We didn't end up discussing it very much, but I highly recommend this video of a debate between Richard Dawkins and Lawrence Krauss on Krauss' book "Something From Nothing."
Video Discussion Between Richard Dawkins and Lawrence Krauss on the "Something From Nothing" Question
youtube.com/watch?v=gH9UvnrARf8
In summary, my personal (admittedly untrained) view is that in this case as in others, the point being argued by Krauss is overstated. If I recall correctly, Dawkins does a good job of dragging out of Krauss that the "nothing" in Krauss's sensational book title isn't really "nothing" as a philsopher would mean it. Instead, what appears to us to be empty space contains energy/fields/forces or whatever. The Epicurean point would be that whatever the thing we're describing turns out to be, it is going to be "natural," and it's not going to be evidence of an intelligent-design-god that overturns the "matter and void" system. Just like throwing the spear shows that the universe has no terminating point, if something is proved to exist then that simply shows it has a natural fundamental basis, and it isn't going to be "infinitely divisible" so as to upend the fundamental world-view.