On the statistical points, my view is that I’m not impressed by statistically significant results of vanishingly small practical significance. Neither, given the biases present in the kinds of studies that we’re discussing am I comfortable with results that only just manage to achieve significance.

However, nothing in this is inconsistent with seeing failure to meet significance as a negative result. To paraphrase Fisher, the experiment has been given its chance disprove the null hypothesis and has failed. It is certainly not evidence for anything – unless you really, really want it to be.

I think that R Barker Bausell provides some sound advise when he cautions that if there are, “no statistically significant (or reliable or clinically significant) differences between the placebo (or sham) group and the treatment group, that says everything consumers need to know about whether they should seek the CAM intervention in question.”

On the question of whether we should be considering the merits of a Bayesian, rather than Frequentist, approach I’m quite open-minded. However, considerations of prior probability (plausibility) certainly add to my currently sceptical judgement of homeopathy. (Steve Novella’s chain of implausibility is a pretty powerful analysis.)

On the NLH CAM analysis, I think we could end up in a very long debate; probably longer than either of us has the time or inclination to pursue. I’d just like to say that my motivation was to try and get an overall feel for the strength of the case for homeopathy. I think that it’s quite possible to make a case for putting individual pieces of evidence in different boxes. I do doubt though that there is a fair case for enough re-binning to change the overall distribution that much.

On your specific examples:
3 – The comment that you attribute to the CRD reviewers is actually one of the authors’ conclusions. The exact phrase, “we found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition” appears on page 834 (under the heading ‘Interpretation’) and, “we found little evidence of effectiveness of any single homoeopathic approach on any single clinical condition” can be found on page 840. [Linde et al. Lancet 1997; 350: 834–43] I think that it’s quite reasonable to take that conclusion as a negative; at best it could make this piece of evidence inconclusive. Add in the cautions offered by Bandolier, and I couldn’t in all honesty see this as a positive. Particularly when what I am interested in when I look for treatment is an intervention that will be effective for a specific condition.

5 – This is a really interesting case. Six studies, evenly split between superiority, inferiority and indeterminacy – for comparisons against conventional treatments – would seem like a tie. This might be argued to infer that, in terms of efficacy, it doesn’t matter which intervention someone choses (at least for the range of conditions considered). One fly in this ointment is that this is a kind of ‘mini-Shang’ where the analysis is trying to come to an overall view of the modality, not a view on the efficacy of the treatments for specific conditions.

The big problem with this is that the DARE summary points out, “Two of the six studies (both non-randomised) suggest that homoeopathic remedies are superior to conventional drug therapy.”

If we are to use the Frequentist tools of Fisher (and others) then we have to accept, as Fisher said, “The theory of estimation presupposes a process of random sampling. All our conclusions within that theory rest on this basis; without it our tests of significance would be worthless.” [Fisher RA. Development of the theory of experimental design. Proceedings of the International Statistical Conferences 1947;3:434–39.]

From a straightforward scientific perspective, lack of randomisation in these kinds of trials is necessarily a fatal flaw. So when the author offers, according to the DARE summary, “Only few comparative clinical trials of homoeopathy exist. None is free from serious methodological flaws. Thus the value of individualised homoeopathy relative to allopathic treatments is unknown.” It seems very fair to call it inconclusive.

(It’s also interesting to note that classical homeopathy fared no better than any other kind in Shang et al. (see particularly the Author’s reply).)

30 – This is another very interesting review. The results are summarised by DARE as follows:

Six RCTs (n=1,076).

All studies: time to first flatus WMD between homeopathy and placebo = -7.4 hours (95% CI -4.0 hours, -10.8 hours), p<0.05. This effect is likely to be clinically relevant.

Excluding studies of low quality (n=676): time to first flatus WMD between homeopathy and placebo = -6.11 hours (95% CI -2.31 hours, -9.91 hours), p<0.05.

Only studies of <12C potency (n=660): time to first flatus WMD between homeopathy and placebo = -6.6 hours (95% CI -2.6 hours, -10.5 hours), p <0.05.

