This is accurate, yes. The cat in the box is conscious presumably, in my opinion of cats at least, but still can be “not an observer” from the POV of the scientist observing the experiment from outside the box.

“Consciousness” is not relevant here at all. You can write down the wave function of a system relative to a rock if you wanted, in a comparable way as writing down the velocity of a train from the “point of view” of a rock. It is coordinate. It has nothing to do with “consciousness.” The cat would perceive a definite state of the system from its reference frame, but the person outside the box would not until they interact with it.

QM is about quite a lot more than coordinate systems

Obviously QM is not just coordinate systems. The coordinate nature of quantum mechanics, the relative nature of it, is merely a property of the theory and not the whole theory. But the rest of the theory does not have any relevance to “consciousness.”

and in my opinion will make it look weird in retrospect once physics expands to a more coherent whole

The theory is fully coherent and internally consistent. It amazes me how many people choose to deny QM and always want to rush to change it. Your philosophy should be guided by the physical sciences, not the other way around. People see QM going against their basic intuitions and their first thought is it must be incomplete and needs to have additional complexity added to it to make it fit their intuitions, rather than just questioning that maybe their basic intuitions are wrong.

Your other comment was to a Wikipedia page which if you clicked the link on your own source it would’ve told you that the scientific consensus on that topic is that what you’re presenting is a misinterpretation.

• https://en.m.wikipedia.org/wiki/Delayed-choice_quantum_eraser#Consensus:_no_retrocausality

A simple search on YouTube could’ve also brought up several videos explaining this to you.

• https://www.youtube.com/watch?v=s5yON4Gs3D0
• https://www.youtube.com/watch?v=RQv5CVELG3U

Edit: Placing my response here as an edit since I don’t care to continue this conversation so I don’t want to notify.

Yes, that was what I said. Er, well… QM, as I understand it, doesn’t have to do anything with shifting coordinate systems per se (and in fact is still incompatible with relativity). They’re just sort of similar in that they both have to define some point of view and make everything else in the model relative to it. I’m still not sure why you brought coordinate systems into it.

A point of view is just a colloquial term to refer to a coordinate system. They are not coordinate in the exact same way but they are both coordinate.

My point was that communication of state to the observer in the system, or not, causes a difference in the outcome. And that from the general intuitions that drive almost all of the rest of physics, that’s weird and sort of should be impossible.

No, it doesn’t not, and you’re never demonstrated that.

Sure. How is it when combined with macro-scale intuition about the way natural laws work, or with general relativity?

We have never observed quantum effects on the scale where gravitational effects would also be observable, so such a theory, if we proposed one, would not be based on empirical evidence.

This is very, very very much not what I am doing. What did I say that gave you the impression I was adding anything to it?

You literally said in your own words we need to take additional things into account we currently are not. You’re now just doing a 180 and pretending you did not say what literally anyone can scroll up and see that you said.

I am not talking about anything about retrocausality here, except maybe accidentally.

Then you don’t understand the experiment since the only reason it is considered interesting is because if you interpret it in certain ways it seems to imply retrocausality. Literally no one has ever treated it as anything more than that. You are just making up your own wild implications from the experiment.

I was emphasizing the second paragraph; “wave behavior can be restored by erasing or otherwise making permanently unavailable the ‘which path’ information.”

The behavior of the system physically changes when it undergoes a physical interaction. How surprising!

There is “observer-dependence” in quantum mechanics in a comparable way that there is observer-dependence in general relativity. It has nothing to do with some “fundamental role of consciousness” but comes from the fact that reality itself depends on how you look at it, it is reference frame dependent. The “observer” is just a chosen coordinate system in which to describe other things. I know, you probably got this from Kastrup too, right? Idealists have been getting desperate and resorting to quantum woo, pretending that something that changes based on coordinate system proves fundamental consciousnesses.

Kastrup is entirely unconvincing because he pretends the only two schools of philosophy in the whole universe are his specific idealism and metaphysical realism which he falsely calls the latter “materialism.” He thus never feels the need to ever address anything outside of a critique of a single Laymen understanding of materialism which is more popular in western countries than eastern countries, ignoring the actual wealth of philosophical literature.

Anyone who actually reads books on philosophy would inevitably find Kastrup to be incredibly unconvincing as he, by focusing primarily on a single school, never justifies many of his premises. He begins from the very beginning talking about “conscious experience” and whatnot when, if you’re not a metaphysical realist, that is what you are supposed to be arguing in the first place. Unless you’re already a dualist or metaphysical realist, if you are pretty much any other philosophical school like contextual realist, dialectical materialist, empiriomonist, etc, you probably already view reality as inherently observable, and thus perception is just reality from a particular point-of-view. It then becomes invalid to add qualifiers to it like “conscious experience” or “subjective experience” as reality itself cannot had qualifiers.

