Why won't we trust experts? What in particular have we got against scientists? Why don't we quite be-lieve them when they tell us that the measles, mumps and rubella triple vaccine is perfectly safe? Why don't we embrace GM crops which, we are assured, are needed to feed the world?
The distrust matters. What humanity needs most of all are things of the spirit - amity, tolerance, unselfishness, goodwill - but we need a material platform, too. We haven't a hope of feeding ourselves sustainably (ten billion people are expected by the middle of this century) or avoiding horrendous epidemics without excellent science and the technologies that science gives rise to. To reject technologies that really can deliver - such as affordable vaccines and even GM foods - is perverse. To withdraw support from experts, the people who truly understand them, looks very like self-immolation. So why have things gone so wrong?
I reckon that there are five big reasons. Scientists and politicians these past 20 years have focused on the one that throws the blame on the rest of us: we, known peremptorily as "the public", are "ignorant" and need bringing up to speed. But the other four reasons run deeper and, in the end, matter more.
The first, orthodox and respectable explanation for public recalcitrance says that we, "the public", respond to GM foods, say, in the way that ancient South Sea Islanders reacted to eclipses of the sun. We are savages under the skin, fearing the unknown, and the findings of science are too far beyond our ken. Change in general bothers us; there is safety in nostalgia. But our memories are selective. While we remember the happy seaside holidays of the postwar years, we forget the drabness, the smogs and the polio.
The media don't help. They "stir things up". Reporters are "irresponsible", and editors want stories rooted in Tolkienesque myths - of races and punch-ups (between rival scientists); of injustice (whistle-blowing scientists done down by the orthodoxy); of skulduggery (scientists who cheat); and best of all, perhaps, the spectres of Drs Frankenstein and Faust (not to mention Moreau and Strangelove). And it is true that the media happily discuss the ideas of music and classical painting but conventionally present science as a shoot-out. Editors who have no education at all can't believe that anyone actually likes ideas; and those who have been educated at the greatest expense at the most ancient English universities have typically been brought up to believe that science is antithetical to the human soul.
In an effort to raise the tone, the Royal Society, the Royal Institution and the British Association for the Advancement of Science founded the Committee on the Public Understanding of Science (Copus) nearly 20 years ago. The committee was founded on the notion that people do not get on well with science because they (we) have not been properly versed in it. But Professor Lewis Wolpert, a former chairman of Copus, has added his own philosophical spin. Most people, he argues, rely on common sense - which works up to a point, but if we want truly to understand how the universe works, it won't do. Common sense seems to tell us that God made human beings in the same way that watchmakers make watches: what else could pull such a trick? Common sense also says that nothing can be in two different places at any one time. But along came science and said that human beings could be shaped by the blind forces of natural selection, with no divine planning, and that photons can be in two places at once. Worse, many of science's special insights spring from maths, which human beings as a species are very bad at.
Thus, to appreciate properly the deep truths that underpin our universe requires a change of mindset, an ability to grasp things that are counter-intuitive. Professional scientists acquire this only after many years of exposure. Those who lack formal grounding cannot be party to it. Horizon-style knowledge is, in the end, illusory; we may press our noses to the laboratory window, but we can never be guests at the party. Diligently though Wolpert has sought to explain science, he has always been keen to emphasise that only "real" scientists can do science, or are in a position to criticise it. The rest of us should eat up our GM foods and give thanks.
Yet Wolpert's view of science is totally at odds with its true spirit. In the Middle Ages, truth was dogma, acquired by revelation and decided by authority; but as the philosophers of the Enlightenment declared, science is the enemy of dogma precisely because it is not arcane. Admittedly, Pythagoras thought that the ideas of natural philosophy should be kept under wraps, and so, somewhat oddly, did Francis Bacon. But the essence of modern science is to be as explicit as possible: "show your working", as they say in maths exams. Science may sometimes be hard, but it is ultimately democratic. Only the initiated can be party to the thoughts of the tribal witch doctor or medieval priest (or of Pythagoras, if he had his way), but the ideas of science are laid out for all to inspect. In principle, we can all have a view; and if democracy means anything, we should have one.