Only studies of 12C potency or more (n=416): time to first flatus WMD between homeopathy and placebo = -3.1 hours (95% CI -7.5 hours, 1.3 hours), not statistically significant.

This could only be considered a positive result if the kind of homeopathy one is interested in is the kind where there could be some medicine in the medicine. The Kentian brand practised in the UK/USA seems wedded to ‘high’ potencies. In this case, for potencies beyond 12C, the result is not statistically significant. Now, I could make a case for calling this inconclusive. However, taking the results on face value flatly contradicts a central tenet of classical homeopathy. This tipped it into the ‘negative’ box for me.

So, in these instances, I really can’t really see a case for changing my analysis.

Anyway, thanks for that. What did you make of my comments (here and particularly here) on your criticisms of Shang et al? When are you going to edit and re-issue your apologia?

All the best,

Adrian

Well, I’m back and refreshed. There are a lot of issues here now, and again I’m not sure I can cover everything. Let’s go back to the beginning. You reiterated your statement about non-significant findings;

“I particularly don’t agree with the part of your analysis where you talk about “a non‐significant trend” in favour of homeopathy; as if that is something which positively favours homeopathy. Do you really think that non-significant trends count as evidence?”

This goes back to my mention of the Miller study. I know you didn’t raise it (I can see that it could look as though I meant that, and I apologise) – I raised it, as an illustration that statistical significance is not the only criterion to use. Recall that I said;
“… Miller et al 2005 meta-analysis of Vitamin E and all-cause mortality, which found a “statistically significant” increase in mortality (namely a 4% increase in relative risk; RR= 1.04, 95% CI 1.01 to 1.07) for high-doses of vitamin E. It’s not clinically significant, and it’s not relevant here…”. The “despite your claims to the contrary” referred to your comments on statistical/other significance in general.

Because the 95% confidence interval did not cross unity, the authors were able to claim statistical significance; but that’s for a 4% increase in RELATIVE risk. You have to plough through the paper to find the ABSOLUTE risk;
“The average death risk across trials in the control groups was 1022 per 10,000 persons.”
So according to the analysis, Vitamin E increased the absolute risk of death from 10.2% to 10.6%. Is that a big enough effect to make you change your behaviour? Put it the other way round; if Vitamin E had been reported as reducing the absolute risk of death from 10.6% to 10.2%, would that persuade you to take it?

The reverse can also be true; failure to achieve statistical significance can hide a real and important effect. Take a (fictional) study that reports, in contrast to Miller; “RR= 1.40, 95% CI 0.95 to 1.70”; that would be unable to claim statistical significance. But the average effect is 10 times that in Miller, so there is, roughly (I’m guessing), a 90% probability of a 40%-sized effect, compared to a 97% probability of a 4% effect.

If they were horses, which would you back? Many statisticians would say that this adds to the argument for using Bayesian statistics instead (results obtained over a pint across the road from the Statistical Society).

So, I didn’t say that non-significant results amounted to clear evidence. what I said was;
“So of those that felt able to draw a conclusion about homeopathy, 81% found it beneficial.” I’ll grant you that it could perhaps be better put as; “81% found it beneficial or likely to be beneficial”, or “81% found definite or probable benefit”.

At the risk of opening up yet another area of detailed debate, I have looked at your analysis of the NeLCAM database, and here are some comments, and comparisons with my own version. To be honest I’m not sure I can manage to go much further with this, because there are papers that I found and you didn’t and vice-versa, and I think this may be the fault of the database, not ours.

Your item:
3. Are the clinical effects of homoeopathy placebo effects: a meta-analysis of placebo-controlled trials
You categorise as negative, and emphasise the quote;
“…we found insufficient evidence from these studies to suggest that homeopathy is clearly efficacious for any single clinical condition.” But that is “written by CRD reviewers”, not by the authors of the paper; it’s another layer of opinion on top of the meta-analytical layer.

