" Rule 2 raises a whole bunch of questions. Does the wave function collapse abruptly or does it take some time? Does the collapse take place as soon as the system interacts with the detector? Or only later, when a record is made? Or perhaps later still, when it is perceived by a conscious mind? Is the collapse a physical change, which means that the quantum state is real? Or is it just a change in our knowledge of the system, which means the "

― Lee Smolin , Einstein's Unfinished Revolution: The Search for What Lies Beyond the Quantum