Yeah, that's the scientific answer to this philosophical, religious koan, as in Lawrence Krauss's book. Nothingness must be empty space, he says, and space turns out to be full enough with quantum fluctuations, given the relevant scientific theories. Krauss was criticized for not thinking deeply enough and for not setting aside his scientific presuppositions.

I define the word differently since the scientific models of the vacuum and of quantum particles are still models of things, meaning they're simplified, pragmatic conceptions of particular subject matters. To think of nothing is to think of that which surpasses any such conception, and thus any scientific model, including quantum mechanics and general relativity. So I equate nothingness with Kant's noumenon, and I treat that in turn as the cosmic totality. And that leads to pantheism, to the epiphany that the "nothing"--the alternative to the field of particulars--is indeed before us at all times, hiding in plain sight.