  The well known interpretational difficulties with nonlinear Schr\"odinger and
von Neumann equations can be reduced to the problem of computing multiple-time
correlation functions in the absence of Heisenberg picture. Having no
Heisenberg picture one often resorts to Zeno-type reasoning which explicitly
involves the projection postulate as a means of computing conditional and joint
probabilities. Although the method works well in linear quantum mechanics, it
completely fails for nonlinear evolutions. We propose an alternative way of
performing the same task in linear quantum mechanics and show that the method
smoothly extends to the nonlinear domain. The trick is to use appropriate
time-dependent Hamiltonians which involve "switching-off functions". We apply
the technique to the EPR problem in nonlinear quantum mechanics and show that
paradoxes of Gisin and Polchinski disappear.
