Water memory

Water memory is one of the concepts central to modern homeopathy (i.e., post-).

Due to the nature of the dilutions in a homeopathic preparation, no molecule of any active ingredient remains in the final product. To get around this fact, homeopaths fall back onto the idea that the solution somehow retains a "memory" of the solute (if you wonder why the mere memory of a substance should be better at performing a given task than the actual substance itself, it's because they believe "like cures like"; the original substance would be actual poison, but the memory must be a "helpful" memory). Although it is possible to argue that only proof of efficacy in homeopathic preparations is important, water memory has become an essential element for anyone trying to offer up rationalizations for a mechanism of action. To highlight its importance, the homeopathic apologist's journal Homeopathy devoted a whole issue to water memory.

This idea takes many forms, each of which is less plausible than the last.

History
proposed water memory in the 1980s, and famously managed to publish some of his results in the journal Nature, for which he earned the first of his two Ig Nobel Prizes. Lacking any objective grounds on which to reject the seemingly impossible paper through the process of peer review (so the many claims that established science merely rejects quack ideas with a closed mind are patently false), the paper was sent to press. The journal's editor John Maddox, however, remained skeptical and allowed the results to be published accompanied by a small editorial on the subject, in which he detailed the number of laws of physics and chemistry such a result would violate, stating that "There are good and particular reasons why prudent people should, for the time being, suspend judgment." The only other remaining condition was that the research mentioned should be independently replicated following publication, and the controversy created a small media storm in 1988. The team sent to investigate Benveniste's claims included James Randi, whose expertise on sleight of hand and fraud detection were put to use in the lab. The report from the team concluded that although Benveniste was innocent of academic misconduct and fraud, he had been misled by flawed experiments. Thus, one of homeopathy's most shining moments was tarnished, and even John Maddox was almost disappointed, concluding "I'm sorry we didn't find something more interesting."

Basics
The central principle of homeopathy is that like cures like. Therefore homeopaths seek out dangerous herbs and other ingredients that produce symptoms of disease (such as nightshade, arsenic, and strychnine) to use these in their preparations. Since these substances would normally kill the patient, the homeopath uses a series of dilution procedures, known as succussion, to dilute the solution so much that any given sample will not contain any of the original ingredients. While most people realize that diluting decreases potency, the homeopath claims the exact opposite — that the more diluted the preparation is the stronger it is. This potency-increasing dilution also magically removes the "negative" side effects of the original poison, whilst somehow keeping the "good" symptom-causing effects.

Homeopaths have failed to prove the efficacy of their treatments after many experimental attempts. Given the complete and utter failure of experimental evidence, many have turned to trying to create mechanistic explanations for how homeopathy could work. These "proof of principle" ideas revolve around finding an explanation for how diluting a solute can increase its effect. The current vogue idea is "water memory": the homeopath believes that their dilution process somehow transfers the properties of the solute to the water molecules themselves, then those molecules of water transfer it to new water and on and on. They propose this as the explanation for the a priori belief that diluting increases potency.

Homeopaths, true to form, have not really tried to prove that there even is such a thing as water memory. One cogent example of this is that James Randi has offered his million dollar paranormal challenge money to anyone that can prove water memory actually exists. No major homeopathic practitioner or company has taken him up on the offer — with the exception of Randi's involvement with the Benveniste case in 1988, which was partially funded by the French Homeopathy Council. However in 1999, Madeleine Ennis of Queen's University of Belfast had claimed to have replicated Benveniste's miraculous findings (those debunked by John Maddox and James Randi a decade earlier). In 2002 the BBC pop science program Horizon did an on-air test replicating this work with Randi to attempt to win the prize. The replication failed completely, with the documentary concluding, "Homeopathy is back where it started without any credible scientific explanation. That won't stop millions of people putting their faith in it, but science is confident. Homeopathy is impossible."

Since the starting premise in most research on water memory is that it is a fact, an explanation for this fact must therefore be sought. There are no analogous situations in the natural world, so unique lines of reasoning have been developed to explain a phenomenon that has never been proven to exist. With no actual data on water memory or how it behaves (since they haven't even proved it exists!), researchers can make up whatever hypothesis they feel like as long as it sounds nice and not have to be worried about complicated stuff like experimental proof or making testable predictions. This is a big reason why this fraud is the epitome of pseudoscience.

Ideas presented by homeopaths
Homeopaths present many odd ideas to try to explain the mechanism behind the phenomenon of water memory. Since water memory has not yet been proven to exist, the hypotheses are a bit premature. Examples include:
 * The silica hypothesis
 * Active oxygen
 * Quantum homeopathy
 * Charcoal nanoparticles

Modeling water memory
One of the most clear-cut examples of how water memory researchers work backwards from assuming their conclusion is in the realm of mathematical modeling. A recent example was published in the aforementioned water memory issue of Homeopathy. The author of this paper took a list of assumed properties of water memory based around assumptions of homeopathy and then constructed a mathematical model that described these assumptions. In the paper, the author has no physical experiments on which to ground his model and no logical constraints other than "it makes the equation do what I want" for most of his manipulations. Exponentials and terms are randomly dropped into the model, with the only explanation being that they were required to make the math work. Mark Chu-Carroll of ScienceBlogs has a full refutation of the work at his site.

