Memory of water is a concept postulated to explain how solutions diluted far beyond the point where they should retain any active ingredients might retain some biological activity. The concept arose from experiments by a group led by the French immunologist Jacques Benveniste; the results were published in Nature, and subsequently attacked as unrepeatable - though homeopaths claim they have been reproduced.[1][2] The phrase itself was coined by the newspaper Le Monde in its account of that work in somewhat different form as the "memory of matter" ("la mémoire de la matière"). The underlying notion is that water can somehow "remember" characteristics of molecules with which it had once been in contact. The concept has been widely cited by some homeopaths as a possible mechanism for the purported efficacy of their remedies. Chemists and physicists, however, consider the concept to be nonsensical. In the current scientific view, liquid water is a continuously rearranging hydrogen-bonded network with motions on the picosecond (10−12 s) time scale; accordingly, there is no room for a water "memory"[3][4][5]
In 1988, Benveniste (and colleagues) published a paper in Nature that indicated that a solution containing a biologically active substance might retain some of that biological activity even when serially diluted beyond the point at which any of the active molecules are present. In particular, they reported effects on a biological process involved in the human immune response.[6]
Human basophils are a granulocyte cell type accounting for 0.1–1% of white blood cells; these cells contain many "granules" which store inflammatory mediators, including histamine, and they can be cultured readily and studied in vitro. Exposing these cells to anti-human-IgE antibodies triggers "degranulation", a process in which the granules fuse with the plasma membrane to release histamine into the extracellular fluid. Basophil activation can be measured in several ways. First, degranulated cells can be stained and then counted; this subjective measurement is prone to variable outcomes. Second, histamine release can be measured using fluorimetric assays. Third, the fusion of granules leads to the expression of CD63 antigen; the percentage of basophils that express CD63 can be determined with flow cytometry, and correlates well with histamine release.
Benveniste reported that very high dilutions of anti-human-IgE (containing no molecules of the antibody) could induce degranulation of basophils. He concluded that it was the 'configuration' of molecules in the water that was biologically active. The French newspaper Le Monde covered this, referring to "la mémoire de la matière" (the memory of matter) and le souvenir de molécules biologiquement actives (recollection [by water] of biologically active molecules). In English, the phrase that became widespread was "memory of water". Le Monde made the paper a front page story, pointing out that if this work were correct, it would overthrow many of the foundations of physics.
Nature published the article with two unprecedented conditions: first, that the results must first be confirmed by other laboratories; second, that a team selected by Nature be allowed to investigate the Benveniste laboratory after publication. Benveniste accepted these conditions; the results were replicated by labs in Italy, Canada, Israel and France, and the article was accompanied by an editorial titled "When to believe the unbelievable."
The follow-up investigation was conducted by a team including the editor of Nature, John Maddox, American scientific fraud investigator and chemist Walter Stewart, and "professional pseudoscience debunker" James Randi. With the cooperation of Benveniste's team, under double-blind conditions, they failed to replicate the results. Benveniste refused to withdraw his claims, and in July 1988 the team published a detailed critique of Benveniste’s study. They concluded that the experiments were badly controlled statistically, that measurements that conflicted with the claim had been excluded, that there was insufficient avoidance of contamination, and that there were questions of undisclosed conflict of interest, as the salaries of two coauthors of the article had been paid under a contract with the homeopathic manufacturing company Boiron et Cie.[7]
Another group led by Benveniste replicated the findings,[8] but other groups failed to reproduce the effects.[9][10] Benveniste contended that the same conditions were not met in those laboratories, and he never retracted his claims. In the issue of Nature that carried the critique, Benveniste vigorously attacked the Nature team’s "mockery of scientific inquiry."[11]
After the Nature debacle, Benveniste became more and more isolated scientifically, and some of his colleagues called for him to resign. He did not lose his job at the French National Institute of Health and Medical Research (INSERM), but funding was progressively withdrawn, and his lab was eventually closed. According to Lionel Milgrom, a chemist and homoeopath who corresponded with Benveniste, "The knocks that he took made him suspicious of virtually everyone". Yet, despite the widespread scepticism, and despite the failure of several other groups to corroborate his findings, Benveniste continued to study the 'memory of water'. According to Brian Josephson (who, after winning the Nobel Prize for Physics in 1973 became a champion of iconoclastic ideas) "That's what good scientists do...He probably became more determined because of the opposition."[12]
Independently, other studies have claimed to reproduce Benveniste's experiments, including one published in the Homeopathy journal,[13][14] edited by homeopathic doctor Peter Fisher (see also Homeopathic coverage, below).
