Quantum Superposition & Philosophy

[Maui]

Why not? What are your examples to support your view?

Okay, i am going to say it - from what you say it follows that you don't understand what matter is. You say we have to stick to our classical concepts, because we don't have a choice. But NOT all of the properties matter fit the classical picture.
Instrumentalism is not viable for philosophy, so we need to move on to the other alternatives.

If there's any, you haven't shown it.

This doesn't mean the approach is wrong. I already stated that i consider the internal workings of the brain an essential part of how the classical notions emerge. Until we have a theory of brains what i propose will lie in obscurity(this holds for the rest of the interpretations as well, imo).

This isn't a definition nor an indication that you've understood what "quantum superposition" is, which is the topic of this thread. In other words, you've not answered my question on what is meant by quantum superposition. I know very well all the physical experiment that has demonstrated quantum superposition, even up to "macroscopic" scale, considering that I've mentioned the Delft/Stony Brook SQUID experiments a gazillion times in the physics forums (just do a search if you don't believe me).

Quantum superposition, while it is a quantum concept, still make use of classical parameters of position, momentum, energy, spin, etc... and the experimental measurements are all classical, i.e. they measured these quantities.

Again, talk is cheap, really. I haven't seen a single example where a classical concept isn't invoked, even in the quantum picture. And please, tell me what "quantum superposition" is!

Zz.

A superposition of states is the simultaneous existence of all possible states of a system at the same time. Including classically impossible states, like left-and-right, up-and-down, dead-and-alive-cat, etc. etc.


Explain to me in classical terms the existence of a virus that's put in superposition of states. I'd prefer a picture/image of it(imagine that we could take a measurement without destroying the superposition).

What does classical model has anything to do with classical concepts of position, etc.? Classical models can be faulty AND has been shown to be limited in applicability. That isn't the issue.

This is the issue. The inadequacy of the classical models. I have no other point to make in this thread, except the limited applicability of the classical concepts for a coherent worldview.

 

[baywax]

Maui, perhaps your magazine has succumbed to the confines of probability theory and is

P(AnotB) + P(AandB) + P(BnotA) + P(notAnotB) = 1 (magazine)

We may be missing a point here:

no observation means there is no observer. There's no way to prove anything else concerning the lack of observation.

 

[apeiron]

Yes, that's how we approximate our models to reality but our classical models are inherently flawed because they are based on those classical concepts. That's NOT how the universe is, is it?

What do you understand by "classical" (so we can get a clearer idea of what would be non-classical)? And what even does "concept" mean here?

A metaphysical concept (such as position or entropy) is a quality (a qualitative description) that justifies a crisp quantitative measurement in its name. In philosophy, such concepts are formed dichotomously - if A, then not-A. So position is defined by its complementary quality of momentum. Position is what doesn't change, and momentum is all the kinds of possible change. With a well-defined pair of terms like this, you can then make quantitative measurements. You have a spectrum of states that lie now between the absolute limits of complete stasis and complete flux.

So whether classical or non-classical, we would expect the same metaphysical game. We would need to anchor the discussion in terms of complementary pairs of qualities, that then would allow the clear quantification of observables.

Now the essense of classicality is surprisingly complex. But it involves a variety of reductions (a causal reduction being the claim that while complementaries may always be necessary, reality can in fact be reduced to one end of the spectrum as a fundamental truth).

So classicality assumes at least all of the following - locality, atomism, determinism, monism, mechanicalism.

And we can see that QM challenges all of these ontic categories.

And we can see that the "other" is already present in the metaphysics of classicality. To have locality as a crisply meaningful concept (something we can actually measure or quantify), we had to have the idea of its "other" - non-locality or globality. We just do not have a well-developed physics which uses globality as a quality, a causal extreme, to which our measurements of the world can be anchored.

It is the same story for the other ontic categories. We have a clear idea of how to measure atomism, but not holism; monism, but not some kind of dualism or dyadicy (or indeed triadicy); mechanicalism, but not some kind of organicism.

Determinism seems a little different as we do have a well-developed way of measuring randomness (whoops, recent discussions here reveal that the basis of this system is not widely understood).

Anyway, QM is indeed a metaphysical challenge to classicality. But the good news is that classicality is itself so sharply defined as a collection of ontic concepts that the "other" is already clearly in sight if you care to look.

We are not waiting for a philosophical revolution. Just for scientists to step back from what they think they know and appreciate the wider view. When people stop worrying about the weirdness of non-locality and start talking about the effects of globality, then the penny will have dropped.

 

[ZapperZ]

Okay, i am going to say it - from what you say it follows that you don't understand what matter is. You say we have to stick to our classical concepts, because we don't have a choice. But NOT all of the properties matter fit the classical picture.
Instrumentalism is not viable for philosophy, so we need to move on to the other alternatives.