I mean, the whole notion of “subjective experience” goes back to Nagel who was a metaphysical realist through-and-through and wrote a whole paper defending that notion, “What is it like to be a Bat?”, and this is what Kastrup assumes his audience already agrees with from the get-go. He never addresses any of the criticisms of metaphysical realism but pretends like they don’t exist and he is the unique sole critic of it and constantly calls metaphysical realism “materialism” as if they’re the same philosophy at all. He then builds all of his arguments off of this premise.

You should look into contextual realism. You might find it interesting. It is a philosophical school from the philosopher Jocelyn Benoist that basically argues that the best way to solve most of the major philosophical problems and paradoxes (i.e. mind-body problem) is to presume the natural world is context variant all the way down, i.e. there simply is no reality independent of specifying some sort of context under which it is described (kind of like a reference frame).

The physicist Francois-Igor Pris points out that if you apply this thinking to quantum mechanics, then the confusion around interpreting it entirely disappears, because the wave function clearly just becomes a way of accounting for the context under which an observer is observing a system, and that value definiteness is just a context variant property, i.e. two people occupying two different contexts will not always describe the system as having the same definite values, but may describe some as indefinite which the other person describes as definite.

“Observation” is just an interaction, and by interacting with a system you are by definition changing your context, and thus you have to change your accounting for your context (i.e. the wave function) in order to make future predictions. Updating the wave function then just becomes like taring a scale, that is to say, it is like re-centering or “zeroing” your coordinate system, and isn’t “collapsing” anything physical. There is no observer-dependence in the sense that observers are somehow fundamental to nature, only that systems depend upon context and so naturally as an observer describing a system you have to take this into account.

Quantum mechanics is incompatible with general relativity, it is perfectly compatible with special relativity, however. I mean, that is literally what quantum field theory is, the unification of special relativity and quantum mechanics into a single framework. You can indeed integrate all aspects of relativity into quantum mechanics just fine except for gravity. It’s more that quantum mechanics is incompatible with gravity and less that it is incompatible with relativity, as all the other aspects we associate with relativity are still part of quantum field theory, like the passage of time being relative, relativity of simultaneity, length contraction, etc.

There shouldn’t be a distinction between quantum and non-quantum objects. That’s the mystery. Why can’t large objects exhibit quantum properties?

What makes quantum mechanics distinct from classical mechanics is the fact that not only are there interference effects, but statistically correlated systems (i.e. “entangled”) can seem to interfere with one another in a way that cannot be explained classically, at least not without superluminal communication, or introducing something else strange like the existence of negative probabilities.

If it wasn’t for these kinds of interference effects, then we could just chalk up quantum randomness to classical randomness, i.e. it would just be the same as any old form of statistical mechanics. The randomness itself isn’t really that much of a defining feature of quantum mechanics.

The reason I say all this is because we actually do know why there is a distinction between quantum and non-quantum objects and why large objects do not exhibit quantum properties. It is a mixture of two factors. First, larger systems like big molecules have smaller wavelengths, so interference with other molecules becomes harder and harder to detect. Second, there is decoherence. Even small particles, if they interact with a ton of other particles and you average over these interactions, you will find that the interference terms (the “coherences” in the density matrix) converge to zero, i.e. when you inject noise into a system its average behavior converges to a classical probability distribution.

Hence, we already know why there is a seeming “transition” from quantum to classical. This doesn’t get rid of the fact that it is still statistical in nature, it doesn’t give you a reason as to why a particle that has a 50% chance of being over there and a 50% chance of being over here, that when you measure it and find it is over here, that it wasn’t over there. Decoherence doesn’t tell you why you actually get the results you do from a measurement, it’s still fundamentally random (which bothers people for some reason?).

But it is well-understood how quantum probabilities converge to classical probabilities. There have even been studies that have reversed the process of decoherence.

That’s actually not quite accurate, although that is how it is commonly interpreted. The reason it is not accurate is because Bell’s theorem simply doesn’t show there is no hidden variables and indeed even Bell himself states very clearly what the theorem proves in the conclusion of his paper.

In a theory in which parameters are added to quantum mechanics to determine the results of individual measurements, without changing the statistical predictions, there must be a mechanism whereby the setting of one measuring device can influence the reading of another instrument, however remote. Moreover, the signal involved must propagate instantaneously, so that such a theory could not be Lorentz invariant.[1]

In other words, you can have hidden variables, but those hidden variables would not be Lorentz invariant. What is Lorentz invariance? Well, to be “invariant” basically means to be absolute, that is to say, unchanging based on reference frame. The term Lorentz here refers to Lorentz transformations under Minkowski space, i.e. the four-dimensional spacetime described by special relativity.

