  An experiment that would measure non--commuting quantum mechanical
observables without collapsing the wave function has been recently proposed by
Y Aharonov and J Anandan. These authors argue that this "protected measurement"
may give indication on "the reality of the wave function". We argue that,
depending of the precise version of the experiment considered, either the
author's prediction is incorrect and the wave function does collapse, or the
measurement is not a measurement on a quantum system. In either case, the
experiment does not provide a way for measuring non--commuting observables
without collapse, and it does not bear on the issue of the "reality of the wave
function".
