The attraction of the many-worlds interpretation, for instance, is its ability to keep the reality in the mathematical physics. In this view, yes, the wave function is real and, yes, it describes a world of matter that obeys mathematical rules, whether someone is watching or not. The price you pay for this position is an infinite number of parallel universes that are infinitely splitting off into an infinity of other parallel universes that then split off into … well, you get the picture. There is a big price to pay for the psi-epistemologist positions too. Physics from this perspective is no longer a description of the world in-and-of itself. Instead, it’s a description of the rules for our interaction with the world. As the American theorist Joseph Eberly says: ‘It’s not the electron’s wave function, it’s your wave function.’