# Pick a card

It seems that Lionel R. Milgrom, “scientist, writer, homeopath,” has replied to my eLetter. He addresses only the point about what happens to the three-way entangled wavefunction when one of the three components collapses, and I will reply when I've had another look at Greenberger *et al*.

But first I want you to imagine a normal pack of 52 playing cards, and that I deal them out half to you and half to me. Neither of us look at the cards we've been given so neither of us know which 26 out of the 52 we have. But if you pick up your cards an examine them, you'll know not only which cards you have but which cards *I* must have. Our hands of cards are entangled, in the sense that whichever ones I have are the ones you don't have. However, if I had another pack of cards under the table and was cheating then I could break the entanglement. Now this is a classical physical system in which the cards all have definite values even before you look - in the Copenhagen interpretation of quantum mechanics the first card would be a superposition of all 52 until you look and collapse its wavefunction. All the other cards' wavefunctions would then instantaneously reduce to being a superposition of the other 51, and so on until you've collapsed all 26 of your cards and you know which 26 are left for mine. Nobody seriously believes that playing cards can exist in superpositions of values but this is at least a vaguely workable analogy for quantum entanglement. It can't really get to explaining the possible violation of the Uncertainty Principle present in the Einstein-Podolsky-Rosen thought experiment but it's the best I've thought of so far.

ext_75681)I think "addresses" is too strong a word for what he did there. How he hopes to respond to a criticism of the maths in his paper without referring to his paper or any maths is a puzzle to me.

He's defending the overall effect, which is arguably the important thing, but you quite explicitly criticised the underlying maths, which he's not even attempted to address. Why he thinks anyone should trust his opinions on quantum mechanics when he gets the maths all wrong is a second puzzle. I guess it's standard woo-fodder: wordiness and hand-waving arguments hold much more sway in their world than testable mathematical proofs.

If we promise to only observe homeopathic RCTs from directly above would that satisfy him? That way we couldn't measure things that happen along the z-axis.