I took note of the numerical findings and categorised it as positive;
“The overall OR (89 trials) was 2.45 (95% CI: 2.05, 2.93) in favour of homeopathy (random-effects model). Results from the various sensitivity analyses indicated that this finding was robust. The summary OR for trials categorised as high quality (26 trials) was 1.66 (95% CI: 1.33, 2.08).” – which are the findings of the actual paper.

Classical homoeopathy versus conventional treatments: a systematic review 
 You class as inconclusive, and quote;
“Thus the value of individualised homoeopathy relative to allopathic treatments is unknown.”

I noted this statement and classed it as positive;
“Two of the six studies (both non-randomised) suggest that homoeopathic remedies are superior to conventional drug therapy. Two trials suggest the opposite. The remaining 2 studies suggest both interventions to be equally effective (or ineffective).”

This of course goes back to our ongoing discussion of what to compare homeopathy to – you recently said;
“Actually, I think that your objection to my point that, “if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports recommend the use of homeopathy in preference to a conventional treatment” is well made. I didn’t express myself as accurately as I would have liked; I should have said, “if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports show that homeopathy works as well as the recommended conventional treatment.”

Well, despite what the author of item 5 (who, if you insist on describing me as peddling homeopathic propaganda, you will have to allow me to describe as well-known for peddling anti-homeopathy propaganda) says, an average from the studies included in this would suggest that they are equally effective (or ineffective).

6. Complementary and alternative medicine in fibromyalgia and related syndromes 
 I didn’t even include this in my analysis

30. Homeopathy for postoperative ileus: a meta-analysis
You class as negative, quoting;
“However several caveats preclude a definitive judgement. These results should form the basis of a randomised controlled trial to resolve the issue.”

I class as positive based on;
“There is evidence that homeopathic treatment can reduce the duration of ileus after abdominal or gynaecologic surgery.” – and on the numerical findings. I’m sorry, but “ These results should form the basis of a randomised controlled trial…” is the academic’s equivalent of “Gissa job”, or “Gissa grant” perhaps.

Is this enough for now? I have to go feed the cats.

“Re your point that high-quality trials don’t tend to support homeopathy, well this is just regression to the mean, isn’t it? If you look at the two funnel-plots in Figure 2 of Shang et al, it’s clear that this is true, as expected, for the trials of conventional medicine as for homeopathy (they call it meta-regression).”

Actually, if you look at the solid lines on Figure 2 which, “indicate predicted treatment effects from meta-regression, with dotted lines representing the 95% CI.” you’ll see as bias is minimised (low SE) the predicted treatment effects from homeopathy tend to an OR=1 (the CI certainly crosses OR=1). For conventional medicine it does not. This is really the main point the paper makes: by doing a meta-regression analysis on all 110 matched pairs of trials they found which was the most significant bias (SE – see Table 3), used that to determine which of the “higher quality” trials were least affected and re-analysed this group.

“But perhaps you can explain something else about Shang et al; in the text (p729 and Table 3) they say; “with each unit increase in the SE, the odds ratio decreased by a factor of 0·17 for homoeopathy and 0·21 for conventional medicine.” In other words the effect to which you referred is greater for conventional medicine than homeopathy. But in Figure 2 the opposite is apparent. What?”

The asymmetry coefficients that you mention are not actually significantly different for the two modalities. As the sentence before the one you quoted points out, “In meta-regression models, the association between SE and treatment effects was similar for trials of homoeopathy and conventional medicine: the respective asymmetry coefficients were 0·17 (95% CI 0·10–0·32) and 0·21 (0·11–0·40).” You’ll note that the 95% CI’s overlap substantially.

Comparing Figure 2/Table 3 to the text it looks like a typo here. The most likely explanation is that the numbers are reversed in the text; but only the authors could say for sure.

What we see here is that the two modalities ‘approach’ the answer at indistinguishable rates. The main point is that the answer is different in each case; for homeopathy the, “finding is compatible with the notion that the clinical effects of homoeopathy are placebo effects”; conventional medicine, however, has an effect betond that of a placebo. It’s about the destination, not the journey.

