Some versions of quantum gravity theory, including string theory, predict that our life-giving universe is but one of an infinite number of universes that altogether make up the multiverse. Among these infinite universes, the full range of values of all the physical constants are represented, and only some of the universes have values for the constants that enable the formation of stars, planets and life as we know it. We find ourselves in one of the lucky universes (because where else?).
Some theologians counter that it is far simpler to invoke God than to postulate the existence of infinitely many universes in order to explain our universe’s life-giving perfection. To them, Carroll retorts that the multiverse wasn’t postulated as a complicated way to explain fine-tuning. On the contrary, it follows as a natural consequence of our best, most elegant theories.
Once again, if or when these theories prove correct, “a multiverse happens, whether you like it or not,” he wrote. And there goes God’s hand in things