This new ontological picture requires that we expand our concept of ‘what is real’ to include an extraspatiotemporal domain of quantum possibility,” write Ruth Kastner, Stuart Kauffman and Michael Epperson.

Considering potential things to be real is not exactly a new idea, as it was a central aspect of the philosophy of Aristotle, 24 centuries ago. An acorn has the potential to become a tree; a tree has the potential to become a wooden table. — Quantum mysteries dissolve if possibilities are realities - Tom Siegfried

Yes, an acorn has the potential to become a tree, as Aristotle would have correctly noted. That simply means that an acorn has the capability or possibility to develop into a tree under certain conditions.

That shouldn't suggest an "extraspatiotemporal" limbo world where tree potentialities exist and evolve until they are actualized as trees in our "spatiotemporal" world. Instead the world we inhabit just is where an acorn develops into a tree.

Similarly, under certain conditions, a series of particles in a dual-slit experiment will form an interference pattern. That is a true statement about the world that we can observe for ourselves.

The positing of an "extraspatiotemporal" domain as against a "spatiotemporal" domain is a variation of The Ghost in the Machine metaphor.

We don't live in a classical world supplemented by an extraclassical domain of existents, possibilities and processes. We live in a quantum world.

That shouldn't suggest an "extraspatiotemporal" limbo world where tree potentialities exist and evolve until they are actualized as trees in our "spatiotemporal" world. — Andrew M

As I thought had been established, the interference pattern in the double-slit experiments is independent of time and space (shown by its rate independence), thus indicating an extraspatiotemporal cause. It might be the same principle as an acorn becoming an oak, but on a far more pervasive and subtle level of existence. Put another way, the possibility equation really does describe 'degrees of reality' which are not actualised until a measurement is made. Hence the 'nothing exists until it is measured', of Neils Bohr.

As I thought had been established, the interference pattern in the double-slit experiments is independent of time and space (shown by its rate independence), thus indicating an extraspatiotemporal cause. — Wayfarer

No, I suggested that idea was a deux ex machina.

Everything follows quantum principles, whether acorns, water waves or particles.

Show me a macroscopic entity existing in superposition.

Show me a macroscopic entity existing in superposition. — Wayfarer

A piezoelectric "tuning fork".

A piezoelectric "tuning fork" has been constructed, which can be placed into a superposition of vibrating and non-vibrating states. The resonator comprises about 10 trillion atoms. — Quantum superposition - Wikipedia

Researchers have demonstrated a device that can pick up single quanta of mechanical vibration similar to those that shake molecules during chemical reactions, and have shown that the device itself, which is the width of a hair, acts as if it exists in two places at once—a "quantum weirdness" feat that so far had only been observed at the scale of molecules.

"This is a milestone," says Wojciech Zurek, a theorist at the Los Alamos National Laboratory in New Mexico. "It confirms what many of us believe, but some continue to resist—that our universe is 'quantum to the core'." — Macro-Weirdness: 'Quantum Microphone' Puts Naked-Eye Object in 2 Places at Once

I drive to Walmart to pick up my wife. She will either be standing at the door we agreed upon, or she will not (still shopping). When I get there, there she is - and the wave function has collapsed. Until I get there I do not know. She resides in that mystical state of superposition, being both there and not there. But I have calculated the probability and it has come out .7 in favor of her standing there and .3 her not.

Partial differential equations model quantum "realities". When you solve the equation there may be several possible solutions - that's just mathematics. Linear combinations of those solutions are also solutions. Until you actually perform the measurements you don't know which is correct. So, in the math, there is nothing weird going on. Mathematics is not a perfect model in would seem.

Very clever experiments but I did notice

As to how the day-to-day reality of objects that we observe, such as furniture and fruit, emerges from such a different and exotic quantum world, that remains a mystery. — Macro-Weirdness: Quantum Microphone Puts Naked-Eye Object in 2 Places at Once

Until I get there I do not know. She resides in that mystical state of superposition, being both there and not there. But I have calculated the probability and it has come out .7 in favor of her standing there and .3 her not. — jgill

It's not a valid analogy, though. The strangeness of the observer problem in physics is that the act of observation itself is instrumental in determination of the outcome. The proper analogy would be that, prior to you seeing your wife, she didn't exist in any specific location at all, she's not simply in an unknown location.

The answer to the question as to where the particle is, prior to measuring its whereabouts, just IS the probability equation, it has no particular existence but only the probability of existence. That's the point.

Very clever experiments but I did notice

"As to how the day-to-day reality of objects that we observe, such as furniture and fruit, emerges from such a different and exotic quantum world, that remains a mystery."
— Macro-Weirdness: Quantum Microphone Puts Naked-Eye Object in 2 Places at Once — Wayfarer

OK. But as physicist Sidney Coleman says (via Peter Woit):

The problem is not the interpretation of quantum mechanics. That’s getting things just backwards. The problem is the interpretation of classical mechanics. — Quantum Mechanics in Your Face - Sidney Coleman (transcript and slides)

Which is to say, we view quantum mechanics through the lens of our classical concepts and intuitions. Coleman notes that, "The thing you want to do is not to interpret the new theory in terms of the old, but the old theory in terms of the new."

Now people say the reduction of the wave packet occurs because it looks like the reduction of the wave packet occurs, and that is indeed true. What I’m asking you in the second main part of this lecture is to consider seriously what it would look like if it were the other way around—if all that ever happened was causal evolution according to quantum mechanics. What I have tried to convince you is that what it looks like is ordinary everyday life. — Quantum Mechanics in Your Face - Sidney Coleman (transcript and slides)

To this, Peter Woit comments:

While some might take this and claim Coleman as an Everettian, note that there’s zero mention anywhere of many-worlds. Likely he found that an empty idea that explains nothing, so not worth mentioning. — Peter Woit

In the lecture, Coleman says, "The position I am going to advocate is associated with Hugh Everett in a classic paper" (referring to Everett's paper, '"Relative State" Formulation of Quantum Mechanics').

Then, from the Q&A:

Question: You said in passing that you were a follower of Everett.

Coleman: Yeah, but that's a tricky thing to say. That's like saying you're a Christian. I mean, Everett wrote this one truly wonderful paper and then everyone got on their horse and rode off in all directions. The position I'm advocating is a position that, at least in my case, was certainly largely inspired by Everett's paper. Whether it's really Everett's position or not I would prefer not to discuss. — Quantum Mechanics in Your Face - Sidney Coleman (video)

Which all leads to:

It's not a valid analogy, though. The strangeness of the observer problem in physics is that the act of observation itself is instrumental in determination of the outcome. The proper analogy would be that, prior to you seeing your wife, she didn't exist in any specific location at all, she's not simply in an unknown location. — Wayfarer

The proper analogy would be that @jgill observed interference effects until he and his wife met up and she pointed out that she had been standing there all the time.