As for the missing trials, are these the ones that Peter Fisher refered to in his Lancet letter? If so, then check the Author’s reply, “Neither of the two studies mentioned by Fisher and colleagues were regarded as large and of high quality. The influenza trial did not meet our prespecified quality criteria and the asthma trial was available as an abstract only and excluded.” If they are then this answer would seem to be fair enough.

As for any arbitrary criteria; I’d have to say that – given all the data that’s available – the piece of work looks pretty transparent and objective to me. They provide a list of their quality criteria in the paper and a definition of the size criteria: trials with SE in the lowest quartile. They have provided a list of excluded studies, complete with the reason for exclusion. Their lists of study characteristics for homeopathy and conventional medicine provide a fair summary and say which were considered to have met the “higher quailty” threshold. I’d say that there’s enough data here for a medical researcher to go and check their application of the quality criteria.

Finally, the point about there being no analyses of other sub-groups. This, if you don’t mind me saying so, misses the point of the paper. The analysis of the 110 matched pairs of trials shows that both small (high SE) and lower-quality trials were not reliable. (See Table 3). Given this, the only sub-group capable of giving a robust answer is the ‘larger trials of higher quality’ group. Looking at other groups is merely adding in more biased trials.

I hope that you are happy with these responses and will be updating your comments on Shang et al in due course.

Just a quick point: I’m a bit puzzled that you wish to disagree (to some extent) with my revision on equal efficacy. If I may, I’d just like to point out that I was directly addressing an earlier concern of yours, “If there exist a homeopathic and a conventional treatment with equal, proven, efficacy, then they are both effective, aren’t they? A patient could choose either, and might well pick the homeopathic because of less side-effects (or other cultural reasons).”” And I agree; so I don’t think you can really disagree with my amendment without disagreeing with yourself!

I think that what you are doing is moving the discussion onto new – and entirely valid – terrain. This is an extension to the debate; unless treatments have proven efficacy these points are moot.

Once the evidence supports the efficacy of treatments (of whatever kind) the risks vs. benefits judgement is clearly very important; we have some common ground here. I’d also like to add that in a resource-limited world (like the NHS) the costs vs. benefits of treatments are very important also.

In fact, a more sophisticated analysis would move us away from your formula of, “equal, proven, efficacy”. Take the case where two treatments are both effective, but to different (and worthwhile) degrees. Now, if the more effective treatment comes with higher risks it could be rational, depending on the circumstances, to forgo the additional benefit to avoid the additional risk.

Anyway, enjoy your holiday and debate at your own pace!

I still don’t entirely agree with; if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports show that homeopathy works as well as the recommended conventional treatment. – because it’s always a risk-benefit assessment. I had a little girl as a patient today who has been shown to have 2 gut parasites; an aunt picked them up in S America and gave them to the whole family it seems. Several adults have been devastated by them; one has benefitted from mega-antibiotic therapy. Should we give the girl the same when she has no symptoms? I say no so far, because what does she gain? Risk vs benefit.

The animation is fantastic, isn’t it?

DD

Thanks for your continued interest. I’m glad that you’ve decided to, “retract the criticism that Shang et al failed to declare their “secret eight.” It looks like I made a small slip with my, “very next issue” comment as well. I’ve corrected my blog post, when are you going to correct your critique?

I’m sorry if my choice of words has offended you. Given that you implied that Ernst is lying and Shang is guilty of misconduct, I didn’t think you’d be that sensitive. Still, now I know and I will take more care in future. After reading Dr Alex Tournier’s presentation from the recent Scientific Research in Homeopathy conference I think it was too harsh to accuse you of “philosophical naivete”; in comparison your philosophical model of science is OK (I’ve edited my piece accordingly).

I think my word-choice was off when I said you were, “peddling homeopathic dogma”. I should have said “peddling homeopathic propaganda” based on your perpetuation of the homoeomythology surrounding Shang’s paper. (I don’t take the view that there was any ad hominem here. My comments were directed against your published views – and I gave my reasons – not against you as a man. Any small discourtesies were merely incidental.)

