The argument is a peer-reviewed prediction of inflationary cosmology, developed most thoroughly by the physicist Max Tegmark, then at the University of Pennsylvania, in a 2003 paper titled simply “Parallel Universes,” published in the conference volume Science and Ultimate Reality for the 90th birthday of John Wheeler. It runs as follows. The observable universe is [...] The post If the universe is infinite — which current cosmology suggests is genuinely possible — then somewhere out there, beyo