My question is based on several theorems which have some features in common. First of them is famous PBR-theorem. It states that quantum state cannot be considered as statistical and does not represent the knowledge of the system's state.

The second theorem demonstrates that superposition cannot be epistemic.

The link: https://arxiv.org/abs/1501.05969

And, finally, the third theorem was derived using the pervious one and states that some macrorealist ontologies are incompatible with quantum mechanics.

The link: https://arxiv.org/abs/1610.00022

I have added links to the last two theorems, because there are some details that are difficult to sum up.

I met some people who used the type of theorems which I mentioned in order to support some implausible interpretations of quantum mechanics such as "consciousness causes collapse". I understand that we should abandon realism in classical sense at least because of Bell's inequalities violation, however, it seems to me that due to decoherence and other various factors we can accept realism that is not ontological, but emerges somehow.

I mean, in my opinion, the poor Schrödinger's cat  is either dead or alive before the box is opened not because it actually has some define ontic state and possesses it after opening the box, but because this state emerges from wavefunction "collapsing" of many-many particles of which this cat is made because of influence of environment. And even if we can put a cat into superposition by isolating it, I don't think that this superposition can be the superposition of two macroscopic observables but of some other states (I know that my description is very rough.) That is why I am confused when authors of, for example, the last theorem extrapolate quantum pure states to macroscopic states which are likely to be mixed states. It seems to me that even if one accepts psi-ontic view, one can also accept that at some level or scale the wavefunction becomes epistemic. But maybe I am not right.

My question is: Are these theorems compatible with the notions of decoherence, coarse-grained measurements, entanglement with the environment and whatever is used to support the features of classical behavior of large systems? Or these theorems imply some kind of solipsism?

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    $\begingroup$ Normally I would downvote this type of question Michael, because, imo, it's not answerable and does not contain a specific physics concept. (But it looks like your first question, so.....) Instead, you are inviting a discussion, which this site is not set up for. I say this in case other people downvote it, but don't explain why. I think the chatroom is a better place, although i would admit similar question have received comments and answers. In my personal opinion, it leans more towards philosophy than specific physics concepts ( you know, the easy stuff :). Good luck with it anyways $\endgroup$ – user167453 Sep 1 '17 at 20:15
  • $\begingroup$ I don't think that my question is not compatible with this website: I saw many discussions on the similar topic there. I agree that my question is in some sense philosophical, but the tag "quantum-interpretations" is not accidentally used here:) And, finally, my question demonstrates the need of mere clarification of concepts which are already used in academic works, which I have mentioned, so I suppose that there is an answer. $\endgroup$ – Michael D Sep 3 '17 at 21:11
  • $\begingroup$ Hi Michael, true enough there have been similar questions asked, and yours is as well put as many of them, imo. I personally don't like that tag, but obviously some here do, so that's that. I would not agree there is an answer to your question, as least in the physics terms of making and falisfying a prediction, but I am happy to upvote and see what the consensus view is. $\endgroup$ – user167453 Sep 4 '17 at 6:27

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