Re: Closer To Truth interview

--- In [email protected], David Deutsch <david.deutsch@...> wrote:
>
> On 9 May 2013, at 13:44, hibbsa <hibbsa@...> wrote:
> 
> > --- In [email protected], David Deutsch <david.deutsch@> wrote:
> >> 
> >> 
> >> On 8 May 2013, at 22:23, Steve <sonatine123@> wrote:
> >> 
> >>> Hello David
> >>> 
> >>> Thanks for this link - what an interesting website!
> >>> 
> >>> I have a question about one of your videos.  In 'Many Worlds Of Quantum Theory' you state a figure of 10 raised to 10 raised to the power of 23 as the number of histories involved when considering a cubic metre of air molecules.  How, in principle at least, is this figure derived ?
> >>> 
> >>> Incidentally I have read both of your books, and know a little about the 'Many Worlds Interpretaion' of quantum mechanics.
> >> 
> >> I can't remember the context in which I said that but it'll be something like this: 10^23 is the number of molecules in a mole (which actually occupies 22.4 litres, not a cubic metre, but never mind). If each molecule is in n different places at once, mostly uncorrelated with the others, then there are about n^(10^23) different histories under way. We can let n be 10 quite arbitrarily because with huge numbers like that, the topmost power is pretty much all that counts for purposes of envisaging it.
> >> 
> >> So it's a ballpark estimate raised to the power of a ballpark estimate raised to the power of a ballpark estimate.
> >> 
> > Why don't these histories become fungible on a higher level? 
> 
> It's because different-histories-becoming-fungibe is an interference phenomenon that requires 'fine-tuning' in the interaction. Assuming that the atoms in question start out un-entangled and with (say) approximately sharp positions and momenta and hence in approximately a single history, generic (non-fine-tuned) interactions will tend to entangle them more and more as they bounce around.
> 
> -- David Deutsch
>

DD...maybe fungibility is the wrong word here. 

But would you say 10^23 instances of the same mole in this universe would result in the same emergent macroscopic properties, to about the same extent 10^23 multiverse histories of that mole would? 

The way I see it, this has to be true, because any one of those multiverse histories can show up in any one of those moles in this universe. 

Also....if the same moles didn't result in the same emergent properties, then we wouldn't have a stable deterministic macroscopic reality. 

But then....in what sense are these multiverse histories ever macroscopically different worlds? 

I mean...with differences that are statistically significant?