, and so on. The chain wends its way up the beach, into the arid scrubland and westwards on towards the Kenya border.
How far do we have to go until we reach our common ancestor with the chimpanzees? It's a surprisingly short way. Allowing one yard per person, we arrive at the ancestor we share with chimpanzees in under 300 miles. We've hardly started to cross the continent; we're still not half way to the great Rift Valley. The ancestor is standing well to the east of Mount Kenya, and holding in her hand an entire chain of her lineal descendants, culminating in you standing on the Somali beach.
The daughter that she is holding in her right hand is the one from whom we are descended. Now the arch-ancestress turns eastward to face the coast, and with her left hand grasps her other daughter, the one from whom the chimpanzees are descended (or son, of course, but let's stick to females for convenience). The two sisters are facing one another, and each holding their mother by the hand. Now the second daughter, the chimpanzee ancestress, holds her daughter's hand, and a new chain is formed, proceeding back towards the coast. First cousin faces first cousin, second cousin faces second cousin, and so on. By the time the folded-back chain has reached the coast again, it consists of modern chimpanzees. You are face to face with your chimpanzee cousin, and you are joined to her by an unbroken chain of mothers holding hands with daughters. If you walked up the line like an inspecting general - past Homo erectus, Homo habilis, perhaps Australopithecus afarensis - and down again the other side (the intermediates on the chimpanzee side are unnamed because, as it happens, no fossils have been found), you would nowhere find any sharp discontinuity. Daughters would resemble mothers just as much (or as little) as they always do. Mothers would love daughters, and feel affinity with them, just as they always do. And this hand-in-hand continuum, joining us seamlessly to chimpanzees, is so short that it barely makes it past the hinterland of Africa, the mother continent.
Our chain of African apes in time, doubling back on itself, is in miniature like the ring of gulls in space, except that the intermediates happen to be dead. The point I want to make is that, as far as morality is concerned, it should be incidental that the intermediates are dead. What if they were not? What if a clutch of intermediate types had survived, enough to link us to modern chimpanzees by a chain, not just of hand-holders, but of interbreeders? Remember the song, 'I've danced
24
? with a man, who's danced with a girl, who's danced with the Prince of Wales'? We can't (quite) interbreed with modern chimpanzees, but we'd need only a handful of intermediate types to be able to sing: 'I've bred with a man, who's bred with a woman, who's bred with a chimpanzee. '
It is sheer luck that this handful of intermediates no longer exists. (Good luck from some points of view: for myself, I should love to meet them. ) But for this chance, our laws and our morals would be very different. We need only discover a single survivor, say a relict Austra- lopithecus in the Budongo Forest, and our precious system of norms and ethics would come crashing about our ears. The boundaries with which we segregate our world would be all shot to pieces. Racism would blur with speciesism in obdurate and vicious confusion. Apartheid, for those that believe in it, would assume a new and perhaps a more urgent import.
But why, a moral philosopher might ask, should this matter to us? Isn't it only the discontinuous mind that wants to erect barriers anyway? So what if, in the continuum of all apes that have lived in Africa, the survivors happen to leave a convenient gap between Homo and Pan? Surely we should, in any case, not base our treatment of animals on whether or not we can interbreed with them. If we want to justify double standards - if society agrees that people should be treated better than, say, cows (cows may be cooked and eaten, people may not) - there must be better reasons than cousinship. Humans may be taxonomically distant from cows, but isn't it more important that we are brainier? Or [better], following Jeremy Bentham, that humans can suffer more. Or that cows, even if they hate pain as much as humans do (and why on earth should we suppose otherwise? ), do not know what is coming to them? Suppose that the octopus lineage had happened to evolve brains and feelings to rival ours. They easily might have done. The mere possibility shows the incidental nature of cousinship. So, the moral philosopher asks, why emphasize the human/chimp continuity?
Yes, in an ideal world we probably should come up with a better reason than cousinship for, say, preferring carnivory to cannibalism. But the melancholy fact is that, at present, society's moral attitudes rest almost entirely on the discontinuous, speciesist imperative.
If somebody succeeded in breeding a chimpanzee/human hybrid, the news would be earth-shattering. Bishops would bleat, lawyers would gloat in anticipation, conservative politicians would thunder, socialists wouldn't know where to put their barricades. The scientist that achieved the feat would be drummed out of common-rooms; denounced in pulpit and gutter press; condemned, perhaps, by an Ayatollah's fatwah. Politics
GAPS IN THE MIND
25
? SCIENCE AND SENSIBILITY
would never be the same again, nor would theology, sociology, psychology or most branches of philosophy. The world that would be so shaken, by such an incidental event as a hybridization, is a speciesist world indeed, dominated by the discontinuous mind.
