[extropy-chat] Role of MWI and Time Travel

[Lee Corbin]

Hi Serifino!  Thanks for the info:

> > The key question then comes down to what is meant, again,
> > by "free will". I studied Conway's idea, and even attended
> > a lecture he gave. But I can't say I understand exactly
> > what he's driving at.  
> 
> The problem I see (perhaps! I'm not sure, eh!), 
> with their approach, based on Bell and Kochen-Specker 
> theorems, is that these theorems keep their validity 
> even when we reverse the 'time arrow'. (The time 
> reversed EPR is called RPE!). If this is true, 
> the 'will' must be 'free' from any past cause
> but also from any future 'cause' (given the factlike,
> but not lawlike, time asymmetry, it seems strange
> to speak of future 'cause!).

Is that what is meant by Conway and the others?
That past causes cannot determine some event in
order for it to be "free"? That is too strange.
Especially---moreover---if it is also added that
future 'causes' are forbidden. The latter I can
only interpret to mean as the event may not leave
an unambiguous record, so that the event may be
(backwards) determined.

> [It seems to me (not sure though) that in MWI 
> we cannot have time symmetry because the merging
> of n worlds would cause some overpopulation.
> I mean n Lee(s) and n Serafino(s) all together.
> It is strange because MWI is strictly based
> on Schroedinger's equation, which has no time 
> arrow.]  

I had always supposed time-reversibility of MWI,
but probably unconsciously---as you say, it is
based upon the SE. But as to what this could
mean, I have no clue.

As for overpopulation, I would simply suppose
that the version of me who saw the photon go
up would smoothly merge into the version of me
who saw it go straight; if we branch into 
separate versions going forward in time, wouldn't
it be very natural to merge into a single version
going backwards?

Lee

> [1] V.A.Fock.
> 
> 'Disskussija S Nilsom Borom', in 'Voprosy Filosofii',
> 1964 (a memorandum, about the interpretation of QM
> and the meaning of wavefunction, he gave to Bohr, 
> in Copenhagen, 1957, who read it and, apparently, 
> changed his mind about several points).
> This paper contained 4 objections to Bohr's ideas on 
> the foundations of QM. 
> 
> 1. The wavefunction represents something "real", as it allows 
> one predict the evolution of probabilities; 
> 
> 2. Only Laplacian determinism was broken down by QM; 
> 
> 3. Complementarity principle expresses limitation (imposed
> by Heisenberg's principle) only on the "classical" description of
> phenomena; 
> 
> 4. There is no "uncontrollable" interaction between
> classical apparata and quantum objects.