> This not quite the case. In the Bohmian interpretation the "collapse"
> is, in fact, determined by the non-local quantum potential pretty
> much as the outcome of a critical phase transition which suppresses
> all the branches of the superposition but the one that matches the
> measured outcome. This is indeed "effective" but hardly pragramatic.
The "collapse" or the "reduction" in the Bohmian theory is something
obscure (to me) and - perhaps - also to the masters like Goldstein
http://plato.stanford.edu/entries/qm-bohm/#cwf and Durr and Valentini
and Cushing, etc. Perhaps it is the effect of the "holistic" nature
of that model :-)
> The Everett Interpretation is just as non-local
> as QM with the peculiar distinction that it accommodates non-locality
> in its peculiar way, where the unconnected "locales" are made relative
> to the different branches of the wave function.
Yes this is also my opinion (and D. Mermin's opinion!). But it is also
true what is saying Bruno Marchal. That it to say, that we must define
non-locality (non-separability, holism, etc.) first! (And I add that
we must check whether non-locality is embedded in the QM formalism