That shouldn't suggest an "extraspatiotemporal" limbo world where tree potentialities exist and evolve until they are actualized as trees in our "spatiotemporal" world. Instead the world we inhabit just is where an acorn develops into a tree. — Andrew M

The problem though, is that with each passing moment the actual acorn, along with the potentialities, changes according to the conditions it is exposed to. Through chemistry we'd understand these changes as changes to the form, or actuality of the physical object, the acorn. But corresponding to these changes to the form, there are changes to the potential which cannot be directly understood simply through an understanding of the chemical changes to the form of the acorn. The potentialities really do evolve along with the changing actuality. We might apply premises from biology, which could state that X physical form is equivalent to Z potential, therefore destruction of X actuality is a destruction of Z potential. However, the theory of evolution, genetics and mutations, shows us that relating actualities to potentials is not so simple in reality. Actualities come and go, potentials change.

Actual forms don't directly correspond with potentials. The physical form is represented as one unity, an entity, or particular. Potential is related to the particular as a multitude of possibilities. Each possibility is itself represented (by us thinking humans) as a particular, to establish a direct relation to the actual, particular form. Thus a multitude of possibilities (possible actualities) is related to one actual form. So "potential" appears as a multitude of possible particulars, each of these particulars having a theoretical rather than a real spacetime representation. The theoretical spacetime representation, which is not a real spacetime representation (analogous to a counterfactual), constitutes what is known as a real possibility by modal logic.

But that is not a real representation of the real existence of "potential", it is only a representation of how potential relates to the actual. We create with our minds, a number of possible actualities which directly relate to the known actuality, and designate these as the real possibilities. But these are representation of actualities which are qualified as "possible", and these are supposed to relate the real potential to the real actual. We have no representation of real potential, only representations of real actualities. So to establish the relationship we represent potential as a multitude of possible actualities. But we also know that what we designate as real possibilities (possible actualities) cannot all be true without defying the laws of spacetime. Therefore we need to conclude that real potential, which is described in terms of incompatible spacetime actualities, is not describable by the laws of spacetime.

The proper analogy would be that jgill observed interference effects until he and his wife met up and she pointed out that she had been standing there all the time. — Andrew M

So we say that @jgill has extremely bad eyes, and all he sees until he's about three metres from his wife is a strange interference pattern? Suppose he's 50 metres away. How would he interpret the interference pattern as probabilities for the actual location of his wife? Consider that if this is a true analogy, the closer that he gets, he ought to be able to observe changes to the interference pattern which would increase his certainty.

But I have calculated the probability and it has come out .7 in favor of her standing there and .3 her not. — jgill

So? How did you interpret that interference pattern, to come up with these numbers? Ultimately, the way that you interpreted the pattern, to come up with accurate probabilities, says something very significant about what the wave interference which you are interpreting, really is.

, ,

Oh well, and here I was trying to follow an important dictum of philosophical dialogue I have learned of on TPF: Wrong, but interesting. :smile:

Cantor's proof assumes an enumeration of the set of real numbers — Andrew M

OK, my mistake, since I was envisioning an enumeration of the rationals to prove that there are irrational numbers. But the proof of that is less complicated.

(any enumeration, not just an ordered one)

How can any enumeration not be ordered?

Copenhagen-style interpretations also generally deny a physical collapse. — ”Andrew M”

Maybe. The list of interpretations on wiki says some of the Copenhagen interpretations say this. This implies at least that there’s more than one interpretation using this name. The reference they give on the ‘maybe’ talks about the epistemic view I mentioned, but then:
“By contrast, the Copenhagen interpretation has also been associated with an ontological view of the quantum state, in which the wave function somehow describes a real wave, and the collapse is a real physical process – presumably induced by the observer. This ontological view is usually attributed to von Neumann in his 1932 textbook exposition of quantum mechanics; … Thus, for Bohr, the wave function is a representation of a quantum system in a particular, classically described, experimental context. … When a measurement is performed (that is, when an irreversible recording has been made; see below), then the context changes, and hence the wave function changes. This can formally be seen as a "collapse" of the wave function, with the square quotes indicating that we are not talking about a physical process in which a real wave collapses.”
Square quotes? Should that say ‘scare quotes’? Anyway, that bit says we’re not talking about a physical collapse.
All this taken from https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
If collapse isn’t physical and isn’t epistemological, then what is it?

A statement about a single body is not completely "meaningless", because we can still state properties of the body itself, and this is meaningful. — Metaphysician Undercover

You know I’m talking about it’s property of motion, in complete absence of a second thing relative to which that motion (or lack of it) is meaningful.

That is, if we take the principle of relativity as our primary premise, and add the observational premise that there are numerous bodies observed to be moving in different ways, we can conclude that noting is immobile.

Non-sequitur. The principle (your chosen wording) seems only to say that there’s no way to tell, not that there cannot be an immobile one.
Anyway, I actually don’t wish to continue hammering this point, which just seems to be a different choice of wording the same thing.

If you can show me a valid concept of rest, lack of change, which can be maintained consistently along with the principle of relativity as well, I would appreciate the demonstration.

My chosen wording of the principle makes no mention of ‘at rest’ or ‘stationary’, nor does it make any mention of internal change, so it’s not mine to demonstrate.

Even if we accept locations to be "at rest" relative to each other in an internal way, and deny Einsteinian relativity, these locations are still not at rest in the wider (external) context. And when we start mapping the points which are supposed to be at rest relative to each other, in comparison with external things, we inevitably find minor inconsistencies which cannot be resolved, as demonstrated by Einstein's train example.

The train example presumes the premises listed. If you deny those premises, then the train example ceases to demonstrate any inconsistencies.
I always took you for somebody in denial of Einstein’s theory precisely because only in one frame (and not an inertial one either) are all the events in ‘the present’ simultaneous with each other. In all other frames, this is not so, so the laws of physics are different between this and that frame, in violation of the principle. This follows from your assertions, ones with which I do not agree.

You know I’m talking about it’s property of motion, in complete absence of a second thing relative to which that motion (or lack of it) is meaningful. — noAxioms

This is unintelligible to me. Motion is a concept. That is why I could give a definition of motion prior to the principle of relativity being produced, and also a definition of motion derived from the principle of relativity. That these differ indicates that the concept of motion has evolved.

