QM has raised doubt as to any matter exists in a fixed form. It depends on the observer. Who is observing then?
Who is observing the observer?
So?
> Who is observing the observer?
No “who”, but anything that interacts with it.
Things happen whether or not you’re around to see them. Things interacted millions of years ago and they will continue to interact until the heat death of the universe. The tree falls in the woods regardless of if anybody is there to witness it. No credible peer-reviewed research has ever claimed that the observer is anything more than a physical process or interaction. It’s the quantum consciousness woo woo pseudoscientists who anthropomorphise “observer” to mean a conscious observer.