The Evidence

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Preface: This article was originally comissioned by a homeopathic group to be included in their literature as a balancing piece. Fourteen months after submission of the completed work, despite repeated enquiries, I had still heard nothing from them as to whether or not it is to be used so, having spent quite a while working on it, I decided to post it here rather than let it languish unread!


There are many reasons why much of the scientific community is sceptical of homeopathy most of which have been the subject of books, articles and papers virtually since homeopathy was devised by Hahnemann some 200 years ago. This essay will briefly explore some of the more common, current arguments and discuss some of the most prominent objections to homeopathy as a valid medical practice.

Mechanisms of action:

One point which receives a disproportionate amount of attention from commentators is homeopathy's various principles, mechanisms and laws.

Extreme dilution, despite its prominence in the debate, is only one of several difficulties which sceptics have with the principles of homeopathy; difficulties which would remain even if materially discernible 'active ingredients' were present in a remedy. The basis by which ingredients are selected, the ability of those ingredients to transmit their characteristics to a remedy and thence into a patient and the subsequent ability of those original characteristics to counteract symptoms and cure disease; all these things are fraught with inconsistencies and implausibilities which defy conventional medical and scientific understanding.

Signs and signatures: Homeopaths claim that certain properties of the principal ingredients are passed into the remedy during the process of manufacture. The why and how of this process present grave difficulties for the mainstream credibility of homeopathy.

A basic tenet of homeopathy is the 'Doctrine of Signatures' (Saxton and Gregory, 2005, p. 2) where for example the dandelion is held to be useful in cases of jaundice by virtue of having a yellow flower, regardless of the presence or otherwise of conventional medicinal properties. Another example is the use of rhino horn in Chinese medicine to improve male potency simply by virtue of its shape. Homeopathic examples would include apis mel, a diluted preparation of female bees which, when taken orally, is claimed to treat symptoms of burning, itching and swelling of a character that might be expected following a sting from a live bee. Proving (i.e. testing on a human volunteer) a remedy derived from a feather of the peregrine falcon reportedly produces an urge to whirl around in the way a soaring raptor does and causes dreams about raw meat, and the remedy derived from the plant Chelidonium majus, which has yellow juice, is believed to have an affinity for the liver and to be useful in cases of jaundice. There is no conventional logic in reasoning that the physical characteristics of any substance (shape, colour, behaviour etc) should determine their usefulness in treating disease.

Law of similars: Homeopathy maintains that substances which cause symptoms in healthy people can cure diseases that have those same symptoms.

If accounts of the various symptoms produced by remedies during a proving are accepted, as distinct from many other potentially unrelated sensations experienced, the next question is what is the mechanism by which a remedy is able to treat these same symptoms in a diseased patient. Even if (to continue with the example) apis mel produces swelling, burning and stinging in a healthy prover why should it follow that it is able to relieve those same symptoms in a sufferer? Why does the homeopath spend so long teasing out a multitude of symptoms from the patient in order to find the ‘simillimum’, the remedy which most closely matches those symptoms. Various analogies are used; the remedy is described as fitting into the patient's symptoms like a key in a lock, and mechanisms are proposed with, to give a few examples, the remedy supposedly filling 'holes' in the patient at molecular, quantum or energetic level, balancing the electromagnetic field of the patient, restoring the ‘vital force’ or boosting the immune system. But all these remain metaphor or speculation, no proven mechanism has yet been demonstrated. There is in fact no reason at all that remedies which allegedly produce a set of symptoms in a healthy subject should somehow 'cancel out' those same symptoms in a patient.

Law of infinitesimals: Homeopathy holds that the more diluted remedies are, the greater their effectiveness.

In current times any one who has studied the subject even superficially will concede that in most homeopathic remedies there are no discernible amounts of the original ingredient remaining. It is possible to find dozens of illustrations of these extreme dilutions involving imaginary water containers larger than the size of the known universe and so forth which make the point that, to conventional science, homeopathic remedies are indistinguishable from the diluents used in their manufacture. Yet homeopathy maintains that not only are such remedies effective but the more dilute they are the stronger they become.

Speculation about possible mechanisms for a ‘memory’ of water have, over the years included a spiritual force, electricity, molecular 'holes', molecular vibrations, the clumping of water molecules (a genuine phenomenon but one which last for nanoseconds only), “spallation”, so called "nano-bubbles", chaos theory and, most popularly, quantum physics. As with the principle of similars though, they remain metaphor or speculation; none are proven. In addition there has never been, in all these theories, any suggestion as to how remedies become more potent with increasing dilution as is claimed.

If the possibility that water has a memory is accepted, what then about dilutions which are made in other substances? A mechanism for the memory of alcohol and lactose also has to be proposed. Furthermore, how is it that the memory of water is selective, with only the imprint of the base ingredient retained and all contaminants forgotten? In comparison with the dilutions employed in homeopathic remedies the smallest impurity, even one stray molecule in millions of gallons, is still a massive level of contamination. Why is it then that during the process of serial dilution and sucussion the water retains the imprint, for example, of the bee but not the glass, the metal or the plastic, all of which will be unavoidably present?

