Science does explain that there are multiple variations on the 'Big Bang' so in a way it tells you that there exists variations of the universe or variations of every past and future--or that from nothing or everything the 'Big Bang' occured. Although this sounds like a classic philosophy, it isn't because it is based on the known science of what is around us. You can call it philosophy but it doesn't fit what the classic form is because it comes from what is observed around us and not what is 'thought' about what is around us.
Variations of every past and future event, or that from nothing or everything the big bang occurred is highly speculative. Future events, M Theory multiple universes, 11 dimensions are not observable. It is not based on "the known science that is around us." These are metaphysical assertions.
Hawking indicates that you can get something from nothing with the law of gravity. A law of gravity or gravity itself is NOT nothing. To call it "nothing" is a gross misuse of the word nothing.
What is "nothing" in Hawking's universe? How should a layman like me define "nothing."