  The transition from the quantum to the classical is governed by randomizing
devices (RD), i.e., dynamical systems that are very sensitive to the
environment. We show that, in the presence of RDs, the usual arguments based on
the linearity of quantum mechanics that lead to the measurement problem do not
apply. RDs are the source of probabilities in quantum mechanics. Hence, the
reason for probabilities in quantum mechanics is the same as the reason for
probabilities in other parts of physics, namely our ignorance of the state of
the environment. This should not be confused with decoherence. The environment
here plays several, equally important roles: it is the dump for energy and
entropy of the RD, it puts the RD close to its transition point and it is the
reason for probabilities in quantum mechanics. We show that, even though the
state of the environment is unknown, the probabilities can be calculated and
are given by the Born rule. We then discuss what this view of quantum mechanics
means for the search of a quantum theory of gravity.