Energy transfer: Even if these objections are set aside, other questions arise. How are the properties of the base ingredient translated into potency or energy and how is this then passed from the base ingredient into the water which is used to dilute it? How is this essence passed into each subsequent dilution in the absence of a chemical carrier or any known property of water which might allow such information to persist? How is this energy ultimately passed on to the prover or patient? Again, many theories abound but no firm explanation exists.

The concerns don't end there. Consideration now has to be given to the practice of 'grafting' commonly used to prepare homeopathic tablets. How is it that the properties of a liquid remedy can be passed on to an entire bottle of dry, inert lactose tablets by instilling a drop of liquid or a single potentised tablet into the bottle? Then, if the veracity of grafting, a signal being passed from liquid remedy to solid pillule, is accepted, why should it not be possible to isolate that signal from the remedy entirely and imbue it into electronic media (Benveniste, 1998) from where it can be transferred to a CD or a remedy making machine like the e-lybra or the voice activated remedy maker or even transmitted via a telephone message or email?

At this point many mainstream practitioners will consider that such examples and others, more esoteric still, such as remedies based on anti-matter or light from the planet Venus or meditative provings (which do not involve the actual taking of a remedy) or remedies prepared by writing the specifications on a piece of paper and placing it close to a container of plain water which then becomes the desired remedy; are simply too far fetched to be taken seriously.

This is no mere reasoning by reductio ad absurdum however and such “absurd ‘new ideas’... that only fanatics of a religious sect could adopt” (Vithoulkas, 2008) cannot be dismissed so easily. To the homeopathic practitioners employing such methods they are used with exactly the same conviction and sincerity as the classical homeopath employs his or her apis mel. To the critic too, they are no more or less unlikely than the doctrine of signatures or the laws of similars and infinitesimals as described above. How is a disinterested observer able to determine whether a remedy based on a dead bee is more or less plausible than one based on moonlight?

Taking the bait: When a sceptic takes issue with homeopathy's unorthodox underpinnings they are to an extent 'taking the bait' and leaving the way open to the counter charge that they are making a case which is purely theoretical, simplistically ignoring homeopathy's clinical applications and attempting to "damn the whole discipline out of hand" (Saxton and Gregory, 2005, p14) merely on the basis of 'argument by incredulity'.

It is not enough though for proponents simply to dismiss such objections, ad hominem, as being made by closed minded critics with Newtonian mindsets or those with vested interests or whatever. While not being the sole reason for the lack of acceptance of homeopathy by sceptical commentators, nevertheless the unlikely nature of its laws and their apparent contradiction of many well established real world principles make them an important hurdle which must be taken seriously by homeopathy's advocates.

If it wishes to be considered a science rather than simply an ideology, and if the wider community is to be convinced that it is homeopathy itself which produces results rather than any one of a number of other more plausible explanations (coincidence, mis-diagnosis, spontaneous resolution, regression to the mean and so forth), then any evidence in its favour must be particularly robust - more so than for, say, a new antibiotic.

This is not simply because of stubbornness or prejudice but because of a general epistemological principle known as the 'principle of simplicity'. This concept, which has profound relevance not just to science but to every day experience, is described most eloquently in a paper by Sehon and Stanley (2010). Put briefly, it states that "given two theories, it is unreasonable to believe the one that leaves significantly more unexplained mysteries". If the reader is interested in a serious consideration of the reasons science is so far unable to take homeopathy seriously then a careful reading of this paper will serve as an excellent starting point.

Another commentator on the same subject states "Principles of parsimony and simplicity mediate the epistemic connection between hypothesis and observations. Perhaps these principles are able to do this because they are surrogates for an empirical background theory... Once this theory is brought out into the open the principle of parsimony is entirely dispensible" (Sober, 2009, p. 739).

In other words, until homeopathy is able to demonstrate its underlying mechanisms convincingly and in meaningful terms, given the implausibility of its fundamentals as described to date, the principle of simplicity will always determine any claim that observed results are caused by (rather than merely associated with) homeopathy remains equally implausible. There will always be another, conventional, explanation which better fits those results.

So, to persist with our example of apis mel, the patient with persistent itching and swelling who recovers has almost certainly done so as a result of known, mundane factors - the activities of the immune system, improved hygiene, conventional medications or simply the natural waxing and waning course of the condition for example - rather than as a result of a remedy which depends for its action upon being able to pass some of the characteristics of a live bee via a solution devoid of content into a dry lactose tablet and then into the patient’s body where it will interact favourably by unknown means to resolve a specific set of symptoms. This is not to say that this is proof that apis mel has not caused the improvement, rather that there are other, more economical explanations which don't require the use of "unexplained, brute mystery" (Sehon and Stanley, 2010).

