Recently I've come across Alexander Vilenkin paper . I can't seem to find the 1988 version so if you can help me with that I would appreciate it. I have 2 basic questions: 1)Am I right in saying that the "nothing" in this paper is not the "philosophical nothing" as in no thing at all ? From my perspective, the paper says the Universe had a material cause (the stuff out of which something is made) but not an efficient cause since it was spontaneous. 2)How does this fit in with the observational data that says the Universe is flat ? Doesn't that refute the paper ? Surely Alexander Vilenkin knows this trivial fact so how does one reconcile his paper with a flat Universe ?