This leads us to the second great glitch. Witch doctors enjoy the kudos. All human beings - in fact, all animals - seek status. We can't all be alphas, but we can be good at what we do, and be respected for it. Tradesmen coalesce into guilds; those who aspire to be intellectuals form "professions". We all like to belong, and to keep out those who don't, and the keenest in this are scientists and medics. Every speciality needs its technical vocabulary - builders have their soffits and their gable ends, and sailors their davits and topgallants - but technical language also becomes tailored, at least to an extent, to repel boarders, and then it becomes jargon. Outsiders may sometimes benefit from this clubbishness: patients get better quicker if they believe in the cure; it doesn't always pay to give the physician a hard time. And exclusiveness ensures, when it's working well, that trades and professions guard their own high standards.
But the lines are difficult to draw. Wolpert and others assure us that science is too hard, partly to keep us at bay. Its magic and status would be compromised if we all knew its secrets, or believed that we could. Many scientists, to their credit (and in apparent defiance of Francis Bacon), truly regret their inability to convey their thoughts to people at large. Public communication has become another growth industry. To some extent, it is just a matter of technique: scientists have saddled themselves with newspeak ("a test tube was taken") and need to relearn the basics, including the use of active verbs ("The Romans killed many Greeks", as I once knew how to say in Latin). But they have to dig deeper. They have to ask themselves, as they are not accustomed to asking, what science actually is; what it can really do for people and what it can't.
The clubbishness of experts leads to the disease identified in particular by Everett Reimer and Ivan Illich in the 1960s: the general drift throughout society towards "professionalisation". Women have babies - and obstetricians are on hand to tell them how. We all need to eat - so professional agriculturalists grow the food, and those trained in hygiene and nutrition tell us what's edible. And so on. Experts are necessary, but it's all too easy for the rest of us to be taken over.
Scientists are particularly prone to professionalise. Many were recently given endless airtime and column inches to explain to the world why they objected to the experiments of Dr Arpad Pusztai, then of the Rowett Research Institute, Aberdeen, who claimed to have shown that genetically modified potatoes make rats ill. What was wrong with his experiments? Wherein had he transgressed? The protesting scientists never told us. They complained that Pusztai had bypassed the normal protocols and spoken to the newspapers before speaking to them. A misdemeanour indeed, but what is important to humanity? Being poisoned (if such is the case), or the dignity of scientists? So, too, with the MMR vaccine. If there has been an authoritative (as opposed to authoritarian) public debate on the evidence and the odds, it has passed me by. Again, public contributions from scientists seem to have focused on rebutting the criticisms, but not on explicit refutation. If the experts truly want to maintain their own position, they should demonstrate why they, the experts, are necessary. Instead, they exhort us simply to believe in their expertise.
The third issue, however, may be the one that runs deepest of all. Historically, science and capitalism grew up together. Their histories can be traced back to classical times (in fact, to the beginnings of all history and doubtless before that), but both arose in their modern form in the 17th century. They fed off each other from the start. As Isaac Newton himself acknowledged and approved, practical, commercial ambitions can inspire fundamental studies - and pay for them. The new global, imperial commerce of Newton's day required more accurate navigation, which in turn needed better astronomy. In similar vein in the 20th century, the theoretical biologist Peter Medawar pointed out that the search for new drugs, say, has often directed researchers' minds to previously unsuspected quirks of physiology.
But the alliance of science and commerce can be too cosy. For the past 400 years, they have formed a positive-feedback loop. Capital provides the cash that finances the research that produces the hi-tech that provides more capital. Indeed, this whirligig has become the great driver of modern economies. Everything else is secondary. The governments that succeed are not those with the most appealing ideologies, but those that encourage the driver of capital/science/hi-tech to operate most vigorously. Tony Blair perceives this; it is the key to all his policies.
Private capital cannot pay for research that does not create more capital, so the only research that's done at all is the kind that can make money. Morality and ideology are allowed into the equation only for marketing purposes: to provide a "green image", for example. No line of inquiry can be pursued, however desirable, unless it leads to cash. Contrariwise, anything that can make money is done, even if its social effects are undesirable. Thus it has become a cliche that drugs for Aids are developed because Aids is a worldwide disease, but they are not distributed where they are needed most because Africans can't afford them. Genetically modified sorghum could bring great benefits to the semi-desert (Sahel) to the south of the Sahara, but development stalls because sorghum growers could not afford the GM seed. Yet GM rape is slipped into the British food chain with government blessing simply to knock a few pence off the wholesale price. In that context, GM has almost nothing to do with feeding the world, or protecting the environment. It is intended simply to increase the breeder's stake in western agriculture.