That something is moving, or in motion, is a human judgement. This judgement requires a spatial temporal perspective, Kant's pure a priori intuitions. This means that there is necessarily an observer, and that observer is human, hence a "second thing". Therefore it's completely nonsensical to talk about the motion of a thing in the complete absence of a second thing.

Non-sequitur. The principle (your chosen wording) seems only to say that there’s no way to tell, not that there cannot be an immobile one. — noAxioms

No, it's a valid conclusion from the premises I stated. You are ignoring the other premise I stated. That premise is derived from empirical observation that there is a multitude of things. observed to be moving in different ways. From that empirical, observational premise, and the principle of relativity as the other premise, we can conclude that nothing is at rest.

I'm really surprised that you are arguing this point, because the absence of absolute rest is often cited as the basic epistemological principle which is derived from the principle of relativity, which is an ontological principle. So we take the principle of relativity (that the motion of a body is only determined relative to another body, and either one if the motion is observed as uniform, could equally be the rest frame), as the major premise. And this is an ontological theory. Then we add the observational data that there is always at least one body moving relative to any other, and this produces the conclusion that nothing is at rest. This principle serves as the epistemic base for the arbitrary application of the concept "rest frame". Since it is known by the logic above, that nothing is truly at rest, then the designation of "rest", or "rest frame" is necessarily completely arbitrary, therefore that designation is based in pragmatic principles, rather than an ontological principle. The ontological principle "relativity" renders "rest" as not true.

However, this puts "time" in a very odd situation. Our measurements of the passing of time are based in the ancient concept of motion within which, we as observers are assumed to be at rest. We observe motions relative to ourselves, assuming ourselves to be at rest, and produce temporal durations from these observations. Then we apply these temporal durations in measurement of other motions. Newton assumed that we ought to continue with "time" based in our rest frame. This is said to be an "absolute time". But it isn't really "absolute" time, it's just maintaining the old principle that we are at rest, and that observations of motions relative to us (as a sort of absolute rest) are the best suited for the measurement of time. You can see there is inconsistency because the principle of relativity denies that any perspective is true rest, but the "absolute time" perspective clings to our perspective as the true rest frame for producing temporal measurement. Einstein saw a way beyond this inconsistency by repealing the "absolute time" perspective.

The train example presumes the premises listed. If you deny those premises, then the train example ceases to demonstrate any inconsistencies.
I always took you for somebody in denial of Einstein’s theory precisely because only in one frame (and not an inertial one either) are all the events in ‘the present’ simultaneous with each other. In all other frames, this is not so, so the laws of physics are different between this and that frame, in violation of the principle. This follows from your assertions, ones with which I do not agree. — noAxioms

This is really confused. I haven't the foggiest idea of what you're trying to say. You seem to be employing the "absolute time" perspective to come up with "the present", yet also using "the relativity of simultaneity" to say that events in the present are not necessarily simultaneous. You cannot conflate these two in that way. They are completely different conceptions of time which are incommensurable. If you employ the relativity of simultaneity, you have no basis for a conception of "the present". And if you have the desire to base "the present" in your own observational perspective, or rest frame, as Newtonian "absolute time" does, this would just be an arbitrary designation, providing no true representation of "the present". This is why the principle of relativity puts "time" into an odd place. We can only measure time from our own perspective, yet relativity removes the validity of that perspective. Therefore we have no valid measurements of time.

The proper analogy would be that jgill observed interference effects until he and his wife met up and she pointed out that she had been standing there all the time.
— Andrew M

So we say that jgill has extremely bad eyes, and all he sees until he's about three metres from his wife is a strange interference pattern? Suppose he's 50 metres away. How would he interpret the interference pattern as probabilities for the actual location of his wife? Consider that if this is a true analogy, the closer that he gets, he ought to be able to observe changes to the interference pattern which would increase his certainty. — Metaphysician Undercover

It's the Wigner's friend thought experiment where the system in question (in this case Walmart rather than a laboratory) is isolated from the rest of the environment.

Per QM, the system could either be weakly measured (giving some information without destroying the superposition) or strongly measured resulting in rapid decoherence. Alternatively, the system could be transformed such that the probabilities change (including to certainty).

Wrong, but interesting. :smile: — jgill

Interesting, yes. See Wigner's friend.

"(any enumeration, not just an ordered one)"

How can any enumeration not be ordered? — noAxioms

I meant, "not just in order of smallest number to largest number."

If collapse isn’t physical and isn’t epistemological, then what is it? — noAxioms

Pragmatic. At some point it's necessary to ground a quantum mechanical description in a definite observation or measurement. So a Heisenberg cut is employed. As Heisenberg put it:

"The dividing line between the system to be observed and the measuring apparatus is immediately defined by the nature of the problem but it obviously signifies no discontinuity of the physical process. For this reason there must, within limits, exist complete freedom in choosing the position of the dividing line." — Heisenberg cut - Wikipedia

Neo-Copenhagen interpretations such as RQM, QBism and Consistent histories also employ this in their respective ways. All of these interpretations conform to the predictions of standard QM, including for Wigner's friend-style experiments. Whereas objective collapse theories are, in principle, experimentally differentiable from standard QM.

Per QM, the system could either be weakly measured (giving some information without destroying the superposition) or strongly measured resulting in rapid decoherence. Alternatively, the system could be transformed such that the probabilities change (including to certainty). — Andrew M

Can you elaborate these three, Andrew? What would be the act of a weak measurement? And, how could the probabilities involved with a specific system be changed to certainty without some form of measurement? To me, such a change would require a cause, and the cause would be a matter of "fixing" the system, like cheating if you're a gambler. But if "fixing" was possible then there would be no real mystery unless only the cheaters had figured it out.

It's the Wigner's friend thought experiment where the system in question (in this case Walmart rather than a laboratory) is isolated from the rest of the environment. — Andrew M

I've explained in other threads, that there is a potential problem with the application of systems theory towards real activity. Conventionally, there is a boundary defined which separates inside the system from outside the system. Any cause of change to the system (analogous to a force which changes the momentum of a body in Newtonian laws), must come from outside the boundary. However, this representation provides no place for what mystics and metaphysicians apprehend as a cause of change which comes from the inside.

So for example, gravity can be modeled as a cause of change (force) to a body's momentum, in the Newtonian way. It's modeled as an external force, acting on the body from the outside. But if gravity really acted on the body through the inside, this would require a completely different model for an accurate representation. And, that it may be the case that gravity acts through the inside is evidenced by the fact that the massive part of the atom is in the centre of the atom, and the massive parts interact directly through gravitation.