You are confusing classical concepts with classical physics. Classical concepts are parameters such as position, momentum, spin, etc. Look in the Schrodinger equation. NO matter how much you think it is a quantum description, it STILL uses classical concepts! Position and momentum and energy, etc. are all the OBSERVABLES of the system!

I'm an experimentalist. I have to be aware of what I'm measuring. I don't just TALK about it on some public forum.

This doesn't mean the approach is wrong. I already stated that i consider the internal workings of the brain an essential part of how the classical notions emerge. Until we have a theory of brains what i propose will lie in obscurity(this holds for the rest of the interpretations as well, imo).

It does mean that you're making things up without any ample justification for its validity other than simply a matter of tastes. I frankly don't have time to debate on someone's favorite color.

A superposition of states is the simultaneous existence of all possible states of a system at the same time. Including classically impossible states, like left-and-right, up-and-down, dead-and-alive-cat, etc. etc.

Explain to me in classical terms the existence of a virus that's put in superposition of states. I'd prefer a picture/image of it(imagine that we could take a measurement without destroying the superposition).

These two paragraphs clearly show that you don't have a firm understanding of quantum superposition.

1. A superposition of states (or what you call "simultaneous existence of all possible states") isn't anything interesting at all. We have classical superposition all the time in wave mechanics. Yet, no one makes any philosophical discussion ad nauseum on that topic on here. So what's so different with quantum superposition?

2. The difference comes in in what has been called as the First Quantization, i.e. the commutation relation of 2 observables or operators, i.e. [A,B]. When one makes a measurement, the naive view of this process is that the wavefunction is an eigenfunction of the operator, such as A, such that a particular value (eigenvalue) will be the outcome. However, this is NOT the full story! If B commutes with A, then if the wavefunction is non-degenerate, then one would have determined the value of B as well with a measurement of A. But what if B does not commute with A? Then the superposition for observable B REMAINS, i.e. the measurement of A does NOT destroy the superposition represented by observable B.

3. What this means is that the question on whether an object "exists" or not as representing "quantum superposition" is a fallacy! "Exist" isn't an observable. A measurement of position is. One doesn't determine the existence of the ENTIRE object. One determines INDIVIDUAL properties, such as position, momentum, energy, spin, charge, etc... etc., where EACH ONE Of these properties are represented by a particular observable operators (Hermitian operators). Thus, the question of the "existence" of a virus in a superposition of states" is meaningless. One can measure, say, the energy eigenvalue, position eigenvalue, etc. (assuming that the wavefunction are eigenfuctions of these observables, i.e. the matrix is purely diagonal), but to ask if such a thing "exist" in a superposition is a bastardization of quantum mechanics.

This is the issue. The inadequacy of the classical models. I have no other point to make in this thread, except the limited applicability of the classical concepts for a coherent worldview.

I don't think you have the ability to make that judgment.

Zz.

 

[Maui]

You are confusing classical concepts with classical physics. Classical concepts are parameters such as position, momentum, spin, etc. Look in the Schrodinger equation. NO matter how much you think it is a quantum description, it STILL uses classical concepts! Position and momentum and energy, etc. are all the OBSERVABLES of the system!

I'm an experimentalist. I have to be aware of what I'm measuring. I don't just TALK about it on some public forum.

I wasn't in any way aguing that position, momentum, spin, etc are not classical descriptions. I thought it was obvious that I was arguing that they are HIGHLY inadequate to convey what the nature of anything is, since that which they PARTIALLY describe is inherently NOT classical. An atom will never be a classical system, no matter how much effort you put into arguing agaist this point. The whole universe is nowhere near being a classical entity and i am not aware of any researcher spending time on something as DUMB as deriving the universe in its entirety from classical concepts.

It does mean that you're making things up without any ample justification for its validity other than simply a matter of tastes. I frankly don't have time to debate on someone's favorite color.

Human beings do not experience directly(read 1:1) reality as it is, but as it is interpreted by the brain. That should be a start in a situation like this of deep conceptual difficulties.

These two paragraphs clearly show that you don't have a firm understanding of quantum superposition.

1. A superposition of states (or what you call "simultaneous existence of all possible states") isn't anything interesting at all. We have classical superposition all the time in wave mechanics. Yet, no one makes any philosophical discussion ad nauseum on that topic on here. So what's so different with quantum superposition?

That there's a classical world. That you are here, among the waves and their superpositions and that we are talking about it. That's a LOT. It's fairly easy to notice that you are not perceiving yourself to be among a field of superpositional waves, but among seemingly solid matter. Yes, that's an amazingly BIG deal with enormous philosophical weight

.

