# Nothing vs. empty space

This question quotes Hawking saying:

[...] you enter a world where conjuring something out of nothing is possible (at least, for a short while). That's because at this scale particles, such as protons, behave according to the laws of nature we call "quantum mechanics", and they really can appear at random, stick around for a while, and then vanish again to reappear somewhere else.

Nowever, is empty space really nothing? is there a distinction between non-existence and the "nothingness" of space?

Perhaps space is something, we just cannot grasp exactly what it is. Anyone can shed light on whether space is something and what exactly that "something" is.

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is empty space really nothing?


The physicist's 'nothing' is an example of something to the philosopher for which 'nothing' is well, let this philosopher explain in a review of "A Universe from Nothing" by Lawrence Krauss:

empty space governed by quantum mechanics (or any other laws of physics, or even just the laws of physics by themselves) is not nothing, and not even an “example” of nothing (whatever an “example of nothing” means), but something. And it remains something rather than nothing even if it is a “good first approximation” to nothing (which is what Krauss presumably meant by “good first example”). When people ask how something could arise from nothing, they don’t mean “How could something arise from almost nothing?” They mean “How could something arise from nothing?” That is to say, from the absence of anything whatsoever -- including the absence of space (empty or otherwise), laws of physics, or anything else.

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thanks. is space really nothing though even from a physics perspective? –  good_ole_ray Jun 10 at 12:27
Even classically, space is not nothing. According to GR, "empty" space can have an energy density (even if it's zero). There can be no property associated with "nothing" for that would be a contradiction. –  Alfred Centauri Jun 10 at 12:48
And, from a QFT perspective, the vacuum is a state of something. Only a thing can have states, and only a thing can be described in terms of physical law. Intuitively, since "Nothing" isn't a thing, there is no physical law that can apply. –  Alfred Centauri Jun 10 at 13:03
you wrote "space can have an energy density (Even if it's zero)" can a zero density be called density? also, what "state" does vacuum have? –  good_ole_ray Jun 10 at 17:13
@good_ole_ray, if I say "the energy density of the system is zero", it must be the case that the system possesses the property "energy density" and that is meaningful to speak of the energy density of the system because, otherwise, I've said nothing meaningful. –  Alfred Centauri Jun 10 at 17:54
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