Where a heretic prescribes, Nature derides

IMAGINE trying to perform a biological dissection of a rat with a garden spade. The mental picture you have formed (my apologies if you're reading this over breakfast) provides a pretty good model for what happens to a complex scientific controversy when subjected to the blunt instrument of television. The best you're likely to end up with is a series of bloody chunks, trailing unanswered questions like . . . well, I won't pursue the analogy, as I'm starting to feel a bit queasy myself.

This isn't to say that the exercise is entirely pointless, just that it's worth keeping in mind that television is an unscientific medium. It can be a brilliant explicator of secure truths, but it doesn't really have the time to slog through the detailed figures and procedures that constitute the dull, heroic work of verification. So Heretics (BBC 2), a new series which examines the cases of scientists who have challenged orthodox opinion and suffered for it, is unlikely to do more than alert us to some problems.

The first case history was that of Jacques Benveniste, a French immunologist with an excellent reputation - until he claimed that he had experimental proof of the principles of homeopathy. The journal Nature, which has a literal power of imprimatur when it comes to scientific theories, took a dim view of this. They eventually agreed to publish his paper on the condition that they were allowed to review the laboratory's work.

In something of an own-goal, John Maddox, Nature's editor, appointed a journalist specialising in scientific fraud, the Amazing Randi, a magician turned hoax-buster, and himself to oversee the experiments. When it comes to homeopathy, I'll help you pile the wood around the stake and then lend you my Zippo to light it, but even I would have to concede that this line-up didn't look very much like impartial peer review. They found, unsurprisingly, that Benveniste's conclusions were mistaken and that his researchers had found what they wanted to find - a touch pot and kettle-ish given the circumstances.

Despite the attacks of French colleagues and threats to his livelihood, Benveniste continued his work, claiming that water has the ability to magnetically 'memorise' the molecular structure of drugs, even after billionfold dilutions. He also claims to have 'potentized' water down a wire ('One day we will get our drugs on the phone,' he said). These extraordinary claims were asserted against a coercive backdrop of bubbling glassware and flickering computer screens, but you couldn't, in the nature of things, be offered anything like scientific proof.

A thought experiment was possible, however. The hypothesis was this: Benveniste is right and has discovered a principle that has destructive consequences not only for much current orthodoxy (including the profits of conventional drug companies) but also for the reputation of his opponents. What might the response look like? Very much like what has happened, I would have thought. Paradigm shifts of this magnitude are as painful as resetting a bone without anaesthetic, and they provoke a belligerent defensiveness from defenders of the status quo.

Some of Benveniste's supporters regard the response to his theories as proof in itself, as if truth could be detected by the allergic reaction it provokes in the Academies. That's nonsense, and I will let my money ride on Dr Maddox and the teams who have been unable to replicate Benveniste's results. But Heretics, while it couldn't prove much, certainly proved that refusing to look isn't going to make any theory go away. Time and money is precious but even so science must suffer fools gladly, just in case, one day, one of the fools is right.