i’m not an academic and can’t follow [this paper](https://www.science.org/doi/10.1126/sciadv.aaw9832) but i’m very intrigued. any help is appreciated.
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You might want to check out this page, which are filled with rebuttals against the conclusion of the experiment: https://dailynous.com/2019/03/21/philosophers-physics-experiment-suggests-theres-no-thing-objective-reality/
You might have heard of Schrodinger’s cat, it’s a thought experiment. A cat is locked in a box, with contains a vial of toxin that will kill the cat. The vial is only broken based on the outcome of a radioactive decay, which as far as we can tell, is random (though we can compute its probability). So until we open the box, we won’t know if the cat is alive or dead. Schrodinger then ask, is that cat in the state of being both alive and dead, and we will collapse that state into 1 possibility by opening the box?
The reason for this Schrodinger’s cat thought experiment is because of the standard interpretation of quantum physics. In this, everything do not have specific values for its properties, each property are (in general) has multiple values at the same time until a measurement is made about it. After this measurement, the object change so that that property has only one value among these different possible value. Hence the Schrodinger’s cat: it is both alive and dead until someone look at it.
Schrodinger originally thought up this experiment as a parody of the standard interpretation of quantum mechanics, he think that the theory is incomplete. After all, it’s inconceivable that a cat is both alive and dead. Unfortunately, as we discover more about quantum physics, it seems harder and harder to dismiss the idea that objects at quantum level do have properties with multiple values at the same time until it’s measured; yet at the same time, objects at macroscopic level, those we seen normally in our everyday life, doesn’t seem to be able to have multiple state like that. But if quantum physics are supposed to be the law of physics, and big objects are made up of quantum objects, shouldn’t big object has multiple values as well? Also, shouldn’t an observer or a measurement device just part of the physical process as well, why would there be something magical about measuring a property that force it to choose one value?
This conundrum leads to various different interpretation of quantum physics. One important question is this: what happen if an observer is also part of a quantum system? Would they have multiple states as well? Would they measure the same thing as someone outside? Is there something special about consciousness that change how physics work? And so on and so forth.
This leads to the Wigner’s friend thought experiment. The gist of the idea is that you have an experimenter making measurement inside a lab, and another experimenter making measurement outside the lab. The one outside should see a superposition of states, but the one inside doesn’t. It’s more complicated than this, but that’s the gist of what make it interesting anyway.
So in any cases, we currently can’t actually perform that experiment, because trying to isolate a lab from outside influence is practically impossible. The “experimenter inside the lab” is replaced by a small quantum system, which the authors argue to be just as good.
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