Allowing that causes of change which come from the inside are very real, and distinct from causes of change which come from the outside, forces the conclusion that systems theory does not provide an adequate representation. By classing all causes of change to the system which are not consistent with the system's inertial progression as "outside" the system, without distinguishing an inside boundary from the outside boundary, conflates these two distinct types of causation, potentially making some types of changes to the system impossible to understand.

The proper analogy would be that jgill observed interference effects until he and his wife met up and she pointed out that she had been standing there all the time. — Andrew M

Until Walmart opened its otherwise impervious doors. Contrary to most of the posts you’re getting, it has nothing to do with anybody actually looking at anything, with good or bad eyes.

How can any enumeration not be ordered?
— noAxioms
I meant, "not just in order of smallest number to largest number."

That’s just a different ordering, but any ordering can have a counting number assigned to each item in order. It’s still ordered.

If collapse isn’t physical and isn’t epistemological, then what is it?
— noAxioms
Pragmatic. At some point it's necessary to ground a quantum mechanical description in a definite observation or measurement.

OK, that seems to be a distinction between objective collapse and relational collapse, both of which are physical.

So a Heisenberg cut is employed.

A Heisenberg cut is a form of relational expression, that a system on one side of the cut is in some state (as represented by the wave function) relative to the system on the other side of the cut. Yes, the placement of the cut is arbitrary. The cut was first introduced as an epistemic cut (what one system knows about the other) but became a metaphysical one once the interpretation moved away from its epistemic roots.

That something is moving, or in motion, is a human judgement. — Metaphysician Undercover

I’m talking about the physics definition of motion, which does not require a human to be around deciding if it’s motion or not, even if it does require a human to have a human saying it’s motion.

Therefore it's completely nonsensical to talk about the motion of a thing in the complete absence of a second thing.

And yet again, your preferred wording of PoR does exactly that.

Then we add the observational data that there is always at least one body moving relative to any other, and this produces the conclusion that nothing is at rest.

I don’t see how that produces that conclusion.

The ontological principle "relativity" renders "rest" as not true.

It renders it meaningless, which is different than ‘not true’.

Our measurements of the passing of time are based in the ancient concept of motion within which, we as observers are assumed to be at rest.

Newton assumed that we ought to continue with "time" based in our rest frame. This is said to be an "absolute time".

Time wasn’t frame dependent back then, so it wasn’t based on any particular designated rest frame.

but the "absolute time" perspective clings to our perspective as the true rest frame for producing temporal measurement.

The absolute perspective has no dependency on the motion of any observer. Assignment of say Earth as the true rest frame is just arrogance and I’ve never seen a modern absolute interpretation that suggests it. Most of them suggest us moving at variable speed of around 350 km/sec and maybe twice that back when the T-rex was the local scary thing. This can be determined because spacetime isn’t Minkowskian, and the PoR only applies to Minkowskian spacetime.
But even those values are a local measurement of time since it varies based on gravitational potential as well, and we can’t know our absolute gravitational potential. So one ‘hour’ is not an actual hour, but a dilated one, even if measured by a stationary clock. So there are absolute theories out there, but even those cannot say how long an actual hour is.

Einstein saw a way beyond this inconsistency by repealing the "absolute time" perspective.

This is really confused. I haven't the foggiest idea of what you're trying to say.

Somehow I’m not surprised. Presentism requires a preferred frame. You don’t know this? Any other frame labels past and future events as simultaneous (ontologically different according to your assertions), which would be a contradiction. So presentism contradicts Einstein’s postulates and his theories along with them.

You seem to be employing the "absolute time" perspective to come up with "the present", yet also using "the relativity of simultaneity" to say that events in the present are not necessarily simultaneous.

Presentism says that all events in the present are necessarily simultaneous, does it not? Relativity of simultaneity is wrong in that case, something only derived from SR postulates, both of which are wrong under any form of absolute space and time.

I’m talking about the physics definition of motion, which does not require a human to be around deciding if it’s motion or not, even if it does require a human to have a human saying it’s motion. — noAxioms

You never provided any such definition, but if you think you can provide me with a definition of motion which does not require observation, be my guest, let's see it. Do you realize that motion is always a comparison? There are two factors, position and time. How do you suppose that motion could occur without a human to judge that time has passed?

The absolute perspective has no dependency on the motion of any observer. — noAxioms

Yes it does. The measurement of time is dependent on the observer's observations of motion. When motion is relative, the observer is necessarily moving if time is passing.

Somehow I’m not surprised. Presentism requires a preferred frame. You don’t know this? Any other frame labels past and future events as simultaneous (ontologically different according to your assertions), which would be a contradiction. So presentism contradicts Einstein’s postulates and his theories along with them. — noAxioms

You don't seem to understand how time is measured. As a result your response to my post doesn't make very much sense. You don't seem to actually address anything I said.

Per QM, the system could either be weakly measured (giving some information without destroying the superposition) or strongly measured resulting in rapid decoherence. Alternatively, the system could be transformed such that the probabilities change (including to certainty).
— Andrew M

Can you elaborate these three, Andrew? What would be the act of a weak measurement? And, how could the probabilities involved with a specific system be changed to certainty without some form of measurement? To me, such a change would require a cause, and the cause would be a matter of "fixing" the system, like cheating if you're a gambler. But if "fixing" was possible then there would be no real mystery unless only the cheaters had figured it out. — Metaphysician Undercover

Note that Wigner's friend is a thought experiment that is not practical (to say the least) with humans, but may one day be done using human-level AI's on a quantum computer.

With that said, suppose the friend's superposition state is:

|psi> = 0.6|here> + 0.8|there>

This means that there's a 36% chance of Wigner measuring the friend to be here as opposed to there (square the numbers to get the percentages).

To visualize the math, consider an XY axis where the |here> and |there> states are arrows (unit vectors) on the positive X and Y axes respectively and |psi> is an arrow from the origin to coordinates (0.6, 0.8).

If Wigner wants to test whether the friend really is in that superposition state, he can measure in the { |psi>, |-psi> } basis (where |-psi> is orthogonal to |psi>) and confirm that the result is |psi> (i.e., he sees +1 on his measurement dial rather than -1). Wigner can do this test multiple times and will always get the same result. This interaction is a weak measurement in the sense that information is extracted while leaving the friend in the initial superposition state.

