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Free will?

LegionOnomaMoi

Veteran Member
Premium Member
Hello PolyHedral

1. Can you kindly explain your double Yes-s

I'm sure PolyHedral will correct me if I am wrong and/or misunderstanding him, but in English (unlike, say, Latin), the word "or" can be exclusive or inclusive. So, for example, if someone asks "Is today Tuesday, or not?" the answer "yes" is always correct, because either it is Tuesday (in which case the answer is "yes it is either Tuesday or not"), or it is not Tuesday (in which case the answer is "yes it is either Tuesday or not"). However, generally speaking if someone were to ask such a question, it is interpreted as an exclusive "or": either it is Tuesday, or it is not, but it is not both. But "formal language" (i.e., symbolic/mathematical logic, as well as most informal use of logic) assumes that the English "or" is inclusive unless otherwise specified.
 

Skeptisch

Well-Known Member
But "formal language" (i.e., symbolic/mathematical logic, as well as most informal use of logic) assumes that the English "or" is inclusive unless otherwise specified.
“…in the nineteenth and twentieth centuries, science became too technical and mathematical for the philosophers or anyone else except for a few specialists. Philosophers reduced the scope of their inquiries so much that Wittgenstein the most famous philosopher this century said 'The sole remaining task for philosophy is the analysis of language.' What a comedown from the great tradition of philosophy from Aristotle to Kant!”
Stephen Hawking
:computer:
 

LegionOnomaMoi

Veteran Member
Premium Member
“…in the nineteenth and twentieth centuries, science became too technical and mathematical for the philosophers or anyone else except for a few specialists. Philosophers reduced the scope of their inquiries so much that Wittgenstein the most famous philosopher this century said 'The sole remaining task for philosophy is the analysis of language.' What a comedown from the great tradition of philosophy from Aristotle to Kant!”
Stephen Hawking
:computer:

Hawking is no philosopher; and Wittgenstein was on to something.
I find both of these statements interesting, but even more so when taken together. As I've said more than once (and probably never aptly), it took a long time for most of what we consider science and mathematics to become distinct from philosophy. I suspect that Willamena knows (and perhaps you do as well, Skeptisch), how much time Aristotle spent on language, and before him Plato. In the early modern period, a good deal of philosophy meant "natural philosophy" (i.e., the physical sciences), but from Aristotle through Kant to modern cosmologists, physicists, philosophers, mathematicians, and cognitive scientists, a key component to using and understanding the scientific methods has been philosophies of language.

And while Hawking is in some sense correct (if overly simplistic), that philosophy has become so much a discipline distinct from fields of mathematics and sciences, people like Hawking (cosmologists and theoretical physicists) spend a great deal of time on metaphysics and the philosophy of mathematics. However, as philosophers are no longer generally considered scientists or mathematicians, I find that many scientists who are essentially philosophers in the older sense of the word (when it subsumed, at least to a certain extent, both science & mathematics) wish to distinguish themselves from philosophers because they fear such an identification will mean a loss of legitimacy.

It is especially easy for someone reading work in cosmology and theoretical physics to get the impression that it seems more like philosophy than science as they understand it to be (performing experiments and publishing studies). Of course, there are plenty of experiments in both, and plenty of studies or reviews filled with advanced mathematics, but a great many concern the philosophy of science, the philosophy of mathematics (and therefore logic, and therefore language), epistemology, and ontology. The foremost proponents of "quantum theories of mind/consciousness" are generally physicists (e.g., Sir Roger Penrose, Henry P. Stapp, Thomas Filk, Giuseppe Vitiello, Kunio Yasue, Huping Hu), especially compared to how many neuroscientists or neuropsychologists explore consciousness at all, let alone quantum dynamics in the brain (although this is changing).

So while it is true that many who are interested in philosophy elect to pursue it in disciplines like physics or cognitive science, and those who actually have doctoral degrees which include the word "philosophy" in them apart from "doctor of philosophy" itself typically do not have the background to understand technical literature in the physical sciences, I disagree with Hawking's statement about mathematics. The one area of mathematics which remains under the purview of philosophy (i.e., specialists here receive a PhD in "philosophy") is logic, which is at the heart of mathematics. The study of language and logic in philosophy means a study of abstract mathematics; category theory, set theory, probability, and similar fields of mathematics are quite frequently the concern of philosophers at least as much as they are mathematicians.

Moreover, a few years ago when I was wondering where to go next in my study of mathematics, I talked to my (former) neighbor who is a Professor of Mathematics at Brown University. During the conversation, I asked certain questions pertaining to statistics, graph theory, and computational mathematics which he not only couldn't answer, but also did not know the terms, names, and works I referred to. This is not because he is a bad mathematician (far from it) but because his specialty is number theory, and as mathematics has become so unbelievably specialized in many respects, most mathematicians know as much about some other field of mathematics as your average sociologist knows about quantum mechanics. Then there is the problem that too many active researchers in certain sciences do not have even a sufficient enough background in mathematics to understand the mathematics they actually use.
 
