----- Original Message -----
From: ""Hal Finney"" <[EMAIL PROTECTED]>
To: <everything-list@eskimo.com>
Sent: Friday, June 03, 2005 05:00 AM
Subject: Re: Many Pasts? Not according to QM...

##
Advertising

> Stephen Paul King writes:
> > I really do not want to be a stick-in-the-mud here, but what do we
base
> > the idea that "copies" could exist upon? What if "I", or any one else's
1st
> > person aspect, can not be copied? If the operation of copying is
impossible,
> > what is the status of all of these thought experiments?
> > If, and this is a HUGE if, there is some thing irreducibly quantum
> > mechanical to this "1st person aspect" then it follows from QM that
copying
> > is not allowed. Neither a quantum state nor a "qubit" can be copied
without
> > destroying the "original".
>
> According to the Bekenstein bound, which is a result from quantum gravity,
> any finite sized system can only hold a finite amount of information.
> That means that it can only be in a finite number of states. If you
> made a large enough number of systems in every possible state, you would
> be guaranteed to have one that matched the state of your target system.
> However you could not in general know which one matched it.
>
> Nevertheless this shows that even if consciousness is a quantum
> phenomenon, it is possible to have copies of it, at the expense of
> some waste.
This is actualy another argument against QTI. There are only a finite number
of different versions of observers. Suppose a 'subjective' time evolution on
the set of all possible observers exists that is always well defined.
Suppose we start with observer O1, and under time evolution it evolves to
O2, which then evolves to O3 etc. Eventually an On will be mapped back to O1
(if this never happened that would contradict the fact that there are only a
finite number of O's). But mapping back to the initial state doesn't
conserve memory. You can thus only subjectively experience yourself evolving
for a finite amount of time.
Saibal