Wigner can then measure her state in the { |here>, |there> } basis. This collapses |psi> to either |here> or |there>.

Alternatively, Wigner can rotate the friend's state onto one of the definite states, say, |here>. Wigner can then measure in the { |here>, |there> } basis which will confirm that she is here.

Allowing that causes of change which come from the inside are very real, and distinct from causes of change which come from the outside, forces the conclusion that systems theory does not provide an adequate representation. — Metaphysician Undercover

There's no problem with the friend acting inside the lab (e.g., moving here or there). However the subsequent measurement and/or rotation operations would be performed by Wigner from outside the lab.

Until Walmart opened its otherwise impervious doors. Contrary to most of the posts you’re getting, it has nothing to do with anybody actually looking at anything, with good or bad eyes. — noAxioms

Except maybe the measurement dials!

That’s just a different ordering, but any ordering can have a counting number assigned to each item in order. It’s still ordered. — noAxioms

:up:

A Heisenberg cut is a form of relational expression, that a system on one side of the cut is in some state (as represented by the wave function) relative to the system on the other side of the cut. Yes, the placement of the cut is arbitrary. The cut was first introduced as an epistemic cut (what one system knows about the other) but became a metaphysical one once the interpretation moved away from its epistemic roots. — noAxioms

:up:

Except maybe the measurement dials! — Andrew M

The entire quantum subject would be better served if "observer" were eliminated everywhere and replaced by "measurement". Then the casual physics dilettante could think, Yes, if I aim my flashlight at my keys on the table I don't disturb the keys, but if the keys were quantum size I might disturb them in the act of "observing" them. Just a comment.

The entire quantum subject would be better served if "observer" were eliminated everywhere and replaced by "measurement". — jgill

Can't have one without the other though. People often say, well measurement is any form of registration on any instrument, but we would never know that, save by checking. Long story short, science is an inextricably human undertaking, we can't perceive reality 'as it is in itself' as if were apart from our act of observing it. That's true all the time, but in quantum physics it becomes impossible to avoid.

The entire quantum subject would be better served if "observer" were eliminated everywhere and replaced by "measurement". — jgill

I think it's useful since we are observers. At any rate, since our understanding of quantum mechanics is incomplete, there's going to be differences of opinion on the best way to talk about it.

This is true even for experts in the field. For example, here's an argument I quoted earlier 'for observation'. And, in the other direction, here's John Bell's argument 'against measurement':

Here are some words which, however legitimate and necessary in application, have no place in a formulation with any pretension to physical precision: system, apparatus, environment, microscopic, macroscopic, reversible, irreversible, observable, information, measurement.

The concepts 'system', 'apparatus', 'environment', immediately imply an artificial division of the world, and an intention to neglect, or take only schematic account of, the interaction across the split. The notions of 'microscopic' and 'macroscopic' defy precise definition. So also do the notions of 'reversible' and 'irreversible'. Einstein said that it is theory which decides what is 'observable'. I think he was right - 'observation' is a complicated and theory-laden business. Then that notion should not appear in the formulation of fundamental theory. Information? Whose information? Information about what?

On this list of bad words from good books, the worst of all is 'measurement'. It must have a section to itself.

Against 'measurement'
...
The first charge against 'measurement', in the fundamental axioms of quantum mechanics, is that it anchors there the shifty split of the world into 'system' and 'apparatus'. A second charge is that the word comes loaded with meaning from everyday life, meaning which is entirely inappropriate in the quantum context. When it is said that something is 'measured' it is difficult not to think of the result as referring to some pre-existing property of the object in question.
...
In other contexts, physicists have been able to take words from everyday language and use them as technical terms with no great harm done. Take for example, the 'strangeness', 'charm', and 'beauty' of elementary particle physics.

No one is taken in by this 'baby talk', as Bruno Touschek called it. Would that it were so with 'measurement'. But in fact the word has had such a damaging effect on the discussion, that I think it should now be banned altogether in quantum mechanics.

The role of experiment
Even in a low-brow practical account, I think it would be good to replace the word 'measurement', in the formulation, by the word 'experiment'. For the latter word is altogether less misleading. However, the idea that quantum mechanics, our most fundamental physical theory, is exclusively even about the results of experiments would remain disappointing.

In the beginning natural philosophers tried to understand the world around them. Trying to do that they hit upon the great idea of contriving artificially simple situations in which the number of factors involved is reduced to a minimum. Divide and conquer. Experimental science was born. But experiment is a tool. The aim remains: to understand the world. To restrict quantum mechanics to be exclusively about piddling laboratory operations is to betray the great enterprise. A serious formulation will not exclude the big world outside the laboratory. — Against ‘measurement’ - John Bell, 1990

Then the casual physics dilettante could think, Yes, if I aim my flashlight at my keys on the table I don't disturb the keys, but if the keys were quantum size I might disturb them in the act of "observing" them. Just a comment. — jgill

If you do lose your quantum car keys, you can just call your local quantum mechanic.

you can just call your local quantum mechanic. — Andrew M

Who could be anywhere :lol:

Until Walmart opened its otherwise impervious doors. Contrary to most of the posts you’re getting, it has nothing to do with anybody actually looking at anything, with good or bad eyes.
— noAxioms
Except maybe the measurement dials! — Andrew M

Even looking at the measurement dials has no impact on the collapse or not. Of course, the descriptions you quote give a special role to an observer (writing down the reading of the dial say), but 1, it doesn’t take a human (or actual ‘observation’) to do that, and 2, it being written down isn’t what causes collapse. If the dial says |here>, then the wave function is collapsed whether or not anything (or person) reads that dial since the dial is not inside Walmart.

The entire quantum subject would be better served if "observer" were eliminated everywhere and replaced by "measurement". — jgill

Pretty much agree, but Andrew quotes a text that bashes even this word since it is still so open to common language interpretation, but I still agree and use the word in its proper context. Bell suggests ‘experiment’, but that loads the whole situation with intent that is meaningless. The dial unobserved seems not to be an experiment since nobody is recording what it says.

Can't have one without the other though. — Wayfarer

Nonsense. You can have measurement without observation such as the dial, reading |here>, but unnoticed by anybody.

People often say, well measurement is any form of registration on any instrument, but we would never know that, save by checking.

That’s an epistemological issue, not a metaphysical one. Measurement results a physical fact (in interpretations with physical collapse), and observation results in knowledge of that fact. The far side of the moon is still there when nobody looks at it since looking at it isn’t what makes it there.