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PolyHedral

Superabacus Mystic
The fact that their study is an experimental finding showing this is not the case. That they observed a violation of time-reversal invariance (a reversal in time) that is not supposed to happen.
It feels as though you're talking out both sides of your mouth. Or did you not notice I said time asymmetry?

T-symmetry is a violation of causality. It means that systems can go backwards or forwards in time.
Even with time-invertible laws of physics, events will still be well-ordered-able; there will simply be two different choices of consistent ordering.

Lightcones and spacetime didn't change either, just the way they were described. A system which is time-symmetric is one which can run forwards or backwards in some "time-like" region. The authors include "violation" in their title because they observed time-reversal in a system that (according to modern physics) is not supposed to happen.
I am led to believe that time-reversal violation was expected to happen, because it was the counterpart to CP-symmetry violation. The fact that the two are both no longer symmetries of physics mean that the combined CPT-symmetry holds, which is apparently important. (This probably has significant implications when combined with Noether's theorem, but I'd have to search to see what it was.)

According to what logic and what model of complexity?
Any model of complexity that establishes a partial order demands a(t least one) least element of the set of configurations that are complex enough to be irreducible. If no such element exists, the set must be empty by the definition of partial order and the fact we're operating on a countable set.

You asked for the difference, now you provided it.
I never asked for a difference. I explicitly disagreed.

The reason that "measurement cannot be described by standard quantum dynamics" is because "measurement" in quantum mechanics means something totally different than it does in classical mechanics.
Your quote from the paper does not say this, or mention anything about measurement meaning different things in relation to QM vs. classical mech. It says exactly what you quoted: "measurement cannot be described by standard quantum dynamics." No qualifiers, no disambiguities, no clarification about what "measurement" means.

The "function(s)" which map the system's state at one time to the state at another do not describe any state of any physical system.
You assert this, and things like it, multiple times in that post. Support this assertion.

...saying "there's the state of the physical cell" by pointing at the model and never checking the "state" of the model against that of the neuron.
We have checked the state of the model again the neuron - they are the same. That is, quantum theory's answers matches reality.

But the only way we could answer this is by saying "well, because we have no idea how our description of the physical system or physical states correspond with anything physical. But we call it that so that when we publish papers it still looks like physics."
You sound like a disbeliever. :p

It's arguably worse than that. We don't know if there's anything physical there to correspond to! :p

...That was a theoretical attack on the quantum-to-classical transition, and by transition I mean all the "vanishing h" stuff which is supposed to "get us" what we experience out of quantum theory, making everything explainable in terms of quantum theory.
You sure about that? Because what it sounds like its attacking is the idea of wavefunctions being things that collapse at a certain size, by demonstrating how you can extend wavefunctions to ludicrous size. This in turn attacks the idea that quantum mechanics is just corrections to a classical reality - hence Everett's interpretation that quantum is everything.

The classical limit as a concept as been around since Relativity, and is entirely unrelated to Schroedinger's cat, because in the classical limit of a vanishing h, superpositions are impossible. Classical mechanics emerging from quantum was shown by Dirac of all people ("The Lagrangian in quantum mechanics", Phys. Z. der Sowjetunion 3: 64-71.) and was a well-known enough result that Feynman's thesis was on it.

However, as QM doesn't deal with physical systems, this is a problem.
See above; you do not - and AFAIK cannot - support this assertion.

Counterfacutal indefinitness does not, but this means that I can't assert anything about particles, because as soon as I do, I have violated counterfactual indefiniteness.
Quantum-y doodads aren't particles. So yes. :p

Good question. I build a model like Rosen's or one used in systems biology. It's a model of a cell. If I am using Hamiltonian mechanics, I try to describe the dynamics of the cell in terms of the "bodies" or parts of it. If I can't, I say my model is an approximation.
So... which part of that is "reality"? The model? :shrug:

"What we expected" the state to be doesn't correspond to the state of the physical system in the first place.
What physical system has the state? You say the equation isn't the system, but then what is? :shrug:

Sure, we can't see it. But we can't see lot's of things in classical mechanics which we can measure (we can't see velocity). And when we describe a classical system in terms of things like our measurements of velocity, angular momentum, etc., we can say what is travelling at x speed in b direction.
Remember, the actual experimental data you have is a series of still images. Everything else is based on extrapolation and theory. :p You can't measure instantaneous velocity, for instance, only differences in position over arbitrarily small differences in time.

...we also can't say anything about the physical system, because what we call the physical system was never physical to begin with.
So what is the physical thing? You'll notice I've asked this question multiple times - there's been multiple times you've assumed that the equations do not model the physical thing, without apparently knowing what the physical thing is.

