What is many-worlds?
AKA as the Everett, relative-state, many-histories or many-universes interpretation or metatheory of quantum theory. Dr Hugh Everett, III, its originator, called it the “relative-state metatheory” or the “theory of the universal wavefunction” [1], but it is generally called “many- worlds” nowadays, after DeWitt [4a],[5]. Many-worlds comprises of two assumptions and some consequences. The assumptions are quite modest: 1) The metaphysical assumption: That the wavefunction does not merely encode all the information about an object, but has an observer-independent objective existence and actually is the object. For a non-relativistic N-particle system the wavefunction is a complex-valued field in a 3-N dimensional space. 2) The physical assumption: The wavefunction obeys the empirically derived standard linear deterministic wave equations at all times. The observer plays no special role in the theory and, consequently, there is no collapse of the wavefunction. For non-relativistic systems
