Sean Carroll, over at Cosmic Variance, has an interesting post on the PEQ (Primordial Existence Question)—"Why is there something, rather than nothing?"
The approach he outlines there, based on a talk by Adolf Grünbaum, (and I'm paraphrasing, truncating, and simplisticifying here) is that there is no reason to believe that nothing is more likely than something—that it's a trick of the human point of view to suppose that the PEQ is really a legitimate question.
My own response is a little different. It seems to me (at least, today) that the word "nothing" may well be meaningless in itself—that there is no such thing as nothing. I mean that last clause literally, though it might also make a very good koan. Certainly none of us has ever experienced nothing (though I remember moments, during certain sermons...).
A vacuum? To begin with, a perfect vacuum is an extrapolation—a theoretical concept. We know there can be more or less of something—say, for example, air—and so we imagine that if you had less and less and less, you would eventually have none at all. But in the real world, this doesn't happen: you just get less and less: no matter how long you pump, you never end up with nothing at all.
Even if you did, that would still not constitute the level of nothing that gets contemplated in the PEQ. That would require an absence, not only of molecules, but of light, radio waves, quarks, electrons (even spontaneous quantum-level events) strings, etc. It would also require the absence of space and time.
My point is that we not only have no reason to believe that nothing is more likely than something—we don't even have any reason to believe that nothing could even be a possibility. However useful nothing may be as an abstract end-point in a theory, in the real world, nothing is more like a unicorn than a real alternative.
We might as well ask, "Why does this universe exist, rather than a unicorn?
The PUQ.
I like it.