Hack what? The system? We don't.
Newtonian mechanics, which, for good reason, has no concept of light. Therefore, you need to adjust it if you want to use it to model vision.

I have no doubt. But the math seems to be the problem here.
I can describe this functional process as formally as you wish, certainly equal to any wavefunctions formal nature. I can make the model of the system as mathematically rigourous as any quantum system in QM.
So describe it to the point where I can put numbers in and get numbers out. :shrug:

Because it is not pure mathematics.
"Does this formal system imply this condition?" is pure mathematics - in fact, for varying systems and conditions, that is all pure mathematics is.

However, the "vanishing h" approach (quantization)...
...I hope what you've written there doesn't imply what I think it implies. Since a vanishing h is the opposite of quantization.

Only if one can derive the classical laws without assuming that they first exist. This approach: doesn't. It assumes the classical laws in order to derive them.
Knowing what we want to derive does not entail "assuming" anything. We could attempt to derive any arbitrary statement, and we wouldn't be "assuming" they first exist in the theory.

The various sources I've cited aren't saying that "what we see is reality" and trying to make quantum "fit that reality", but recognizing that the solution we've been using so far, to imagine that our "vanishing h" or decoherence can be used to derive classical physics from quantum reality not only has no theoretical basis (and never really did),
Vanishing h has nothing to do with decoherence. :facepalm: Also, you better take away Feynman's PhD if constructing classical physics from quantum has "no theorectical basis."

"An example of the latter stance is the Copenhagen interpretation of quantum mechanics, which postulates a fundamental dualism between a microscopic “quantum” domain and a macroscopic “classical” realm.
Today, our view has changed drastically. On the one hand, quantum effects have been observed in the laboratory far beyond the microscopic domain. Researchers have created mesoscopic and macroscopic "Schrödinger kittens” such as superpositions of microampere currents flowing in opposite directions and interference patterns for massive molecules composed of dozens of carbon atoms"
from Schlosshauer's Decoherence and the Quantum-to-Classical Transition (The Frontiers Collection; Springer, 2007)
I repeat: why does the Everett interpretation care about how big your coherent wavefunction is?

The idea was that quantum processes like superpostion states, entanglements, etc., somehow "decohered" so rapidly beyond the subatomic level that their effects were never felt...
...So you agree with me. Reality is quantum, and classical stuff is just a nice abstraction that leaks around the edges, both in terms of mathematical modelling, and, critically, in experiment. There is no limit to the extent - in space or time - of a quantum object, because, in reality everything is a quantum object - we just happen to be highly entangled with all of the ones we consider "classical."
 

PolyHedral

Superabacus Mystic
Hello PolyHedral

1. Can you kindly explain your double Yes-s (highlighted in red above)?
The someone exists, and the first question is a false dichotomy. Wise and considered judgements are not mutually exclusive from determinism.

When someone says "I have fee will", what is meant by the "I"? Is the "I" known independent of name-and form attributes?
No, the I is a mental/social construct.

Can a bunch of attributes ever have any free will?
Depends. What's "free will?" :D

OTOH, can a causally determined intellect (an inevitable inference of the determinism) assert that "I do not have free will"?
Sure. May or may not mean its true, though.
 

idav

Being
Premium Member
...So you agree with me. Reality is quantum, and classical stuff is just a nice abstraction that leaks around the edges, both in terms of mathematical modelling, and, critically, in experiment. There is no limit to the extent - in space or time - of a quantum object, because, in reality everything is a quantum object - we just happen to be highly entangled with all of the ones we consider "classical."

Those particles interact in such a way that it proves they are actual particles. You send a bunch of bucky balls though the slits you get a pattern. It can be calculated if enough is known, spin, mass and actual location for starters would help. I say actual location because a superposition isn't the real particle.
 

PolyHedral

Superabacus Mystic
Those particles interact in such a way that it proves they are actual particles. You send a bunch of bucky balls though the slits you get a pattern. It can be calculated if enough is known, spin, mass and actual location for starters would help. I say actual location because a superposition isn't the real particle.
Definite, deterministic answers cannot be calculated, regardless of information. For one thing, your measurements will disturb and invalidate your previous measurements.
 

LegionOnomaMoi

Veteran Member
Premium Member
Since this is kind of a seperate issue, and yet not, I'm going to address it seperately because it really requires a rather thorough treatment:
It feels as though you're talking out both sides of your mouth. Or did you not notice I said time asymmetry?
I did notice. And don't blame me for talking about of both sides of my mouth, blame quantum field theory. That's the name of the game. But I'll try to do better here.

