You can't create something out of nothing can you! And yet, here we exist. Is this not the most relevant question we can't answer?
@ Jonathan: If I may, I think Leibniz's analogy is faulty. The constraints on what counts as a good explanation of why there have been any books at all (or any books bearing a particular title) need not be constraints on what counts as a good explanation of why there have been any states of the universe at all. I try to explain why in this brief article .