  The basic concepts of classical mechanics are given in the operator form.
Then, the hybrid systems approach, with the operator formulation of both
quantum and classical sector, is applied to the case of an ideal nonselective
measurement. It is found that the dynamical equation, consisting of the
Schr\"odinger and Liouville dynamics, produces noncausal evolution when the
initial state of measured system and measuring apparatus is chosen to be as it
is demanded in discussions regarding the problem of measurement. Nonuniqueness
of possible realizations of transition from pure noncorrelated to mixed
correlated state is analyzed in details. It is concluded that collapse of state
is the only possible way of evolution of physical systems in this case.
