Unfortunately, I can’t say much about the physics underlying the claims Stephen Hawking reportedly makes in his new book The Grand Design (co-written with Leonard Mlodinow, author of the excellent The Drunkard’s Walk). First because I’m not a physicist, and second because I haven’t read the book yet. But one of the claims Hawking apparently makes is that god is no longer necessary to explain the origins of the universe. The extent to which god was ever necessary to explain the origins of the universe is of course itself highly debatable – especially if, by “god” we mean some particular version of god.
In other words, it’s all good and well to say that the universe was created by something we don’t (perhaps, yet) understand, but it’s a massive leap to go from that proposition to far more specific ones, such as “god is good”, “god wants me to wear plaid”, or “god wants you to give me money“. In short, we’ve got very little idea of how the universe came about, and the physics that “explains” it is highly speculative. Other physicists and philosophers of physics – even those who don’t believe in god themselves – have also been quick to point out that they don’t think Hawking is right or consistent on the physics.