I have argued that the discontinuous gap between humans and 'apes' that we erect in our minds is regrettable. I have also argued that, in any case, the present position of the hallowed gap is arbitrary, the result of evolutionary accident. If the contingencies of survival and extinction had been different, the gap would be in a different place. Ethical principles that are based upon accidental caprice should not be respected as if cast in stone.
26
? 1.
Science, Genetics and Ethics:
Memo for Tony Blair
Senior Ministers could be forgiven for seeing scientists as little more than alternate igniters and quenchers of public panic. If a scientist appears in a newspaper today, it will usually be to pronounce on the dangers of food additives, mobile phones, sunbathing or electricity pylons. I suppose this is inevitable, given the equally forgivable preoc- cupation of citizens with their own personal safety, and their tendency to hold governments responsible for it. But it casts scientists in a sadly negative role. And it fosters the unfortunate impression that their credentials flow from factual knowledge. What really makes scientists special is less their knowledge than their method of acquiring it - a method that anybody could adopt with advantage.
Even more important, it leaves out the cultural and aesthetic value of science. It is as though one met Picasso and devoted the whole convers- ation to the dangers of licking one's brush. Or met Bradman* and talked only of the best box protector to put down one's trousers. Science, like painting (and some would say like cricket), has a higher aesthetic. Science can be poetry. Science can be spiritual, even religious in a non- supernatural sense of the word.
In a short memo it is obviously unrealistic to attempt comprehensive coverage of the kind that you will anyway get from civil service briefings. Instead, I thought I would pick out a few isolated topics, vignettes almost, that I find interesting and I hope that you might too. Given more space, I would have mentioned other vignettes (such as nanotechnology, which I suspect we shall be hearing a lot about in the twenty-first century).
Genetics
It is hard to exaggerate the sheer intellectual excitement of post- Watson/Crick genetics. What has happened is that genetics has become
*Note to American readers: Sir Donald Bradman (1908-2001) was a cricketer widely regarded, even outside Australia, as the best batsman ever.
27
? SCIENCE AND SENSIBILITY
a branch of Information Technology. The genetic code is truly digital, in exactly the same sense as computer codes. This is not some vague analogy, it is the literal truth. Moreover, unlike computer codes, the genetic code is universal. Modern computers are built around a number of mutually incompatible machine languages, determined by their processor chips. The genetic code, on the other hand, with a few very minor exceptions, is identical in every living creature on this planet, from sulphur bacteria to giant redwood trees, from mushrooms to men. All living creatures, on this planet at least, are the same 'make'.
The consequences are amazing. It means that a software subroutine (that's exactly what a gene is) can be Copied from one species and Pasted into another species, where it will work exactly as it did in the original species. This is why the famous 'antifreeze' gene, originally evolved by Arctic fish, can save a tomato from frost damage. In the same way, a NASA programmer who wants a neat square root routine for his rocket guidance system might import one from a financial spreadsheet. A square root is a square root is a square root. A program to compute it will serve as well in a space rocket as in a financial projection.
What, then, of the widespread gut hostility, amounting to revulsion, against all such 'transgenic' imports? I suspect that it comes from a pre- Watson/Crick misconception. Surely, the appealing but erroneous reasoning goes, an antifreeze gene from a fish must come with a fishy 'flavour'. Surely some of its fishiness must rub off? Surely it is 'unnatural' to splice a fish gene, which was only ever 'meant' to work in a fish, into the alien environment of a tomato cell? Yet nobody thinks that a square root subroutine carries a 'financial flavour' with it when you paste it into a rocket guidance system. The very idea of 'flavour' in this sense is not just wrong but profoundly and interestingly wrong. It is a cheerful thought, by the way, that most young people today understand computer software far better than their elders, and they should grasp the point instantly. The present Luddism over genetic engineering may die a natural death as the computer-illiterate generation is superseded.
