I've read some of the Hawkings works, and you won't get proper responses for the critique of Hawkings idea is because critique has a valid point. Here is a little background where Hawking is coming from. Before the Big Bang (whatever maybe the correct term) was known, physicists used to believe that the Universe always existed. After the Big Bang was known, we now know that this Universe had an starting point. So that brings creation, God, etc... into the equation. So Hawking thought if he removes God from it, it would be better for scientific advancement (not his exact words, but google you will find he said something like this in an interview). So he throws back the all ways existed argument before this Universe (lets say mother Universe) which always existed, and in it child universes keeps popping up randomly. So he is trying to bring pre-big bang beliefs again in a different form that ok this Universe started at a point but the mother Universe (for the lack of better term) always existed. He doesn't call it Mother Universe, but I'm trying to translate into something that summarizes his point of view. He describes it in imaginary time and some sort of gravity that existed pre big bang in the parent universe which has all the ingredients for universes popping up randomly. Correct me, if I mis-paraphrased him, but thats what I understood from his work.