Comment: When science facts become science fiction

AFTER A week of claim and counter-claim over genetically modified food, the public may be forgiven for feeling a bit confused. First we had the British Medical Association (BMA) saying it wanted a moratorium on growing crops because of the risks to the environment, then we had the Royal Society denouncing the research into GM potatoes that started it all. Finally, we had the Government's Chief Scientist, Sir Robert May, suggesting that commercial crop-growing should go ahead only when everything is shown to be safe for the environment - which may or may not be the moratorium the Government has refused to accept - but that GM food itself is safe.

The spin doctors within the Government are no doubt rattled about losing the public relations battle over GM crops and food, which is why they prepared a media offensive spearheaded by tame scientists willing to go on the radio to defend the Government's line. With so much at stake, and so few signs of a consensus on the GM issue, we might ask why we should believe any scientist who works in this controversial area. In fact, some might go as far as to ask why we should believe in science at all.

If someone were to knock on the door of your house tomorrow morning and offer you the elixir of life, you would most probably decline the kind offer. Yet scientists offer us different elixirs of life all the time, from new treatments for cancer to little blue tablets for curing male impotence. Why should we believe scientists any more than we believe the pedlars of snake oil?

One reason is that scientists are expertly qualified, but this is a vague term that needs some explanation. The BMA is a body of experts. But in my non-expert opinion its views on GM crops are no more and no less worthwhile than mine. The BMA - which is effectively a trade union for doctors - has expertise in certain areas of health, but it is quite out of its depth when it comes to commenting on the environmental risks of GM crops. Last week the BMA was shamelessly using its position as an expert body to cast judgement on something outside its remit and, judging by the headlines, it worked.

Real scientists recognise the limitations of commenting on areas outside their specialism, which is why the most trustworthy ones often stick rigidly to what they know. However, expert qualifications on their own are not enough to prove the credibility of a scientist. Scientists are also supposed to be independent of outside influence, particularly of a commercial nature. A Monsanto scientist saying that GM food is safe is not quite the same as a scientist from a university paid to investigate the same issue with public money saying so. This distinction between private and public research was well-defined 20 years ago, but Mrs Thatcher's drive to make academics more market-aware has blurred the distinction. Many eminently trustworthy scientists from university and government laboratories now have to look for industry funding to carry out their work, making it more difficult for them to be seen to be free of vested interests.

This makes them an easy target for environmentalists who have argued that much of the research into genetic engineering, even within universities, is funded by commercial organisations. This also causes problems for those scientists who become government advisers. Without such funding, they cannot conduct the very work that provides them with the expert credentials to make them worthwhile advisers in the first place. They are damned if they take private funding, and out in the cold if they don't.

But independence is not all there is to scientific trustworthiness. Publicity is another potential killer of a scientist's credentials. Arpad Pusztai, the researcher whose GM potato experiment was rubbished this week by the Royal Society, now knows the downside of making announcements through the media before getting them accepted by peer-reviewed scientific journals. Yet the desire for publicity is a real dilemma for scientists, who are expected to be media-friendly in order to further the understanding of science by the public who pay their wages.

Every scientist knows that science is science only when it is published in a reputable scientific journal, and even then experimental results may fail to stand the test of time. Evidence of life on a Martian meteorite - announced in a blaze of publicity in 1996 - took the world by storm, but the caveats really became apparent only when the work was published in the journal Science. Over the following two years, other scientists produced equally convincing evidence that the meteorite researchers might have mistaken the extraterrestrial "life forms" for Earthly contamination.

The essential difficulty with science is that it is difficult. Experimental findings can sometimes be wrong for the right reasons and new evidence can always come along to overturn accepted dogma - Dolly is living proof of that. In a world that increasingly looks for simple answers to difficult questions, the need for the public to understand science, and for scientists to understand the public, has never been greater.