  Could we hear the pop of a wave-function collapse, and if so, what would it
sound like? There exist reconstructions or modifications of quantum mechanics
(collapse models) where this archetypal signature of randomness exists and can
in principle be witnessed. But, perhaps surprisingly, the resulting sound is
disappointingly banal, indistinguishable from any other click. The problem of
finding the right description of the world between two completely different
classes of models -- where wave functions jump and where they do not -- is
empirically undecidable. Behind this seemingly trivial observation lie deep
lessons about the rigidity of quantum mechanics, the difficulty to blame
unpredictability on intrinsic randomness, and more generally the physical
limitations to our knowledge of reality.
