The concept that every choice spawns a new universe is closely tied to the Many-Worlds Interpretation (MWI) of quantum mechanics. Developed primarily as a way to resolve the wave function collapse issue in quantum physics, the Many-Worlds Interpretation postulates that all possible outcomes of a quantum event actually occur, each in its own separate, parallel universe.
In traditional quantum mechanics, a system is described by a wave function, which encapsulates all possible outcomes of a quantum event. When an observation occurs, the wave function 'collapses' to a single outcome. This observation problem, or the issue of wave function collapse, is notably addressed by the MWI by eliminating the collapse entirely. Instead, the universe branches at every quantum event, forming an ever-multiplying number of universes where each possible outcome is realized.
For example, when a quantum particle is in a superposition of being in state A and state B, and an observation is made, the universe splits into two distinct universes: in one universe, the particle is observed in state A, and in another universe, it is observed in state B. This interpretation implies that there exists a potentially infinite number of universes, each representing different possible histories and futures.
While compelling, the Many-Worlds Interpretation remains controversial. It challenges the classical notion of a singular, linear history of the universe and raises profound questions about the nature of reality, identity, and the conservation of information. Moreover, it is nearly impossible to test or validate experimentally, because the separate branches of the Universe do not interact or influence each other, making empirical validation a significant challenge in quantum mechanics.
Advocates of the MWI argue that it provides a mathematically consistent view of quantum mechanics without requiring arbitrary boundaries like wave function collapse. Detractors, however, question its philosophical and ontological implications, particularly regarding the existence of multiple realities. Nonetheless, the Many-Worlds Interpretation continues to be a potent subject of discourse in theoretical physics, challenging conventional perceptions of the cosmos by suggesting an ever-branching multiverse.