The multiverse hypothesis proposes that our observable universe is merely one region within a much larger, perhaps infinite, ensemble of universes. This concept has transitioned from philosophical speculation to theoretical physics primarily through the convergence of cosmic inflation and string theory.

Mechanisms of Generation The primary engine for the multiverse is eternal inflation. Inflationary theory suggests the early universe underwent rapid exponential expansion. In "eternal" models, this expansion ends in some regions, forming stable "bubble" or "pocket" universes (like ours), while continuing in others. This process creates an infinite fractal structure of isolated universes.

Diversity of Laws String theory ...