That's a pretty broad definition, which reflects just how subjective of a term it is! Physics is absolutely more complicated than any conceived explanation for our universe, as physics is currently incomplete. There always lurks the question of origin. Yes, there was a big bang, but what caused it? Some paper I read the abstract for several months ago outlined two "higher dimensional branes" colliding, which manifested the initial energy density that set the big bang in motion. OK, sure... so what set the higher dimensional branes in motion? I'm not here to argue for agnosticism though. Atheism also seems perfectly justified to me, I flirt with the idea myself quite often. But the bearded throne guy? Doesn't seem too likely, to me. Thank you for listening. :) Cheers!