As I, too, have posted elsewhere . . . . 'nothing' is a nonsequiter . . . .
Hi Karen.
A non-sequitur is something that doesn't logically follow. Treating 'nothing' as a state of being or as a dark and empty place, would seem to me to be an oxymoron (a self-contradictory phrase).
I think that it was the Presocratic Greek philosopher Parmenides that noted (in so many words) that 'nonexistence doesn't exist'.
I agree with both of you on that.
'Nothing' seems to me to be a sort of a boundary-concept. Reality only extends as far as the boundary and
there is no beyond the boundary. Big bang cosmologies that extrapolate the expansion of the space-time-matter universe back to a singularity a finite distance of time in the past might arguably be said to have reached such a boundary. Reality only extends so far and no further.
Theistic creation myths are similar, with a created world that only extends as far back as creation, except that they always plant their God beyond the boundary and in their schemes God most emphatically isn't nothing.
there is always 'something', even if only (?) potential - e.g., potential vacuum fluctuations of 'something' (Hint: Energy field)
How can there be vacuums or fields if there is no spatial extension? How can there be fluctuations if there is no temporal extension? (Imagining everything happening in abstract mathematical spaces still assumes the existence of abstract mathematical spaces.)
The problem that I see is that if we interpret 'nothing' as the absence of
everything, then any proposed physical explanation of the 'something from nothing' problem, in which the universe is theoretically derived from a prior state,
could only be a non-sequitur since by definition there could be no prior state.
The existence of physical laws would become problematic as well, since they only seem to have meaning correlating physical events. Take away the physical events and the universe in which they occur, and there wouldn't be any more physical laws. (Unless we give the laws a Platonic realism that would turn them into peculiar abstract
somethings. Logic and mathematics in the abstract would probably encounter similar problems.
What Krauss and his ilk appear to me be doing is deriving the supposed initial state of the universe, the 'Big Bang' from what seems to them to be a minimal set of physical and theoretical assumptions that include a very active vacuum, fields and all of the relevant laws of physics.
And that's most emphatically not 'nothing'.
Historically 'vacuum' did mean 'void' which was interpreted to mean 'nothing'. Add that to the 'nonexistence doesn't exist' idea and we have the explanation for the historical belief that 'nature abhors a vacuum'. I get the impression that people like Krauss are exploiting that ambiguity of the word 'vacuum', interpreting it in the modern way so as to slip all their beloved fields and quantum processes into it, while interpreting it the ancient way so as to pretend that they have somehow answered the fundamental metaphysical question 'How can something come from nothing'.
Actually these people aren't addressing the older and deeper question at all.