# wave function collapse

```Hi meekerdb

There are a number of theories to explain the collapse of the quantum wave
function
(see below). ```
```
1) In subjective theories, the collapse is attributed
to consciousness (presumably of the intent or decision to make
a measurement).

2) In objective or decoherence theories, some physical
event (such as using a probe to make a measurement)
in itself causes decoherence of the wave function. To me,
this is the simplest and most sensible answer (Occam's Razor).

3) There is also the many-worlds interpretation, in which collapse
of the wave is avoided by creating an entire universe.
This sounds like overkill to me.

So I vote for decoherence of the wave by a probe.

Roger Clough

--------------------------------------------------------------------
Wave function collapse.

http://en.wikipedia.org/wiki/Wave_function_collapse

"The cluster of phenomena described by the expression wave function collapse
is a fundamental problem in the interpretation of quantum mechanics, and is
known
as the measurement problem. The problem is not really confronted by the
Copenhagen
Interpretation, which postulates that this is a special characteristic of the
"measurement" process.

The Many-Worlds Interpretation deals with it by discarding the
collapse-process,
thus reformulating the relation between measurement apparatus and system in
such a way that the linear laws of quantum mechanics are universally valid;
that is, the only process according to which a quantum system evolves is
governed
by the Schr?inger equation or some relativistic equivalent. Often tied in with
the Many-Worlds
Interpretation, but not limited to it, is the physical process of decoherence,
which
causes an apparent collapse. Decoherence is also important for the
interpretation
based on Consistent Histories.

A general description of the evolution of quantum mechanical systems is
possible by
using density operators and quantum operations. In this formalism (which is
closely
related to the C*-algebraic formalism) the collapse of the wave function
corresponds
to a non-unitary quantum operation.

The significance ascribed to the wave function varies from interpretation to
interpretation,
and varies even within an interpretation (such as the Copenhagen
Interpretation).
If the wave function merely encodes an observer's knowledge of the universe
then
the wave function collapse corresponds to the receipt of new information.
This is somewhat analogous to the situation in classical physics, except that
the classical "wave function" does not necessarily obey a wave equation.
If the wave function is physically real, in some sense and to some extent,
then the collapse of the wave function is also seen as a real process, to the
same extent."

Roger Clough, rclo...@verizon.net
10/23/2012
"Forever is a long time, especially near the end." -Woody Allen

----- Receiving the following content -----
From: meekerdb
Time: 2012-10-22, 12:26:39
Subject: Re: Continuous Game of Life

On 10/22/2012 12:51 AM, Quentin Anciaux wrote:

2012/10/22 Jason Resch

On Sun, Oct 21, 2012 at 12:46 PM, John Clark wrote:

On Sun, Oct 21, 2012 Bruno Marchal wrote:

>> I stopped reading after your proof of the existence of a new type of
>> indeterminacy never seen before because the proof was in error, so there
>> was no point in reading about things built on top of that

> From your "error" you have been obliged to say that in the WM duplication,
> you will live both at W and at W

Yes.

yet your agree that both copy will feel to live in only one place

Yes.

> so the error you have seen was dues to a confusion between first person and
> third person.

Somebody is certainly confused but it's not me. The fact is that if we are
identical then my first person experience of looking at you is identical to
your first person experience of looking at me, and both our actions are
identical for a third person looking at both of us. As long as we're identical
it's meaningless to talk about 2 conscious beings regardless of how many bodies
or brains have been duplicated.

Your confusion stems from saying "you have been duplicated" but then not
thinking about what that really means, you haven't realized that a noun (like a
brain) has been duplicated but a adjective (like Bruno Marchal) has not been as
long as they are identical; you are treating adjectives as if they were nouns
and that's bound to cause confusion. You are also confused by the fact that if
2 identical things change in nonidentical ways, such as by forming different
memories, then they are no longer identical. And finally you are confused by
the fact that although they are not each other any more after those changes
both still have a equal right to call themselves Bruno Marchal. After reading
these multiple confusions in one step of your proof I saw no point in reading
more, and I still don't.

John,

I think you are missing something. It is a problem that I noticed after
watching the movie "The Prestige" and it eventually led me to join this list.

Unless you consider yourself to be only a single momentary atom of thought, you
probably believe there is some stream of thoughts/consciousness that you
identify with. You further believe that these thoughts and consciousness are
produced by some activity of your brain. Unlike Craig, you believe that
whatever horrible injury you suffered, even if every atom in your body were
separated from every other atom, in principle you could be put back together,
and if the atoms are put back just right, you will be removed and alive and
well, and conscious again.

Further, you probably believe it doesn't matter if we even re-use the same
atoms or not, since atoms of the same elements and isotopes are functionally
equivalent. We could take apart your current atoms, then put you back together
with atoms from a different pile and your consciousness would continue right
where it left off (from before you were obliterated). It would be as if a
simulation of your brain were running on a VM, we paused the VM, moved it to a
different physical computer and then resumed it. From your perspective inside,
there was no interruption, yet your physical incarnation and location has
changed.

Assuming you are with me so far, an interesting question emerges: what happens
to your consciousness when duplicated? Either an atom for atom replica of
yourself is created in two places or your VM image which contains your brain
emulation is copied to two different computers while paused, and then both are
resumed. Initially, the sensory input to the two duplicates could be the same,
and in a sense they are still the same mind, just with two instances, but then
something interesting happens once different input is fed to the two instances:
they split. You could say they split in the same sense as when someone opens
the steel box to see whether the cat is alive or dead. All the splitting in
quantum mechanics may be the result of our infinite instances
discovering/learning different things about our infinite environments.

I would add that what's interresting in the duplication is the what happens
next probability (when the "two" copies diverge). If you're about to do an
experience (for exemple opening a door and looking what is behind) and that
just before opening the door, your are duplicated, the copy is put in the same
position in front of an identical door, the fact that you were originally (just
before duplication) in front of a door that opens on new york city, what is the
probability that when you open it *it is* new york city... in case of a single
universe (limited) where not duplications of state could appear the answer is
straighforward, it is 100%, but in case of comp or MWI, the probability is not
100%, you must take in account all duplications (now and then) and there
relative measure. That is the "measure" problem. The "before" divergence is not
interresting, that's the point where John stays stuck willingly.

Quentin

There is something puzzling here. Duplication at the lowest level, cloning the
quantum state, is impossible. And even duplicates at a relatively high state,
e.g. nuerons, must quickly diverge just because of interactions with the
uncontrolled environment - and in fact if QM is correct it is the interaction
with the environment that permits the "higher" classical level to exist. In
this thought experiments, Bruno sweeps these problems aside by considering
conscious states. Conscious states are very crude things. We're not aware of
very much of the world. So Bruno notes that a given conscious state is
consistent with a lot of different worlds - different computational states in
different computational threads of a UD. Then he proposes that the physical
world is just a kind of consistency class within all the consciousness threads
(intersujective agreement). But each thread of computation that contributes to
a given consciousness only does so in virtue of being consistent with the other
threads (one is never literally of two minds). So it seems that consciousness,
by this theory, is an epiphenomena on certain classes of computation (e.g.
those that 'hang together' enough to be conscious "of" something). Then we're
back to the same sort of question asked of materialism, but instead of "Why is
this physical process conscious and not that one?" the question is "Why is this
bundle of computational states conscious and not that one?"

Brent

--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to