The standard text book Copenhagen Interpretation of quantum mechanics formed by Bohr is a not a realist physical theory about "what is", but instead an idealist/positivist non-physical probabilistic theory of "what we can know".
This has led modern physics into a black hole of endless fruitless speculations with the Many Worlds Interpretation by Everett as the absurd result of anyway seeking to give a physical meaning to the non-physical Copenhagen Interpretation.
Now, it is a fact that the microscopic world of atoms interacts with the macroscopic world we perceive as being real physical. If the microscopic world is declared to be non-real non-physical, then the interaction becomes a mystery. That real physics can interact with real physics is obvious, but to think of interaction between non-real and real physics makes you dizzy as expressed so well by Bohr:
- Anyone who is not shocked by quantum theory has not understood it.
- Anyone who can contemplate quantum mechanics whit getting dizzy, hasn't understood it.
To keep being paid a physicist would say: Look, after all an atom is real as being composed of electron "particles orbiting" a kernel, and the non-real aspect is just that the physics is hidden to inspection and that we cannot know the whereabouts of these particles over time. So atoms are real but the nature of the reality is beyond human perception because you get dizzy when seeking to understand.
In particular it is to Bohr inexplicable that electron particles orbiting a kernel of an atom in ground state do not radiate and allows the ground state to be stable.
In realQM the charge distribution of an atom in ground state does not change in time and thus is not source of radiation and the atom can remain stable. On the other hand the charge distribution of a superposition of ground and excited states does vary with time and thus may radiate at the beat frequency as the difference between excited and ground frequency.
To Bohr contact with the inner microscopic world of an atom from the macroscopic would take place at a moment of observation, but that leaves out the constant interaction between micro and macro-scopics taking place in radiation.
An atom in ground state is not radiating and the inner mechanics of the atom is closed to inspection.
For this case one could argue that Bohr's view could be upheld, since one would be free to describe the inner mechanics in many different ways, for example in terms of probabilities of electron particle configurations, all impossible to experimentally verify.
The relevant problem is then the radiating atom in interaction with an outer macroscopic world and here Bohr has little to say because he believes that interaction micro-macro takes place only at observation in the form of "collapse of the wave function".
A real actuality of the inner mechanics of an atom may interact with an actual real outer world, with or without probability, but a probability of an inner particle mechanics of an atom cannot interact with an outer reality, and Bohr discards the first option...actualities can interact but not potentialities...
Let me sum up: The inner microscopics of a radiating atom interacts with outer macroscopics, and the interaction requires the microscopics to share physics with the macroscopics. This not the case in The Copenhagen Interpretation which thus must be false.