I have written on the subject of homeopathy a number of times before and it’s elicited some pretty ferocious responses. Not to be deterred, I thought no science blog could be complete without some comment on what is, in my opinion potentially one of the most perniciously dangerous piece of pseudoscience out there.
Very briefly, homeopathy is a form of alternative medicine that takes a substance which causes similar symptoms to some disease or ailment, then hugely dilutes that substance in the belief that it will then act as a therapy. To give an example, the common cold causes a dripping nose and running eyes. Onions also cause similar symptoms. Therefore the common cold can be treated by taking an extract of onion and diluting it typically by a factor of 10 followed by 60 zeros (ie one part onion to 1060 parts water). This dilution in the language of homeopathy is called 30C, because it is diluted a hundred-fold, thirty times. Of course at such a huge dilution there’s not a single molecule of anything from the onion left, which means that the homeopathic remedy is actually just water. To illustrate how dilute this is, the Earth contains an estimated 1050 atoms and so a 30C dilution would statistically be about ten billion times more dilute than one atom in the entire planet.
So what’s the harm if some gullible people want to spend their money on rather expensive water? If homeopathy was confined to treating running noses, then perhaps that’s not so bad. The trouble is however, that homeopathy has been advocated for much more serious conditions such as haemophilia, Aids, a replacement for vaccination and recently in the treatment of ebola. There are homeopathic organisations that are careful in what they recommend and some even say that homeopathy should not replace regular medication. I’ll give credit for an attempt at ethical behaviour, but not all homeopaths are so moral. Many homeopaths are also claiming that homeopathy is good science, and by inference all the genuine medical researchers in the world are bad scientists. Believe me homeopathy is not science by any definition of the word but this does not stop the proponents of homeopathy from attempting to sound scientific.
The counter argument for homeopathy has focused on the huge dilution factors. Skeptics point out that the idea that something can become pharmacologically more potent the more it is diluted contradicts the laws of physics, chemistry, biology and just about any other legitimate science. Homeopaths respond by quoting a theory that water has a memory of the starting material, although this has never been convincingly demonstrated. Homeopaths point out that it’s not just dilution that’s carried out but there’s a particular way the dilution-vial has to be struck in a process they call “succussion”. The physics behind succussion remains unclear.
There are numerous clinical studies that have looked at homeopathy. The homeopaths will select those that claim to show efficacy, science will look at all the data and conclude there is no effect. For my part, I don’t find the clinical studies that helpful as the very premise of homeopathy is so utterly scientifically implausible in the first place. And for my money, although the theory of increased dilution leading to increased potency is absurd, this does not actually deliver the homeopathic coupe de grass. There is another aspect of homeopathy that is strangely often overlooked and that is the idea that a substance that causes similar symptoms to some ailment is going to be an effective cure. This is what’s known in homeopathic circles as the law of similars.
Let’s imagine that a scientist with the combined mental acuity of Newton, Einstein and Feynman won the Nobel Prize by showing that water did indeed have a ‘memory’. Homeopathy proven, right? Well no, because it still doesn’t explain how (to use the above example) onion was selected as a remedy for the common cold based upon the fact that both are symptomatic of a runny nose. Back before it was known that germs caused disease, back when leeches were state of the art medicine, back when people died of what we might consider minor ailments today, there was a belief that there were ‘signposts’ placed in nature to guide the physician towards the right cure. Plants with heart-shaped leaves, for example, could be used to cure cardiovascular disease. If you are not familiar with the mushroom Phallus impudicus then Google an image and take a guess as to what medical condition it might be used for. These were the origins of the law of similars based upon medieval superstitions. Samuel Hahnemann continued with those traditions and applied the law of similars when he invented homeopathy in 1796. The idea that the shape of a plant directs a physician towards its therapeutic use is not part of modern science in any respect. Neither is the idea that because some substance in high concentration causes symptoms similar to those of a particular disease, then it can be diluted out of existence to cure that disease. It is no different to preparing a potion of mandrake and eye of newt whilst saying the magic words “expecto patronum", in a Harry Potter fantasy. Those that argue against homeopathy seem to focus on the ridiculousness of the dilution but not so much on the ridiculousness of the law of similars. I am not sure why because either one of these hypotheses invalidates homeopathy as a science but the two together are synergistic.
Some homeopaths will provide lists of credentials (sometimes rather dubious) and lists of celebrities and other famous people who believe in homeopathy. Some will pepper their narratives with the language of science. Some become indignant and fire off salvos of ad hominems at their critics. Some even just make stuff up in order to try and win the argument. Not all homeopaths do this and many may genuinely believe in what they do, but none of these things makes it real, none of these things makes it science.