"The Anthropic Principle is the idea that we live in a universe set up to allow our existence. If the universe were any other way, we would not exist, and would hence be unable to make any observations. Since it was introduced by the theoretical physicist Brandon Carter in 1973, the Anthropic Principle has progressively come into vogue among the physics and philosophical communities, providing a simple explanation for some otherwise very perplexing coincidences. For example, why are certain physical constants so oddly fine-tuned? While some people view this as evidence for a supernatural creator, materialists simply observe that if it were any other way, we wouldn't be here.
Due to the Many Worlds Interpretation of quantum mechanics, many physicists have come to view our universe as one among many--possibly an infinite number, or superset of universes sometimes called "the multiverse." Though we know nothing about the underlying process which could generate such universes, presumably it is random, leading to universes with a variety of different sizes, ages, densities, dimensions, and fundamental physical laws.
Due to the Many Worlds Interpretation of quantum mechanics, many physicists have come to view our universe as one among many--possibly an infinite number, or superset of universes sometimes called "the multiverse." Though we know nothing about the underlying process which could generate such universes, presumably it is random, leading to universes with a variety of different sizes, ages, densities, dimensions, and fundamental physical laws.