The problem (apart from the fact that I have probably explained things badly), is that
1) The terms in QFT with respect to time symmetry, transformations, and reversals don't even equate in general with the "similar" processes in classical mechanics, let alone the vernacular
2) The counter-intuitive nature of QFT itself makes it rather difficult to explain what is desired and why, and how the use of technical terms corresponds to something a normal person might say
&
3) What is "desired" at a macroscopic scale (and even at times in the universe as a whole) and at the macroscopic local level are often different (or opposite) things

So I'm going to attempt a more complete explanation of the study you linked to, and the concepts in it, but in the wider context of modern physics (and the problems associated with it) in general.

I'm sure you know that even in classical mechanics, the "arrow of time" was a problem in two ways. First, classical physics required, for the most part (or at least implied) that time was symmetric. The idea is that for any given system, if you know all the laws and reverse them, you get what you started with. Time-symmetry is required for this. Yet we don't experience time symmetry, we only experience time going in one direction. So both time asymmetry and time symmetry are "problems", which were sort of resolved by thermodynamics in classical physics. Enter relativity and quantum theory, and a whole new way of dealing with these issues. Now, as long as we've thrown all reality as we know it out the window at the quantum level, why not throw in time-reversal too? If we can get microscopically local reversable systems, and do the same "vanishing h" act that we do with quantum nonlocality, we get two birds with one stones (and why not? after all, we have live and dead cats in two places at once).

But we need a new language for the new physics. Enter the CPT theorem which you are probably familiar with. Charge conjugation, spatial (parity) reflection, and time-reversal = CPT. Quantum field theory pretty much requires CPT invariance. In other words, at the quantum level, we need a system to be completely symmetric or reversable. It's fundamental to QFT, and unlike nonlocality (which nobody ever wanted), some manner of making localized systems symmetric which included time, but somehow explained why we experience time asymmetry, was just fantastic. How wonderful. Sure, there was an intial worry with the maximal violation of C and P, but with some nifty mathematics, we retained CP symmetry (and CPT invariance) and the world breathed a sigh of relief. Or rather, the small subset whom the rest of the world paid to deal with crap like this.

Your study is the latest in a series that began in 1964 which has yet to be resolved and is fundamentally problematic: CP violations themselves. But what has this to do with time?

Well, unlike the violations of C and P, the violation of CP together with the assumption of CPT invariance (again, that fundamental component of QFT), means a violation of time-reversal symmetry. To put it another way: assume that CPT invariance holds. If CP is violated, then given this assumption it can only be that we have a violation of CP and T reversals. Under the assumption that reversing the system dynamics gets you the same system (that foundational component of QFT we call CPT invariance), we find that this violates CPT symmetry.

T-reversal is a bit misleading. And by a bit I mean totally. Because while it is "time-reversal" in some sense, it's really motion reversal. And as, in quantum mechanics, "motion" is such a difficult thing to deal with (so difficult, we don't deal with them, we ignore the actual system dynamics and make up something else we call the system), the idea of CPT invariance is about as fundamental as you can get in modern physics. Being able to, at the very least, take our mathematical systems and demonstrate how our "measurements" exhibit the desired symmetry brings us one step closer to explaining how the macroscopic world we experience derives from quantum reality.


As Bigi & Sanda put it in the opening of their book CP Violation (Cambridge Monographs on Particle Physics, Nuclear Physics, and Cosmology, vol. 28), the disparity between how we experience time and how it is described in physics could (we hoped), be "understood" if "microscopic T invariance" existed in such a way that the same invariance is "so unlikely to occur for a macroscopic system." However:
"It came as a great shock that microscopic T invariance is violated in nature, that ‘nature makes a difference between past and future’ even on the most fundamental level."

It is CP violations, along with the assumption of CPT invariance, which get us the time-reversal asymmetries we don't want at the microscopic level, because we needed these to explain how (like other quantum processes) something like "decoherence" made these vanish at the macroscopic level.

The study you linked to was "direct evidence" (relative to other evidence, anyway) of this reversal violation.

So on the one hand, it is a study which provides further evidence that quantum field theory's explanation for our uni-directional experience of time fails, and it does this through demonstrating that the means behind this explanation (microscopic symmetry which becomes unbelievably improbable at the macroscopic level), is violated.
It is another challenge for QFT theory, and another step back in deriving the "classical" world from the quantum "reality".
 
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LegionOnomaMoi

Veteran Member
Premium Member
The fact that the two are both no longer symmetries of physics mean that the combined CPT-symmetry holds, which is apparently important. (This probably has significant implications when combined with Noether's theorem, but I'd have to search to see what it was.)

This is rather fundamental, just in case it was missed above. It does not mean that CPT-symmetry holds. It means under the assumption that it holds, a violation of CP-symmetry entails a violation of T-symmetry. And that is what is found experimentally in (for example) the study you linked to, which means a fundamental component in our model of time asymmetry at the macroscopic level (which we get by doing some "vanishing h" disappearing act) is gone.