2. The difference comes in in what has been called as the First Quantization, i.e. the commutation relation of 2 observables or operators, i.e. [A,B]. When one makes a measurement, the naive view of this process is that the wavefunction is an eigenfunction of the operator, such as A, such that a particular value (eigenvalue) will be the outcome. However, this is NOT the full story! If B commutes with A, then if the wavefunction is non-degenerate, then one would have determined the value of B as well with a measurement of A. But what if B does not commute with A? Then the superposition for observable B REMAINS, i.e. the measurement of A does NOT destroy the superposition represented by observable B.

Yes, the uncertainty relationship holds for quantum systems and not for larger objects(though it still holds for quantized superpositional electromagnetic fields), but i don't see how that's relevant to the argument that classical concepts are highly inadequate to explain what the nature is of that which exists.

3. What this means is that the question on whether an object "exists" or not as representing "quantum superposition" is a fallacy! "Exist" isn't an observable. A measurement of position is. One doesn't determine the existence of the ENTIRE object. One determines INDIVIDUAL properties, such as position, momentum, energy, spin, charge, etc... etc., where EACH ONE Of these properties are represented by a particular observable operators (Hermitian operators). Thus, the question of the "existence" of a virus in a superposition of states" is meaningless. One can measure, say, the energy eigenvalue, position eigenvalue, etc. (assuming that the wavefunction are eigenfuctions of these observables, i.e. the matrix is purely diagonal), but to ask if such a thing "exist" in a superposition is a bastardization of quantum mechanics.

I didn't ask if a virus existed in a superposition but whether the classical description was adequate. It isn't. It's adequate for a crude model of what and how the universe is, but it is inherently flawed, the further we push science, the more we understand that it's deeply flawed. It's all just a dramatic human misconception to think of the universe as bodies floating in spacetime.

I don't think you have the ability to make that judgment.

Well, I can't step out of my human body and mind and see where the classical pictures go terribly wrong, but it's obvious that it's all wrong, all our models are wrong on a deeper level as a desciption of what exists. "Judgments" are opinions and since there's no TOE, everything proposed to what really exists is good for a philosophical discussion, but ultimately it is just someone's judgement(a matter of tastes, as you say). But it can't keep us from noticing that the classical concepts and the image we build upon them are JUST the tip of the iceberg.

 

[ZapperZ]

I wasn't in any way aguing that position, momentum, spin, etc are not classical descriptions. I thought it was obvious that I was arguing that they are HIGHLY inadequate to convey what the nature of anything is, since that which they PARTIALLY describe is inherently NOT classical. An atom will never be a classical system, no matter how much effort you put into arguing agaist this point. The whole universe is nowhere near being a classical entity and i am not aware of any researcher spending time on something as DUMB as deriving the universe in its entirety from classical concepts.

But these FUNDAMENTAL CONCEPTS are unavoidable! That's why I kept asking you for alternatives! All you have done is whine about how they are "inadequate" without offering any alternatives! That's the same as complaining about space-time. We can't cannot use them! Our fundamental way of describing the universe from First Principles (the Lagrangians and Hamiltonians) explicitly used such a concept! And that is MY EVIDENCE that such a thing is unavoidable. You have NONE! All you have is simply an argument based on tastes!

Human beings do not experience directly(read 1:1) reality as it is, but as it is interpreted by the brain. That should be a start in a situation like this of deep conceptual difficulties.

Prove that what we observe is DIFFERENT than what it really is. Show such empirical evidence!

That there's a classical world. That you are here, among the waves and their superpositions and that we are talking about it. That's a LOT. It's fairly easy to notice that you are not perceiving yourself to be among a field of superpositional waves, but among seemingly solid matter. Yes, that's an amazingly BIG deal with enormous philosophical weight

Yes, the uncertainty relationship holds for quantum systems and not for larger objects(though it still holds for quantized superpositional electromagnetic fields), but i don't see how that's relevant to the argument that classical concepts are highly inadequate to explain what the nature is of that which exists.

I didn't ask if a virus existed in a superposition but whether the classical description was adequate. It isn't. It's adequate for a crude model of what and how the universe is, but it is inherently flawed, the further we push science, the more we understand that it's deeply flawed. It's all just a dramatic human misconception to think of the universe as bodies floating in spacetime.

Well, I can't step out of my human body and mind and see where the classical pictures go terribly wrong, but it's obvious that it's all wrong, all our models are wrong on a deeper level as a desciption of what exists. "Judgments" are opinions and since there's no TOE, everything proposed to what really exists is good for a philosophical discussion, but ultimately it is just someone's judgement(a matter of tastes, as you say).

This set of responses are simply red herrings. You are responding to my "brief lesson" on quantum superposition and to show why YOUR UNDERSTANDING of what it is is severely inadequate. So now you think you know MORE about such a thing than I do?