Is there nothing, then, absolutely nothing, in the misgivings of Prince Charles, Lord Melchett and their friends? I wouldn't go that far, although they are certainly muddleheaded. * The square root analogy might be unfair in the following respect. What if it isn't a square root that the rocket guidance program needs, but another function which is
*I explained why in an Open Letter to Prince Charles, The Observer, 21 May 2000, http://www. guardian. co. uk/Archive/Article/0,4273,4020558,00. html. See also my article on Lord Melchett's vandalizing of scientific trials of GM crops, The Observer, 24 September 2000, http://www. guardian. co. uk/gmdebate/Story/0,2763,372528,00. html.
28
? not literally identical to the financial equivalent? Suppose it is sufficiently similar that the main routine can indeed be borrowed, but it still needs tweaking in detail. In that case, it is possible that the rocket could misfire if we naively import the subroutine raw. Switching back to biology, although genes really are watertight subroutines of digital software, they are not watertight in their effects on the development of the organism, for here they interact with their environment, including importantly the environment furnished by other genes. The antifreeze gene might depend, for optimal effect, on an interaction with other genes in the fish. Plonk it down in the foreign genetic climate of a tomato, and it might not work properly unless tweaked (which can be done) to mesh with the existing tomato genes.
What this means is that there is a case to be made on both sides of the argument, and we need to exercise subtle judgement. The genetic engineers are right that we can save time and trouble by climbing on the back of the millions of years of R & D that Darwinian natural selection has put into developing biological antifreeze (or whatever we are seeking). But the doomsayers would also have a point if they softened their stance from emotional gut rejection to a rational plea for rigorous safety testing. No reputable scientist would oppose such a plea. It is rightly routine for all new products, not just genetically engineered ones.
A largely unrecognized danger of the obsessive hysteria surrounding genetically modified foods is crying wolf. I fear that, if the green move- ment's high-amplitude warnings over GMOs turn out to be empty, people will be dangerously disinclined to listen to other and more serious warnings. The evolution of antibiotic resistance among bacteria is a vicious wolf of proven danger. Yet the menacing footfalls of this certain peril are all but drowned out in the caterwauling shrieks over genetically modified foods, whose dangers are speculative at most. To be more precise, genetic modification, like any other kind of modification, is good if you modify in a good direction, bad if you modify in a bad direction. Like domestic breeding, and like natural selection itself, the trick is to introduce the right new DNA software. The realization that software is all it is, written in exactly the same language as the organism's 'own' DNA, should go a long way towards dispelling the gut fears that rule most discussions of GMOs.
I can't leave the subject of gut feelings without a favourite quote from the lamented Carl Sagan. When asked a futurological question, he said that not enough was known to answer it. The questioner pressed him on what he really thought. 'What is your gut feeling? ' Sagan's reply is
SCIENCE, GENETICS A N D ETHICS
29
? SCIENCE AND SENSIBILITY
immortal: 'But I try not to think with my gut. ' Gut thinking is one of the main problems we have to contend with in public attitudes to science. I shall return to the point under Ethics. Meanwhile, some more remarks on the future of genetics in the twenty-first century, especially in the wake of the Human Genome Project (HGP).
The HGP, which will be completed any time now, is really a twentieth-century accomplishment. It is an outstanding success story, but it has limited scope. We have taken the human hard disk and transcribed every jot and tittle of the 11000101000010000111-style bits of information on it, regardless of what they mean in the software as a whole. The HGP needs to be followed up by a twenty-first-century Human Embryology Project (HEP) which, in effect, deciphers all the high-level software routines in which the machine-code instructions are embedded. An easier task will be a series of genome projects for different species (like the Arabidopsis plant genome project, whose completion is announced on the day that I write). These would be quicker and easier than the HGP, not because the other genomes are smaller or simpler than ours, but because the collective expertise of scientists increases cumulatively and rapidly with experience.
There is a frustrating aspect of this cumulative improvement. Given the rate of technological advance, with hindsight, when we started the Human Genome Project it wasn't worth starting. It would have been better to do nothing until the last two years and start then! Indeed, that is pretty much what the rival firm of Dr Craig Venter did. The fallacy in the 'never bother to start' maxim is that later technologies cannot get into a position to 'overtake' without the experience gained in developing the earlier ones. *
The HGP implicitly plays down the differences between individuals. But, with the intriguing exception of identical twins, everybody's genome is unique, and you might wonder whose genome is being sequenced in the HGP. Has some dignitary been singled out for the honour, is it a random person pulled off the street, or even an anonymous clone of cells in a tissue culture lab? It makes a difference. I have brown eyes while you have blue. I can't curl my tongue into a tube, whereas it's 50/50 that you can. Which version of the tongue-curling gene makes it into the published Human Genome? Which is the canonical eye colour? The answer is that, for the few 'letters' of the DNA text that vary, the canonical genome is the majority 'vote' among a sample of
*I have discussed the implications of the rapid growth of our understanding of genetics in more detail in 'Son of Moore's Law' (see pp. 107-15).
