[extropy-chat] Role of MWI and Time Travel

[scerir]

Hi Lee!

> Uh, I have already retracted that as written, as it gives
> the erroneous impression that in non-deterministic systems
> "free will" would not be awkward. 

Oh, I'm sorry. Since I'm receiving just ... about ... 
1% of the messages of this list - due to ISP's new
general spam filter, which makes confusion between 
'extropy' and ... 'extasy' and 'ecstasy' - I did not 
receive the next messages of the thread.

> > But that has nothing to do with the definiteness
> > of the predicted outcome of the possible measurement
> > performable on a specific system while it is in a given 
> > prepared state.

> Yes, but your case of a specific system in a given prepared
> state is not the general case. In the general case, it's
> not possible, as you know, to announce ahead of time which
> Everett branch you'll be in, at least in the sense of being
> able to win bets. (You can always say that you'll be in 
> both or all branches.)

Yes, it's not possible to announce ahead of time which
Everett branch you'll be in. Eugene Wigner (together 
with Fock, in Russia, Wigner was the only *big* name 
of the *orthodox* wing, at Princeton, who refused 
to believe in what Bohr and von Neumann were saying 
about quantum measurement theory) called that: 
'Everett's indeterminism'.  

> > Even within MWI one cannot predict, in a deterministic
> > way, the definite outcome of the possible measurement
> > performable on a specific system

> A way in which it is "sort of" possible to predict the
> definite outcome is to predict the probabilities of the
> outcomes; 

Usually determinism, in QM, is defined such that 
the probability of the outcome must be 0 or 1. 
(But your position is what V.Fock [1] tried to explain
to the late Bohr, with some, little success).

> then, in MWI, one assumes that the branches
> split deterministically according to the prescribed
> probabilities.

> 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!).

[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.]  

> Russell gave as good a definition
> as I've ever seen:

    Free will is defined as the state of affairs
    where the causal matrix that determines the
    outcome includes your mind as a significant
    part.

Fine indeed.

s.

[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.