More broadly, it begins to seem that no expert of any kind, scientist or lawyer or auditor, is likely to be employed at all except by private companies; and their publicly expressed opinions are adjusted accordingly. A leading professor of public health told me that, in nutritional science, it is difficult to find any research, even in the most respected universities, that is not financed at least in part by food companies. The scientists are not expected to lie; but funds dry up if they produce too many negative results.
To some extent, the loop of capital/science/hi-tech is inevitable. Game theory shows that it was bound to come into being, and to dominate. But it has also become official policy. Before the 1970s, academic bodies had their own funds and decided what research should be done. University scientists were discouraged from even talking to industry - which verged on preciousness, but at least protected their "purity". In the early 1970s, however, Lord Rothschild argued in a report for Edward Heath's government that those who benefit most directly from science should pay for it; and the payers should in turn determine what is actually done. Thus was born the "customer-contractor" principle. It fitted perfectly the ideology that Margaret Thatcher and Keith Joseph developed a few years later. Thatcher (and Ronald Reagan and most other western leaders) was able to cut public funds for research, and make a virtue of it. It had become a matter of principle that private companies should pay. Britain's scientists now typically spend two days a week scratching after commercial grants - rewriting the same proposal time and again to fit the particular "mission statements" and ambitions of each granting body. If you believe the general conceit that "what's good for General Motors is good for the US", then everything in the garden is wonderful. If, however, you are not a dyed-in-the-wool, shoot-from-the-hip, Ronald Reagan/George W Bush style of American Republican, then you might be a little worried by the present way of running things, even if Blair seems happy enough with it.
The fourth reason for distrusting experts is that they can and do get things wrong. To some extent, this is inevitable: the whole point of science, after all, is to investigate the unknown. It is very dangerous, too, to be cynical. Bush may prefer to believe that the greenhouse effect is just another boffins' whim, but it probably isn't. Admittedly, we were threatened with a new ice age just a few years ago - the "snowball world" - but science really does advance, and the belief in the greenhouse effect is based on better data and more intricate calculations, done by much bigger computers. In any case, Pascal's wager with God applies: it's better to believe in global warming because, if we don't and it's real, we would be in very deep trouble, while the things we need to do to avoid it (such as cutting the use of fossil fuels) are worth doing anyway. But alarm bells rightly ring when obvious uncertainties are presented with finger-wagging authority. We really were told, no doubt about it, that BSE could not spread from cows to people. Those who remained cautious might claim yet another triumph, albeit hollow, for common sense.
The final reason for public disaffection again dates from the 17th century. Thomas Hobbes said (with a little extrapolation) that nobody should do anything that affects anybody else, without a mandate. It would be fine for companies to grow GM foods in Suffolk, say, if the people of Britain had specifically invited them to do so. Failing such spontaneous expression of public desire, those who aspire to grow these crops should explain what they want to do, and why, and then ask permission. But nothing like this happened. The GM crops were planted, and when people at large said "Hang on a minute!", the companies declared that the protesters were fools (and vandals), and the government queued up to hold their coats. (Jack Cunningham, then the agriculture minister, looked very stern on the telly.) The risk is very small, we were told, with echoes of BSE. Actually, though, the risk is unknown and in detail unknowable, which is a different matter; and even if it is small, there is no obvious need to take any risk at all, so we would rather you didn't, if you don't mind.
So what might restore people's faith in scientists? After nearly four centuries of recognisably modern science, the outstanding task is to prise it loose from the capitalist loop in which it has grown up. Contrariwise, we still need to find politically and economically acceptable ways to pay for the kind of science that addresses the real needs of humanity. For the past few centuries, science and money have run as a free-wheeling, self-propelling engine that societies at large can hop aboard if they are lucky, and are crushed by if they are not. As the world grows more crowded and resources dwindle, that won't do.
Bizarre and even blasphemous though it may seem in this age of new Labour, it looks as if we're going to have to reinvent socialism: the broad idea of public expenditure for public good. But it will still be wise to treat all experts with extreme caution.
Colin Tudge's book The Variety of Life: a survey and a celebration of all the creatures that have ever lived is soon to be published in paperback by Oxford University Press (£14.99)