The author treats the Copenhagen interpretation as if it shows that there are no observer-independent things, when in reality it simply states that quantum theory is not about them.
"Bohr (1937), Heisenberg (1947), Frank (1936) and others explained carefully -- but did not prove -- that the theory makes no assertions concerning autonomous, i.e. observer-independent, things: that all its statements are about experimental situations. (This is why Bohr, and initially also Rosenfeld, stated that no special theory of measurement was necessary: they believed that quantum mechanics was already a theory of measurement.)" From Mario Bunge (1979) "The Einstein-Bohr debate over quantum mechanics: Who was right about what?"
"Bohr (1937), Heisenberg (1947), Frank (1936) and others explained carefully -- but did not prove -- that the theory makes no assertions concerning autonomous, i.e. observer-independent, things: that all its statements are about experimental situations. (This is why Bohr, and initially also Rosenfeld, stated that no special theory of measurement was necessary: they believed that quantum mechanics was already a theory of measurement.)" From Mario Bunge (1979) "The Einstein-Bohr debate over quantum mechanics: Who was right about what?"