Lawrence Krauss (the officianados call him Larry;) has answered the question Why Is There Something Rather Than Nothing? in his new book, A Universe from Nothing: Why There Is Something Rather than Nothing, or should I say he has claimed to have answered the question.
But I’m sure old Martin Heidegger, Nazi sympathizer that he was, is rolling over in his grave now saying, “No, he hasn’t. The Nothing that Krauss uses is really not the true Nothing, but already a Something. The true Nothing is not empty space but the absence of empty space altogether, in fact, “There was not then what is nor what is not.”, as found in the Song of Creation from the Rig Veda is perhaps an approximate, and only approximate, way of characterizing the Nothing.”
I hope my translation of his German is accurate. Old Martin was talking really fast and sputtering in frustration from his grave there. But I think I caught the gist of it, I hope.