Re: Many Pasts? Not according to QM...

From: Hal Finney <hal.domain.name.hidden>
Date: Thu, 2 Jun 2005 20:00:55 -0700 (PDT)

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.

Hal Finney
Received on Thu Jun 02 2005 - 23:52:45 PDT