21 Dec 04
Originally posted by DoctorScribblesOk. But what if A says, the die roll was 1, and A's
There is not just one wave function in play. There are two, one for each system comprised of an observer and that which is being observed. B is only an observer of the system in which B is an observer. Same for A. When A observes his system, this does not mean that B's system has been observed; B is observing an entirely different system that includes him as the observer.
(unlike some people's) word is unquestionably true.
Did B's system close without his knowing it and now
he knows it after the fact?
Nemesio
21 Dec 04
Originally posted by nemesioNo. By definition of observer, it collapses when B says it does and not before.
Ok. But what if A says, the die roll was 1, and A's
(unlike some people's) word is unquestionably true.
Did B's system close without his knowing it and now
he knows it after the fact?
Nemesio
21 Dec 04
Originally posted by bbarrI don't mean to be. I do so in ignorance.
You seem to be equivocating between these two [b]metaphysically distinct items.[/b]
By metaphysically distinct, to you mean from the perception
of either observer A or B? Isn't there are 'True Answer,' and
A has it?
Nemesio
21 Dec 04
1 edit
Originally posted by nemesioA has the true answer to the question A was asking.
I don't mean to be. I do so in ignorance.
By metaphysically distinct, to you mean from the perception
of either observer A or B? Isn't there are 'True Answer,' and
A has it?
Nemesio
B has yet to obtain the true answer to the question B was asking.
I'm not sure whether it can be said that B has the true answer to the question A was asking.
In any case there is no True Answer because in the quantum framework, there is no True Question. A and B each have their own, albeit apparently quite similar, questions.
21 Dec 04
1 edit
Originally posted by nemesioI mean metaphysically distinct in that the die element of System 1 arnd the die element of System 2 do not satisfy Leibniz's Law; they have relational properties that aren't shared, so they cannot be strictly identical. Perhaps they are numerically identical, but numerical identity doesn't suffice to get you a logical contradiction of the sort that would spell real trouble for the very coherence of QM (e.g., I'm numerically identical to the child born to Charles and Kathleen Barr back in '75, but I'm not strictly identical to that child, I can drink beer legally and that child cannot.) If you want to do away with these implications, you have a range of options. They are indeterminate, however. No, I'm just kidding, they are determinate options. The are also unattractive. You can advocate some wacko Sliders/Quantum Leap style Many-Worlds hypothesis or the even crazier Many-Minds hypothesis, or you can advocate a hidden variables theory of QM a la Bohm and his fancy-pants implicate order, and deny that S's wave equation is a complete and exhaustive description of the systems to which it applies. Unfortunately, the famous Bell experiments seem to rule out any hidden variable theories (well, at least those where the variables at issue are somthing like instruction sets). I wrote a paper a couple years back on the Bell experiments, I'll see if I can dig it up.
I don't mean to be. I do so in ignorance.
By metaphysically distinct, to you mean from the perception
of either observer A or B? Isn't there are 'True Answer,' and
A has it?
Nemesio
21 Dec 04
Originally posted by DoctorScribblesI worked with Arthur Fine and Marc Lange on philosophy of physics, but I started out as an undergrad interested in psych. and physics. I went into phil. 'cause the physics dept. didn't really talk about QM to undergrads and the psych. dept. didn't talk about consciousness.
Holy Christ! Were you a physics undergrad, or did you master quantum physics as part of your work in philosophy?
21 Dec 04
Originally posted by bbarrThat is, the difference in these two numerically identical systems
I'm numerically identical to the child born to Charles and Kathleen Barr back in '75, but I'm not strictly identical to that child, I can drink beer legally and that child cannot.
that keep them from being strictly identical is the passage of time?
21 Dec 04
Originally posted by nemesioNo, I also have all sorts of intrinsic properties that my child counterpart lacks. I'm much bigger and hairier, for instance. You can think of numerically identical entities as two different vertical slices of the same space-time worm (a space-time worm is the path an entity carves through space over time).
That is, the difference in these two numerically identical systems
that keep them from being strictly identical is the passage of time?
21 Dec 04
Originally posted by bbarrGot it! Worms. Tralfmadorians in Vonnegut's Slaughterhouse Five.
