GREAT PIECE by Amit Varma about homeopathy:

I won't do a detailed debunking of homeopathy here. For that, I refer you to books like Ben Goldacre's Bad Science and Simon Singh & Edzard Ernst's Trick or Treatment, as well as this classic talk by James Randi. To summarise, the methodology of homeopathy makes no sense whatsoever, and scientific trials, when carried out with proper rigour, have shown homeopathic medicine to be no better than placebo, the standard for judging the efficacy of any new medicine.

The most bizarre thing about its methodology is the composition of the medicine itself. In homeopathic medicine, the substance being used to treat a patient has to be so diluted that there is generally not a chance that a single molecule of the substance remains in the medicine a patient is taking. In Randi's video, for example, he displays a homeopathic sleeping aid that contains, as its active ingredient, caffeine. (Homeopaths believe that the substances that cause a particular condition should be used to treat it. Go figure.) The dilution of the caffeine in the medicine: "10 to the power of 1500."

Randi asked the maths writer Martin Gardner if there was a way of explaining to the layman how much that really was. Gardner explained, "That's equivalent to taking one grain of rice, crushing it to a powder, dissolving it in a sphere of water the size of the solar system, with the sun at the centre and the orbit of Pluto at the outside, and then repeating that process 2 million times."

In Bad Science, Goldacre offers another analogy: "Imagine a sphere of water with a diameter of 150 million kilometers (the distance from the earth to the sun). It takes light eight minutes to travel that distance. Picture a sphere of water that size, with one molecule of a substance in it: that's a 30c dilution."

By these standards, there are so many impurities in regular drinking water that we are probably being treated for every major disease anyway.

Read the rest. And if you have 15 minutes to spare, don't miss the video of Randi's conference linked above. It's worth it.