Actually, I think that your objection to my point that, “if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports recommend the use of homeopathy in preference to a conventional treatment” is well made. I didn’t express myself as accurately as I would have liked; I should have said, “if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports show that homeopathy works as well as the recommended conventional treatment.” I’ve corrected my post accordingly; thanks for the suggestion.

Now, where are the homeopathic treatments with “equal, proven, efficacy”? I didn’t find any when I looked through the NLH database; though I may, of course, have overlooked them.

Even though my academic training was in physics and I now work in engineering, I am not expecting concrete results (see here for some of my views on uncertainty). I do, however, believe that it is possible to come to reasonable assessments of medical interventions on the basis of evidence and determine whether, on balance, they are worth the candle.

With that in mind, I had a go at looking in the round at the database (here). I appreciate that I am an amateur in such matters and that a professional such as yourself may well come to different conclusions. I’d be happy to debate the detail.

I particularly don’t agree with the part of your analysis where you talk about “a non‐significant trend” in favour of homeopathy; as if that is something which positively favours homeopathy. Do you really think that non-significant trends count as evidence?

Also, your comment that, “16 concluded that there was “insufficient data” to draw a conclusion either way” may encourage a reader to think that those sixteen reports actually use the expression “insufficient data”. I couldn’t find these sixteen direct quotations. Could you please point them out to me?

As for the positive evidence in this database: the strongest endorsement I found concluded that, “larger trials are required.”

When it comes to trial quality, it’s not really my point per se that high-quality trials tend to be more negative: I’m just pointing out what studies by Linde, Cucherat and Shang concluded. Is it really just regression to the mean? I think that there are also quite a lot of other biases present. However, I guess the key is what mean is being approached. For Shang it was a mean of ineffectiveness (relative to placebo), in contrast to conventional treatment. Even Linde, in his positive meta-analysis of homeopathy concluded that they, “found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition.”

Your comments on Shang are interesting. Perhaps when you update your critique you can use them instead of the “secret eight” story. I’m a bit busy at the moment; but, when I have some time, I’ll have a re-read and see if I can come to any conclusions. However, I suspect that this is a matter you need to take up with the authors. Afterall, if there are serious problems with the paper they need to be debated in the open literature. In the meantime, could you tell me which three studies were missed out?

On the matter of whether Shang is “a good example of the arbitrary, often unspecified, criteria” I think you’ll have to concede that the paper does specify the criteria, “Trials described as doubleblind, with adequate methods for the generation of allocation sequence and adequate concealment of allocation, were classified as of higher methodological quality.” And for ‘larger trials’: “Trials with SE in the lowest quartile were defined as larger trials.”

Is that arbitrary? Certainly the ‘quality’ criteria are not. Neither am I persuaded that the size criterion is arbitary. The use of quartiles, quintiles and deciles is pretty standard. If they divided their dataset more finely then there would have been fewer than 8/6 studies left; which would probably be too few to draw sensible conclusions from. If they divided their data less finely, then they would just be adding in trials containing more bias. I think I am persuaded that this was a reasonable objective measure.

Anyhow, with the references now available I would think that other workers could examine this if they wished. Perhaps there’s a paper in this for you?

Anyway, I think that it’s interesting that after your comment disparaging meta-analyses that your critique relies on an analysis of those in the NLH database. Don’t you think that this is just a little inconsistent?

Your critique mentioned a, “recent review of RCTs of homeopathy”. I’m still interested to know the identity of this study. Could you please provide some details? Where is it published?

Your “point about microtubules and kinesin” didn’t really convince me; the animation was fantastic though! When you say, “I imagine any of us could think of things that are, or used to be, just as scientifically implausible as homeopathy” I struggle to find examples. Some things that are about as implausible might be an extra-terrestrial explanation of UFO’s and crop circles; the Loch Ness Monster, Yetti, and Bigfoot. Things that used to be considered implausible were rendered plausible and then accepted as the result of careful study and the production of high-quality evidence.

The fact that quite a lot of good quality work has been done which fails to show a benefit beyond that of a placebo is persuasive. I think that if there were profound therapeutic effects here they would have been discovered by now. The contention of classical homeopaths, and others, that increasingly small probabilities of the presence of an alleged therapeutic agent deliver increasing therapeutic effect is so amazing that it would need more than the current collection of irrelevant, poorly executed experiments or wishful thinking currently on offer to persuade me.