This thread is a clear example of what we're trying to get away from in the Philosophy forum, i.e. a discussion based on IGNORANCE of the material being discussed. One would think that the most logical methodology of discussing something is to start with a clear understanding of the issues being discussed, in this case "quantum superposition". A brief reading about quantum superposition in pop-science articles are laughably and seriously (in superposition) inadequate. So people have been essentially discussing something that they know nothing about! A discussion on quantum superposition, BEFORE one tries to make any "philosophical meaning" out of it, requires a very clear understanding of what it is (i.e. the physics), the premise surrounding it (i.e. why is this clearest for eigenvectors and eigenvalues of the system), and what are the empirical evidence and advancement for it! So if one is discussing this and is totally ignorance of the Delft/Stony Brook experiments, and Tony Leggett's treatise on the measurement problem that was the impetus for the Delft/Stony Brook's experiments, then one doesn't have a clear idea of what we know about quantum superposition! One is talking about something based on ignorance!

This was why I asked for people who've been involved with this thread lately to show me what they know about quantum superposition. It is very disheartening that only one person even offered an attempt at defining what it is. Did the others simply made it up? Have the quality of discussion here done SO FAR downhill that one no longer has any self-respect as to not care if what one is discussing is based on an accurate understanding of the subject matter?

Zz.

 

[Maui]

Prove that what we observe is DIFFERENT than what it really is. Show such empirical evidence!

Are you seriously asking for empirical evidence for SR and QM? And you are accusing me of chasing red-herrings, duh.

This set of responses are simply red herrings. You are responding to my "brief lesson" on quantum superposition and to show why YOUR UNDERSTANDING of what it is is severely inadequate. So now you think you know MORE about such a thing than I do?

And yours was SO adequate, that you couldn't even produce 1 meaningful CLASSICAL description of superpositional states. Well done!

This thread is a clear example of what we're trying to get away from in the Philosophy forum, i.e. a discussion based on IGNORANCE of the material being discussed.

Nice cop out, but I and everyone else here, are still waiting for your classical description of a macro object put in a superposition of states.

This was why I asked for people who've been involved with this thread lately to show me what they know about quantum superposition. It is very disheartening that only one person even offered an attempt at defining what it is. Did the others simply made it up? Have the quality of discussion here done SO FAR downhill that one no longer has any self-respect as to not care if what one is discussing is based on an accurate understanding of the subject matter?

Zz.

I claim that you don't have an adequate understanding of superpositions(mind you, i used the word 'understanding', not 'knowledge'). I am also claiming that the involved classical thinking about them is very inadequate. And you are going round in circles without addressing the core issue - that the classical way of thinking and its notions are highly deficient for a coherent worldview.

 

[ZapperZ]

Are you seriously asking for empirical evidence for SR and QM? And you are accusing me of chasing red-herrings, duh.

Yes, if you are claiming that you can find empirical evidence that does not make one single use of those classical concepts that I've stated! I would LOVE to see such empirical evidence out of SR and QM, especially considering that my line of work is nothing but experiments involving both of those fields.

And yours was SO adequate, that you couldn't even produce 1 meaningful CLASSICAL description of superpositional states. Well done!

I don't think you can either, because the phrase "classical description of superpositional states" can't be found in classical mechanics/wave mechanics text. Did you just made it up as you go along?

Nice cop out, but I and everyone else here, are still waiting for your classical description of a macro object put in a superposition of states.

When you make a measurement, the OUTCOME is classical! If you make a measurement of the ENERGY eigenvalue of a quantum state, that concept of energy is CLASSICAL! Now, the BEHAVIOR of the energy eigenvalue may be described via quantum formulation (i.e. it is quantized, have specific values, will only go through one slit or the other), but the CONCEPT OF ENERGY itself is classical!

This appears to be something very difficult for you to understand, even after being told repeatedly.

I claim that you don't have an adequate understanding of superpositions(mind you, i used the word 'understanding', not 'knowledge'). I am also claiming that the involved classical thinking about them is very inadequate. And you are going round in circles without addressing the core issue - that the classical way of thinking and its notions are highly deficient for a coherent worldview.

And I claim that you have no idea what you are talking about. You have PROVEN a very shallow understanding of quantum superposition, based directly on the evidence provided by YOU. You also cannot distinguish between the description of the concept, versus the concept itself. You somehow cannot distinguish that the concept of position is classical, but that position value itself can be dynamically described quantum mechanically.

I've argued where your responses are wrong in terms of physics. All you have done is argue why my responses are wrong based on your TASTES! It is why I put no emphasis on your opinion that I don't understand superposition.

Zz.

