Note: The James Randi Educational Foundation (JREF) is publishing a new series of e-books. The first two offerings are an excellent new book on critical thinking by Bob Carroll, Unnatural Acts, and the first in a planned series of republications of classic skeptical works, Homeopathy and Its Kindred Delusions, by Oliver Wendell Holmes. I was asked to write the introduction for the latter, and the JREF has kindly given their permission for me to reproduce it here.
The German philosopher Hegel said, “We learn from history that we don’t learn from history.” “Homeopathy and Its Kindred Delusions” is a remarkable little book based on two lectures Oliver Wendell Holmes gave in 1842. It is a masterful debunking of homeopathy. If his lessons had been taken to heart, homeopathy would not have survived and we could have avoided a great number of other medical delusions that continue to plague us today, both from charlatans and from well-meaning advocates who lack Holmes’ critical thinking skills.
To realize just how remarkable this book is, imagine the world of 1842. Samuel Hahnemann, the inventor of homeopathy, was still alive. Roentgen wouldn’t discover x-rays until 1895. The germ theory was not yet established. Semmelweis wouldn’t make his observations on puerperal fever until 3 years later. It wasn’t until 1854 that John Snow removed the Broad Street pump handle and stopped a cholera epidemic. Koch’s postulates for determining infectious causes of disease weren’t published until 1890. Doctors didn’t wash their hands or use sterile precautions for surgery. Bloodletting to “balance the humors“ was still a common practice. The randomized placebo-controlled trial wouldn’t appear for another century. Contemporary medicine often did more harm than good. In fact, Holmes himself famously quipped “I firmly believe that if the whole materia medica could be sunk to the bottom of the sea, it would be all the better for mankind and all the worse for the fishes.”
Oliver Wendell Holmes did not have any of the advantages of modern medical science, but he did have a good brain and knew how to use it. He begins by saying that stories of cures are of little value because of the fluctuations of disease and the fallacies of observation, a lesson that today’s proponents of questionable treatments have yet to learn. We are constantly having to tell them that the plural of anecdote is not data and that even the most intuitively obvious medical beliefs must be tested. Holmes points out that ineffective treatments commonly appear to benefit patients through an influence on their imaginations, but advocating them is as deceptive and unethical as passing counterfeit money.
In his first lecture, Holmes reviews four nonsensical treatments to illustrate “the fallacy of popular belief and the uncertainty of asserted facts in medical experience.” The kings of England used to touch people by the thousands to cure scrofula, the weapon ointment was applied to weapons to heal the wounds they had caused, the estimable Bishop Berkeley promoted tar-water as a panacea for everything from smallpox to asthma, and patients were stroked with metallic rods, Perkins’ tractors, to relieve a variety of symptoms. These delusions were widely accepted over varying periods of time by the public, by respected clergymen, and even by doctors.
He explains why so many people were so easily fooled. Testimonials were called “facts,” and fallacious arguments were believed. The same arguments are being used today: “I know it works because I saw it with my own eyes,” they laughed at Galileo, doctors are suppressing a cure in order to protect their livelihood, we shouldn’t reject something just because we don’t understand how it works, science doesn’t know everything, the proponents couldn’t be wrong because they are benevolent people who treat the poor gratis, etc. People often do believe ineffective treatments made them better. Sometimes the natural course of their disease would have resulted in improvement without any treatment. Sometimes they “cheated themselves into a false and short-lived belief that they were cured.”
With this foundation, Holmes proceeds in the second lecture to an examination of homeopathy. Homeopathy began in hostility, claiming that all existing medical knowledge was false and inventing the term “allopathy” to denigrate medical practitioners who were not homeopaths. Holmes shows that homeopathy had already failed a number of simple tests, and there is no point in further testing: history shows that experiments disproving delusional medical practices achieve nothing because they are always explained away by true believers.
There are three basic doctrines in homeopathy:
1. “Like cures like:” the proper medicine for a disease is one that produces the symptoms of the disease in healthy people. Holmes stresses that this is different from “same cures same.”
2. The Law of Infinitesimals: homeopathic preparations are diluted by an elaborate process and the strength supposedly increases with the dilution. Holmes explains that a 12C dilution contains only one quadrillionth of the original substance. When Avogadro’s number later came into use, we could calculate the minuscule probability that even a single molecule remained; but even without Avogadro, Holmes was able to show that the amount of liquid required to directly make such a dilution would be impossibly huge.
3. Hahnemann claimed that “psora” or itch was the cause of seven eighths of all chronic diseases, everything from insanity to scoliosis. Even many of his own followers have rejected this doctrine.
Holmes points out that “Many persons, and most physicians and scientific men, would be satisfied with the statement of these doctrines, and examine them no further. They would consider it vastly more probable that any observer in so fallacious and difficult a field of inquiry as medicine had been led into error, or walked into it of his own accord, than that such numerous and extraordinary facts had really just come to light.”
Homeopathy just begs to be ridiculed, but Holmes tries to avoid ridicule and seriously examine the claims. He asks how likely it is that any single individual could have made three such unconnected momentous discoveries and overturned all other medical knowledge. He shows that the laundry lists of symptoms listed in the homeopathic Materia Medica and used to guide selection of remedies include irrelevant normal sensations that everyone experiences. He presents evidence from those who have experimented with the remedies and failed to substantiate Hahnemann’s claims. He critiques Hahnemann’s citations of earlier authorities whose writings supposedly supported homeopathic principles. He shows that comparisons of homeopathy with vaccination and treatment of frostbite are false analogies. He shows the fallacy of reporting success rates of homeopathy without comparison to patients treated otherwise and the fallacy of attributing every recovery to the homeopathic remedy itself. He shows that published case reports of homeopathic cures are nothing but meaningless propaganda. He exposes special pleading and the error of attributing a cure to homeopathy when other concomitantly given treatments probably deserved the credit. He mentions the meaninglessness of popular endorsements of homeopathy, for instance by the nobility in Britain, which unfortunately persist to this day in the form of the very gullible alternative medicine advocate Prince Charles.
He expected homeopathy to eventually break up and disappear, and he conjectured about how that might happen. He says “If it should claim a longer existence [than Perkins’ tractors], it can only be by falling into the hands of the sordid wretches who wring their bread from the cold grasp of disease and death in the hovels of ignorant poverty.” Holmes did his best to combat the harmful delusions of homeopathy, and to teach his readers how to think about medical claims in general. Alas, his effort was a drop in the bucket that had no chance against the power of human credulity.
This book is a classic. It speaks as clearly to our needs today as it did to readers in 1842; and its approach to critical thinking about medical claims is even more important today than it was back then, because we are flooded with vast amounts of misinformation through the Internet and other media. If his language is a bit convoluted for modern tastes, it offers unique pleasures: it is studded with gems in the form of delightful turns of phrase. Read, think, and enjoy!