We suggest scattering experiments which implement the concept of “protective measurements” allowing the measurement of the complete wave function even when only one quantum system (rather than an ensemble) is available. Such scattering experiments require massive, slow, projectiles with kinetic energies lower than the first excitation of the system in question. The results of such experiments can have a (probabilistic) distribution (as is the case when the Born approximation for the scattering is valid) or be deterministic (in a semiclassical limit).

We argue that the Aharonov-Anandan-Vaidman model, by using the notion of so-called “protective measurements,” cannot claim to have dispensed with the ldcollapse of the wave function,” because it does not succeed in avoiding the quantum measurement problem. Its claim to be able to distinguish between two nonorthogonal states is also critically examined.