 More commonly—and this is part of the basis for the popular wisdom—physicists have resolved the  quantum measurement problem  by postulating that some process of “collapse of the wavefunction” occurs during measurements or observations that interrupts Schrödinger evolution. The collapse process is usually postulated to be indeterministic, with probabilities for various outcomes, via Born’s rule, calculable on the basis of a system’s wavefunction. The once-standard Copenhagen interpretation of QM posits such a collapse. It has the virtue of solving certain problems such as the infamous Schrödinger’s cat paradox, but few philosophers or physicists can take it very seriously unless they are instrumentalists about the theory. The reason is simple: the collapse process is not physically well-defined, is characterised in terms of an anthropomorphic notion (measurement) and feels too ad hoc to be a fundamental part of nature’s  laws.[8]