M. Jammer's "The Philosophy of Quantum Mechanics"

"as long as a quantum mechanical one-body or many-body system does not
interact with macroscopic objects, as long as its motion is described by
the deterministic Schrodinger time-dependent equation, no events could
be considered to take place in the system. ... In other words, if the
whole physical universe were composed only of microphysical entities, as
it should be according to the atomic theory, it would be a universe of
evolving potentialities ... but not of real events." [p. 474]