Re: Memory erasure

From: Hal Finney <hal.domain.name.hidden>
Date: Sun, 1 May 2005 10:30:34 -0700 (PDT)

Saibal Mitra writes:
> Although (quantum) suicide experiments can never be successful, memory
> erasure could still work. Suppose you are an artifically intelligent
> machine and you can erase any part of your memory. One day you receive
> news that an asteroid is on its way to earth which will completely
> destroy the planet. If you just erase this from your memory and check
> the news again you will very likely not hear about this anymore.

That's a cool idea. Once you erase your memory, your consciousness spans
(i.e. is instantiated in) all universes where the event either happens or
does not. If it is an unlikely event, then the fraction of the multiverse
where that event happens is a small fraction of the set of universes which
share your consciousness. So the chance that you will then discover the
bad news is similarly small.

Believers in quantum suicide may for similar reasons argue that memory
erasure is impossible. There is a universe where your memory erasure
attempt fails, and your conscious train of thought proceeds unchanged in
those universes. Universes where you do erase your memory terminate your
train of thought and, from a narrow perspective, kill your current-moment
conscious mind. Hence your mind will proceed only down the pathways
where its consciousness continues to exist, and from your conscious
perspective it will appear that the memory erasure never works.

Arguing against this is that every night you fall asleep, a similar
loss of consciousness (often with memory erasure of the last few
thoughts before sleep). This theory would predict that each night you
only experience universes where, for whatever reason, you never again
lose consciousness.

You can turn this whole chain of logic around and make it an argument
against QS. Sleep proves that loss of consciousness is possible,
and that memory erasure is possible. Imagine memory erasure becoming
so complete that it erases your entire life. Is that possible? If so,
isn't it essentially the same as suicide? Or if it's not possible, where
is the dividing line between the amount of memory erasure that is and
is not possible?

Hal Finney
Received on Sun May 01 2005 - 13:38:07 PDT