No More Learning

In theory, people could switch allegiance from any one 'truth' to any
other if they decide it has greater merit. On what basis might they do so? Why would one change from, say, Kikuyu truth to Navajo truth? Such merit-driven switches are rare. With one crucially important excep- tion. Scientific truth is the only member of the list which regularly persuades converts of its superiority. People are loyal to other belief systems for one reason only: they were brought up that way, and they have never known anything better. When people are lucky enough to be offered the opportunity to vote with their feet, doctors and their kind prosper while witch doctors decline. Even those who do not, or cannot, avail themselves of a scientific education, choose to benefit from the technology that is made possible by the scientific education of others. Admittedly, religious missionaries have successfully claimed converts in great numbers all over the underdeveloped world. But they succeed not because of the merits of their religion but because of the science-based technology for which it is pardonably, but wrongly, given credit.
Surely the Christian God must be superior to our Juju, because Christ's representatives come bearing rifles, telescopes, chainsaws, radios, almanacs that predict eclipses to the minute, and medicines that work.
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So much for cultural relativism. A different type of truth-heckler prefers to drop the name of Karl Popper or (more fashionably) Thomas Kuhn:
There is no absolute truth. Your scientific truths are merely hypotheses that have so far failed to be falsified, destined to be superseded. At worst, after the next scientific revolution, today's 'truths' will seem quaint and absurd, if not actually false. The best you scientists can hope for is a series of approximations which progressively reduce errors but never eliminate them.
The Popperian heckle partly stems from the accidental fact that philosophers of science are traditionally obsessed with one piece of scientific history: the comparison between Newton's and Einstein's theories of gravitation. It is true that Newton's inverse square law has turned out to be an approximation, a special case of Einstein's more general formula. If this is the only piece of scientific history you know, you might indeed conclude that all apparent truths are mere approxi- mations, fated to be superseded. There is even a quite interesting sense in which all our sensory perceptions - the 'real' things that we 'see with our own eyes' - may be regarded as unfalsified 'hypotheses' about the world, vulnerable to change. This provides a good way to think about illusions such as the Necker Cube.
The flat pattern of ink on paper is compatible with two alternative 'hypotheses' of solidity. So we see a solid cube which, after a few seconds, 'flips' to a different cube, then flips back to the first cube, and so on. Perhaps sense data only ever confirm or reject mental 'hypotheses'
16 about what is out there.
Well, that is an interesting theory; so is the philosopher's notion that science proceeds by conjecture and refutation; and so is the analogy between the two. This line of thought - all our percepts are hypo- thetical models in the brain - might lead us to fear some future blurring of the distinction between reality and illusion in our descendants, whose lives will be even more dominated by computers capable of
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? generating vivid models of their own. Without venturing into the high- tech worlds of virtual reality, we already know that our senses are easily deceived. Conjurors - professional illusionists - can persuade us, if we lack a sceptical foothold in reality, that something supernatural is going on. Indeed, some notorious erstwhile conjurors make a fat living doing exactly that: a living much fatter than they ever enjoyed when they frankly admitted that they were conjurors. * Scientists, alas, are not best equipped to unmask telepathists, mediums and spoon-bending charlatans. This is a job which is best handed over to the professionals, and that means other conjurors. The lesson that conjurors, the honest variety and the impostors, teach us is that an uncritical faith in our own senses is not an infallible guide to truth.
But none of this seems to undermine our ordinary concept of what it means for something to be true. If I am in the witness box, and prosecuting counsel wags his stern finger and demands, 'Is it or is it not true that you were in Chicago on the night of the murder? ', I should get pretty short shrift if I said,
What do you mean by true? The hypothesis that I was in Chicago has not so far been falsified, but it is only a matter of time before we see that it is a mere approximation.
Or, reverting to the first heckle, I would not expect a jury, even a Bongolese jury, to give a sympathetic hearing to my plea that,
It is only in your western scientific sense of the word 'in' that I was in Chicago. The Bongolese have a completely different concept of 'in', according to which you are only truly 'in' a place if you are an anointed elder entitled to take snuff from the dried scrotum of a goat.
It is simply true that the Sun is hotter than the Earth, true that the desk on which I am writing is made of wood. These are not hypotheses awaiting falsification; not temporary approximations to an ever-elusive truth; not local truths that might be denied in another culture. And the same can safely be said of many scientific truths, even where we can't see them 'with our own eyes'. It is forever true that DNA is a double helix, true that if you and a chimpanzee (or an octopus or a kangaroo)
'Performing psychics and mystics, who happily perform in front of scientists, will con- veniently plead a headache and refuse to go on if informed that a contingent of professional conjurors is in the front row of the stalls. It is for the same reason that the then Editor of Nature, John Maddox, took James 'The Amazing' Randi with him when investigating a suspected case of homeopathic fraud. This caused some resentment at the time, but it was an entirely reasonable decision. Any genuine scientist has nothing to fear from a sceptical conjuror looking over his shoulder.
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trace your ancestors back far enough you will eventually hit a shared ancestor. To a pedant, these are still hypotheses which might be falsified tomorrow. But they never will be. Strictly, the truth that there were no human beings in the Jurassic Period is still a conjecture, which could be refuted at any time by the discovery of a single fossil, authentically dated by a battery of radiometric methods. It could happen. Want a bet? Even if they are nominally hypotheses on probation, these statements are true in exactly the same sense as the ordinary truths of everyday life; true in the same sense as it is true that you have a head, and that my desk is wooden. If scientific truth is open to philosophic doubt, it is no more so than common sense truth. Let's at least be even-handed in our philosophical heckling.
