Abstract

Precursing now popular ‘spontaneous reduction’ views, this chapter argues that the measurement problem in quantum mechanics is not a problem of measurement at all. Reductions happen in a variety of circumstances and are particularly important in the preparation of quantum states. But there is no reason to think there is any simple physical characterization of situations in which reduction of the wave packet occurs from when it does not. There is a difference in the mathematical characteristics of the evolution operator between the two, but this mathematical difference need mark no interesting physical difference distinguishing the situations to which operators apply.