https://www.quora.com/Why-does-anything-exist-at-allDoes science have an answer? The physicist Lawrence Krauss explicitly claims there is an answer to the question of Why There Is Something Rather than Nothing. Mathematical Physicist I. S. Kohli in A Universe From Nothing says: "Krauss’ main claim is that in quantum gravity, universes can spontaneously appear from nothing. The claims made in fact are widely not supported by general relativity or quantum field theory in curved space-time.
For Krauss' proposal to be considered as a valid physics-based proposal, it has to be at least in principle, testable. It is not clear how at the present time that we could even begin to consider how this could be accomplished. Krauss describes as particles being spontaneously emitted from a vacuum state. This in itself is quite problematic, as it is based on the naïve particle interpretation of quantum field theory. The very definition of particles is undefined for general curved space-times, and only defined in the context of general relativity for asymptotically flat space-times. There is not spontaneous particle emission from “nothing” in any sense of the word.