The use of evidence:

Despite its unorthodox foundations however, the main problem sceptics have with homeopathy is not its underlying principles. The criticism of those who argue against homeopathy purely because of its unlikely mode of action is, to an extent (the above arguments notwithstanding), justified. After all the medical world is replete with examples of things which are now commonplace in spite of the initial lack of a plausible mechanism or having faced scepticism by the mainstream community. To be fair though, the critic would counter that there are far larger numbers of practices which also had no plausible mechanism of action and faced scepticism and whose proponents were as convinced of their veracity as homeopaths are of theirs but which are now thoroughly discredited.

It is the attitude of the discipline of homeopathy to evidence, both scientific and clinical, that gives many commentators greatest cause for concern. Remarks from homeopaths such as "the only reason for conducting clinical trials of homeopathic substances is to demonstrate the efficacy of the homeopathic system to allopathic observers", such results being of "supreme indifference" to homeopaths themselves (Coulter, 1980, p. 155); "the ultimate test for a therapeutic system is a cured patient" (Saxton and Gregory, 2005, p24) and “No amount of placebo-controlled crossover trials is going to convince me that the effects of homoeopathy, which I observe daily in practice, are a delusion” (Gregory, 2003) all suggest that homeopaths are a priori convinced of the effectiveness of their discipline and that the purpose of the clinical trial is not to test homeopathy but to prove it. In every case it seems, personal experience in the field outweighs any number of research results. To quote the clinical director of the Royal London Hospital for Integrated Medicine, "[Randomised Controlled Trials] RCT's are unlikely to capture the possible benefits of homeopathy" (Fisher and Scott, 2001).

Personal experience however, is subjective and one of the least reliable ways of assessing whether or not a treatment has been effective. The ultimate aim of the scientific method is to eliminate errors of reasoning such as cognitive bias and the straightforward 'will to believe' but homeopathy uniquely, while still claiming to be scientifically based, prefers to rely on evidence from sources which virtually guarantee this type of error - the patient outcome survey and clinical experience. This is not to cast aspersions on anyone's wit or intelligence, it is simply to say that we are all human, and therefore fallible.

Clinically too it appears to the neutral observer that there are few if any outcomes which could persuade its practitioners that homeopathy was ineffective. A variety of alleged phenomena such as obstacles to cure, suppression, miasmatic influences and aggravation are all means by which virtually any change in the patient's status, whether for better or worse, can be rationalised to allow for the validity of homeopathy.

It is the sum of these attitudes, that there is apparently no foreseeable set of results either clinical or research based which would cause a homeopath to doubt the veracity of their chosen discipline, which has led many critics to accuse homeopathy of being essentially unfalsifiable.

Falsifiability is a fundamental scientific principal which states that for a hypothesis to have credence, it must be inherently disprovable before it can become accepted scientific proof (Shuttleworth, 2008). In other words if a thing cannot be disproved, it cannot be tested, and is essentially unscientific. The self confessed attitude of the homeopath to the scientific trial above indicates that the hypothesis 'homeopathy is effective' has stepped out of the realm of science and into the realm of ideology. This is why many commentators consider homeopathy to be ‘out of the game’ when it comes to science.


Science doesn’t claim to be perfect or to know everything. What it does do very well though is test claims to see if they work. It is self correcting in the long term so the inevitable mistakes which occur in the process (it is, after all, run by fallible humans) will eventually be weeded out to improve the accumulated body of knowledge. The changing nature of scientific applications such as medicine is a sign of strength of the system as things are adapted or even abandoned in the face of new evidence. But the one thing followers of any modality which claims a scientific basis must be prepared to do is to change their minds when the evidence warrants. So far the balance of evidence, however much its followers might suggest otherwise and no matter what discoveries are allegedly just around the corner, is that homeopathy’s effectiveness remains unproven and, at best, its remedies perform no better than placebo.


Benveniste, J., (1998), Understanding Digital Biology, DigiBio [online] [accessed 26/1/11]

Coulter, H.L., (1980), Homoeopathic Science and Modern Medicine, North Atlantic Books/Homeopathic Educational Services, Berkeley, Calif.

Fisher, P. and Scott, D.L., (2001) A randomized controlled trial of homeopathy in rheumatoid arthritis Rheumatology Vol. 40 pp 1052-1055 [internal link]

Gregory, P., (2003), Homoeopathy 'doesn't need proof' (letter) Veterinary Times Vol. 33, no. 22 pp 7-8

Saxton, J. and Gregory, P., (2005) Textbook of Veterinary Homeopathy, Beaconsfield Publishers ltd

Sehon, S. and Stanley, D., (2010) Evidence and simplicity: why we should reject homeopathy, Journal of Evaluation in Clinical Practice Vol. 16, no. 2 pp 276-281 [internal link]

Shuttleworth, M., (2008) Falsifiability, Experiment Resources [online] [Accessed 26/1/11]

Sober, E., (2009) 'Simplicity' in Dancy, J., Sosa, E., Steup, M., (eds) A Companion to Epistemology, John Wiley and Sons [Available online] [Accessed 16/1/11]

Vithoulkas, G., (2008) British media attacks on homeopathy: Are they justified?, Homeopathy Vol. 97, pp 103-106 [internal link]

The honey bee, moonlight, dinosaur bones and storms...

Just a few of the unlikely ingredients used in homeopathic remedies