The amazing thing about the paper — which isn't particularly clever or conclusive by the normal standards of science — is that this is somehow considered to be cutting-edge research in the world of alternative medicine. There is no empirical grounding whatsoever for this research (and as Richard Feynman said, "It does not make any difference how smart you are, who made the guess, or what his name is – if it disagrees with experiment it is wrong.") or logical constraints at all. This is, frankly, terrible science, yet it's the best research into these extraordinary claims that anyone has to offer. It is no wonder that so few people take this stuff seriously. It's completely baffling how anyone can.

Thermodynamics of water memory


According to thermodynamic principles, the thermodynamic functions (such as enthalpy, entropy, etc.) of a substance are determined only by the current state of the system, in terms of its pressure, temperature, volume, etc. Included in this are the distribution of velocities, internal vibrations and rotations. The study of thermodynamics has shown that the ultimate change to a state is independent of the path to the state; basically, there is no "memory" of former temperatures, pressures, etc. or dissolved substances. If water did have a memory, it would be an example of a Nobel Prize-winning concept, as it would violate current thermodynamic concepts.

There are some forms of substances that are thermodynamically unstable or "metastable" (such as supersaturated solutions or allotropes of elements) in existence, which are prevented kinetically from approaching thermodynamic stability because of lacking a pathway. However, water has relatively weak hydrogen bonding, since the intermolecular forces (relative to covalent bonds) are easily overcome at room temperature and very short-lived. Once a solute is removed from the water, the water will rapidly reach a state of equilibrium, when all evidence that the solute was ever in the water will be gone.

Various physical properties of water can be altered by small amounts of dissolved substances; these properties are called "colligative properties", and have been explored in great detail by physical chemists. Hence, the purity of the water, including dissolved gases, is paramount in determining any physical properties. There are clusters of water molecules as well as hydronium ions, hydroxide ions and associated hydrogen bonded species of these ions; however, there is no evidence that these exist over macroscopic scales as suggested by the water memory enthusiasts. Water memory also likely violates the principle of microscopic reversibility.

Tap water of death
One of the interesting questions surrounding the concept of water memory, is explaining how billions of people worldwide drinking out of natural and tap sources of water are not dropping dead of overdoses. One environmental watchdog group has documented over 500 chemicals in an average glass of tap water, many of which are used in homeopathic treatments. The EPA of course sets maximum concentration for these chemicals in water, and over time the maximum concentration has decreased considerably. Many people consider this to be a way of making tap water safer to drink, but according to the logic of homeopathy that's actually making it worse! More dilution equals stronger effect.

Most homeopaths seem to ignore this consequence of their theory or offer post-hoc rationalizations such as succussion being needed to "potentiate the solution". If water truly had a memory then city tap water would be one of the most dangerous substances on the planet. However, many others see this as a prime opportunity to make even more money. Various products and magic cleansing waters are sold over the Internet to eliminate these nefarious toxins, with prices potentially exceeding a thousand dollars.

The far more parsimonious explanation is that water does not have a memory and that the well-established physical laws involving dilutions are true. But this will never stop a True Believer.

Beer prove
If your friends insist on water memory, next time you have a drink give them the emptied beer or wine bottles filled with water. They'll be drunk in no time…

Better yet, since "Like cures like," you should drink that water, since it ought to sober you right up!

More questions coming your way
So if water has memory, does beer have memory? How about tea, or coffee? And is it possible that milk also has memory? Oh, how about pee then; does it have memory too? I mean, the list could go on and on.

Next, since water is composed of hydrogen and oxygen, is it hydrogen that keeps the so called memory or oxygen? And if, for the sake of the argument, it is the hydrogen element that is keeping this memory, so how about all other molecules containing hydrogen? Do they have memory too? E.g., Does H2S have memory too?

Last but not least, (and I know this is stupid, but hey, this whole thing is batshit crazy, right?) if water has memory, does water dream too?

Summary
The completely unscientific nature of these hypotheses has been explored elsewhere, but they have a number of flaws in common. The explorations start with the assumption that the phenomenon in question actually exists, and moves from there to try to find a reason why it exists. None of these reasons have any scientific plausibility. Furthermore, the experiments fail to provide adequate control and rigorous determinations of purity, and fail to assess error in the measurements. The proponents also give possible explanations of the phenomenon without any link between their "data" and the proposed physical explanations. Explanations include increased or decreased levels of hydrogen bonding; macroscopic clustering of water molecules; and polymerization (which is impossible unless you have the right trading card in your hand).