Finally, you ask “I’m trying to be impartial here; are you?” Well I’d say that I am trying. As you point out, I have no vested interests here one way or the other. I’d certainly endorse homeopathic treatments if high-quality evidence clearly, and consistently, demonstrated therapeutic benefits that usefully exceeded that of placebos. As far as I can tell, the opposite is the case.

First off, I’m happy to retract the criticism that Shang et al failed to declare their “secret eight”, given that they did list them in an Authors’ Reply, and agreed that they “should have been identified”. But since this is dated 4 months after the paper, those who levelled this criticism at that time were correct, surely? And how does a 16 week interval make it the “very next issue”?

I’m still puzzled, though, at the charge that I have been “peddling homeopathic dogma”; in what way are you not doing the same on the other side? I think you could have been less ad hominem, btw; in the first few sentences I’m an “apologist”, “rather silly”, guilty of “empty carping” and “philosophical naivete”, and of course “peddling homeopathic dogma”. Isn’t this the language of the propagandist, rather than scientific discourse? And isn’t the pot calling the kettle black?

You then seek to substantiate this on the basis of my reading of the NLH section on homeopathy. But you haven’t yet addressed my point about how you interpret the data. You say; “if you are concerned with either treating patients, or recovering from illness, what you really need to know is how many of these reports recommend the use of homeopathy in preference to a conventional treatment.”

To which I said, and still do; “Well, no. If there exist a homeopathic and a conventional treatment with equal, proven, efficacy, then they are both effective, aren’t they? A patient could choose either, and might well pick the homeopathic because of less side-effects (or other cultural reasons).”

It’s because of your apparent misunderstanding here that I felt justified to open the discussion about who you are, what you do and what you say. Were I to express an opinion on ground vehicle aerodynamics, you would be entitled to point out the limitations of my knowledge and understanding, and the impact of my field of study/expertise/work on that understanding. So, for my part, I do wonder whether your background in a physical science means that you expect to be able to find concrete, black and white, results even in the biomedical sphere, where believe me, it’s always more complex. I’ll reiterate that you’re entitled to discuss this (as a potential patient if nothing else, as you point out)

Re your point that high-quality trials don’t tend to support homeopathy, well this is just regression to the mean, isn’t it? If you look at the two funnel-plots in Figure 2 of Shang et al, it’s clear that this is true, as expected, for the trials of conventional medicine as for homeopathy (they call it meta-regression).

But perhaps you can explain something else about Shang et al; in the text (p729 and Table 3) they say; “with each unit increase in the SE, the odds ratio decreased by a factor of 0·17 for homoeopathy and 0·21 for conventional medicine.” In other words the effect to which you referred is greater for conventional medicine than homeopathy. But in Figure 2 the opposite is apparent. What?

It has also been pointed out that Shang omitted 3 homeopathy studies which had been ranked highly by previous analyses (only one of which is listed in the excluded papers), all of which had positive results, and the inclusion of which would have shifted the slope of the line in Figure 2 to more vertical.

Shang is thus a good example of the arbitrary, often unspecified, criteria to which I referred. The text states; “When the analysis was restricted to the larger trials of higher reported methodological quality, the odds ratio from random-effects meta-analysis was 0·88 (0·65–1·19) based on eight trials of homoeopathy and 0·58 (0·39–0·85) based on six trials of conventional medicine.” It doesn’t report the odds ratios at any other level of its stated criteria. Even though they subsequently listed the eight (and the six) papers, they haven’t specified the cutoff point for high quality, and the list of included studies in the final eight still looks arbitrary.

I do think it’s a bit disingenuous of David Colquhoun to suggest that Ernst has no vested interest while practitioners do. He has a vested interest in holding his job and promoting his unit, but even more so in selling books, which has to be potentially more lucrative than seeing sick people – though probably worse than being a succesful GP these days! Frankly it’s hard to think of anybody without a vested interest. Doctors or practitioners on either side? Obvious. Academics? Worrying about grants, sometimes looking for an industry consultancy. Journal editors? Appeasing their advertisers and promoting their journal. Ironically our aerodynamicist might be the only one here without a vested interest.

