What is the least inflationary or most everyday common sense interpretation of QM? Given that it's philosophy and not physics, the questions seems a good one.
Cited here, there are three alternative propositions that can be denied
1.A The wave-function of a system is complete , i.e. the wave-function specifies (directly or indirectly) all of the physical properties of a system. 1. B The wave-function always evolves in accord with a linear dynamical equation (e.g. the Schrödinger equation). 1. C Measurements of, e.g., the spin of an electron always (or at least usually) have determinate outcomes, i.e., at the end of the measurement the measuring device is either in a state which indicates spin up (and not down) or spin down (and not up).
Madulin, The Essence of Space-Time, p7
Many world interpretations give up 1C. Here, Schrödinger’s cat is not both dead and alive because these two events are kept separate by doceherence.
In other words, when the box is opened, the observer and the possibly-dead cat split into an observer looking at a box with a dead cat, and an observer looking at a box with a live cat. But since the dead and alive states are decoherent...
In the Copenhagen interpretation of 1B
According to Schrödinger, the Copenhagen interpretation implies that the cat remains both alive and dead until the state is observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics
Rejecting 1A occurs in hidden variable interpretations, but seems to give philosophy too strong a hand.
Which interpretation of QM which allows most for common sense? In particular, has it been demonstrated that it's only in the (extra-ordinary) many world interpretations that
the equations of physics that model the time evolution of systems without embedded observers are sufficient for modelling systems which do contain observers; in particular there is no observation-triggered wave function collapse which the Copenhagen interpretation proposes.
If so, can we limit the branching that, in the MW interpretation, occurs upon observation, into something unreal?