It is fashionable to blame the media for the public face of science - but the public clearly yearns to be alternately alarmed and reassured and to be given quasi-evangelical causes. To be newsworthy, biology has to be crusading, frightening or reassuring. If the media are tempted to titivate biology, it is only because most people would otherwise find it boring. Given this, can we be certain that scientific truths are being fairly presented by the media? Can we even be certain that there are scientific truths in the first place? Perhaps the science itself is so unreliable - so fragile - that it does not merit our emotional energy, a simple case of much ado about nothing. The science itself could be faulty, nobody yet knowing the real truth. Or there could be pressues so great that neither scientists nor media are putting truth above all else.

Biology is a science, and in science mistakes are not really mistakes. Current truths are nothing of the sort; they are merely the best contemporary insight into a situation. And no matter how logical such insights might seem, they exist only for as long as it takes new research to prove them wrong. As a science, biology need have little concern for these mistakes; the mistakes of the past are simply stepping stones to the truths of the future. But to everybody else - all those who depend on biological advice to organise their lives and safeguard their health and future - such mistakes do matter.

So how good is the science behind the media hypes of our times? If such a major mistake as Thalidomide can have been made so recently, what are the chances that mistakes are also being made now?


It isn't at all surprising - with such a difference between our evolved state and modern life - that skin cancer is on the increase. The question though, is whether the whole package of 21st century life is to blame or whether in the extensive list there is one main culprit.


One suggestion is that a bout of depression tests the level of support available from a partner, extended family and wider society... a frequent thought in the mind of suicidal depressices is that their family would be better off without them. If this were ever true - that close kin really would benefit reproductively from the depressive's death - then even suicide could be evolutionarily adaptive. Apart from being unpleasant, though, all such hypotheses are untested and probably untestable.

Life events are not entirely random; some people are more prone to suffer trauma than others and in part the reason is genetic. Studies of twins suggest that about one-quarter of life events that twins experience even when living apart are linked to their shared genes. For examples, twins with depressive genes that attract them to drinking alcohol may be more likely to have car accidents or provoke fights than twins without those genes.

There is a long-standing link between alcoholism and depression... but do the genes for depression also chemically predispose a person to alcoholism? Or does depression drive a person to drink? Or does alcohol cause depression? Much more work needs to be done before we can unravel the true relationship between alcohol and depression.

Apart from the discovery that there is a genetic predisposition to depression, everything else is a collection of maybes. Maybe depression is on the increase, more common in Western societies, and is more common in women - but maybe not. Maybe it is cause by life events, low serotonin levels, and prescriptive and recreational drugs - but maybe not. And maybe treatments such as psychotherapy, antidepressants and ECT help patients come out of depression - but maybe not. Hard evidence is difficult, sometimes impossible, to obtain even in principle.


Good news! The world is getting warmer and the tropics are heading for the poles. The bleak northern - and southern - winters are soon to be banished to the textbooks of climatic history. By the end of the 21st century, heating and clothing bills will be slashed and there will be no need to fly away for that holiday in the sun... of course, this isn't the hype surrounding global warming, though it could have been.

How good is the science behind the gloom? There are three main questions that we need science to answer: 1) is the earth really warming up?; 2) how much of the change, if any, is our fault; and 3) can we - or should we - change the future, anyway?

Since the last ice age ended about 10,000 years ago, the climate has been remarkably stable. The earth warmed by about 1 degree over about 400 years in medieval times between 950 and 1350 - the most balmy weather in recorded history. And in a mini ice age in the 17th century it fell by a similar amount. What caused the changes on these occasions is unclear - but it wasn't human activity. Evidently, therefore, the earth has been quite capable of warming up and cooling down without any help from us.

If we shut down all the world's power stations today, the cooling from their aerosols would virtually disappear within a week. But the greenhouse effect from past emissions of carbon dioxide would continue for many decades. The planet may have already reached the point where shutting down all the power stations would simply create a massive and entirely unpredictable convulsion in the atmosphere and its weather systems.

Scientists haven't yet found enough consistent evidence or powerful enough analytical tools to reach a consensus - even among themselves, let alone to convince self-interested governments and industries. There are two very good reasons for science's impotence over the matter: first, the situation is impossibly complex,a nd secondly, it defies proper scientific study. There cannot be experiments, or controls. All analyses and interpretations depend on correlation - or correlations or correlations.

