Comment by layer8

The issue with Copenhagen is that it doesn’t describe when precisely wave-function collapse actually happens, i.e., when the physical process deviates from the Schrödinger equation. It is not a proper theory in that sense. There are objective-collapse theories that do, and therefore provide different predictions from Many-Worlds (which simply says that the Schrödinger equation always holds). We haven’t come up with experiments yet that could test those different predictions, but we may in the future.