The Hydra lives:
more on homeopathy
There’s no rest for the wicked, it seems. My wickedness was to voice criticisms, here and on the Nature site, of a collection of papers on the ‘memory of water’ published in the journal Homeopathy, and I return from holiday to find many responses (see Nature’s weblog and the comments on my article below) to attend to. So here goes.
I am gratified that I found the right metaphor: the ‘memory of water’ does indeed seem to be a many-headed Hydra on which new heads appear as fast as you can lop them off. I’ve discussed several of the papers in the journal, but it seems that I’m being called upon to address them all. Peter Fisher complains that I don’t discuss the experiments at all, but surely he must now know about my Nature column, in which I say:
“These papers report several experimental results that, at face value, are intriguing and puzzling. Louis Rey, a private researcher in Switzerland, reports that salt solutions show markedly different thermoluminescence signals, for different homeopathic dilutions, when frozen and then rewarmed. Bohumil Vybíral and Pavel Vorácek of the University of Hradec Králové in the Czech Republic describe curious viscosity changes in water left to stand undisturbed. And Benveniste's collaborator Yolène Thomas, of the Andre Lwoff Institute in Villejuif, outside Paris, reports some of the results of radiofrequency 'programming' of water with specific biomolecular behaviour, including the induction of Escherichia coli -like 'signals', the inhibition of protein coagulation, and blood-vessel dilation in a guinea pig heart.”
To do a thorough analysis of all the papers would require far more words than I can put into a Nature news article, or could reasonably post even on my own blog (the original piece below already ran to over 2000 words). The problem is that, as I’ve said before, the devil is in the details – and there are a lot of details.
Let me illustrate that with reference to Rustum Roy’s paper (Rao et al.), which Martin Chaplin, Dana Ullman (apologies for the gender confusion) and Rustum himself all seem keen that I talk about. I’m all too happy to acknowledge Rustum’s credentials. I have the highest respect for his work, and in fact I once attempted to organize a symposium for a Materials Research Society meeting with him on the ethics of that topic (something that was shamefully declined by the MRS, of which I am otherwise a huge fan, on the grounds that it would arouse too much controversy).
The paper is hard to evaluate on its own – it indicates that the full details will be published elsewhere. They key experimental claim is that the UV-Vis spectra of different remedies (Natrum muriaticum and Nux vomica) are distinguishable not only from one another but also among the different potencies (6C, 12C, 30C) of remedy. That is surprising if, chemically speaking, the solutions are all ‘identical’ mixtures of 95% ethanol in water. But are they? Who knows. There is no way of evaluating that here. There is no analysis of chemical composition – it looks as though the remedies were simply bought from suppliers and not analysed by any other means than those reported. So I find these to be a really odd set of experiments: in effect, someone hands you a collection of bottles without any clear indication of what’s in them, you conduct spectroscopy on them and find that the spectra are different, and then you conclude, without checking further, that the differences cannot be chemical. If indeed these solutions are all nominally identical ethanol solutions that differ only in the way they have been prepared, these findings are hard to explain. But this paper alone does not make that case – it simply asks us to believe it. One does not have to be a resolute sceptic to demand more information.
There is a troubling issue, however. In searching around to see what else had been written about this special issue, I came across a comment on Paul Wilson’s web site suggesting that the comparisons shown in Figures 1 and 2 are misleading. In short, the comparisons of spectra of Nat mur and Nux vom in Figure 1 are said to be “representative”. Figure 2, meanwhile, shows the range of variation for 10 preparations of each of these two remedies. But the plot for Nat mur in Figure 1 corresponds to the lowest boundary of the range shown in Figure 2, while the plot for Nux vom corresponds to the uppermost boundary. In other words, Figure 1 shows not representative spectra at all, but the two that are the most different out of all 10 samples. I have checked this suggestion for myself, and found it to be true, at least for the 30C samples. I may simply be misunderstanding something here, but if not, it’s hard not to see this aspect of the paper as very misleading, whatever the explanation for it. Why wasn’t it picked up in peer review?
I’m not going to comment at any length on the hypotheses put forward in Rao et al., because they aren’t in any way directly connected to the experiments, and so there’s simply no support for them at all in the results. I don’t see for a moment, however, either how these hypotheses can be sustained in their own right, or (less still) how they can explain any physiological effects of the remedies.
I don’t, as Rustum implies, demand an explanation for alleged ‘memory of water’ effects before I will accept them as genuine – I agree that experiment should take primacy. I merely want to point out that the ‘explanations’ on offer do not offer much cause to think that a great deal of critical thinking is going on here. Rustum is perhaps right to suggest that I may have been too acquiescent to the Nature news editor’s erudite suggestion for the title of my column. I’m not sure, however, that Keats really meant to imply that his name would so soon be forgotten…
On the Nature site, George Vithoulkas gives me great delight, for it seems that homeopaths aren’t even sufficiently agreed about how their remedies are supposed to work that they can distinguish ‘evidence’ for a mechanism from its opposite. My only other comment in this regard is to use Vithoulkas’s comment to point out that the common attribution of this ‘like cures like’ notion, as a general principle of medicine, to Paracelsus is wrong (not that this would give it any greater credibility!).
OK, am I excused now?
The Faculty of Homeopathy has just issued the following rejoinder to Richard Dawkins' TV programme last night in which he exposed the lack of scientific credibility of homeopathy. This special issue of Homeopathy on the memory of water has been cited as 'evidence' that there is some scientific weight to the field after all. This is exactly what I knew would happen: the mere fact of the papers' existence will now be used to defend homeopathy as a science. Let's hope that some people, at least, will be moved to examine the quality of that evidence.
I hope to comment on Richard's series in a later post. It was nice to see him being more charming and less bristling than he tends to be when talking about religion - his points carry much more force this way.
Statement in response to The Enemies of Reason - “The Irrational Health Service” Channel 4, Monday 20 August
The Faculty of Homeopathy and British Homeopathic Association support an easily understood approach to difficult scientific issues. However, Professor Richard Dawkins’ Channel 4 programme “The Irrational Health Service” presented an unbalanced and biased picture of the facts and evidence about homeopathy.
Contrary to the impression given by the programme, there has never been more evidence for the effectiveness of homeopathy than now: http://www.trusthomeopathy.org/pdf/Summaryofresearchevidence.pdf This comes from audits and outcome studies, cost effectiveness studies, narrative medicine and statistical overviews (or meta-analyses). Four out of five meta-analyses of homeopathy as a whole show positive effect for homeopathy, as do several focusing on specific conditions.
There is also an increasing body of work about the scientific properties of highly diluted substances, which Professor Dawkins dismissed. The most recent issue of the Faculty of Homeopathy’s journal Homeopathy contains articles by scientists from around the world, which are a timely reminder about how much there is still to learn about the science of these dilutions. The outright dismissal of any potential activity of these substances is increasingly untenable.