Homeopathy is based on the idea that extremely tiny doses of substances that cause disease symptoms in a healthy person can alleviate similar symptoms in a sick person. Samuel Hahnemann (1755-1843), a German physician, was the first to apply this notion systematically. He also added what he called the "law of infinitesimals," the proposition that the smaller the dose, the more powerful the medicine. So he treated people with extremely diluted substances—so diluted that, in many homeopathic medicines, not even one molecule of the substance remained. Hahnemann acknowledged this fact but believed that the substances somehow left behind an imperceptible "spirit-like" essence, or memory, that effected cures. This essence was supposed to revitalize the "vital force" in the body.
The homeopathic hypothesis, then, can be stated as follows:
Extremely diluted solutions of substances that produce symptoms in a healthy person can cure those same symptoms in a sick person.This hypothesis is offered as an explanation of why people taking homeopathic remedies seem to get better. They get better because homeopathy works.
There is an alternative explanation for why people taking homeopathic remedies seem to get better:
People taking homeopathic remedies feel better because of the placebo effect. That is, homeopathy doesn’t work as advertised, but people think that it does because of the power of placebos (inactive or fake treatments).
The placebo effect is a very well-documented phenomenon in which people given a placebo respond with improvements in the way they feel. Placebos can have at least a modest impact on how people feel, especially their experience of pain. Because placebos can have an effect, they are used in all well-designed clinical trials (i.e., studies testing the effectiveness of treatments).
Which of these explanations (that homeopathy works or the placebo effect) is the best explanation for why people who take homeopathic remedies seem to get better?