 

[yoda jedi]

It's a great question OP. A great mystery and perhaps the only mystery. Feynman said if you can answer this question you can answer everything about quantum mechanics.

These days people do not like the Copenhagen Interpretation. They prefer dechoherence or MWI. Dechoerence (simply) states that at some point when objects are large enough their wave function collapses. A flimsy answer imho especially as we are now observing macroscopic objects (although in very specific states) in a superposition. It is based on peoples reluctance to think that our reality may be much stranger than we imagine.

not stranger...
STRONGER.

...and INDEPENDENT.

at the beggining of the universe who observes ?


Reality is above us.

 

[apeiron]

And I claim that you have no idea what you are talking about. You have PROVEN a very shallow understanding of quantum superposition, based directly on the evidence provided by YOU. You also cannot distinguish between the description of the concept, versus the concept itself. You somehow cannot distinguish that the concept of position is classical, but that position value itself can be dynamically described quantum mechanically.

You may again be missing the essential metaphysical or philosophy of science issue here.

Central to the concept of classicality is locality. And therefore what strict classicality requires is the localisation of all properties of particles. The weirdness of QM is that measurements such as position~momentum are not commutative. You cannot localise the properties to an instant in spacetime as strict classicality would require.

Yes, you can still use the classical concepts themselves individually and orthogonally. In fact it is a major finding that there is a tight dichotomous relationship between complementary forms of measurement. We can start building a revised metaphysics based on this new concept (complementarity).

But it is quite wrong to say that QM does not challenge a central plank of classical physics. Patently it does.

 

[ZapperZ]

You may again be missing the essential metaphysical or philosophy of science issue here.

Central to the concept of classicality is locality. And therefore what strict classicality requires is the localisation of all properties of particles. The weirdness of QM is that measurements such as position~momentum are not commutative. You cannot localise the properties to an instant in spacetime as strict classicality would require.

Yes, you can still use the classical concepts themselves individually and orthogonally. In fact it is a major finding that there is a tight dichotomous relationship between complementary forms of measurement. We can start building a revised metaphysics based on this new concept (complementarity).

But it is quite wrong to say that QM does not challenge a central plank of classical physics. Patently it does.

I think it is my turn to say that you are missing my point here. I'm not arguing that QM is different than classical physics! This would be silly. I use QM ALL THE TIME! I've been trained as a condensed matter physicist, a subject area that was built on QM! In fact, I'll even point out that superconductivity, which is an area of study in condensed matter, in the words of Carver Mead, is the clearest manifestation of quantum phenomena anywhere in nature!

So are we clear now about the validity of QM?

What I pointed out to be wrong is the claim that one can get completely away from classical concepts. I even listed examples of what I said to be classical concepts, such as position, momentum, spin, energy, etc.. etc. Why are they classical concepts? Because they represent observables that we know of, AND, they represent the outcome of our measurements. All measurements that we make are inherently classical, because the system will interact with a large degree of freedom to make itself known to produce a particular observable outcome!

I'm not particular impressed with "building a revised metaphysics" (whatever that means) when people trying to do that have a faulty understanding of what they are using as building blocks! I'm not here to participate in such a building (I'm already busy building my own project, which is an actual build, rather than a metaphysical one). What I'm pointing out is that people here do not seem to CARE that they have either an ignorant, or a lack of, understanding of the things they are discussing or using.

I don't know if this is the ONLY area of study where people who are not experts in a particular subject area are told that "Hey, you might want to double check what you are using. That is not really correct!", they turn on you! You are welcome to "metaphysicalize" all you want, but if you do that based on a lack of understanding of what you are using, don't you think this requires correcting?

I have already stated why I think the understanding of "quantum superposition" that has been discussed has been severely lacking. I just don't TELL people that. Instead, I obviously "wasted" my time and effort to try and give as clear as an explanation that I can! But somehow, that explanation offended SOME people!

Zz.

 

[apeiron]

I'm not particular impressed with "building a revised metaphysics" (whatever that means) when people trying to do that have a faulty understanding of what they are using as building blocks! I'm not here to participate in such a building (I'm already busy building my own project, which is an actual build, rather than a metaphysical one). What I'm pointing out is that people here do not seem to CARE that they have either an ignorant, or a lack of, understanding of the things they are discussing or using.

We can all agree it is a great advantage to really understand what you want to discuss - and if not, be here to learn. In the past, you have pointed me at some key recent QM experiments, which I appreciate.

But there seems less point jumping up and down in a philosophy sub-forum about people wanting to do too much philosophy for your tastes. We get that you can get by in your daily work without raising wider questions.

Now back to the essential point. You are incorrect if you say that using classical concepts in a non-commutative fashion is the same as using them in the commutative fashion that classicality presumes.

