Well, I finished A Universe From Nothing, and the “nothing” business was cleared up in the end.
Apparently “nothing is unstable” is a fundamental principle which gives rise to the inevitability that out of nothing something will eventually arise. Nothing can’t stay nothing for long, it seems. For me this is still a bit like poetry; I’m not having much luck envisioning total emptiness, bereft even of space. I keep thinking, “How do I begin to think about that?” Krauss himself admits that talking about “why is there something rather than nothing?” can seem a bit like counting the angels on the head of a pin (a favorite pastime of medieval theologians). The difference is, of course, that “physicists can count their angels and can get it right to the nearest angel in a total of 10 billion.” That last phrase is from Richard Dawkins’ afterword.
I’m now listening to Krauss on the Point of Inquiry podcast, hoping he can shed some further light on nothingness for me.