Any model of complexity that establishes a partial order demands a(t least one) least element of the set of configurations that are complex enough to be irreducible. If no such element exists, the set must be empty by the definition of partial order and the fact we're operating on a countable set.

How on earth are you relating posets to irreducible models? From relative computational complexity or some similar aspect of computability? Many-one relations, Turing reducibility, & Degree structure reducibility all describe sets which are computable, or reducible to some computable set via a computable function. If you can configure the set, it's computable and reducible. A poset (partially ordered set) requires a function (or relation) of a specific type such that it is antisymmetric, reflexive, and transitive. By definition, a partial order on a set entails a computable function. Irreducible complexity means (in this case) that the function itself is both intrinsic, essential, and fundamental to the system and is also uncomputable. It cannot be computed because any model of the process has no order required for computability. Or, in terms which are inherent to computer science, computability, systems analysis, and biology, the heirarchy of processses in biological systems (which, if the system is reducible, can be explained entirely in terms of the physics governing the the parts and their interactions) cannot be represented in a computable model (it is not reducible). Self-referentiality in computable models must be at least reducible to some discretely defined process, such that any "loop" takes place through time. It's easy in a programming language to have a step in the program in which a variable, function, or whatever modifies itself at some point, but such self-referentiality must at least imitate that of a discrete, stochastic system. Computers are finite state machines, after all.

Rosen and those after him have proved that their is no algorithm which can represent the most basic cellular function (metabolic-repair) because it is not reducible to any finite set in which the M-R function can be considered a relation on the set of elements (or component parts) of the cell. In order to be a complete model which simulates this process, the function cannot be well-defined, nor can it be reduced to one which is, because there is no formal distinction between the domain, function, and image, only a conceptual one.

This conceptual distinction has proven to be extremely useful in systems biology, in which holistic models are used and are valuable. But these models, while computable, can be made arbitrarily more complex or simplified depending on what the goal is.

I never asked for a difference.
You did:
Despite my explicitly asking you to, you never compared this to the classical method. Doing a classical experiment, we set up the system so it does something under specific conditions, and observe what happens. The only difference AFAIK in quantum is that we need to observe more carefully, because the observations affect the system's evolution in a non-trivial way.

You asked repeatedly for how the problems of measurement and so forth were all that different from classical measurements. Well, the answer is that both "systems" and "measurements" in quantum mechanics were completely redefined.

Your quote from the paper does not say this, or mention anything about measurement meaning different things in relation to QM vs. classical mech. It says exactly what you quoted: "measurement cannot be described by standard quantum dynamics." No qualifiers, no disambiguities, no clarification about what "measurement" means.

That's because it's not an intro textbook, not wikipedia, and not intended for the general audience. It's part of technical literature, which means that you are supposed to know that "standard quantum dynamics" are described by quantum theory as fundamentally indeterministic, yet quantum mechanics "measures" them using deterministic methods, which therefore cannot even in principle be a measurement of any quantum dynamics, as the "measurements" in QM are only obtained by treating the "systems" as deterministic.
 
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LegionOnomaMoi

Veteran Member
Premium Member
You assert this, and things like it, multiple times in that post. Support this assertion.

I have. Repeatedly. I provided the most consise, clear statement of this I could, and provided you with a link to an entire academic volume you could access free of charge:
I think MacKinnon put it as concisely as possible in the preface to Interpreting Physics: Language and the Classical/Quantum Divide (Boston Studies in the Philosophy of Science, Vol. 289): "In contemporary particle physics conclusions from a theory are never tested against observations. They are tested against inferences based on observations and a network of presuppositions supporting the inferential process of experimental physics."

For a more detailed account of the measurement problem, see Measurements in Quantum Mechanics, or even just the first chapter (it's free).

You responded
...What?
The sentence you quoted appears to either misunderstand how inferential science works, or is suggesting that physics is not science.


I don't know if you bothered to check out the link, but I tried again:

It's another way of saying this: "In classical physics, the notion of the “state” of a physical system is quite intuitive...there exists a one-to-one correspondence between the physical properties of the object (and thus the entities of the physical world) and their formal and mathematical representation in the theory...With the advent of quantum theory in the early twentieth century, this straightforward bijectivism between the physical world and its mathematical representation in the theory came to a sudden end. Instead of describing the state of a physical system by means of intuitive symbols that corresponded directly to the “objectively existing” physical properties of our experience, in quantum mechanics we have at our disposal only an abstract quantum state that is defined as a vector (or, more generally, as a ray) in a similarly abstract Hilbert vector space.
The conceptual leap associated with this abstraction is hard to overestimate. In fact, the discussions regarding the 'interpretation of quantum mechanics' that have occupied countless physicists and philosophers since the early years of quantum theory are to a large part rooted precisely in the question of how to relate the abstract quantum state to the 'physical reality out there.' (pp. 14-15)
from Schlosshauer's Decoherence and the Quantum-to-Classical Transition (from Springer's monograph series The Frontiers Collection; 2007)
but you seem to have confused this with some issue of nominalism or some other problem about the relationship between mathematics and models and reality, instead of what it is: neither the state of the actual system, nor the system itself, corresponds to anything in the math. This is why your link said that "measurement" had no classical analogue (there were indirect measurements in classical physics, btw), this is what the measurement problem really concerns, and this is the biggest problem facing modern physics. But I described this elsewhere too:

