Re: Quantum Time Travel

From: Russell Standish <>
Date: Thu, 27 Apr 2000 09:33:04 +1000 (EST)

Sorry about the position eigenstate. You're quite right.

> > However, observers will constrain the form of the
> > universal wavefunction such that the measure is
> > nonuniform, effectively giving it a value.
> The above sentence doesn't make sense. First, the
> term 'measure' is only defined with respect to
> observer-moments. Second, obsevers do not change the
> universal wavefunction, though they do for many
> practical purposes have to deal only with the relative
> state.

A lot of things have measure, not just observer moments. For example,
all strings in the Schmidhuber plenitude have a measure given by the
Universal Prior. Not all strings are observer moments.

Observers select which universal wavefunction they live in (Anthropic

> > The more information one has, the more non-uniform
> > will be the measure.
> The objective measure distribution itself remains
> the same, but one can define a conditional measure
> distribution to reflect the information, useful for
> Bayesian purposes. (One can work with the origianl
> objective measure and carefully apply Bayesian
> analysis.)

The point is that all distributions are conditional. The universal
wavefunction one sees is selected by the fact that one is an observer.

> > But it is still the observer selecting a quantum
> > history that defines the measure.
> What's a "quantum history"?
> An observer-moment doesn't see a history.

The observer sees the history. The history is still there, whether you
believe the observer actually experiences that history, or merely
infers it from information buried within the observer-moment.

My own position is that the observer experiences history from the
moment of birth, but also must infer details of additional history (eg
prior to birth) from records contained within the environment. I
realise I part company with a number of you on this point.

The point being that information (or knowledge) accumulates within the
observer through time, thus constraining the form of the measure
distribution as a function of this time.

> =====
> - - - - - - -
> Jacques Mallah (
> Physicist / Many Worlder / Devil's Advocate
> "I know what no one else knows" - 'Runaway Train', Soul Asylum
> My URL:
> __________________________________________________
> Do You Yahoo!?
> Send online invitations with Yahoo! Invites.

Dr. Russell Standish Director
High Performance Computing Support Unit, Phone 9385 6967
UNSW SYDNEY 2052 Fax 9385 6965
Room 2075, Red Centre
Received on Wed Apr 26 2000 - 16:29:48 PDT

This archive was generated by hypermail 2.3.0 : Fri Feb 16 2018 - 13:20:06 PST