30
? people carefully chosen to give a good spread of human diversity.
But the diversity itself is expunged from the record.
By contrast the Human Genome Diversity Project (HGDP), now under way, builds on the foundation of the HGP but focuses on those relatively few nucleotide sites that vary from person to person, and from group to group. Incidentally, a surprisingly small proportion of that variance consists of between-race variance, a fact that has sadly failed to reassure spokesmen for various ethnic groups, especially in America. They have dreamed up influential political objections to the project which they see as exploitative and tarred with the brush of eugenics.
The medical benefits of studying human variation could be immense. Hitherto, almost all medical prescribing has assumed that patients are pretty much the same, and that every disease has an optimal recom- mended cure. Doctors of tomorrow will be more like vets in this respect. Doctors have only one species of patient, but in future they will subdivide that species by genotype, as a vet subdivides his patients by species. For the special needs of blood transfusions, doctors already recognize a few genetic typings (OAB, Rh) etc. In the future, every patient's personal record will include the results of numerous genetic tests: not their entire genome (that will be too expensive for the foreseeable future) but, as the century goes on, an increasing sampling of the variable regions of the genome, and far more than the present 'blood group' typings. The point is that for some diseases there may be as many different optimal treatments as there are different genotypes at a locus - more even, because genetic loci may interact to affect susceptibility to disease.
Another important use of the genetics of human diversity is forensic. Precisely because DNA is digital like computer bytes, genetic finger- printing is potentially many many orders of magnitude more accurate and reliable than any other means of individual identification, including direct facial recognition (despite the unshakeable gut feeling of jurors that eyewitness identification trumps everything). Moreover, identity can be established from a tiny trace of blood, sweat or tears (or spit, semen or hairs).
DNA evidence is widely regarded as controversial, and I need to say a little about why. Firstly, human error can obviously vitiate the accuracy of the method. But that is true of all evidence. Courts are already accustomed to taking precautions to avoid the muddling up of specimens, and such precautions now become even more important. DNA finger- printing can establish, almost infinitely far beyond all reasonable doubt, whether a smear of blood came from a particular individual. But
SCIENCE, GENETICS AND ETHICS
31
? SCIENCE AND SENSIBILITY
obviously you must test the right smear.
Secondly, astronomical though the odds against mistaken identity by
DNA fingerprinting theoretically are, it is possible for geneticists and statisticians to come up with what seem like widely different estimates
19
of the precise odds. I quote from Unweaving the Rainbow (Chapter 5,
which is devoted to explain DNA fingerprinting in lay terms).
Lawyers are accustomed to pouncing when expert witnesses seem to disagree. If two geneticists are summoned to the stand and are asked to estimate the probability of a misidentification with DNA evidence, the first may say 1,000,000 to one while the second may say only 100,000 to one. Pounce. 'Aha! AHA! The experts disagree! Ladies and gentlemen of the jury, what confidence can we place in a scientific method, if the experts themselves can't get within a factor of ten of one another? Obviously the only thing to do is throw the entire evidence out, lock, stock and barrel. '
But. . . any disagreement. . . is only over whether the odds against a wrongful identification are hyper-mega-astronomical, or just plain astronomical. The odds cannot normally be lower than thousands to one, and they may well be up in the billions. Even on the most conservative estimate, the odds against wrongful identification are hugely greater than they are in an ordinary identity parade. 'M'lud, an identity parade of only 20 men is grossly unfair on my client. I demand a line-up of at least a million men! '
The idea of a nationwide database, in which all citizens' DNA finger- prints would be held, is now being discussed (only a sample of genes, of course: doing the whole genome would be overkill, far too expensive). I don't see this as a sinister, Big Brotherish idea (and I have written to my doctor volunteering to be a guinea pig in the pilot study of 500,000 now being prepared). But there are potential problems, of a civil liberties character. If your house is burgled, the police will routinely look for (traditional, old-fashioned) fingerprints of the burglar. They need to fingerprint the householder's family too, for elimination purposes, and most people are happy to oblige. Obviously the same principle will apply to DNA fingerprinting, but many people would want to stop well short of a nationwide database. Presumably they would also object to a nationwide database of conventional, old-fashioned fingerprints, but perhaps that is not a practical issue because it would take too long to search through it for a match. DNA fingerprinting doesn't suffer from this difficulty. Computer searches of huge DNA databases could be accomplished swiftly.
