Khanzhoren

I agree with you I don't entirely agree with you because one also talks about the size of an atom, a molecule, or a solid, for example, within the framework of quantum physics (even if it's not exactly the same as the classical concept). These "sizes" moreover depend on the localization, movement, and interactions of the constituents with the environment. These are described by quantum mechanics and are related to the uncertainty principle, among other things. I agree with you because actually, when I said quantum description, I was referring to a quantum theory of gravity as well.

It is evident that the rock existed before the astronaut arrived. Didn't the universe itself exist before humans appeared? In my view, the existence of matter and its macroscopic properties does not strongly depend on the existence of conscious being that could make a 'measurement' but on the interactions between its constituents and with the environment. I am in favor of a view (related to the concept of quantum decoherence : https://en.wikipedia.org/wiki/Quantum_decoherence) which affirms that the properties of matter already result from the interactions that exist between its constituents and its environments (independent of the existence of a conscious observer). But the arrival of the observer could simply change certain things depending on their actions on the system. That being said, it is clear that, in Reality, the cat is already either alive or dead according to the results of the interactions of the cat's constituents with their environment (as described by the concept of quantum decoherence) without the need for the intervention of conscious observer to look.

I think that the transformations under consideration are not conventional 3-parameter LCTs but rather some kind of multidimensional generalization of them wherein (among other things) spacetime replaces time.

Why ?

In quantum theory, due to the uncertainty principle, the exact values of coordinates (position) and momenta (related to velocity) cannot generally be known simultaneously. Consequently, a description of acceleration is not trivial ... However, Ehrenfest's theorem ( https://en.wikipedia.org/wiki/Ehrenfest_theorem) allows us to describe the time evolution of the mean values of quantum observables. Thus, we can still consider for a quantum particle an instantaneous average position (in the quantum sense of mean values), a kind of mean value of velocity (time derivative of the average position), and subsequently a kind of mean value of acceleration: it suffices to use Ehrenfest's theorem to relate these quantities. One can even show that there are some equivalents to Newton's laws in terms of these mean values"

I think the issue lies in our tendency to anthropomorphize particles, assuming they possess consciousness like we do. Remember, the only beings we know for certain to be conscious are humans. Even other living beings likely experience existence in a way that's not fully conscious. Now, particles of matter are inert; they aren't aware of their existence or capable of feeling like ours. So, in my view, the best we can do in certain cases (like with photons) is to have a mathematical representation of their behavior. We also tend to conflate the notions of observers and reference frames. An observer necessarily need to be a conscious being? A reference frame can simply be a mathematical concept. It's inherent in the nature of ordinary particles that we can associate rest frames with them. However, this isn't possible for photons, which is simply a consequence of the mathematics describing them. Ultimately, we can't say anything definitive about what a photon might 'experience' (since it doesn't think or feel or have consciousness) like when it comes to certain quantum phenomena. However, the question would become truly meaningful if a conscious entity could actually travel at the speed of light.

Hello, in my opinion , "singularity" or "object with size 0" cannot realy exist because of the quantum uncertainty principle. And as it is known GR is incomplete because, in particular, it is not a quantum theory. So the real solution to the problem related to singularity should be from quantum description.