The
many-worlds interpretation is an
interpretation of quantum mechanics that asserts the
objective reality of the
universal wavefunction and denies the actuality of
wavefunction collapse. Many-worlds implies that all
possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In lay terms, the hypothesis states there is a very large—perhaps infinite—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. The theory is also referred to as
MWI, the
relative state formulation, the
Everett interpretation, the
theory of the universal wavefunction,
many-universes interpretation, or just
many-worlds.