The latest issue [96 (3)] of Homeopathy is dedicated to the memory of water. There's not much point in me actually dealing with the idea of the memory of water itself, firstly because the paper  with Rustum Roy  on it is being dealt with elsewhere, and secondly because there's a paper  in this very issue which explains why any structures which develop in liquid water don't really persist on their own for much more than a picosecond, and furthermore that there are plenty of ways in which a sample can get contaminated .
Because you see the memory of water wouldn't really be a non-trivial quantum effect  - it wouldn't be anything to do with the physically unfeasible macroentanglement  and Weak Quantum Theory  which Milgrom has been going on about for the past seven years [10-16]. (I'd like to note though that he gets the units of Planck's constant right this time, even if he still misspells Gribbin, Auyang and Del Giudice [17-19].)
Milgrom writes a lot about nonlocality and mentions “recent” experiments, citing Aspect et. al. from 1982 . Nonlocality means that information travels through space “instantaneously” instead of being limited by the speed of light, and the work by Bell  on the Einstein-Podolsky-Rosen  thought experiment said that the answers which quantum mechanics gives mean that we can't keep both locality and realism. I presume Milgrom has not heard of the (actually) recent work by Gröblacher et. at.  which theoretically and experimentally rules out quite a broad class of nonlocal Hidden variable theories and therefore rather knackers the assumption of realism. But anyway, it's not worth spending too much time on the Collapse of the Wavefunction and the Copenhagen interpretation, because nobody bothers with that stuff anymore [24,25]. Milgrom quotes Richard Feynman saying that “Anyone who thinks they have understood quantum theory has probably got it wrong!”  but this doesn't mean that just because Milgrom doesn't understand quantum theory (he thinks it's non-deterministic, for heaven's sake) that he's a clever as Feynman.
Anyway I should get on to entanglement. This is a phenomenon in which the wavefunction of a system cannot be split up into the wavefunctions of the components to be treated separately: you have to take the whole lot if you want to get the right answer. Now if you're a nonlocal realist who still believes in the nonunitary collapse of the wavefunction you may have to face the fact that the wavefunction collapses everywhere in space at the same moment, when viewed from any inertial frame at all. Luckily the wavefunction itself is not a real object and the collapse cannot actually be used to transmit information . (If you think this explanation is bad you should try the one in Weingärtner's paper .)
But quantum-coherent states tend to be destroyed quite quickly by interactions - superconductors and superfluids only work because the particles within them are protected against interacting with each other by being forbidden to absorb or emit quantities of energy which are smaller than some threshold (or something) - so these hypothetical large clusters of water molecules are specifically not going to be coherent in a quantum sense (Del Giudice et. al.  were talking about coherence in the sense of all the water molecules lining up in an externally imposed electric field - something else entirely). So entanglement is irrelevant .
Oh well. I wonder if we'll now start to see more fighting amongst homeopaths? That can only be a good thing, since the sooner they sort out amongst themselves what they think is really going on in a homeopathic preparation, the sooner the rest of us can tell them how wrong they are.
- Manju Lata Rao, Rustum Roy, Iris R. Bell, and Richard Hoover. The defining role of structure (including epitaxy) in the plausibility of homeopathy. Homeopathy 96 (3) 175-182 (2007)
- Rustum Roy, William A. Tiller, Iris Bell, and M. Richard Hoover. The Structure of Liquid Water; Novel Insights from Materials Research; Potential Relevance to Homeopathy. Mater. Res. Innov. 9 (4) 577-608 (2005)
- José Teixeira. Can water possibly have a memory? A sceptical view. Homeopathy 96 (3) 158-162 (2007)
- L. R. Milgrom, K. R. King, J. Lee, and A. S. Pinkus. On the investigation of homeopathic potencies using low resolution NMR T2 relaxation times: an experimental and critical survey of the work of Roland Conte et al. Brit. Homeopathy J. 90 (1) 5-13 (2001)
- L. R. Milgrom. Conspicuous by its absence: the Memory of Water, macro-entanglement, and the possibility of homeopathy. Homeopathy 96 (3) 209-219 (2007)
- Otto Weingärtner. The nature of the active ingredient in ultramolecular dilutions. Homeopathy 96 (3) 220-226 (2007)
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- Lionel R. Milgrom. Patient-Practitioner-Remedy (PPR) entanglement. Part 1. a qualitative, non-local metaphor for homeopathy based on quantum theory. Homeopathy 91 (4) 239-248 (2002)
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- Lionel R. Milgrom. Patient-Practitioner-Remedy (PPR) Entanglement, Part 7: A Gyroscopic Metaphor for the Vital Force and Its Use to Illustrate Some of the Empirical Laws of Homeopathy. Forsch. Komplementmed. 11 (4) 212-223 (2004)
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