I’m talking about the physics definition of motion, which does not require a human to be around deciding if it’s motion or not, even if it does require a human to have a human saying it’s motion.
— noAxioms
You never provided any such definition, but if you think you can provide me with a definition of motion which does not require observation, be my guest, let's see it. — Metaphysician Undercover

Well I googled ‘motion definition in physics’ and get a britannica one saying “change with time of the position or orientation of a body.“ which makes no mention of a requirement for observation (human or otherwise) to be involved. You seem to be attempting to worm in the definition of ‘measurement of motion’ or ‘human concept of motion’ or some other obfuscation hiding behind the line between map and territory.
Admittedly the definition that first comes up makes an implicit reference to a coordinate system without which the position or orientation of the object in question is not meaningful.
Wiki says something similar but adds “with respect to time”.
UW-Madison (a university, so must be far better than wiki per your post above) says unhelpfully: “Motion is the area of physics that studies how things move” which is just a self reference, useless without the definition of ‘move’. It also attempts to define the ‘study of motion’ which is quite different than the definition of motion itself.

Do you realize that motion is always a comparison?

It is a difference of position states at two different times. It is still motion even if those two positions are not compared by anything.

How do you suppose that motion could occur without a human to judge that time has passed?

That’s a pretty idealistic assertion. Are you one of those people that suggest that nothing happened before humans came along? I think that position can be driven to solipsism, which means motion cannot occur without you specifically to judge that time has passed, and that’s assuming that time is something that passes, something else with which I don’t agree, and which none of the definitions above require.

The absolute perspective has no dependency on the motion of any observer.
— noAxioms
Yes it does. The measurement of time is dependent on the observer's observations of motion.

I wasn’t speaking of measurement. Absolute time has no dependency on its being measured. If it flows, the rate (and direction) at which it does so is entirely independent of anything’s perception or measurement of it. You seem to keep attempting to make everything about your knowledge of something, about the map and not about the territory.

When motion is relative, the observer is necessarily moving if time is passing.

Apologies for ragging on every word, but you seem to be going out of your way with the weird suggestions this time. This statement here is no exception. If I’m here now and here later, that seems to be not-moving relative to ‘here’. OK, one might express that as motion at velocity (relative to here) of zero, which is arguably still motion. I would accept that.

You don't seem to understand how time is measured.

Again, I’m talking about time, not about how it is measured, so I’ve given no demonstration of my understanding of how time is measured or my lack thereof.

The far side of the moon is still there when nobody looks at it since looking at it isn’t what makes it there — noAxioms

You do recall the anecdote that Einstein once exclaimed, when walking with one of his friends, 'surely the moon still exists when no-one is looking at it!' This was in relation to the very assumption you're making, and he said it because of the challenge that quantum mechanics poses to scientific realism. In fact it's what this whole debate is about. When it comes to the denizens of quantum physics - purportedly the most fundamental constituents of physical existence - Bohr said 'no elementary phenomenon is a phenomenon until it is observed'.

Can't have one without the other though. — Wayfarer

What if the purely "mechanical" act of measurement produces a numerical result that goes automatically into a computer file and is never "observed" as it sits there and rots? :smile:

I think it's useful since we are observers. At any rate, since our understanding of quantum mechanics is incomplete, there's going to be differences of opinion on the best way to talk about it. — Andrew M

Thanks for your thoughtful reply.

If you do lose your quantum car keys, you can just call your local quantum mechanic. — Andrew M

Who could be anywhere :lol: — Wayfarer

Having imbibed a bit too much at the local pub he enters a state of superposition, thoroughly confused, an unknowing victim of a partial differential equation.

Measurement results a physical fact (in interpretations with physical collapse), and observation results in knowledge of that fact. — noAxioms

:up: :cool:

What if the purely "mechanical" act of measurement produces a numerical result that goes automatically into a computer file and is never "observed" as it sits there and rots? — jgill

As I said - through inductive reasoning, we can expect that the measurement is taken, that the data exists on that system unobserved. But you won't empirically verify that inductive step without observing the result. And isn't this very much at the heart of the whole issue? The realist attitude is, well all these processes simply occur, whether we're observing or not. But if that were so, then we wouldn't even be having this discussion!

Just noticed the mechanic... :lol:

The far side of the moon is still there when nobody looks at it since looking at it isn’t what makes it there
— noAxioms

You do recall the anecdote that Einstein once exclaimed, when walking with one of his friends, 'surely the moon still exists when no-one is looking at it!' — Wayfarer

That comment was what made the moon the thing to exist (or not) based on watching it, sort of like the cat became the classic thing in the box.

This was in relation to the very assumption you're making

But I'm not making the assumption you probably think I am. I suspect the principle of counterfactual definiteness (scientific realism) is false. I'm pretty public about that. I take more a relational view.
First of all, 'looking at it' has nothing to do with anything. It is impossible for any human (dead or alive) to not be continuously measuring the moon.
Secondly, since the moon had been measured, it cannot suddenly jump into a nonexistent state. It's not a solution to the moon's wave function, or at least not one with a probability of zero to more digits than you can imagine. That's what I mean by the moon still being there when nobody looks at it. The moon has been measured and cannot be unmeasured.

he said it because of the challenge that quantum mechanics poses to scientific realism.

Which is why I'm not such a realist. If I say the moon exists, I mean that I've measured it, which doesn't involve looking or any other conscious function.

Bohr said 'no elementary phenomenon is a phenomenon until it is observed'.

But that's true classically. A human phenomenon by definition involves a human observation. Quantum collapse doesn't. It involves an interaction between two systems. Andrew M quoted Bohr on this distinction just a few posts above in the part labeled 'Against measurement'.

What if the purely "mechanical" act of measurement produces a numerical result that goes automatically into a computer file and is never "observed" as it sits there and rots? — jgill

It was observed in that scenario, so it makes no sense to say it was subsequently not observed. The statement attempts to use the dictionary definition of observation.

As I said - through inductive reasoning, we can expect that the measurement is taken, that the data exists on that system unobserved. — Wayfarer

You seem to do likewise. Conscious observation plays zero role except epistemic.

But you won't empirically verify that inductive step without observing the result. And isn't this very much at the heart of the whole issue? — Wayfarer

No, that's just an epistemic effect that has nothing to do with whether the result took place or not.

The realist attitude is, well all these processes simply occur, whether we're observing or not.