"Unlike those of classical statistical physics, quantum objects and processes become irreducibly inaccessible to all our knowledge and conception, and hence are beyond any possibility of explaining the physical nature of the processes, beyond any possible specific ontology, apart from the fact they exist, which is all we can say about them." from Plotnitsky's "Prediction and Repetition in Quantum Mechanics: The EPR Experiment and Quantum Probability" (AIP Conf. Proc. 889).

I even gave you a description of the process of experimentation in quantum physics:
transforms his information about the preparation of the system into an initial wave function. Then he applies to it some linear transformation, calculated perhaps from the Schrödinger initial wave function into a final wave function. This final wave function, which is built on the degrees of freedom of the measured system, is then folded into the wave function corresponding to a possible result. This gives the transition amplitude, which is multiplied by its complex conjugate to give the predicted transition probability...
The above account describes how quantum theory is used in practice. The essential points are that attention is focused on some system that is first prepared in a specified manner and later examined in a specified manner. Quantum theory is a procedure for calculating the predicted probability that the specified type of examination will yield some specified result.
The wave functions used in these calculations are functions of a set of variables characteristic of the prepared and measured systems. These systems are often microscopic and not directly observable. No wave functions of the preparing and measuring devices enter into the calculation. These devices are described operationally. They are described in terms of things that can be recognized and/or acted upon by technicians. These descriptions refer to the macroscopic properties of the preparing and measuring devices.
The crucial question is: How does one determine the transformations A → ΨA and B → ΨB? These transformations transcribe procedural descriptions of the manner in which technicians prepare macroscopic objects, and recognize macroscopic responses, into mathematical functions built on the degrees of freedom of the (microscopic) prepared and measured systems. The problem of constructing this mapping is the famous “problem of measurement” in quantum theory." pp. 53-54 of Mind, Matter and Quantum Mechanics (Springer, 2009)

If you read the description above carefully, you'll notice exactly what you asked for (once again): the "system" and the "states" are entirely prepared by macroscopic devices (which allow some actual quantum system to run), but the quantum processes which result from the set-up are never related directly to the mathematical formalisms which are then called the "system". The initial state is specified macroscopically and is described by parameters set in advance in a deterministic manner at odds with what quantum theory holds is true of quantum dynamics via some formalism, and the resulting "measurements" are never tested at any time such that the variables describing the "state" of the system are actually "measured" in anything similar to any classical method.
But I will add to the above another (hopefully clearer) statement from the source cited immediately above:
"The orthodox interpretation of quantum theory dispenses altogether with these superfluous classical particles. It represents any physical system by a waveform alone." Now, whether or not you agree with "orthodox" quantum theory and its relationship to the Copenhagen interpretation, every time you refer to a source on "quantum systems", "measurements", and "states", these are not described by actual physical states, measurements, or systems, but by the theorized states which are always abstracted from the actual quantum systems and which are always specified macroscopically and deterministically so that there can be a "measurement" and a "system" and some "states", but nobody knows how the mathematics correspond to actual quantum systems, quantum states, or anything else, which is why this:

We have checked the state of the model again the neuron - they are the same. That is, quantum theory's answers matches reality.

is nonsense. "Quantum theory" holds that actual quantum systems are fundamentally indeterministic. You seem to agree (you even support counterfactual indefiniteness). But this means that any "measurement" cannot be a measurement of the state of the system. It's preparing your "system" as if it were someone with a bow and arrow, only you never describe the actual characteristics of the bow (e.g., the length, the tension, how far the bowstring is pulled back, etc.) or the arrow, and instead of watching where it lands you calculate it based on general theories of bows and arrows, and then drop an atomic bomb where you think it landed, measure some spread of debris, and announce that the distribution of the debris is where the aarrow landed. If quantum systems are really counterfactually indefinite, then we can't use wavefunctions or measurements which describe their states, because these give use definite values. If they are counterfactually definite, then we can't use quantum mechanics.

You sound like a disbeliever. :p

You should start reading some of the technical literature from practicing physicists (not studies themselves, which are extremely limited in scope). If you think I sound skeptical, you haven't heard anything yet.
 
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LegionOnomaMoi

Veteran Member
Premium Member
See above; you do not - and AFAIK cannot - support this assertion.

