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the distinction between observer and the observed is entirely artificial.

Could you develop that point further, or any chance of posting that segment of your IM chat?

(Or maybe Migeru is already planning to include it in his diary on quantum mechanics and ontology?)

Truth unfolds in time through a communal process.

by marco on Wed Jan 2nd, 2008 at 08:10:30 PM EST
[ Parent ]
No, the diary on ontology is going to be on boring stuff such as
what is an object?
take the physics of quasiparticles and the whole idea of objects falls apart
what constitutes the identity of an object?
take the physics of fermion, boson, anyon statistics and compare with maxwell-boltzmann; take the Gibbs paradox

but if these topics are a prerequisite for discussing ontology, who can take part in the discussion?

it takes the fun out of philosophy
</lecture>

As for the requested discussion on the separation between subject and object:
Migeru: it's funny how QM philosophical problems always end up at the conscious observer
... but I think it's about philosophy, not about quantum consciousness
Colman: Yes.
Migeru: it's like the philosophhy of probability: it's also broken
Colman: It's an artificial split between system and observer. Or somethign along those lines.
Migeru: do you know about the holographic principle in quantum gravity?
Colman: I've heard of it. But I forget...
Migeru: it says roughly... you can put a boundary wherever you want
the area of the boundary is a bound on the information entropy of either half
it appears likely to be a key principle of the new theory
but quite what it has to do with consciousness...
though it does seem to have something to do with these boundaries between systems
Colman: Hm.
Migeru: subject and object, etc
Colman: Could do. The distincition is artifical.
Migeru: the problem is
since we don't understand consciousness
we can't do a toy model of a self-aware entity
Colman: No.
Migeru: so there's no way to put that in QM
and talking about QM as the basis of consciousness just confuses things even more!
Flame away!

We have met the enemy, and he is us — Pogo
by Migeru (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 08:21:53 PM EST
[ Parent ]
How is the Philosophy of probability broken?

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 08:31:14 PM EST
[ Parent ]
One of the main ways IMHO is that the frequentist probability interpretation confuses the definition of probability with the operational way in which probabilities are measured. It takes the law of large numbers as the definition of probability, which makes the conceptual edifice dangerously close to circular.

A big problem with the interpretation of Quantum Mechanics is actually disentangling the philosophy of probability from specifically quantum mechanical conceptual problems.

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 08:35:27 PM EST
[ Parent ]
now that's going to take at least a pint, a bath, and an hour of thinking to come up with an answer to.

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 08:52:44 PM EST
[ Parent ]
You guys are in danger of disappearing up your own arses, so a bath would be good.  I'm told that long threads are almost always the result of flame wars and there hasn't been a bit of excitement here all night!  Can someone please light a fire under these guys so I can scramble some lieutenants?

Index of Frank's Diaries
by Frank Schnittger (mail Frankschnittger at hot male dotty communists) on Wed Jan 2nd, 2008 at 09:17:53 PM EST
[ Parent ]
But aren't there interpretations which don't assume consciousness is necessary?

This seems to be a good thing because otherwise you end up in a solipsistic universe, where you personally are a cause of the Big Bang and all 13 and a bit billion years of everything that happened afterwards. (For varying and approximate values of 'you', at least.)

Assuming consciousness is essential seems to be another spin around the implicit dualism of mind over matter. Although it looks as if it's saying that mind and matter are linked, the implication is really that matter only appears when mind decides it does - which could be a little bit suspect, I think.

How much of a mind do you need before it's conscious enough to start deciding observables?

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 08:53:28 PM EST
[ Parent ]
Why would it have to be you? perhaps your existence is only guaranteed by the existence of another individual who is the actual observer. That would mean that the biblical "thou shalt not kill" might be to guarantee your own existence  and that of the universe, by maintaining the life of the observer.

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 09:03:26 PM EST
[ Parent ]
That's why I asked about how much consciousness you need.

There's a neat paradox which says that if you try to kill yourself in a quantum experiment, you can't do it. If you did you wouldn't be able to observe the result of the experiment. So it would never happen.

Your colleagues meanwhile can see a quantum suicide note, and possibly a dead body.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Wed Jan 2nd, 2008 at 09:21:13 PM EST
[ Parent ]
The flip side of that one is that we're all immortal, we only see other people die and there's at least one history of the universe in which the observer persists.

We have met the enemy, and he is us — Pogo
by Migeru (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 09:22:33 PM EST
[ Parent ]
So that makes the worlds militarists, those who are not taking Pascal's wager in that form.

Any idiot can face a crisis - it's day to day living that wears you out.
by ceebs (ceebs (at) eurotrib (dot) com) on Wed Jan 2nd, 2008 at 10:42:47 PM EST
[ Parent ]
You're right, there are interpretations that do not require a conscious observer: "consistent histories" for instance. But here's the thing: most of these interpretations address primarily the problem of decoherence, that is, the passage from quantum-mechanical interference of complex amplitudes to classical addition of real (and positive) probabilities. What none of them address is the (not quantum-mechanical but probabilistic) problem of actuality (which of the actual histories is realised), which is basically the (probabilistic, not quantum mechanical) problem of assigning a probability to a single event.

Finally, there's an additional twist to this whole discussion which is that decoherence is supposed to be about breaking entanglement, a concept which figures prominently in gaianne's writeup and seems central to the "everything is connected" woo-woo (excuse me) narratives. Now the twist is that entanglement itself is not well defined. It is possible to write down a state of three particles such that depending on the result of a measurement made on A, B and C may or may not be entangled (and cyclic permutations of A, B and C). So, "connectedness" of A, B and C means that "connectedness" of B and C depends on what happens to A far away. This state is called sometimes a Borromean state, by analogy with the borromean rings which are not linked pairwise, but are linked as a set of three.