No, not at all. The realist attitude is that these things (objectively?) occur whether or not there is interaction with some other system. It has nothing to do with observation as you seem to be using the word: an action that a human does and a rock doesn't. Being forced to choose, I chose to discard objective realism of this sort, and for this reason.

since the moon had been measured, it cannot suddenly jump into a nonexistent state. It's not a solution to the moon's wave function, or at least not one with a probability of zero to more digits than you can imagine. That's what I mean by the moon still being there when nobody looks at it. The moon has been measured and cannot be unmeasured. — noAxioms

I think there's a deeper underlying issue. Despite your professed scepticism about scientific realism, I think your philosophical framework is still committed to a form of realism. This is an opportunity to explore the implications of that.

It is often said by way of objection to philosophical idealism, that idealism must mean that things go into or pass out of existence depending on whether they're being observed. After all that appears to be the implication of Berkeley's 'esse est percipe' - 'to be is to be perceived'.

But I don't think this is what philosophical idealism means - not, at least, as I understand it. This has to do with the nature of the objects of perception. Realism posits that the existence of those objects is independent of our perception or experience. They exist just so - in the case of the moon for billions of years. So it is preposterous to claim that they could cease to exist simply because nobody is looking at them. Yet this is what idealism seems to claim.

And I think this was the point of Einstein's rhetorical question. Realism expects that all such objects are really existent, independently of any mind or anyone's perception. That is, after all, the very definition of realism. This is the gist of Einstein's well-known declaration that he 'cannot seriously believe in [the quantum theory] because it cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance.'

But an alternative is to acknowledge that the existence of sensable objects is contingent and not absolute. This not to assert that objects exist in any absolute sense, on the one hand, but neither is it to claim that they cease to exist when they're not observed, on the other. It is to acknowledge that judgement concerning the reality of objects is a function of human sensory perception and reason, and that it is therefore not absolute. From the human point of view, all such objects exist - you'd better believe it! - but their existence is contingent and not absolute.

So this attitude does call realism into question but without falling into a caricature of idealism that it is easily taken to imply. I think it teaches us to respect that science is a human undertaking and that it's not a revelation of what is truly the case independently of any observer.

Or, put another way, that physics alone cannot constitute the totality of our experience.

Bell suggests ‘experiment’, but that loads the whole situation with intent that is meaningless. — noAxioms

It's not meaningless to point out the intent which is inherent within observation, measurement, etc.. And the intent is much more evident with the word "experiment". It's a fundamental fact that experiments are designed, and this points to the theory-laden nature of measurements and observations.

In general, the fact that experiments are designed is a very good feature of the scientific method. It allows us to control for specifics. However, design under defective theories, defective premises, etc., can also allow us to be drawn down long paths of misunderstanding.

The fact that the apparatus, rather than the human senses, does the observing, is something which the implications of, needs to be considered. The apparatus has the position of being a medium between the thing observed, and the human observer. Because of this, it is essential to know exactly what the apparatus is doing in this position, as necessary to an accurate interpretation of the observations. In the case of quantum experiments, the issue of exactly what the apparatus is doing, is where the experiments are very theory-laden.

To understand what I am saying, consider making observations through a magnifying glass. The magnifying glass is the medium between the observer and the thing observed, it's the apparatus. When interpreting your observations it is essential to know what the magnifying glass is doing in this position, because it could produce some sort of interference which would not be there naturally, (like the way it can focus light on the object to burn it) and you might interpret this interference as a natural part of the thing you are observing. The magnifying glass is a very simple thing, but it can have a strong causal effect on the observed thing, as the burning example shows. As we move toward more and more complicated observational apparatus, the microscope, the electron microscope, the need to understand the theory involved, and the soundness of the theory, in making interpretations becomes more and more important.

Well I googled ‘motion definition in physics’ and get a britannica one saying “change with time of the position or orientation of a body.“ which makes no mention of a requirement for observation (human or otherwise) to be involved. — noAxioms

I told you, time requires observation, it is the outcome of observation. So "change with time of the position..." does require observation. Time is part of the map. And, once you realize this, you'll see that "position" also is part of the map. It is a human designation of where a thing is in relation to other things. "Position" also requires observation. This is Kant's point when he says that space and time are fundamental "intuitions". They exist as part of the human being's observational apparatus, as intuitional theory, not as part of the thing being observed.

That’s a pretty idealistic assertion. Are you one of those people that suggest that nothing happened before humans came along? — noAxioms

I think there was no descriptions derived from human observations (of which "motion" is one), before humans came along.

Absolute time has no dependency on its being measured. If it flows, the rate (and direction) at which it does so is entirely independent of anything’s perception or measurement of it. You seem to keep attempting to make everything about your knowledge of something, about the map and not about the territory. — noAxioms

"Absolute time" is a misnomer. I told you this already. What is referred to as the perspective of "absolute time", is the assumption that one's position on the earth is the grounding point, as the position of rest, from which all passage of time is assumed to be relative to. Any measurement of time passing, the "flow" you refer to is done from this rest frame. It is said to be "absolute" because it serves as the grounding for the measurement of time for all frames of reference, unlike special relativity which allows the measurement of time to be frame specific.

Nevertheless, what is referred to as "absolute time" is a theoretical proposal, a condition of the observational perspective. It does not refer to something independent of the perspective, but it is a definitional feature of the perspective. So in the map analogy it is part of the "key", or "legend", which i necessary for interpreting and using the map. Therefore it is part of the map rather than the territory.

If I’m here now and here later, that seems to be not-moving relative to ‘here’. — noAxioms

Come on Axioms, your pretense of naivety is overwhelming me. This statement is so filled with problems that it is actually bordering on ridiculous. First, what the hell does "here" refer to? The term gives no positional reference. It's just a matter of you stipulating I am "here", and the place I call "here" at one time is the same place I call "here" at another time. Even if we could assume that "here" refers to the exact same position in "here now", as it refers to in "here later", thus creating the appearance that you have not moved, there's nothing to exclude the possibility that you flew around the whole universe in the meantime. So your sense of "seems to be not-moving" is not at all a logical conclusion, and is just as much an illusion as it is a case of you simply stipulating "I am here therefore I am not moving".

Even looking at the measurement dials has no impact on the collapse or not. Of course, the descriptions you quote give a special role to an observer (writing down the reading of the dial say), but 1, it doesn’t take a human (or actual ‘observation’) to do that, and 2, it being written down isn’t what causes collapse. If the dial says |here>, then the wave function is collapsed whether or not anything (or person) reads that dial since the dial is not inside Walmart. — noAxioms

Yes, decoherence doesn't depend on whether anyone looks or not.

Nonetheless the observer - or, even better, agent or person - closes the loop in the sense that it is human experience that grounds quantum theory and the quantities that can be measured.