"The problem of measurement in quantum mechanics arises in standard treatments as the requirement of an external process called the reduction process when a measurement takes place. Such process is not contained within the unitary evolution of the quantum theory but has to be postulated externally and is not unitary. It is usually justified through the interaction with a large, classical measuring device and an environment with many degrees of freedom. Attempts to formulate a coherent framework with purely quantum rules taking into account the environment have however failed to provide a consistent picture of quantum mechanics and the measurement process."

International Journal of Modern Physics D 20(5) 2011
The paper ("Undecidability as solution to the problem of measurement") concludes:
We have shown that fundamental quantum noise in the preparation procedure and in the observables being measured prevents one from distinguishing between a collapsed state and an evolved state. This is done by noticing that even if one takes the measuring apparatus to occupy the whole universe, which would decrease its errors to a minimum, quantum uncertainties will completely blur the different outcomes. We show that undecidability ultimately occurs, even though one cannot define sharply when it occurs"

I linked to the entire paper early, but as you write:

...I hope what you've written there doesn't imply what I think it implies. Since a vanishing h is the opposite of quantization.

"It is generally believed that classical mechanics is the contraction of quantum mechanics in some appropriate limit of vanishing h. Thus in principle every classical observable...is the contraction of some quantum observable. However, quantum observables are generally constructed by the quantization of classical observables...Obviously this introduces circularity when one invokes the correspon dence principle. This is unsatisfactory if quantum mechanics were to be internally coherent and autonomous from classical mechanics."


"At the microscopic level, the formalism of QM assigns probability amplitudes to various possible behaviors of the system...Now, when we extrapolate the QM formalism to the macroscopic level of cats and detectors, it is unarguable that in suitable circumstances (such as those postulated by Schrödinger in his original paper) it assigns simultaneous nonzero amplitudes to two or more macroscopically distinct states. Of course, it is generally agreed that, as a result of the decoherence predicted, under any normally realistic conditions, by the QM formalism itself, it is no longer possible to see the effects of interference between the two or more ‘branches’ of the superposition. However, the quantum formalism is exactly the same at the microscopic and the macroscopic level; if, therefore, a given interpretation is excluded in the former case, it cannot become permitted in the latter! The above formulation shows clearly that the phenomenon of decoherence, while it may no doubt be an essential ingredient in any future resolution of the realization paradox, cannot by itself constitute such a resolution."

"Realism and the physical world" Reports on Progress in Physics 71 (2008)



"Quantum measurements differ from classical ones in two respects. On the one hand, quantum mechanics is an irreducibly probabilistic theory. What is called a ‘‘state of a system’’, whether it is represented by a wavefunction, a ket or a density operator, refers to a statistical ensemble of systems, all prepared before the initial time under the same conditions as the system in hand...On the other hand, the perturbation of S induced by a measurement cannot be neglected in quantum physics, whereas nothing in classical physics prevents us from making it smaller and smaller. Consider first the apparatus. If we include in A the registration device, any measurement, whether classical or quantal, must perturb A so as to be informative. This perturbation, when induced by a microscopic system S, should be sufficiently strong so as to make A undergo a macroscopic change. In many real measurements, this interaction process drastically modifies the system S itself and may even destroy it."
"Dynamics of a quantum measurement" Physica E 29 (2005)


What physical system has the state? You say the equation isn't the system, but then what is? :shrug:

If you figure that out, let physicists know. You'll get a nobel prize at least.

Remember, the actual experimental data you have is a series of still images.
In classical physics, the "measurement" meant the mathematical representation of some state, process, characteristic, etc., of some system which could be said (via some indirect or direct measurement of that system) to correspond to a particular state of the system. In QM, the experiments do none of this. The "system" is set up by the experiment in 2 divergent ways: one corresponds to the devices which cause some quantum processes, and the other corresponds to some mathematical description in which the "state" never corresponds to anything quantum at all, ever, and cannot even in principle (according to quantum theory) do so.

So what is the physical thing? You'll notice I've asked this question multiple times - there's been multiple times you've assumed that the equations do not model the physical thing, without apparently knowing what the physical thing is.

Nobody knows what the physical thing is, but that's irrelevant. You seem to think that the physical or non-phyical thing is somehow characterized perfectly fine by the math. Only physicists disagree (of course, when they say "here's the problem" you say "I don't see the problem"). Because they know that every experiment performed means setting up some macroscopic devices which will create some processes of some system to happen in the physical world, but they don't even attempt to make their model equate to this system of these processes in any coherent way. They can't. But if you want to assume that it's just probability and understand that quantum reality involves counterfactual indefiniteness, fine. But then all your measurements are meaningless. They cannot even in principle describe any actual state, because they are definite. And the system has no definite states.


