Without science, explaining why there is something rather than nothing requires explaining every leaf, rock, beetle and star.
Cosmology and evolutionary theory pare the explanation requirement down … we might have to explain only a physical law or three, and everything else … can follow naturally. … [I]t might be that we don’t have to explain why there is matter and energy, perhaps not even why there is three-dimensional space and time or why physical constants have the values they have.
It is also possible, although harder to conceive, that we could explain everything down to nothing: no physical laws, only logic. Putting that another way, it might be that naive mental pictures of nothing are logically impossible.
Aaron C. Brown, reviewing Why There is Something Rather than Nothing by Lawrence Krauss