And the question can not be known as long as the answer is known in the same universe. If it was to become known, the universe would cease to exist and a more complex one would be created. This may have already happened, more than once even, and our universe may be the result.
Has anyone else actually read the whole book series. Not just read the first, saw the movie, or heard a lot of references. I highly recommended it. If you don't like reading find an audiobook or the BBC radio broadcast, but I hear the radio series has some differences, still closer than the movie though.