A more profound difficulty now arises for our scientific concept of truth. Science is very much not synonymous with common sense. Admittedly, that doughty scientific hero T. H. Huxley said:
Science is nothing but trained and organized common sense, differing from the latter only as a veteran may differ from a raw recruit: and its methods differ from those of common sense only as far as the guardsman's cut and thrust differ from the manner in which a savage wields his club.
But Huxley was talking about the methods of science, not its conclusions. As Lewis Wolpert emphasized in The Unnatural Nature of
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Science, the conclusions can be disturbingly counter-intuitive.
Quantum theory is counter-intuitive to the point where the physicist sometimes seems to be battling insanity. We are asked to believe that a single quantum behaves like a particle in going through one hole instead of another, but simultaneously behaves like a wave in interfer- ing with a non-existent copy of itself, if another hole is opened through which that non-existent copy could have travelled (if it had existed). It gets worse, to the point where some physicists resort to a vast number of parallel but mutually unreachable worlds, which proliferate to accommodate every alternative quantum event; while other physicists, equally desperate, suggest that quantum events are determined retro- spectively by our decision to examine their consequences. Quantum theory strikes us as so weird, so defiant of common sense, that even the great Richard Feynman was moved to remark, T think I can safely say that nobody understands quantum mechanics. ' Yet the many predic- tions by which quantum theory has been tested stand up, with an accuracy so stupendous that Feynman compared it to measuring the distance between New York and Los Angeles accurately to the width of one human hair. On the basis of these stunningly successful
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? predictions, quantum theory, or some version of it, seems to be as true as anything we know.
Modern physics teaches us that there is more to truth than meets the eye; or than meets the all too limited human mind, evolved as it was to cope with medium-sized objects moving at medium speeds through medium distances in Africa. In the face of these profound and sublime mysteries, the low-grade intellectual poodling of pseudo-philosophical poseurs seems unworthy of adult attention.
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? Gaps in the Mind
Sir,
You appeal for money to save the gorillas. Very laudable, no doubt. But it doesn't seem to have occurred to you that there are thousands of human children suffering on the very same continent of Africa. There'll be time enough to worry about gorillas when we've taken care of every last one of the kiddies. Let's get our priorities right, p/ease!
This hypothetical letter could have been written by almost any well- meaning person today. In lampooning it, I don't mean to imply that a good case could not be made for giving human children priority. I expect
it could, and also that a good case could be made the other way. I'm only trying to point the finger at the automatic, unthinking nature of the speciesist double standard. To many people it is simply self-evident, without any discussion, that humans are entitled to special treatment. To see this, consider the following variant on the same letter:
Sir,
You appeal for money to save the gorillas. Very laudable, no doubt. But it doesn't seem to have occurred to you that there are thousands of aardvarks suffering on the very same continent of Africa. There'll be time enough to worry about gorillas when we've saved every last one of the aardvarks. Let's get our priorities right, p/ease!
This second letter could not fail to provoke the question: What's so special about aardvarks? A good question, and one to which we should require a satisfactory answer before we took the letter seriously. Yet the first letter, I suggest, would not for most people provoke the equivalent question, 'What's so special about humans? ' As I said, I don't deny that this question, unlike the aardvark question, very probably has a power- ful answer. All that I am criticizing is an unthinking failure to realize in the case of humans that the question even arises.
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? The speciesist* assumption that lurks here is very simple. Humans are humans and gorillas are animals. There is an unquestioned yawning gulf between them such that the life of a single human child is worth more than the lives of all the gorillas in the world. The 'worth' of an animal's life is just its replacement cost to its owner - or, in the case of
a rare species, to humanity. But tie the label Homo sapiens even to a tiny piece of insensible, embryonic tissue, and its life suddenly leaps to infinite, uncomputable value.
This way of thinking characterizes what I want to call the discontinuous mind. We'd all agree that a six-foot woman is tall, and a five-foot woman is not. Words like 'tall' and 'short' tempt us to force the world into qualitative classes, but this doesn't mean that the world really is discontinuously distributed. Were you to tell me that a woman is five feet nine inches tall, and ask me to decide whether she should therefore be called tall or not, I'd shrug and say, 'She's five foot nine, doesn't that tell you what you need to know? ' But the discontinuous mind, to caricature it a little, would go to court to decide (probably at great expense) whether the woman was tall or short. Indeed, I hardly need to say caricature. For years, South African courts have done a brisk trade adjudicating whether particular individuals of mixed parentage count as white, black or 'coloured'. t
The discontinuous mind is ubiquitous. It is especially influential when it afflicts lawyers and the religious (not only are all judges lawyers; a high proportion of politicians are too, and all politicians have to woo the religious vote). Recently, after giving a public lecture, I was cross-examined by a lawyer in the audience. He brought the full weight of his legal acumen to bear on a nice point of evolution. If species A evolves into a later species B, he reasoned closely, there must come a point when a mother belongs to the old species A and her child belongs to the new species B. Members of different species cannot interbreed with one another. I put it to you, he went on, that a child could hardly be so different from its parents that it could not interbreed with their kind. So, he wound up triumphantly, isn't this a fatal flaw in the theory of evolution?
But it is we that choose to divide animals up into discontinuous species. On the evolutionary view of life there must have been inter- mediates, even though, conveniently for our naming rituals, they are today usually extinct. They are not always extinct. The lawyer would be
'Coined by Richard Ryder and given currency by Peter Singer, the analogy is to racism. tThankfully no longer. The apartheid regime is one of history's monuments to the tyranny of the discontinuous mind.
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surprised and, I hope, intrigued by so-called 'ring species'. The best- known case is the Herring Gull/Lesser Black-backed Gull ring. 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.
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? 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
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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
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? 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
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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.
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? 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.
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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.
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? 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
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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).
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? 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
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? 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
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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
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? 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.