What, then, are the civil liberties problems? Surely, those with nothing to hide will have nothing to fear? Perhaps not, but some
32
? people do have legitimate reasons to hide information, not from the law but from each other. A surprisingly large number of people, of all ages, are genetically unrelated to the man they think is their father. To put it mildly, it is not clear that to disillusion them, with conclusive DNA evidence, would increase the sum of human happiness. If a national DNA database were in place, it might be hard to control unauthorized access to it. If a tabloid newspaper were to discover that the official heir to a Dukedom was actually sired by the gamekeeper, the consternation in the College of Heralds might be mildly amusing. But in the population at large it doesn't take much to imagine the family recriminations and sheer private misery that could flow from freely available information of true paternity. Nevertheless, the existence of a national DNA database wouldn't alter the situation much. It is already perfectly feasible for a jealous husband, say, to take a saliva or blood sample from one of his supposed children and compare it with his own, in order to confirm his suspicion that he is not the real father. What the national database could add is a swift computer search to find out who, out of all the males in the entire country, is\
More generally, the study of human diversity is one of very few areas where a good (though in my opinion not overwhelming) case can be made against the pure disinterested search for knowledge: one of very few areas where we might actually be better off ignorant. It is possible that, by the end of the twenty-first century, doctors will be able accurately to predict the manner and time of death of everybody, from the day they are conceived. At present this kind of deterministic prognostica- tion can be achieved only for possessors of genes such as Huntington's Chorea. * For the rest of us, all that is possible is the vague statistical forecast of the life insurance actuary, based on our smoking and drink- ing habits, and a quick listen through a stethoscope. The whole life insurance business depends upon such forecasts being vague and statistical. Those who die old subsidize (the heirs of) those who die young. If the day comes when deterministic forecasting (along Huntington's Chorea lines) becomes universal, life insurance as we know it will collapse. That problem is soluble (presumably by universal compulsory life insurance with no individual medical risk assessment). What will be
*The folk singer Woody Guthrie died of Huntington's Chorea, a horrible disease that waits till early middle age before killing you. It's a dominant gene, so each of Woody's children knows that he has an exactly 50 per cent chance of suffering the same horrible fate. Some people, given these odds, prefer not to be tested. They'd rather not know until they have to. IVF doctors can now push the test back to the newly fertilized zygote, and choose to implant only those that lack the fatal gene. This is obviously a huge boon, but it is attacked by ignorant lobbies fearful of 'scientists playing God'.
SCIENCE, GENETICS AND ETHICS
33
? SCIENCE AND SENSIBILITY
less easy to solve is the angst which will hang over everyone's psychology. As things are now, we all know we are going to die, but most of us don't know when, so it doesn't feel like a death sentence. That may change, and society should be prepared for difficulties as people struggle to adjust their psychologies to it.
Ethics
I have already touched on some ethical issues. Science has no methods for deciding what is ethical. That is a matter for individuals and for society. But science can clarify the questions being asked, and can clear up obfuscating misunderstandings. This usually amounts to the useful 'You cannot have it both ways' style of arguing. I'll give five examples, before turning to a more unusual interpretation of the phrase 'science and ethics'.
Science cannot tell you whether abortion is wrong, but it can point out that the (embryological) continuum that seamlessly joins a non- sentient foetus to a sentient adult is analogous to the (evolutionary) continuum that joins humans to other species. If the embryological continuum appears to be more seamless, this is only because the evolutionary continuum is divided by the accident of extinction. Fundamental principles of ethics should not depend on the accidental contingencies of extinction. * To repeat, science cannot tell you whether abortion is murder, but it can warn you that you may be being inconsistent if you think abortion is murder but killing chimpanzees is not. You cannot have it both ways.
Science cannot tell you whether it is wrong to clone a whole human being. But it can tell you that a Dolly-style clone is just an identical twin, though of a different age. It can tell you that, if you want to object to cloning humans, you must not appeal to arguments such as 'The clone wouldn't be a full person' or 'The clone wouldn't have a soul'. Science cannot tell you whether anybody has a soul, but it can tell you that, if ordinary identical twins have souls, so do Dolly-style clones. f You cannot have it both ways.
