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

p.s. to the other post coming out with this one.

It seems to me you need conscious decisions for multiverse histories to see macroscopic divergence of a significant kind. 

Which sort of puts MWI in the dock for one of the problems it claims to solve: putting conscious observers at the heart of things. 
>