Back to the beginning, consciousness is not essential but unless a conscious observer is involved, philosophical problems with quantum mechanics seem rather mild to nonexistent, which again suggest a philosophical problem, not a problem with quantum mechanics. The central question is: how are entanglement or interference perceived? Remember Bohr's "no phenomenon is a phenomenon unless it is an observed phenomenon".

We have met the enemy, and he is us — Pogo

by Migeru (migeru at eurotrib dot com) on Wed Jan 2nd, 2008 at 09:20:25 PM EST
[ Parent ]
"'woo woo' is not shorthand, it's rudeness."--Bertrand Russell

http://www.watchingyou.com/woowoo.html

There are 41 statements to the Woo Woo credo, many of which demonstrate that it is a term coming out of Usenet flamewars--or somesuch.  To understand if a person is a woo woo, one would have to run their comments via the list--and if they matched up, you can then call them "woo woos" and start an argument--it's an argumentative term, with some humour but clearly aimed at a certain Usenet type of character (the kind who reports you to the sys admin etc.)  The list does have some enjoyable moments.  I recommend numbers 4, 8, 9, 12, 22...wow, 22!  But I don't recommend using it as shorthand because it is clearly meant to be derogatory.


Don't fight forces, use them R. Buckminster Fuller.

by rg (leopold dot lepster at google mail dot com) on Thu Jan 3rd, 2008 at 04:55:21 AM EST
[ Parent ]
But there's another interpretation which is a kind of extremist Copenhagen view. It says that QM is a tool which calculates probabilities. And that's all it is.

It doesn't try to define what really happens, it doesn't assume that wave functions are 'real' or even that they evolve. All it says is that if you measure a system at time t, the probabilities of the different outcomes are the real part of etc.

The fact that states can be in various baroque non-local superpositions before the interaction doesn't change this. The probabilities will still be consistent and computable.

Migeru:

What none of them address is the (not quantum-mechanical but probabilistic) problem of actuality (which of the actual histories is realised), which is basically the (probabilistic, not quantum mechanical) problem of assigning a probability to a single event.

"It's random within probabilistic constraints" seems to be all that QM can tell you.

There may be a theory which defines the ontology in more detail. But QM doesn't seem to be it.

The only difference between an observer and a non-observer is that the observer is consciously aware of a measured value. But that doesn't define the value.

What's annoying about QM is that it tries to conflate different issues. There's a difference between the physical interaction needed to make a measurement and the mental process of experiencing the measurement. There's also non-locality, which supposedly makes everything very spooky and has somehow - for some reason which has never been properly explained, because it's not really needed - been linked to mental experience, even though it's completely distinct.

Consciousness
Micro to macro amplification ('measurement')
Non-locality etc
'It's all one' woo woo

are all different. I'll take the middle two. I won't accept the other two until someone does an experiment in which two observers measure two contradictory observables from the same quantum system at the same time.

Migeru:

Remember Bohr's "no phenomenon is a phenomenon unless it is an observed phenomenon".

That's almost makes sense, but doesn't, because in the limit it says that nothing in the universe exists unless it's observed. Which seems unlikely - otherwise you're back to solipsism again, with every possible wave function in the entire history of the universe converging on your viewpoint.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Thu Jan 3rd, 2008 at 06:13:12 AM EST
[ Parent ]
Great comment.

Regarding Bohr, isn't that very similar to what Kand said about noumenon and phenomenon? Aren't there serious epistemological issues at the core of all this?

ThatBritGuy:

"It's random within probabilistic constraints" seems to be all that QM can tell you.

There may be a theory which defines the ontology in more detail. But QM doesn't seem to be it.

The only difference between an observer and a non-observer is that the observer is consciously aware of a measured value. But that doesn't define the value.

Which is why I want to make a diary referring to a number of out-there models and experiments from Quantum Mechanics and ask people to hash out the ontology. Because things like "what is an object" are not quite clear. And it is a lot easier to say "the universe is purely relational" than to build any useful model out of that insight, which is why a lot of physicist will talk in those terms around a pool table, but few papers get written.

We have met the enemy, and he is us — Pogo
by Migeru (migeru at eurotrib dot com) on Thu Jan 3rd, 2008 at 06:21:27 AM EST
[ Parent ]
And it is a lot easier to say "the universe is purely relational" than to build any useful model out of that insight, which is why a lot of physicist will talk in those terms around a pool table, but few papers get written.

sniff, sniff  Chris, is that you cooking up another batch of your pudding somewhere?

Truth unfolds in time through a communal process.

by marco on Thu Jan 3rd, 2008 at 06:48:39 AM EST
[ Parent ]
Migeru:
Regarding Bohr, isn't that very similar to what Kand said about noumenon and phenomenon? Aren't there serious epistemological issues at the core of all this?

That depends what you expect physics to do. There's a difference between explaining reality, modelling reality, and defining reality.

I think realistically (sic) the best you can hope for is models of increasing sophistication and usefulness. Explaining reality is best left to theologians. (Not that they have a clue either, but it keeps them busy.)

No one should be trying to define reality, ever, but it's easy to fall into the trap of believing that a theory with predictive power is what's going on ontologically.

Too much physics is still cursed by Platonism. According to Penrose et el., models supposedly float around outside reality telling it what to do.

But there's a huge gap between using experimental recipes to predict what's going to happen next, and assuming there's a Central Recipe Database running things behind the scenes.

One is pattern recognition, the other is metaphysics. One assumes that reality works consistently and the consistency can be enumerated. The other makes unwarranted assumptions about the mechanisms which create that consistency.

by ThatBritGuy (thatbritguy (at) googlemail.com) on Thu Jan 3rd, 2008 at 10:19:21 AM EST
[ Parent ]

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