No, I also have all sorts of intrinsic properties that my child counterpart lacks. I'm much bigger and hairier, for instance. You can think of numerically identical entities as two different vertical slices of the same space-time worm (a space-time worm is the path an entity carves through space over time).
Ok.
But what two things can be strictly identical?
The doctor wrote 'In any case there is no True Answer because in the
quantum framework, there is no True Question. A and B each have
their own, albeit apparently quite similar, questions.'
This seems to suggest that there is a metaphysically different die in
A's and B's case.
Does A's telling B the die result bring them into strict identicalness?
Nemesio
21 Dec 04
Originally posted by AThousandYoungAs I mentioned: it is all just models. There is no "wave/particle duality". Both are just models: neither is "right". Don't believe that because something's behaviour can be estimated (in ensamble) by an equation that the equation defines the thing. It doesn't.
"Particle model of quantum behaviour"? "Equivalent wave model"?
I have no idea what you are talking about. There's only one model incorporating both particle and wave characteristics as far as I understand it. They are related by the de Broglie formula. The more particle like something is, the less wavelike it is. The more wavelike it is, ...[text shortened]... ion.
What the hell are you talking about? Can you explain please?
You must be trolling me.
I mentioned Green's theorm onlt as is used extensively in statistical mechanics to derive macroscopic behaviour models from quantum models. I was hoping to lance the idea that "because something works it is true" from your mind. I've clearly failed. Well, no matter: I strongly suspect most physics grads suffer the same problems and they all passed, so don't worry about it.
Best of luck for the exams: don't let me (or anyone else) confuse you just when you don't need it!
And PS to Bbar: gosh! A philosopher that seems as if they have a grasp of QM? I'm astonished. Call me a collapsing wave equation! I've heard so much tripe about "wave /particle duality" from philosophers who have no grasp of QM what-so-ever. Give the man a gold star!
21 Dec 04
Why can't the system be described as collapsing an infinite
number of times between two moments in time, just that
no one observes it? That is, between 0 and t, if I look at
the die roll 10 times, it collapses 10 times, but if I had kept
my eyes closed for half, it only collapsed 5 times?
Wouldn't it be easier to say that it collapsed a bazillion times,
just the no one measured it? And, if someone theoretically
measured it and infinite number of times, wouldn't it just add
up to the probabilities in the function itself? That is, the information
was there and was always there, just that no one collected it
and it is now lost?
Nemesio
21 Dec 04
2 edits
Originally posted by nemesioIn science, untestable theories are discarded in favor of testable theories which have equal power of explanation.
Why can't the system be described as collapsing an infinite
number of times between two moments in time, just that
no one observes it?
Your proposed idea of having a model that says the wave function collapses bazillions of times between observations is untestable, for to test it you'd need to observe that which is unobservable under the model you describe.
It's not anymore testable than saying an invisible dragon gobbled up the system in question, did two fast laps around Jupiter, and then came back and spit it out.
The same for the various Multi-verse and Multi-mind models that bbarr has alluded to. They're primarily fanciful explanations that we can't conceive to be testable or verifiable.
You could think of it that way in your head, but it contributes nothing to the usefulness of the model. To say that the wave function collapses only upon observation is equally powerful for descriptive and predictive purposes as saying that it collapses continuously, but the former is testable.
22 Dec 04
Originally posted by DoctorScribblesDoesn't function collapse every time I observe something?
Your proposed idea of having a model that says the wave function collapses bazillions of times between observations is untestable, for to test it you'd need to observe that which is unobservable under the model you describe.
I observe the event 1 time a minute, it collapses once, no?
If observe the even 30 times a minute, it collapses 30
times, no? Can't I extrapolate that if I observe at more
frequent intervals, the wave function collapses that many
times and, at infinity, the graphed points of observation
would mirror the wave function exactly?
Am I totally lost? 🙁
Nemesio
22 Dec 04
Originally posted by nemesioThis experiment cannot be carried out, for it is not well-defined.
If observe the event 30 times a minute
From the perspective of any single observer, a quantum event can only be observed once. The second observation made must be of a different event.
The quantum notions of Event and Observation come in unique pairs.