A further point is that you won't ever find a contradiction when comparing what has been observed. It's the assumptions about what hasn't been observed that can lead to trouble as Bell's Theorem shows. Sometimes it's not even clear what should count as a measurement. For example, consider this passage from Sidney Coleman's lecture:

Neville Mott worried way back in 1929 about cloud chambers. He said: “Look, an atom releases an ionizing particle at the center of a cloud chamber in an s-wave. And it makes a straight line track.

Why should it make a straight line track? If I think about an s-wave, it is spherically symmetric. Why do they not get some spherically symmetric random distribution of sprinkles? Why should the track be a straight line? — Quantum Mechanics in Your Face - Sidney Coleman

One possible answer is that the cloud chamber is making a rapid series of measurements that constrain the particle to a straight line. Mott's answer (now the generally accepted answer) is that the cloud chamber is also a quantum system which evolves together with the particle and the potential paths not on the straight line cancel out. So nothing clearly qualifies as a measurement here.

Having imbibed a bit too much at the local pub he enters a state of superposition, thoroughly confused, an unknowing victim of a partial differential equation. — jgill

You might enjoy this excerpt from Coleman's lecture:

Now I will give an argument due to David Albert[21] with respect to Zurek’s question. Zurek asked: “Why do I always have the perception that I have observed a definite outcome?” To answer this question, no cheating: we can’t assume Zurek is some vitalistic spirit loaded with élan vital unobeying the laws of quantum mechanics. We have to say the observer—well I don’t want to make it Zurek, that would be using him without his permission, I’ll make it me, Sidney—has some Hilbert space of states, and some condition in Sidney’s consciousness corresponds to the perception that he has observed a definite outcome, so there is some projection operator on it, the definiteness operator. If you want, we could give it an operational definition: the state where the definiteness operator is +1 is one where a hypothetical polite interrogator asks Sidney: “Have you observed a definite outcome?”, and he says: “Yes”. In the orthogonal states he would say: “No, gee, I was looking someplace else when that sign flashed” or “I forgot” or “Don’t bother me, man, I’m stoned out of my mind” or, you know, any of those things. — Quantum Mechanics in Your Face - Sidney Coleman

In Coleman's account, these are all potential paths that can interfere.

Nonetheless the observer - or, even better, agent or person - closes the loop in the sense that it is human experience that grounds quantum theory and the quantities that can be measured. — Andrew M

That also seems true of say Newtonian theory. Is there some way in which human agency or observation makes a difference in (grounds) QT in a way that it doesn’t in NT? That would be a pretty incredible claim, that physics (and not just human theories/knowledge of physics) is different in the presence of humans than it is in a universe absent them.

But I don't think this is what philosophical idealism means - not, at least, as I understand it. This has to do with the nature of the objects of perception. Realism posits that the existence of those objects is independent of our perception or experience. — Wayfarer

But the converse is not true. It being independent of perception doesn’t necessitate a stance of realism. My ontology has nothing to do with perception, and yet I don’t suggest things ‘are real’ in any objective sense.

They exist just so - in the case of the moon for billions of years.

For instance, I wouldn’t make statements like that, but a realist would.

So it is preposterous to claim that they could cease to exist simply because nobody is looking at them. Yet this is what idealism seems to claim.

OK, but I’m not claiming idealism as you describe it. That’s about perception as you say.

And I think this was the point of Einstein's rhetorical question. Realism expects that all such objects are really existent, independently of any mind or anyone's perception. That is, after all, the very definition of realism. This is the gist of Einstein's well-known declaration that he 'cannot seriously believe in [the quantum theory] because it cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance.'

I don’t think quantum theory suggests idealism. Perhaps there was a suspicion way back then. People were just coming to terms with the new implications, watching all their classical assumptions getting trampled. The conversation by Einstein was part of that realization that the classical assumptions cannot all be correct. Bell went on later to prove that, saying that either realism or locality had to go. I think Einstein would have had a much harder time letting go of locality since all his relativity theory rests on premises that assume it.

But an alternative is to acknowledge that the existence of sensable objects is contingent and not absolute. This not to assert that objects exist in any absolute sense, on the one hand, but neither is it to claim that they cease to exist when they're not observed, on the other. It is to acknowledge that judgement concerning the reality of objects is a function of human sensory perception and reason, and that it is therefore not absolute. From the human point of view, all such objects exist - you'd better believe it! - but their existence is contingent and not absolute.

Don’t think any of that contradicts what I’m saying. Reality itself is neither absolute nor a function of perception, but judgment of it is a function of perception.

I think it teaches us to respect that science is a human undertaking and that it's not a revelation of what is truly the case independently of any observer.

I don’t see how that follows, sorry.

It's not meaningless to point out the intent which is inherent within observation, measurement, etc.. And the intent is much more evident with the word "experiment". It's a fundamental fact that experiments are designed, and this points to the theory-laden nature of measurements and observations. — Metaphysician Undercover

Usage of the word implies that quantum effects only occur when there is intent behind the measurements. There’s no evidence for that and heavy evidence against it. I’m not saying there’s anything wrong with intent in scientific experiments. That’s the point after all.

The magnifying glass is the medium between the observer and the thing observed, it's the apparatus.

Poor example I think since a magnifying glass doesn’t usually qualify as a measurement. They’re used in multiple places in typical laser experiments and they don’t collapse wave functions in them, else the experiments would fail. They’re not detectors, only refractors, and refraction wouldn’t work (wouldn’t bend light) at all if it constituted a measurement.

I told you, time requires observation, it is the outcome of observation.

How very idealistic of you. See Wayfarer’s post above about if perception is required for the reality of something.

I think there was no descriptions derived from human observations (of which "motion" is one), before humans came along.

But I wasn’t asking about descriptions. You say time requires observation. You didn’t say a description of time requires observation. I’d have agreed to that. So you’re evading the question instead by answering a different one.

First, what the hell does "here" refer to?

The origin of the coordinate system defined by the series of events at which I am present.

The term gives no positional reference.

Don’t be silly. You know it does. It is the location of that which said ‘here’.

there's nothing to exclude the possibility that you flew around the whole universe in the meantime.

But you said that being stationary was not possible, so you seem to exclude the possibility that you didn’t go anywhere during that interval. And as for my statement, had I indeed flown all around during that interval, at no time would I not be where I am, thus I’d always still be ‘here’. I’d simply not be inertial, so the coordinate system in which I am perpetually at the origin would not be an inertial coordinate system.