There is an ongoing debate between mainstream science (including conventional medicine) on the one hand and complementary medicine (including homeopathy) on the other.
This has taken on some of the flavour of the science vs religion debate, with anything that cannot be scientifically explained getting chucked on the ‘irrational beliefs’ pile. There is consequently a prevailing idea that homeopathy is not proper medicine, because how it actually works cannot be explained scientifically. However, there is an increasing body of sound evidence that homeopathy works as an effective form of medicine for some illnesses. As it can be repeatedly observed to work, there’s definitely something going on with homeopathy – it doesn’t make sense to reject it as irrational just because it has yet to be fully understood.
The phenomenon of the ‘Law of Similars’ on which homeopathy is based has been observed in action for around 200 years, but scientific study of it did not begin in earnest until the past 20 years or so. Homeopathy, in other words, is an old art but a new science. There have been many years of systematic observation and recording of homeopathy in clinical practice, but the technology which enables detailed experimentation to investigate how it might actually be working is very new.
Conventional medical drugs can be described simply as chemicals that interact directly with the body’s biochemistry. As homeopathic medicines are too dilute to contain molecules of the original substances they are made from, we know that they don’t work in this biochemical way and must therefore have an entirely different mechanism of action. Detractors claim that homeopathic remedies are ‘nothing but water’ because they are so dilute, but it is now becoming clear that there are observable physical differences between homeopathically prepared samples and plain water or other solvents.
The process by which homeopathic remedies are made seems to imprint information from the active ingredient into the water it is dissolved in, so that even when there are no longer any molecules of the ingredient left, its characteristics remain in the water. This has become popularly known as the ‘memory of water’, and research is now investigating the idea of homeopathic remedies holding a form of information, rather than an active chemical, which can influence biological processes.
Some further reading:
An excellent summary of the current state of the scientific evidence for homeopathy by Dr Peter Fischer of the Faculty of Homeopathy
More information on recent scientific investigations into the action of ultra high dilutions from the Society of Homeopaths