What is it then? If you say it’s a wave, well, that wave is in Hilbert space which is infinitely dimensional, not in spacetime which is four dimensional, so what does it mean to say the wave is “going through” the slit if it doesn’t exist in spacetime? Personally, I think all the confusion around QM stems from trying to objectify a probability distribution, which is what people do when they claim it turns into a literal wave.

To be honest, I think it’s cheating. People are used to physics being continuous, but in quantum mechanics it is discrete. Schrodinger showed that if you take any operator and compute a derivative, you can “fill in the gaps” in between interactions, but this is just purely metaphysical. You never see these “in between” gaps. It’s just a nice little mathematical trick and nothing more. Even Schrodinger later abandoned this idea and admitted that trying to fill in the gaps between interactions just leads to confusion in his book Nature and the Greeks and Science and Humanism.

What’s even more problematic about this viewpoint is that Schrodinger’s wave equation is a result of a very particular mathematical formalism. It is not actually needed to make correct predictions. Heisenberg had developed what is known as matrix mechanics whereby you evolve the observables themselves rather than the state vector. Every time there is an interaction, you apply a discrete change to the observables. You always get the right statistical predictions and yet you don’t need the wave function at all.

The wave function is purely a result of a particular mathematical formalism and there is no reason to assign it ontological reality. Even then, if you have ever worked with quantum mechanics, it is quite apparent that the wave function is just a function for picking probability amplitudes from a state vector, and the state vector is merely a list of, well, probability amplitudes. Quantum mechanics is probabilistic so we assign things a list of probabilities. Treating a list of probabilities as if it has ontological existence doesn’t even make any sense, and it baffles me that it is so popular for people to do so.

This is why Hilbert space is infinitely dimensional. If I have a single qubit, there are two possible outcomes, 0 and 1. If I have two qubits, there are four possible outcomes, 00, 01, 10, and 11. If I have three qubits, there are eight possible outcomes, 000, 001, 010, 011, 100, 101, 110, and 111. If I assigned a probability amplitude to each event occurring, then the degrees of freedom would grow exponentially as I include more qubits into my system. The number of degrees of freedom are unbounded.

This is exactly how Hilbert space works. Interpreting this as a physical infinitely dimensional space where waves really propagate through it just makes absolutely no sense!

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.

Yes, the problem with quantum mechanics is it’s not just your Deepak Chopras of the world that get sucked into quantum woo, but even a lot of respectable academics with serious credentials, thus giving credence to these ideas. Quantum mechanics is a context-dependent theory, the properties of systems are context variant. It is not observer-dependent. The observer just occupies their own unique context and since it is context-dependent, they have to describe things from their own context.

It is kind of like velocity in Galilean relativity, you have to take into account reference frame. Two observers in Galilean relativity could disagree on certain things, such as the velocity of an object but the disagreement is not “confusing” because if you understand relativity, you’d know it’s just a difference in reference frame. Nothing important about “observers” here.

I do not understand what is with so many academics in fully understanding that properties of systems can be variant under different reference frames in special relativity, but when it comes to quantum mechanics their heads explode trying to interpret the contextual nature of it and resort to silly claims like saying it proves some fundamental role for the conscious observer. All it shows is that the properties of systems are context variant. There is nothing else.

Once you accept that, then everything else follows. All of the unintuitive aspects of quantum mechanics disappear, you do not need to posit systems in two places at once, some special role for observers, a multiverse, nonlocality, hidden variables, nothing. All the “paradoxes” disappear if you just accept the context variance of the states of systems.

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.

Quantum internet is way overhyped and likely will never exist. There are not only no practical benefits to using QM for internet but it has huge inherent problems that make it unlikely to ever scale.

• While technically yes you can make “unbreakable encryption” this is just a glorified one-time cipher which requires the key to be the same length of the message, and AES256 is already considered unbreakable even by quantum computers, so good luck cutting your internet bandwidth in half for purely theoretical benefits that exist on paper but will never be noticeable in practice!
• Since it’s a symmetric cipher it doesn’t even work for internet communication unless you have a way to distribute keys, and there is something called quantum key distribution (QKD) based around algorithms like BB84. However, this algorithm only allows you to guarantee that you can exchange keys without anyone snooping in on it being undetected, but it does not actually stop them from snooping in on your key like Diffie-Hellman achieves. Meaning, a person can literally shut down the entire network traffic just by observing the packets in transit without having to even do anything to do them. How can the government and private companies possibly build an internet whereby you guarantee nobody ever looks at packages as they’re transmitted through the network?
• QKD is also susceptible to man-in-the-middle attacks just like Diffie-Hellman, which we solve that problem in classical cryptography with digital signature algorithms. There are quantum digital signature algorithms (QDS) but they rely on Holevo’s theorem which says that the “collapse” is effectively a one-way process and only limited amount of information can be extrapolated from it, and thus you cannot derive the qubit’s initial state simply by measuring it. The problem, however, is Holevo’s theorem also says if you had tons of copies of the same qubit, you could derive even more information from it. Meaning, all public keys would have to be consumable, because making copies of them would undermine their security, and this makes it just not something that can scale.

And all this for what? You have all these drawbacks for what? Imagined security benefits that you won’t actually notice in real life? Only people I could ever see using this are governments that are hyperparanoid. A government intranet could be highly controlled, highly centralized, and not particularly large scale by its very nature that you don’t want many people having access to it. So I could see such a government getting something like that to work, but there would be no reason to replace the internet with it.