Can you provide some argument that locality - the core concept in the classical view, as the nearest philosophy of physics book on my bookshelf attests - does not demand that properties of particles be localised in spacetime?

If attempts to localise one kind of measurement sends the other off into orbit, then that is a clear breach of classicality.

Yes, you may be happy to ignore this metaphysical difficulty, shrug your shoulders and say I still use classical concepts to make my measurements. In my working life, I step over the gapping holes in the principle of locality.

But you have not shown that the gap doesn't exist. And you are demonstrating a faulty and misleading understanding of the metaphysics if you continue to insist there is no issue. Is this really your intention here?

 

[pftest]

This quote fits in nicely here:

"If you are not completely confused by quantum mechanics, you do not understand it."
- John Wheeler

 

[Maui]

Yes, if you are claiming that you can find empirical evidence that does not make one single use of those classical concepts that I've stated! I would LOVE to see such empirical evidence out of SR and QM, especially considering that my line of work is nothing but experiments involving both of those fields.

Let's focus on wave-particle duality. The classical picture is supposed to be a 'wavicle'. So what is a "wavicle"? An object, idea, knowledge, bit, me, you, god? Can you ever know based on the classical concepts?(that's a rhetorical question of course)
I am not arguing that it IS 100% possible to imagine or comprehend a non-classical reality, I'm not certain myself, but i was pointing out the need to soften the classical grip to break new grounds.

I don't think you can either, because the phrase "classical description of superpositional states" can't be found in classical mechanics/wave mechanics text. Did you just made it up as you go along?

Yes, it's not in the textbooks, because there is no classical description and it defies imagination. But if you look at the top of the page, it says "philosophy forum", so I am sure you wouldn't be breaking any rules if you engaged in the philosophical implications of observed non-classical behavior.

When you make a measurement, the OUTCOME is classical! If you make a measurement of the ENERGY eigenvalue of a quantum state, that concept of energy is CLASSICAL! Now, the BEHAVIOR of the energy eigenvalue may be described via quantum formulation (i.e. it is quantized, have specific values, will only go through one slit or the other), but the CONCEPT OF ENERGY itself is classical!

This appears to be something very difficult for you to understand, even after being told repeatedly.

It's not what i was saying, this is probably the 10th time i will point out that that what you measure is classical, but what you don't isn't. That which you measure is how the world responds to your methods of inquiry(not what the world is or how the world is), and that which you don't measure is what the world actually IS(a grand unified field, a non-classical world or whatever you want to name it). The knowledge about that which is unmeasured is inferred from experiment such as the twin-slit, the dce, Delft/Stony Brook SQUID experiment, etc.

You somehow cannot distinguish that the concept of position is classical, but that position value itself can be dynamically described quantum mechanically.

It's misleading to say that a position of an electron is always classical. It's not, it's all over the place, all it takes is knowledge about the other noncommuting variable. A wavepacket is not a classical concept as well.

I've argued where your responses are wrong in terms of physics. All you have done is argue why my responses are wrong based on your TASTES! It is why I put no emphasis on your opinion that I don't understand superposition.

Zz.

Okay, let me re-phrase one more time - it's obvious that the world exists and that it doesn't succumb to a coherent classical description(impossible to interpret in a classical way fundamental building blocks of matter acting on a dynamical spacetime). Is this the universe's fault or are YOUR instruments and methods of inquiry/analysis at fault?

 

[Maui]

But it is quite wrong to say that QM does not challenge a central plank of classical physics. Patently it does.

Don't worry, he doesn't understand much of anything as far as how everything is supposed to fit in a coherent world picture, based on those classical concepts. And you are right that the philosophical baggage of QM is enormous.

 

[ZapperZ]

Let's focus on wave-particle duality. The classical picture is supposed to be a 'wavicle'. So what is a "wavicle"? An object, idea, knowledge, bit, me, you, god? Can you ever know based on the classical concepts?(that's a rhetorical question of course)
I am not arguing that it IS 100% possible to imagine or comprehend a non-classical reality, I'm not certain myself, but i was pointing out the need to soften the classical grip to break new grounds.

This is where you confused over the main issue. A 'wave-particle' isn't a "measurement or an observable"! It is a generic description of a series of observation in which a system behaves like a classical wave or a classical particle. Thus, when we apply it to our knowledge of classical physics, we say that that system has a wave-particle duality.

But "wave-particle duality" doesn't exist in QM! Read the FAQ in the General Physics forum! Yet, even in making such measurement, we have to determine location (i.e. position), especially in those which-way experiments! These are classical parameters inside a quantum description!

Your example has continued to prove my point. I'm still waiting for your example that does not use such classical concepts.