Frustratingly, the most prudent course of action is probably the one least likely to win votes: to wait and see, or prudent inertia.

Will our great-great-grandchildren live in a climate very different from ours? If so, will change be a balmy source of pleasure to them, or will it make their lives hell? We cannot tell whether they will thank use or blame us. But the chances are that if we could look into the future and see their faces, they would simply smile back at us in wry amusement at how easuly we could be panicked by scientific hype.


The planet will continue until an expanding sun finally swallows it in 5,000 million years' time. Our actions are not killing the planet, they are not even making it unhabitable, but they are certainly changing it. The question we have to ask is whether that change is for better or worse - or whether it is simply change. After all, was the last mass extinction 65 million years ago a good event, a bad event - or just an event?

There is a good, if not better, a correlation - both historically and geographically - between fertility and life expectancy as there is between fertility and the use of modern contraceptives. In the early 1900s, without a contraceptive in sight, hunter-gatherer women, whose children had an excellent chance of survival, used to give birth, on average, to only three to four children. In contrast, when a woman fears that every child born is likely to die, she will have many - as in developed countries two centuries ago and as in many Third World countries today.


Modern humans probably eat nothing that has not been deliberately altered or that deserves the label 'natural'. There is little that is natural about a cow that can produce 10 gallons of milk per day.

It speaks volumes for the nature of the labelling argument that the demand is simply to have food marked as 'containing GM food' or not. The implication is that all GM food carries the same risks - both for human health and for the environment. This is blatantly untrue, which rather suggests that the demands for labelling are founded less on an understanding of the science behind Gm foods than on a question of principle: any tinkering with genes must be bad.

Consumers want reassurance that GM foods are safe. This is a tall order because such reassurances cannot be given for any food, even those conventionally produced. Kidney beans are toxic; so are parts of crab. Dozens of people die each year from the cyanide in peach seeds. Some people die from eating peanuts. The best that scientists can aspire to over the new produce is to offer reassurance that any new GM food is no more dangerous than the non-GM versions that went before. This isn't easy either. If something is only toxic in large amounts such a test is almost impossible.
The only convincing reassurance - or otherwise - will finally come from the massive nationwide experiments on the people and environments of the US and China.


For the moment, conditional genes resist the conventional methods of investigation; their heritability cannot be estimated. The genes that show up in heritability studies are dictator genes - they force a trait on people irrespective of their environment or their experiences. Conditional genes show up in twin studies as either shared or unique environmental effects. They could be sets of genes that can be switched on and off in different combinations by environmental triggers. It seems that identical genes can orchestrate even the differences between identical twins.


The intention of this book was neither to cheer nor depress but to illustrate simply that biology, as a science, is fragile. Fragility has many causes. The most common arises from one of the favourite statistical tools for scientific investigation: correlation. All too easily, correlations masquerade as cause-and-effect. Controlled experiments should be the most robust of scientific tools - but are sometimes no more than correlations in disguise.

It is very difficult to experiment on humans, and just because something seems safe when tested on rodents doesn't mean it will inevitably be safe when given to humans. Other species often seem to have unique defences. Equally, just because something causes, say, cancer in rodents doesn't necessarily mean that it will do so in humans. Other species may have unique vulnerabilities.

An even weaker route to scientific proof than correlation is the computer model. As a way of marshalling complex ideas and understanding interactions they are wonderful - but they do not prove anything. As anybody who has used such models knows, the desired answer is rarely further away than a tinkering with assumptions and formulae. Over the last two decades, the science of global warming has seen endless such tinkering, trying to make models fit data, yet still they produce only the crudest of approximations to the pattern of climate change during the 20th century. As a result, they prove nothing about what might happen in the 21st.

The media - the shapers of perspectives - are the biggest cause of science's fragility. They can destory good science and promote bad without any real conscience or comeback. After all, it may be twenty years before anybody knows whether the media's slant was justified or not - and they have a job to do: not only 'to inform the public' but to sell copies or improve ratings. Just like many scientists, the media find the short-term marketability of science far more important than its truth and accuracy.

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