The following correction was printed in the Guardian's Corrections and clarifications column, Saturday June 3 2006
In the article below, we underestimated the dilution process in homeopathy in saying that a substance labelled 6c would be 600 parts water to one part active substance. Each "c" dilution is 1:100, so a 1c mixture is 100 times weaker than the original but a 2c dilution is 10,000 times weaker, and so on.
Peter Fisher, clinical director of the Royal London Homeopathic Hospital and the man at the centre of this week's storm over alternative medicine in the NHS, blames Descartes.
Although he spends a lot of time arguing the scientific evidence for alternative treatments, it really does no good to separate out what is going on in the patient's mind from what is happening in their body, he says.
"Are they depressed because they are ill or are they ill because they are depressed? You get bogged down in sterile argument. Descartes is to blame."
This week the rationalists have turned some heavy firepower on what they say are scientifically unproven treatments provided on the NHS. Thirteen eminent doctors, led by Michael Baum, emeritus professor of surgery at the same Trust as Fisher - University College London Hospitals - urged that the NHS should not pay for alternative therapies.
The Royal London Homeopathic Hospital, recently reopened after a £20m refurbishment, is entirely NHS funded. Great Ormond Street children's hospital shares its building - you can tell the homeopathic corridors by their stimulating lime green paint and natural wood floors.
GPs and consultants refer patients there. It costs the NHS about £3.4m a year. And, says Dr Fisher, the 27,000 patients who come for homeopathy, acupuncture, nutritional therapy and other treatments it offers do well. But if he won't admit - as someone who studied medicine at Cambridge University and a conventional rheumatologist - that homeopathy is implausible, he does agree it is controversial.
In the pharmacy thousands of little bottles, exactly the same size and shape, are lined up ready for use. The theory behind homeopathy is treating a condition with a very tiny amount of what caused it - something like the vaccination principle.
The dilution varies. Dr Fisher picks up one labelled 6c - that is, 600 parts water to one part active substance. Another is 9c - 900 parts water. "As near as dammit there is no molecule in that one," he said. "But it works - absolutely."
Clear tubes full of tiny sugar pills are stored nearby. A couple of drops of the liquid go on each pill. The homeopath will prescribe how many such pills are to be taken each day.
"I know it's controversial," says Dr Fisher. "Part of what got me into this is sheer scientific curiosity. I thought, I'm going to be the one to crack this."
He hasn't cracked it, although, he says, "we have made a lot of progress." He cites studies that show people have got better in certain conditions with homeopathy.
His critics counter with studies that show they haven't. Could it be a placebo effect? He doesn't like the term. "I much prefer non-specific effect." But no - he is, he says, "an unapologetic homeopath" and believes something really happens.
It began for Dr Fisher when he went to China as a medical student at the tail end of the Cultural Revolution, when Mao was still alive and the Gang of Four were in control. "I saw a woman on an operating table with her entire abdomen open, talking to the surgeons, with three needles in her ear. I became convinced something very interesting was going on."
Upstairs a mass acupuncture session is being held, an experiment in cost-effectiveness. Patients recline on four of the eight day-beds with trouser legs and skirts rolled up, their knees stuck with metal pins attached to electrodes. All have arthritis. It is a condition for which there is good evidence that acupuncture works.
Three out of the four say they have less pain. "I used to get a burning sensation in my knee every day. That's finished. I don't like needles, but this reduces the swelling and everything," said Pamela Picking from Finchley, north London.
Mumtas Rizui from Golders Green, north London, trained as a chemist and says a surgeon friend made fun of him for coming. "But I say seeing is believing. It is helping me."
But Aqila Azhar and her husband Ilyas are unconvinced. Acupuncture did not help her knees - she preferred homeopathy. Mr Azhar said the recent questioning of homeopathy might be harmful. "If you go for any treatment, you must have faith like my wife," he said
Some patients travel long distances. Adam Frankel lives in Devon. He has a long history of illnesses that made him spend months in bed. The NHS had done nothing for him, he says. He arrived at the hospital about nine years ago with abscesses in his gums and has been taking a variety of homeopathic medicines since.
The remedies have helped him and his family - and, he says, even the cat.