Yes, it's not in the textbooks, because there is no classical description and it defies imagination. But if you look at the top of the page, it says "philosophy forum", so I am sure you wouldn't be breaking any rules if you engaged in the philosophical implications of observed non-classical behavior.

But you asked for a measurement to be determined, which is now in the realm of physics (since when is a physical measurement done in Philosophy?). The "topic" may be philosophy, but if you use physics concepts as the topic of discussion, then it must also be valid in physics. If not, you are not discussion philosophy of science, and you're doing the same type of garbage that the worst of post-modernists did to science (and got soundly embarrassed by the infamous Sokal Hoax). If that is what you are doing here, you are also in violation of the PF Rules.

It's not what i was saying, this is probably the 10th time i will point out that that what you measure is classical, but what you don't isn't. That which you measure is how the world responds to your methods of inquiry(not what the world is or how the world is), and that which you don't measure is what the world actually IS(a grand unified field, a non-classical world or whatever you want to name it). The knowledge about that which is unmeasured is inferred from experiment such as the twin-slit, the dce, Delft/Stony Brook SQUID experiment, etc.

This makes no sense.

If what I measure is represented by eigen operators, and each of them produce results are are classical (as even you admitted), then these are classical parameters/concepts! Observables in QM are x (position), p (momentum), H (energy), etc... etc... The Hamiltonian/Schodinger equation is built using these quantities. So while the evolution and description of these parameters are quantum mechanical and not classical, these parameters themselves are STILL CLASSICAL AND HAVE CLASSICAL DEFINITIONS!

So for the 10th time or more, that is THE WHOLE POINT THAT I'VE BEEN TRYING TO GET ACROSS TO YOU!

It's misleading to say that a position of an electron is always classical. It's not, it's all over the place, all it takes is knowledge about the other noncommuting variable. A wavepacket is not a classical concept as well.

Read above! The way the position of an electron is described by QM is NOT classical. But the concept of position itself is classical! It is why we go "huh?" when we look at how QM grabs hold of this concept and caused it to produce very weird, non-classical description.

Furthermore, what does "non commuting variable" have anything to do with the spread in position? The spread in position observable has nothing to do with that observable commuting or non-commuting with another observable. This is highly puzzling.

Okay, let me re-phrase one more time - it's obvious that the world exists and that it doesn't succumb to a coherent classical description(impossible to interpret in a classical way fundamental building blocks of matter acting on a dynamical spacetime). Is this the universe's fault or are YOUR instruments and methods of inquiry/analysis at fault?

No one is saying that classical description works all the time! I have NEVER said, in any of the post, about classical description dominating all of physics. This is what you kept harping on, and you need to stop it.

Do yourself a favor, and look at the Schrodinger Equation. Pay attention to the parameters used in that equation (i.e. either the Laplacian, or if in 1D, the spatial derivative). Those parameters are classical. The equation is quantum mechanical!

Now, which part of that did not NOT understand?

Zz.

 

[ZapperZ]

Don't worry, he doesn't understand much of anything as far as how everything is supposed to fit in a coherent world picture, based on those classical concepts. And you are right that the philosophical baggage of QM is enormous.

To understand the baggage of QM, you have to understand QM first, and not simply some superficial idea of what it is, which was what has been demonstrated on here. You think the philosophical baggage of QM is enormous? You haven't even seen anything yet! You guys are still arguing about "superposition" and "duality", etc... while the rest of us have gone on to observe "spin-charge separation" and "low-dimensional universe"... etc.

But of course, *I* don't understand much of anything as to how these things are supposed to fit in. It requires a lack of understanding of QM as a required skill to be able to see such a thing.

Zz.

 

[apeiron]

If what I measure is represented by eigen operators, and each of them produce results are are classical (as even you admitted), then these are classical parameters/concepts! Observables in QM are x (position), p (momentum), H (energy), etc... etc... The Hamiltonian/Schodinger equation is built using these quantities. So while the evolution and description of these parameters are quantum mechanical and not classical, these parameters themselves are STILL CLASSICAL AND HAVE CLASSICAL DEFINITIONS!

So for the 10th time or more, that is THE WHOLE POINT THAT I'VE BEEN TRYING TO GET ACROSS TO YOU!

Thank you for correcting your statements to accord more with the facts. Classical parameters used within a quantum mechanical setting.

But this still creates the valid metaphysical issue of how we now conceive of this QM context - what is our concept of that? Despite your 10th go round, you still seem to believe this is not something that is a rightful topic for others to be discussing here.

Are you denying that locality is a central plank of the classical view? It is for instance what allowed Newton to talk intelligibly about velocity - change at an infinitesimal instant. And QM is non-classical in that it had to give up this central plank of classicality (even if still retaining other bits of the observational furniture such as position and momentum).