Science cannot tell you whether stem cell cloning for 'spare parts' is wrong. But it can challenge you to explain how stem cell cloning differs morally from something that has long been accepted: tissue culture. Tissue culture has been a mainstay of cancer research for decades. The famous HeLa cell line, which originated in the late Henrietta Lacks in
? See 'Gaps in the Mind' (pp. 20-6) for a fuller discussion. tSee 'Dolly and the Cloth Heads' (pp. 152-5).
34
? 1951, is now being grown in labs all over the world. A typical lab, at the University of California, grows 48 litres of HeLa cells per day, as a routine service to researchers in the university. The total daily worldwide production of HeLa cells must be measured in tons - all a gigantic clone of Henrietta Lacks. In the half century since this mass production began, nobody seems to have objected to it. Those who agitate to stop stem cell research today have to explain why they do not object to the mass cultivation of HeLa cells. You cannot have it both ways.
Science cannot tell you whether it is right to kill 'Mary' to save her conjoined twin 'Jodie' (or whether both twins should be allowed to die). * But science can tell you that a placenta is a true clone of the baby it nourishes. You could legitimately 'spin' the story of any placenta as a 'twin' of the baby that it nourishes, to be discarded when its role is completed. Admittedly, nobody is tempted to call their placenta Mary, but one might equally question the emotional wisdom of bestowing such a name on a Siamese twin with no heart or lungs, and only a primitive brain. And if anybody wishes to invoke 'slippery slopes' and 'thin ends of wedges' here, let them think on the following.
In 1998, a television gastronome served on screen a new gourmet dish: human placenta. He
flash-fried strips of the placenta with shallots and blended two thirds into a puree. The rest was flambeed in brandy, and then sage and lime juice were added. The family of the baby concerned ate it, with twenty of their friends. The father thought it so delicious that he had fourteen helpings.
The whole thing was presented in the papers as a bit of a lark. Yet those who worry about slippery slopes need to ask themselves why that television dinner should not be called cannibalism. Cannibalism is one of our oldest and deepest taboos, and a devotee of the 'slippery slope' or 'thin end of the wedge' style of argument might do well to worry at the slightest breach of that taboo. I suspect that, if the television executives had known enough science to understand that a placenta is
? These were widely publicized pseudonyms given to a pair of conjoined 'Siamese' twins who came to Britain for medical treatment around this time. The authorities wanted, against the parents' wishes, to separate the twins, in a mammoth operation which could have given Jodie (some sort of) life but would certainly result in Mary's death. Without the operation both twins would die, because Mary, who lacked most vital organs including a functioning brain, subsisted parasitically on Jodie. Many liberal people thought it right to over-rule the parents' religiously-based reluctance to 'kill' Mary to save Jodie. I thought the parents were right to reject the operation, although for the wrong reasons, and that in any case their wishes should have been respected because it was they whose lives were likely to be profoundly affected by the demands of the severely handicapped surviving twin.
SCIENCE, GENETICS AND ETHICS
35
? SCIENCE AND SENSIBILITY
a true clone of a baby, the dinner would never have gone ahead, especially at the height of the Dolly-inspired cloning controversy. You cannot have it both ways.
I want to conclude with a rather idiosyncratic approach to the matter of science and ethics: ethical treatment of scientific truth itself. I want to suggest that objective truth sometimes needs the same kind of protection as the libel laws now give to individuals. Or at least to suggest that the Trades Descriptions Act might be more imaginatively invoked. I'll say a little about this first, in the light of Prince Charles's recent plea for public money to do research into 'alternative medicine'.
If a pharmaceutical company advertises its pills as curing headaches, it must be able to demonstrate, in double-blind controlled trials, that its pills do indeed cure headaches. Double-blind means, of course, that neither the patients, nor the testers, know until afterwards which patients received the dose, and which the placebo control. If the pills cannot pass this test - if numerous strenuous efforts fail to distinguish them from a neutral placebo - I presume the company might be in danger of prosecution under the Trades Descriptions Act.