I thought the review of Ernst & Singh’s book in Nature was interesting. It concludes; “For now, the certainty expressed in Trick or Treatment? mirrors that of the proponents of alternative therapies, leaving each position as entrenched as ever.” Which has resonance here, I think; none of you has so far, to my knowledge, said that if the clinical evidence clearly pointed in favour of homeopathy working (I’m not saying it does, only that it’s starting to trend in that direction) you would accept it. Hence my point about microtubules and kinesin. I’m trying to be impartial here; are you?

Thank you for posting the link to that animation, it was rather like watching a choreographed dance at times – I found actin and microtubule assembly more interesting than I would have imagined.

I’m only an amateur with an interest in science, and limited knowledge of the subject, but it seems to me that the problem with homeopathy is not simply that it is implausible. If we are to believe that the “higher potencies” work, we have to accept that nothing can do something. The “high potency” homeopathic remedies contain not a single molecule of the active ingredient, as the active has been diluted out of existence. I would have thought that it would therefore be impossible rather than merely implausible for “high potency” remedies to actually work (i.e., have an effect over and above placebo). This is backed up by the trials that have been already conducted into homeopathy.* Comparing the implausibility of something that has been shown not to work with the implausibility of something shown to be real seems a bit, well, dodgy to me. Particularly when the something that has been shown not to work may actually be impossible rather than implausible.

I’ve read that the highest dilution that can be made without diluting the original substance out of existence is equivalent to 12C or 24X, so all the remedies of “higher potency” than 12C or 24X are actually zero potency. In a vain attempt to explain how homeopathy could work advocates invented the memory of water hypothesis, which was promptly debunked – if you would describe what water has as a ‘memory’, then this memory lasts only femto-seconds ["liquid water essentially loses the memory of persistent correlations in its structure within 50 fs", according to doi:10.1038/nature03383] and I doubt that even the swiftest of practitioners could administer a homeopathic remedy in less than 50fs.

Have homeopaths ever done anything remarkable that is true? Yes – they’ve managed to turn water into money. [With apologies to Dr Tony Copperfield]

*[To paraphrase D Colquhoun: A sufficient number of good [RCTs] have been done to be able to say with some certainty that neither is better than placebo. We can already see that, plausible or implausible, homeopathy simply doesn’t work.]

Cheers,
jdc

I guess I owe you gents (and any ladies I may have missed) an apology; I haven’t been checking for responses to my posting. I’m impressed by your rapidity – but don’t you folks have jobs?? I’ll post in detail soon, but meanwhile:

There was a technical error on the new ANH website which caused my original item to be unavailable – my apologies. It is now there at
http://www.anhcampaign.org/documents/lies-damned-lies-and-professor-ernsts-new-book
Apologies for the glitch.

I imagine any of us could think of things that are, or used to be, just as scientifically implausible as homeopathy. Off the top of my head, how about the cytoskeleton? Who would have thought that there was a compex structure within every cell, and molecules like kinesin that WALK along them to deliver proteins? Have a look at this gorgeous animation;
http://aimediaserver.com/studiodaily/videoplayer/?src=harvard/harvard.swf&width=640&height=520

Back soon.
DD

Another Downing cheap shot didn’t dawn on me until I’d replied. He wibbles on about his problems with meta-analyses as if that somehow justifed his position. In his diatribe against Ernst he was quite happy to cite this kind of evidence (though dubiously interpreted).

Refering to the NHS CAM database homeopathy evidence he comments that it, “…contains 32 systematic reviews and meta‐analyses of its use in a wide range of disorders … Of the 32, 7 report a statistically significant clinical effect from homeopathy, 6 show a non‐significant trend in its favour, and 3 show no effect …”

So it would seem that he has no problems with this type of evidence as long as he is citing (and misrepresenting) it.