The many-worlds interpretation or MWI (also known as the relative state formulation, theory of the universal wavefunction, parallel universes, many-universes interpretation or just many worlds), is an interpretation of quantum mechanics. Many-worlds denies the objective reality of wavefunction collapse, instead explaining the subjective appearance of wavefunction collapse with the mechanism of quantum decoherence. Many-worlds claims to resolve all the "paradoxes" of quantum theory since every possible outcome to every event defines or exists in its own "history" or "world." In layman's terms, this means that there is a very large, perhaps infinite, number of universes and that everything that could possibly happen in our universe (but doesn't) does happen in some other universe(s).