Homeopathic remedies are big business, they are advertised as efficacious in various ways, yet they have never been demonstrated to have any effect at all. Personal testimony is ubiquitous, but it is useless evidence because of the notorious power of the placebo effect. This is exactly why 'orthodox' medicines are obliged to prove themselves in double-blind trials. *
I do not want to imply that all so-called 'alternative medicines' are as useless as homeopathy. For all I know, some of them may work. But they must be demonstrated to work, by double-blind placebo-control trials or some equivalent experimental design. And if they pass that test, there is then no longer any reason to call them 'alternative'. Mainstream medicine would simply adopt them. As the distinguished journalist John Diamond wrote movingly (like many patients dying of cancer, he had false hopes cruelly raised by a succession of plausible quacks) in The Independent recently:
There is really no such thing as alternative medicine, just medicine that works and medicine that doesn't. . . There isn't an 'alternative' physiology or anatomy or nervous system any more than there's an alternative map of London which lets you get to Battersea from Chelsea without crossing the Thames.
? Homeopathy has special problems with double-blind control testing. I discuss this in my Foreword to John Diamond's Snake Oil (see pp. 181-4).
36
? But I began this final section in more radical terms. I wanted to extend the concept of libel to include lies that may not damage particular people but damage truth itself. Some twenty years ago, long before Dolly showed it was plausible, a book was published claiming, in great detail, that a rich man in South America had had himself cloned, by a scientist code-named Darwin. As a work of science fiction it would have been unexceptionable, but it was sold as sober fact. The author and publishers were sued, by Dr Derek Bromhall, who claimed that his reputation as a scientist was damaged by his being quoted in the book. My point is that whatever damage may or may not have been done to Dr Bromhall, far more important was the damage done to scientific truth itself.
That book has faded from memory and I bring it up only as an example. Obviously I want to generalize the principle to all deliberate falsifications, misrepresentations, of scientific truth. Why should a Derek Bromhall have to prove himself personally damaged, before we can prosecute a book which wantonly publishes lies about the universe? As will be obvious I'm no lawyer but, if I was, rather than constantly feel the need to drag things down to the question of whether particular humans have been damaged, I think I would like to stand up and defend truth itself. No doubt I shall be told - and convinced - that a court of law is not the right place for this. But in the wider world, if I am asked for a single phrase to characterize my role as Professor of Public Understanding of Science, I think I would choose Advocate for Disinterested Truth.
SCIENCE, GENETICS A N D ETHICS
37
? /
1. 5 Trial By Jury
Trial by jury must be one of the most conspicuously bad good ideas anyone ever had. Its devisers can hardly be blamed. They lived before the principles of statistical sampling and experimental design had been worked out. They weren't scientists. Let me explain using an analogy. And if, at the end, somebody objects to my argument on the grounds that humans aren't herring gulls, I'll have failed to get my point across.
Adult herring gulls have a bright yellow bill with a conspicuous red spot near the tip. Their babies peck at the red spot, which induces the parents to regurgitate food for them. Niko Tinbergen, Nobel Prize- winning zoologist and my old maestro at Oxford, offered naive young chicks a range of cardboard dummy gull heads varying in bill and spot colour, and shape. For each colour, shape or combination, Tinbergen measured the preferences of the baby chicks by counting their pecks in a standard time. The idea was to discover whether naive gull chicks are born with a built-in preference for long yellow things with red spots. If so, this would suggest that genes equip the young birds with detailed prior knowledge of the world in which they are about to hatch - a world in which food comes out of adult herring gull beaks.
Never mind the reason for the research, and never mind the con- clusions. Consider, instead, the methods you must use, and the pitfalls you must avoid, if you want to get a correct result in any such experiment. These turn out to be general principles which apply to human juries as strongly as to gull chicks.
First, you obviously must test more than one chick. It could be that some chicks are red-biased, others blue-biased, with no tendency for herring gull chicks in general to share the same favourite colour. So, by picking out a single chick, you are measuring nothing more than individual bias.
So, we must test more than one chick. How many? Is two enough? No, nor is three, and now we must start to think statistically. To make
38
? it simple, suppose that in a particular experiment we are comparing only red spots versus blue spots, both on a yellow background, and always presented simultaneously. If we test just two chicks separately, suppose the first chick chooses red. It had a 50 per cent chance of doing so, at random. Now the second chick also happens to choose red. Again, the odds were 50 per cent that it would do so at random, even if it were colourblind. There's a 50 per cent chance that two randomly choosing chicks will agree (half of the four possibilities: red red, red blue, blue red, blue blue). Three chicks aren't enough either.