This implies you can actually have hidden variables under one of two conditions:

1. Those hidden variables are invariant under some other framework that is not special relativity, basically meaning the signals would have to travel faster than light and thus would contradict special relativity and you would need to replace it with some other framework.
2. Those hidden variables are variant. That would mean they do indeed change based on reference frame. This would allow local hidden variable theories and thus even allow for current quantum mechanics to be interpreted as a statistical theory in a more classical sense as it even evades the PBR theorem.[2]

The first view is unpopular because special relativity is the basis of quantum field theory, and thus contradicting it would contradict with one of our best theories of nature. There has been some fringe research into figuring out ways to reformulate special relativity to make it compatible with invariant hidden variables,[3] but given quantum mechanics has been around for over a century and nobody has figured this out, I wouldn’t get your hopes up.

The second view is unpopular because it can be shown to violate a more subtle intuition we all tend to have, but is taken for granted so much I’m not sure if there’s even a name for it. The intuition is that not only should there be no mathematical contradictions within a single given reference frame so that an observer will never see the laws of physics break down, but that there should additionally be no contradictions when all possible reference frames are considered simultaneously.

It is not physically possible to observe all reference frames simulatenously, and thus one can argue that such an assumption should be abandoned because it is metaphysical and not something you can ever observe in practice.[4] Note that inconsistency between all reference frames considered simulatenously does not mean observers will disagree over the facts, because if one observer asks another for information about a measurement result, they are still acquiring information about that result from their reference frame, just indirectly, and thus they would never run into a disagreement in practice.

However, people still tend to find it too intuitive to abandon this notion of simultaneous consistency, so it remains unpopular and most physicists choose to just interpret quantum mechanics as if there are no hidden variables at all. #1 you can argue is enforced by the evidence, but #2 is more of a philosophical position, so ultimately the view that there are no hidden variables is not “proven” but proven if you accept certain philosophical assumptions.

There is actually a second way to restore local hidden variables which I did not go into detail here which is superdeterminism. Superdeterminism basically argues that if you did just have a theory which describes how particles behave now but a more holistic theory that includes the entire initial state of the universe going back to the Big Bang and tracing out how all particles evolved to the state they are now, you can place restrictions on how that system would develop that would such that it would always reproduce the correlations we see even with hidden variables that is indeed Lorentz invariant.

Although, the obvious problem is that it would never actually be possible to have such a theory, we cannot know the complete initial configuration of all particles in the universe, and so it’s not obvious how you would derive the correlations between particles beforehand. You would instead have to just assume they “know” how to be correlated already, which makes them equivalent to nonlocal hidden variable theories, and thus it is not entirely clear how they could be made Lorentz invariant. Not sure if anyone’s ever put forward a complete model in this framework either, same issue with nonlocal hidden variable theories.

well IBM does have cloud accessible quantum computers that they don’t charge to use

I used those to teach myself some stuff about quantum information science

The traditional notion of cause and effect is not something all philosophers even agree upon, I mean many materialist philosophers largely rejected the notion of simple cause-and-effect chains that go back to the “first cause” since the 1800s, and that idea is still pretty popular in some eastern countries.

For example, in China they teach “dialectical materialist” philosophy part of required “common core” in universities for any degree, and that philosophical school sees cause and effect as in a sense dependent upon point of view, that an effect being described as a particular cause is just a way of looking at things, and the same relationship under a different point of view may in fact reverse what is considered the cause and the effect, viewing the effect as the cause and vice-versa. Other points of view may even ascribe entirely different things as the cause.

It has a very holistic view of the material world so there really is no single cause to any effect, so what you choose to identify as the cause is more of a label placed by an individual based on causes that are relevant to them and not necessarily because those are truly the only causes. In a more holistic view of nature, Laplacian-style determinism doesn’t even make sense because it implies nature is reducible down to separable causes which can all be isolated from the rest and their properties can then be fully accounted for, allowing one to predict the future with certainty.

However, in a more holistic view of nature, it makes no sense to speak of the universe being reducible to separable causes as, again, what we label as causes are human constructs and the universe is not actually separable. In fact, the physicists Dmitry Blokhintsev had written a paper in response to a paper Albert Einstein wrote criticizing Einstein’s distaste for quantum mechanics as based on his adherence to the notion of separability which stems from Newtonian and Kantian philosophy, something which dialectical materialists, which Blokhintsev self-identified as, had rejected on philosophical grounds.

He wrote this paper many many years prior to the publication of Bell’s theorem which showed that giving up on separability (and by extension absolute determinism) really is a necessity in quantum mechanics. Blokhintsev would then go on to write a whole book called The Philosophy of Quantum Mechanics where in it he argues that separability in nature is an illusion and under a more holistic picture absolute determinism makes no sense, again, purely from materialistic grounds.

The point I’m making is ultimately just that a lot of the properties people try to ascribe to “materialists” or “naturalists” which then later try to show quantum mechanics is in contradiction with, they seem to forget that these are large umbrella philosophies with many different sects and there have been materialist philosophers criticizing absolute determinism as even being a meaningful concept since at least the 1800s.