The world exists only when it is not observed

Abstract: In my talk, I will review the Everettian interpretation of quantum physics in the light of two catchphrases. The first is that “unperformed measurements have no outcomes” (Peres) and the second is that “unobserved outcomes can affect future measurements” (Sudbery). The beauty of the view that the whole Universe is quantum (which in my view is what Everett is all about) is that the distinction between the observer and the observed vanishes and that all the information resides in various entanglements between different subsystems while the entropy of the whole could well be zero. Plus, this version of quantum physics is easiest to reconcile with relativity or any other symmetry principle imported from classical physics.