"Does this formal system imply this condition?" is pure mathematics - in fact, for varying systems and conditions, that is all pure mathematics is.
What formal system? The system is a model of physics. If it's "pure mathematics", we wouldn't have physicists. We'd just have mathematicians.


Knowing what we want to derive does not entail "assuming" anything.
Certainly if you don't actually work that into your equations. But that's what's done.


Vanishing h has nothing to do with decoherence. :facepalm:

Sure, if you haven't any clue how both are actually understood and how both relate to the QCC/quantum-to-classical transition issues.

Also, you better take away Feynman's PhD if constructing classical physics from quantum has "no theorectical basis."

And should you take away Einstein's nobel prize? Or disregard Schroedinger? Or how about the PhD's of all the authors, from those writing papers (such as "Quantum Correlations in Biomolecules" from 22nd Solvay conference on Chemistry), or perhaps from the authors of studies/reviews such as these:

So the QCC problem is trivial? Or perhaps you mean trivial for something like the brain? In which case you might want to tell the researchers who published the study Quantum-classical correspondence in the brain: scaling, action distances and predictability behind neural signals

Or perhaps this study:
"The boundary between quantum theory and classical physics is still largely unknown. Quantum theory obviously applies on length scales smaller than atomic radii but beyond that it is not entirely clear where it should be superseded by Newtonian mechanics. Here we argue that recent criticisms of the use of quantum mechanics in biology are not very convincing since they ignore the already existing evidence for quantum effects in biological systems. In this paper we investigate three particular systems of special importance: the cell membrane, microtubules (MTs), and ion channels which are some of the most important parts of a neuron in the human brain. We argue that these subsystems are the best candidates for possible sites of quantum effects." (Journal of Physics: Conference Series, 2011)

Or any number of sources I've already mentioned (which continually gets me links to wiki articles or even less) on the utter inadequacy of this "vanishing h".

I repeat: why does the Everett interpretation care about how big your coherent wavefunction is?

It doesn't. But it does fundamentally conflict with your view. Because in it our measurements our meaningless. Macroscopic reality is the constant splitting of universes into parallels. So if you think that reality is "computed" by the universe, then you are in absolute disagreement with Everett, whose theory literally involves constant, total, and ever-present superpositions represented only in parallel universes, but never observed, measured, or represented by any physical systems in one universe.
 
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LegionOnomaMoi

Veteran Member
Premium Member
The classical limit as a concept as been around since Relativity, and is entirely unrelated to Schroedinger's cat, because in the classical limit of a vanishing h, superpositions are impossible. Classical mechanics emerging from quantum was shown by Dirac of all people ("The Lagrangian in quantum mechanics", Phys. Z. der Sowjetunion 3: 64-71.) and was a well-known enough result that Feynman's thesis was on it.

And it is now dated (also, it has everything to do with Schroedinger's cat, and neither Bohr, nor Dirac, nor Feynmann changed this, as the "superposition" and "vanishing h" was the method introduced primarily by Bohr to explain why quantum processes like superposition states "disappear" at the macroscopic level) :
"Despite their successes, QM and GTR are beset by problems that raise worries about the foundations of these theories—QM by the measurement problem and associated problems of non-locality, GTR by the problems that are the focus of this study. Some physicists harbor the hope that both sets of problems will be resolved by the sought-after quantum theory of gravity. It is difficult to assess this hope since we can now only dimly perceive the shape that a successful marriage of QM and GTR will take. And even if the hope is eventually realized, it is important to pursue these foundational problems for the light they may shed on the correct path towards the marriage.
For many purposes, the measurement problem in QM can be ignored by experimentalists and theoreticians alike. Not surprisingly, it was ignored by a large segment of the physics community, and the opinion was once widespread that this problem is merely a Scheinproblem. I vividly recall the occasion of a lecture on the measurement problem given in the early 1970s at The Rockefeller University by a Nobel laureate in physics. The reaction of the audience, composed largely of theoretical physicists and mathematicians, was distinctly cool if not unfriendly. The skepticism was directed not so much at the proposed solution as to the notion that there was a problem to be solved. After the lecture, the laureate remarked ruefully: "I suppose that I will have to do something new to restore my reputation." Today his lecture would likely get a different reception, at least judging from the fact that The Physical Review, the most prestigious journal in theoretical physics, now routinely publishes articles on this topic. The implied change in attitude reflects a recognition that the measurement problem poses a fundamental challenge for QM, although how to state the challenge is controversial. On the one hand, the problem can be seen as revealing that there is something rotten at the core of the theory because of its inability to give a satisfactory description of what occurs in the interaction between an object system and a measurement apparatus."

That was all the way back in '95, from Earman's Bangs, Crunches, Whimpers, and Shrieks: Singularities and Acausalities in Relativistic Spacetimes (Oxford University Press). In case you're wondering, that was after Feynmann, and the situatation hasn't improved. It's gotten worse.
 
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