As much as it riles up proponents of science-based medicine like myself, homeopathy can be a great teaching tool. But most of the time this opportunity is squandered. Articles, lectures, papers, and talks critical of homeopathy quickly skip over the chemistry and the math that makes the philosophy so implausible. “The molar limit,” is casually thrown out as the smoking gun, but guessing that most people haven’t had a chemistry class after high school, this is potentially as bad as simply stating, “Water has memory.” What is more important is the why, the how, and of course the math.
I believe that you won’t get at an entrenched audience simply sounding the bulls**t claxon; you have to build upon the scaffolding most people already have, and work your way up to the skeptical position. In communication research, this is called schema theory, and it predicts that new information is best understood when you have some prior framework to understand it with.
As Phil Plait said, “If you teach a man to reason, he will think for a lifetime.” Likewise, I believe that if you teach someone the reason why homeopathy can’t work, it is much more powerful. To that end, and just in time to dovetail with Steven Novella’s homeopathy debate, I aim to provide a neutral explainer below focusing on chemistry of homeopathy’s main claim—high dilution equals high potency.
So what is the molar limit? What is Avogadro’s number? We have to start with the basics.
In the early 19th century Italian scientist Amedeo Avogadro proposed the idea that the volume of a gas is proportional to the number of molecules or atoms in that gas, regardless of its state (temperature, pressure, etc.). Fill a balloon with a liter of helium, as the theory goes, and you would be able to figure out how many helium atoms are inside.
This formed the basis for the mole; a unit describing how many elementary particles (molecules, atoms, or ions) are in some standard amount of stuff. That standard was made to be exactly 12 grams of carbon-12 (a form of carbon with 6 protons and 6 neutrons). So, one mole of carbon-12 equals 12 grams.