"In his new book, Stephen Hawking reiterates that there is no big gap in the scientific account of the big bang. The laws of physics can explain, he says, how a universe of space, time and matter could emerge spontaneously, without the need for God. And most cosmologists agree: we don't need a god-of-the-gaps to make the big bang go bang. It can happen as part of a natural process. A much tougher problem now looms, however. What is the source of those ingenious laws that enable a universe to pop into being from nothing?"Stephen Hawking's big bang gaps | Paul Davies | Comment is free | The Guardian
There is always something that needs explanation: even if you have explained all the process, there is still the natural laws: how come they are the way there are? In fact, why should there be laws at all?