You can't have it both ways - insist that others recognise what aspects of classicality are preserved in QM, yet not yourself acknowledged what aspects got junked.

The wavicle, complementarity principle, hidden variables, many worlds, and other such concepts have indeed been attempts to rethink what a quantum reality might mean.

There is an important point being buried here - that in fact we don't have to completely abandon classicality and jump to some new bizarre QM metaphysics (like MWI or observer-created realities for example). Saner middleground approaches like environmental decoherence are emerging - which you could say deliver quasi-locality. It would be nice if these were a popular topic of discussion.

But instead we are only hearing the extreme views - either that there are no answers at all (if you think you understand QM, then you prove you don't really), or that we should not even be asking the questions,

 

[Maui]

The forum ate a rather long reply i made(it logs me out constantly) . I'll see if i can find the motivation to write it again today.

 

[Maui]

But this still creates the valid metaphysical issue of how we now conceive of this QM context - what is our concept of that? Despite your 10th go round, you still seem to believe this is not something that is a rightful topic for others to be discussing here.

Reminds me of a quote from a well known movie:

"The fish doesn't think, because the fish knows everything"

This is where you confused over the main issue. A 'wave-particle' isn't a "measurement or an observable"! It is a generic description of a series of observation in which a system behaves like a classical wave or a classical particle. Thus, when we apply it to our knowledge of classical physics, we say that that system has a wave-particle duality.

Yes, a "wave-particle' is just a generic description, and very misleading at that, BECAUSE it's classical and inadequate. There is no classical picture for what a 'wavicle' is, hence you(and everyone else) are forced to acknowledge that you don't know what anything really is. That's why i insisted that we need to soften up the grip on the classical concepts. On a more personal level, i find it much more consistent to think of the universe in terms of relations, not in terms of objects, ala Carlo Rovelli's:

"Quantum mechanics is a theory about the physical description of physical systems relative to other systems, and this is a complete description of the world"

though, philosophically, that statement is lacking in content and is missing something essential.

But "wave-particle duality" doesn't exist in QM! Read the FAQ in the General Physics forum! Yet, even in making such measurement, we have to determine location (i.e. position), especially in those which-way experiments! These are classical parameters inside a quantum description!

So what are you arguing about? Just everyone agrees that using the established scientific method, we can only conclude that the quantum world is primary(if not fundamental), whereas the classical is only a limited, special case.

Your example has continued to prove my point. I'm still waiting for your example that does not use such classical concepts.

I never argued that we don't use classical concepts, but that they are often inadequate. Again, i don't see what this argument is about. People of the same opinion don't argue.

But you asked for a measurement to be determined, which is now in the realm of physics (since when is a physical measurement done in Philosophy?). The "topic" may be philosophy, but if you use physics concepts as the topic of discussion, then it must also be valid in physics. If not, you are not discussion philosophy of science, and you're doing the same type of garbage that the worst of post-modernists did to science (and got soundly embarrassed by the infamous Sokal Hoax). If that is what you are doing here, you are also in violation of the PF Rules.

We are doing physics even before we make a measurement to get a classical result. Yes, calculations are physics. Those calculations tell us something about the world that doesn't fit the classical worldview.

This makes no sense.

If what I measure is represented by eigen operators, and each of them produce results are are classical (as even you admitted), then these are classical parameters/concepts! Observables in QM are x (position), p (momentum), H (energy), etc... etc... The Hamiltonian/Schodinger equation is built using these quantities. So while the evolution and description of these parameters are quantum mechanical and not classical, these parameters themselves are STILL CLASSICAL AND HAVE CLASSICAL DEFINITIONS! So for the 10th time or more, that is THE WHOLE POINT THAT I'VE BEEN TRYING TO GET ACROSS TO YOU!

I agree, but that was not my point. There is no disagreement on what you are saying which is fairly obvious.

Read above! The way the position of an electron is described by QM is NOT classical. But the concept of position itself is classical! It is why we go "huh?" when we look at how QM grabs hold of this concept and caused it to produce very weird, non-classical description.

No disagreement here.

Furthermore, what does "non commuting variable" have anything to do with the spread in position? The spread in position observable has nothing to do with that observable commuting or non-commuting with another observable. This is highly puzzling.

The spread in position is determined by knowledge of the other non-commuting variable - momentum. Same with wave-particle duality.

No one is saying that classical description works all the time! I have NEVER said, in any of the post, about classical description dominating all of physics. This is what you kept harping on, and you need to stop it.

Do yourself a favor, and look at the Schrodinger Equation. Pay attention to the parameters used in that equation (i.e. either the Laplacian, or if in 1D, the spatial derivative). Those parameters are classical. The equation is quantum mechanical!

Now, which part of that did not NOT understand?

Zz.

We are not arguing any more.