Voodoo 2: Homeopathy
(This column was first published in the March 27, 2000 Buffalo News.)
Just over 200 years ago Samuel Hahnemann proposed the two ideas that undergird homeopathy, an alternative medicine that continues to be practiced today: (1) his law of similars -- "like cures like" -- and (2) his law of infinitesimals -- "less is better." In fact, recently the German health minister said of this practice: "Although there have been many attempts to prove otherwise, the success of homeopathy cannot be denied."
Indeed. I find the minister's statement ridiculous after reading Robert Park's careful analysis of this pseudoscience in his book, Voodoo Science (to be published in May by Oxford University Press.) Park is a University of Maryland physicist who also represents the scientific community in our nation's capital; last Saturday he spoke here at the Center for Inquiry--International. I follow Park's exposition in much of the remainder of this column.
First, let us see what those two homeopathic fundamentals mean. According to the law of similars, substances that produce a certain set of symptoms can also cure those symptoms in someone who is sick, even though those substances may be highly toxic. According to this principle, for example, the homeopathic cure for a poison ivy rash is the application of Rhus toxicodendron, a tincture made, according to one homeopathy text, "from fresh leaves of poison ivy picked during the night when they are at their most poisonous."
Here is where the second law comes in. The tincture is diluted, in this case by what is denoted as "6c". The "c" means 100 and the original liquid is mixed with 99 parts of dilute alcohol or water. This is shaken thoroughly and the process is repeated to a total of 6 times. Some straightforward math shows that the "poison ivy" part of the mix is now only 1 part in 1,000,000,000,000.
This is more reasonable than applying poison ivy directly to cure a poison ivy rash or, for that matter, any of the other complaints for which it is recommended: blisters, diaper rash, osteoarthritis, and rheumatism. Clearly this dilution process would reduce the side effects of the original poison and it might even serve in some way -- perhaps by stimulating the body's defenses -- to alleviate symptoms.
But Hahnemann and his followers went too far. Many of the prescribed dosages for toxins like aconite (the hunting arrow poison), belladonna (deadly nightshade) and gelsemium (a Carolina jasmine extract that causes paralysis) are 30c. That would mean one part toxin to the number represented by a 1 followed by 60 zeros. (You could read that number as one trillion trillion trillion trillion trillion.)
By one of those odd historical coincidences just one year before Hahnemann published his theories, an Italian physicist named Armedeo Avogadro introduced a fundamental chemical constant so important that every chemist knows Avogadro's number and how it is applied. And applied here it means that the chance of still having one molecule in the final dilute is essentially zero. As they say, the baby has been flushed out with the bath water.
This is where the sad side of homeopathy turns up. Faced with this fact, practitioners claim that the solute, even though it no longer contains the original material, remembers it and thus retains its power.
I cannot resist quoting Park here: "The standard homeopathy joke concerns the patient who died of an overdose after taking ordinary water by mistake."
Clearly homeopathy is an example of what researchers call the placebo (sugar pill) effect in action: "If you think it will cure you, it may indeed do just that."
Another case of voodoo science good only for April fools.-- Gerry Rising