User talk:Filll/homeopathypotencyrewrite

Three potency scales are in regular use in homeopathy. Hahnemann created the centesimal or "C scale", diluting a substance by a factor of 100 at each stage. The centesimal scale was favored by Hahnemann for most of his life. A 2C dilution requires a substance to be diluted to one part in one hundred, and then some of that diluted solution is diluted by a further factor of one hundred. This works out to one part of the original solution mixed into 9,999 parts (100 x 100 -1 ) of the diluent. A 6C dilution repeats this process six times, ending up with the original material diluted by a factor of  1,000,000,000,000. (100 &times; 100 &times; 100 &times; 100 &times; 100 &times; 100, or 1006). Higher dilutions follow the same pattern. In homeopathy, a solution that is more dilute is described as having a higher potency. Higher potencies (that is, more dilute substances) are considered by homeopaths to be stronger and deeper-acting remedies.

Hahnemann advocated 30C dilutions for most purposes (that is, dilution by a factor of 1060). A popular homeopathic treatment for the flu is a 200C dilution of duck liver, marketed under the name Oscillococcinum. Comparing these levels of dilution to Avogadro's number, a typical 12C homeopathic dose might contain on average only about one molecule of the original substance. Similarly, the chance of a single molecule of the original substance remaining in the same size dose with a potency of 15C is about one in a million, and about one in a trillion trillion trillion (1036) for a 30C solution.

Commonly, critics of homeopathy, as well as homeopaths themselves, attempt to illustrate the dilutions involved in homeopathy with examples. Hahnemann is reported to have joked that a suitable procedure to deal with an epidemic would be to empty a bottle of poison into Lake Geneva, if it could be succussed 60 times. Another example given by a critic of homeopathy states that a 12C solution is equivalent to a "pinch of salt in both the North and South Atlantic Oceans",  which is approximately correct. One third of a drop of some original substance diluted into all the water on earth would produce a remedy with a concentration of about 13C. Another common illustration involves comparing homeopathic dilution to dissolving the therapeutic substance in a swimming pool. One example inspired by a problem found in a set of popular algebra textbooks states that there are on the order of 1032 molecules of water in an Olympic-size swimming pool and if such a pool were filled with a 15C homeopathic remedy, to have a 63% chance of consuming at least one molecule of the original substance, one would need to swallow 1% of the volume of such a pool, or roughly 25 metric tons of water.

For further perspective, 1 ml of a solution which has gone through a 30C dilution would have been diluted into a cube of water measuring 1,000,000,000,000,000,000 metres per side, which is about 106 light years. Thus, homeopathic remedies of standard potencies contain, almost certainly, only water (or alcohol, as well as sugar and other nontherapeutic ingredients). Homeopaths maintain that this water retains some "essential property" of the original material, because the preparation has been shaken after each dilution. Hahnemann believed that the dynamisation or shaking of the solution caused a "spirit-like" healing force to be released from within the substance. Even though the homeopathic remedies are often extremely diluted, homeopaths maintain that some healing force is retained by these homeopathic preparations.

Some homeopaths developed a decimal scale (D or X), diluting the substance to ten times its original volume each stage. The D or X scale dilution is therefore half that of the same value of the C scale; for example, "12X" is the same level of dilution as "6C". Hahnemann never used this scale but it was very popular throughout the 19th century and still is in Europe. This potency scale appears to have been introduced in the 1830s by the American homeopath, Dr. Constantine Hering. In the last ten years of his life, Hahnemann also developed a quintamillesimal (Q) or LM scale diluting the drug 1 part in 50,000 parts of diluent. A given dilution on the Q scale is roughly 2.35 times its designation on the C scale. For example a remedy described as "20Q" has about the same concentration as a "47C" remedy.