Yes, that’s clear. But on large scales, it is similar?
In any case, the question was more whether, as a result of this, there really is any reality at all on any scale, because it sounds like there are those who advocate an approach according to which there is literally no physical property out there in reality somewhere, but rather something like a multi-participant Matrix.
An approach that Einstein strongly opposed.

That is one interpretation of several problems in quantum mechanics. One interpretation of the problem raised by Schrödinger’s cat is “Wigner’s friend.” That is the more “spiritual” and bizarre interpretation of quantum mechanics.
The second interpretation is Hugh Everett’s many-worlds.

In any case, both perspectives are interpretations that belong more to philosophy than to physics.

That’s clear, but at the end of the day, does the Rabbi think that modern ruling leads us to give up the existence of almost every physical property outside human consciousness? Or does the material world still remain in existence, and we are not talking only about a Matrix of multiple consciousnesses?

For example, if we talk about a property like waviness, then in reality itself matter on large scales is obviously not wave-like, but if every component of it is, then how is the whole not? Or more precisely, is it correct to say that as a whole it is not?

It’s clear that our thinking colors reality, but still, is it correct to say that modern science has in fact already stripped matter of almost every physical property outside human consciousness? Meaning, that we are dealing with a kind of multi-participant Matrix game.
For example, if reality on small scales is not at all close to reality on large scales (infinite waves versus particles), doesn’t that mean there is some difficulty in assuming that the reality outside is in fact physical?

There is such an esoteric approach, according to which “super-reality” is everything that is possible. And the reality of the conscious human being is that reality (a result of “super-reality”) that allows for his existence. And that is what he sees.
In other words, there are 3 stages: super-reality (metaphysics), reality (physics), and what the human being sees (consciousness).

The contradiction arises between ordinary logic and reality. What we thought in logic was possible or impossible turns out to be incorrect.

Rabbi, in light of your remarks, what do you think about this discussion: http://forum.otzar.org/viewtopic.php?f=17&t=50793

The sages of Chelm?

As I wrote, our consciousness colors reality, regardless of science and quantum theory. But the difference from the Matrix is essential. The Matrix is deception. You think you are living in world A while in fact you are living in B. Here, by contrast, there is no deception at all. This is the correct perception of reality itself. Rather, the perception of an electromagnetic wave of a certain wavelength is light in the corresponding color within consciousness. So this is really not a Matrix.
I have written more than once that those who interpret Kant’s distinction between the thing in itself and the thing as it appears to us as a limitation of perception are mistaken. There is no limitation here. This is the meaning of perception: fitting reality into my own system of concepts and awareness. Mark this well.

Elisha,
Why Chelm? It seems to me a very meaningful discussion indeed. When you have an auditory experience without actually having heard, the question is whether you have fulfilled your obligation of hearing.
And it is not comparable to hearing through a loudspeaker or radio, because there one is receiving information from outside, and it can certainly be called hearing. But here the information is produced inside me and does not come from outside. Is such a thing hearing? I wonder.

Okay, I think I understood what you meant.
If so, just as a not-so-related question: does matter ultimately have a genuinely particle-like dimension and not only a wave-like one? I mean, not just approximations at large scales, but really so? Otherwise, how can one speak of velocity?

Quantum theory sees matter as entities that take on a wave-like or particle-like character, depending on the circumstances. When they are particles they have position but not velocity, and when they are waves the opposite is true. Note well: it is דווקא the particles that do not have a defined velocity. Of course, usually these entities are in some sort of intermediate state. But all this is on the micro level. On the macro level, these phenomena disappear.

Why specifically “character”? Is that just the common wording, or do you hold that they are actually different entities altogether, and only appear to us this way or that way?

I don’t really understand this stuff; I thought momentum applies to particles with velocity and mass. Obviously, if you are talking about a specific defined position, then it has no velocity there. But it can still have velocity relative to its surroundings. Even when the table moves, it has velocity and the surroundings are fixed relative to it, so it’s not clear.

In any case, it isn’t clear that this has any practical difference, as you said.

Why did you use the term “character”—because that’s the usual way of speaking, or do you think they are some third thing that we just understand as either a wave or a particle?

I actually thought particles have momentum and velocity with mass, but maybe you mean that the position of a particle means it has no velocity there at all, and velocity is only relative to the change in environment it undergoes. But if so, that’s a bit paradoxical (if at every point the stone has no velocity, how does it travel?).

In any case, I don’t know whether this has any practical difference, as you said it depends on our understanding. But still, there is something annoying about thinking that matter is wave-like, even if probabilistically we simply almost never see or experience that. Except for some tiny slit.

Indeed, in my opinion there is some third thing there. It is described by the wave function.
Everything else is just the basics of quantum theory, and if it annoys you, you’re in good company.