Trust in scientific experts has declined. However, if we don't trust science, we risk putting our faith in something far more dangerous, argues Dick Taverne
'Why is it that people ignore scientific evidence in much of their daily lives? Consider the popularity of alternative medicine. Some 40 per cent of general practitioners in Britain now offer complementary therapies as part of their services and many are qualified homeopaths.
In fact homeopathy is nonsense on stilts. It was founded on the proposition that "like cures like", for which there is no evidence, and since this involves treating patients with toxic substances that can poison them, a second law was invented, the law of infinitesimals. This states that the more a substance is diluted, the greater the benefit. A dilution to the power of 30 is standard, that is, one part to 1,000,000,000,000,000,000,000,000,000,000. None of the original substance remains and any success is achieved through the placebo effect.
Organic food is another case in point. It is promoted by intensive propaganda, assisted by supermarkets that benefit from its premium prices, and its virtues are accepted by restaurateurs and lifestyle magazines.
Yet claims made for it have been consistently rejected for lack of scientific evidence. However, its supporters do not need the support of science, claiming "the current tools of understanding that are available to the scientific community are not sufficiently well developed" to measure the merits of organic farming.
Many buy organic food because they wish to avoid pesticides. They believe there is an increased incidence of cancer caused by chemicals in the environment and residues in food. In fact our food is safer than before. Permitted levels for pesticide residues are rarely exceeded and are set far below safety levels.
Elsewhere, the campaign against transgenic crops is not based on scientific evidence. Although genetically modified crops are now cultivated on over 70m hectares in 18 countries, there has been no evidence of harm to human health or to the environment. GM food is subjected to far more rigorous safety tests than many traditional ingredients of our diet.
Why have popular belief and scientific fact diverged, and why are people so reluctant to apply scientific knowledge to their own behaviour? First, trust in experts has declined. Tragedies associated with thalidomide and BSE inspired widespread mistrust, especially in government experts, and a suspicion that they often cover up uncomfortable facts. Hence the reaction by parents in the UK against the triple mumps-measles-rubella vaccine, greatly stimulated by the media.
Second, the success of science has itself led to increased anxiety. Since vaccination and antibiotics have stopped us dying from so many diseases, people have no experience of smallpox, whooping cough or measles and can afford to believe vaccination is a dangerous interference.
A more serious explanation of the current malaise lies in the rise of the environmental movement and the pervasive influence within it of a dogmatism based on the belief that modern technology adversely affects our relationship with nature.
During the 1970s, pressure groups such as Greenpeace and Friends of the Earth played an important role in rousing public opinion from complacency about environmental degradation. But as the environmental movement has grown in influence, it has become more fundamentalist. The trashing of GM crops during field trials showed that the campaign against them had become a crusade and that Greenpeace has become impervious to evidence. When the huge international success of GM cotton cultivated by six million small farmers is denied and the potential benefits of crops like golden rice are ridiculed , it is clear that dogma prevails over reason.
Because its cause, saving the planet, is noble, the new faith has much popular appeal and support among the media. If the new religion spreads, much of the progress that science brings could be jeopardised.