In 2003 Louis Rey, a chemist from Lausanne, reported that frozen samples of lithium and sodium chloride solutions prepared according to homeopathic prescriptions showed — after being exposed to radiation — different thermoluminescence peaks compared with pure water. Rey claimed that this suggested that the networks of hydrogen bonds in homeopathic dilutions were different. [15] These results have never been replicated and are not generally accepted - even Benveniste criticised them, pointing out that they were not blinded [16]
In January 2009, Luc Montagnier, the Nobel Laureate virologist who led the team that discovered the human immunodeficiency virus (HIV), claimed (in a paper published in a journal that he set up, which seems to have avoided conventional peer review as it was accepted three days after submission) that the DNA of pathogenic bacteria and viruses massively diluted in water emit radio waves that he can detect.[17] This, he claimed, can also be used to detect the medicine in a homeopathic remedy.[18][19] The device used to detect these signals was developed by Jacques Benveniste, and was independently tested, with the co-operation of the Benveniste team, at the request of the United States Defense Advanced Research Projects Agency. That investigation was unable to replicate any effects of digital signals using the device.[20]
In 2010, at the age of 78, Montagnier announced that he would take on the leadership of a new research institute at Jiaotong University in Shanghai, where he plans to continue this work. He claims that the findings "are very reproducible and we are waiting for confirmation by other labs", but said, in an interview with Science, "There is a kind of fear around this topic in Europe. I am told that some people have reproduced Benveniste's results, but they are afraid to publish it because of the intellectual terror from people who don't understand it." Montagnier had called Benveniste "a modern Galileo", but the problem was that "his results weren't 100% reproducible".[21]
Claims about supernatural or mystical qualities of water have been made by some "alternative healers". For example, practitioners of the Silva Method[22] claim to "program" water to heal a person, long after the healer has programmed the water and is personally unavailable. These alternative healers focus on the effects of energies, generated by people, on water. In Qigong (in Traditional Chinese Medicine):
"Subtle, or vibrational, energy is broadly defined as energy that is not generally recognized by mainstream physics and for which there are no means of measurement. ...
It is fundamental to many unexplained phenomena such as the power of spirituality and prayer, the effect of remote intention, the operation of homeopathy, and the functioning of the mind/body information network..."[23]
Masaru Emoto built a business selling water products. In a series of books — beginning with Messages from Water (1999) — he claimed that ice crystals reflect the words, music, pictures — even thoughts and intentions —to which the droplets of water were exposed before being frozen. He also claimed to find effects of 'healing energy' on water (Pranic Healing):
"After the healers projected their energy toward the water, ... the water that was healed with Pranic energy had impeccable crystal formation while the tap water's internal structure was chaotic."[24]
Emoto makes some remarkable claims:
"So where is the solution to the problem of global warming in this book? Well, because it shows that we can extract energy out of water. For example, the crystal photograph on the cover is shining beautifully. This is a result of when the cameraman and the water resonated."[25]
To most orthodox scientists, the "memory of water" is not something that deserves serious consideration; the only evidence is the flawed Benveniste work. By contrast, the notion of "memory of water" has been taken seriously among homeopaths. For them, it seemed to be part of a possible explanation of why some of their remedies might work. An overview of the issues surrounding the memory of water was the subject of a special issue of Homeopathy. In an editorial, the editor of Homeopathy, Peter Fisher, acknowledged that Benveniste’s original method does not yield reproducible results and declared "...the memory of water is a bad memory: it casts a long shadow over homeopathy and is just about all that many scientists recall about the scientific investigation of homeopathy, equating it with poor or even fraudulent science." The issue was an attempt to restore some credibility to the notion with articles proposing various, very different theories of water memory, such as: electromagnetic exchange of information between molecules, breaking of temporal symmetry, thermoluminescence, entanglement described by a new quantum theory, formation of hydrogen peroxide, clathrate formation, etc. Some of the proposed mechanisms would require overthrowing much of 20th century physics.[26]
In 2010, a team of scientists from India found that some commercially manufactured metal-derived homeopathic remedies in fact contained nanoparticles of the metals and their aggregates, despite the claimed high-dilution.[27][28] In 2015, a study in India found that homeopathic remedies in fact contained nanoparticles of the resource medicine, despite the claimed high-dilution.[29] Another team of scientists found that Quartz, Sulfur and Copper Sulfate-derived homeopathic remedies in fact contained nanoparticles of those substances and their aggregates, despite the claimed high-dilution.[30] Traditional homeopathic preparation methods are very different from the controlled microchemical procedures used for serial dilutions in scientific laboratories, and the assumption that homeopathic remedies are in fact diluted to the extent claimed may be wrong. As pointed out in an editorial in Homeopathy, "The skeptics have gotten the homeopathic world so busy trying to defend various theories of water memory that we have overlooked the possibility that some of the material somehow actually persists in highly diluted homeopathic medicines."[31]