The scientific answer to that is “we start where the evidence starts”.
The thing is, reality exists in spacetime, while nothing does not. Nothing is dimensionless: at least one of the dimensions of the universe is time. The correlation between temporal reality and timeless nothing is difficult – though mathematicians are skillful at working through incompatibilities. It would seem that any entity requires time in order to exist, so “when there was nothing” is non-meaningful. The universe has always existed, because it defines time recursively.
Doesn’t it? A bit of a philosophical statement there. One could just as well argue that there are an infinity of nothing in any given volume of space, given that it itself occupies no space.
I’m not necessarily taking that position, just saying that discussion of “nothing” is complex both from a physics and a philosophical point of view.
I didn’t say “when”, and I did not intend to speak temporally.
It’s true that I described two states and separated them with the word “then” but this is just the awkwardness of trying to describe metaphysics in everyday language. You also used the word “becoming” in your description, which also sounds temporal.
It used to be, maybe 10 years ago, that asking any questions about the initial state of the universe was always met with “That’s like asking what’s north of the north pole”. You basically weren’t allowed to ask any further questions.
That’s changed now and most cosmologists are happy to have that discussion, on the basis that even if our pocket of space time has a clear start point, our pocket is not necessarily all that there is.
But in any case, from my perspective, it doesn’t make much difference. Saying that we cannot talk about a “before” doesn’t explain anything in itself. “There is no explanation” is not an explanation, because an explanation is something which allows us to make valid inferences.
Is that deliberately ironic?
I love these discussions, and can get lost down my own toroidal quantum naval of infinfine radius with the best of you but my philosophical question is:
If the universe is an uncaring giant quantum energy value, and there are an infinite number of universes, why are we all still killing each other?
I have no idea what the two parts of that sentence have to do with each other.
That sounds about right, Enola. I don’t think that the OP’s question can be answered, correctly, I mean, by a living, breathing human being. It isn’t something we can know.
Would you like some toast?
Just stumbled upon Sabine’s diatribe on whether the universe is infinite
and it raises an interesting question.
She states that, if the universe curves back on itself, we would observe wallpaper: repeating patterns of the same thing. If we look over there, we would see the same galaxies that we see over this way.
But, if that were how it worked, the divers views of the galaxies would be from different angles, so, even if we could measure really well, is it certain we could discern that they are the same entity? It seems to me likely that universal-curvature would introduce “visual” distortion that would be very hard to correct for – something we would/will have to figure out.
That depends on how large it is. We know that, if the Universe does curve back on itself, it does so only on very large scales. We know this precisely because we don’t see those repetitions.
An earlier thread of mine:
See all the way around the universe? - Factual Questions - Straight Dope Message Board
Well, we might not see these repetitions, but that may be because we haven’t examined the evidence correctly. If there was a repetition where the universe looped back on itself, we have no guarantee that it would appear to us at the same time as another copy, or even in the same relative orientation. So comparisons may be difficult.
In the linked video above, Sabine Hossenfelder makes the point that we’d see galaxies from different angles if we see the same ones looped. Another issue is that we’d see them at different times. One image may be from, say 4 billion years ago, while another image of the same galaxy could be from 6 billion years ago. A galaxy can change a lot in various ways in 2 billion years. Galactic clusters would also change a lot in that time.
So I don’t think that has eliminated the possibility that the universe is curved. The evidence from the Cosmic MIcrowave Background Radiation, which indicates the universe is flat, is better.
Hehe, I knew I had gotten that idea from somewhere recently. Turns out I had watched the linked video above about two weeks ago and forgotten it was one I’d seen.
I admit i dont understand all the complicated Comments here in this thread. But i was wondering, is there a possibility for a universe like our own, to create another universe (a’la big bang, Black holes singularities?) and would that new universe be visible or detectable for us? If not detectable, would that be an explanation why we dont detect the time before our own universe? Could this have been going on for eternity, universes creating new universes infinitely in our past?
Then the whole previous infinity of universes could stop with us? If The conditions unusually isnt perfect to expand into a new universe… So if the infinity goes backwards, but its uncertain if it will continue forwards?
And as i asked, would we observe something like that? If it happened i OUR universe? Or would it create a new dimension thats out of our observable reach?
Clumsily written, hope you get the gist of what i mean to say.
(Not english speaker, i must add. Just learned english by watching Cosmos an Cheers 
)
I think this was addressed earlier in the thread. Time is an integral part of our universe. “Before our universe” is not meaningful in the way we understand time. The analogy used is: go to the South Pole, and once you are there, proceed southward (not the North Pole just now, the fat guy is busy).
In other words, the existence of our universe defines time. There was no time before time, so how can you describe a “before” in which there is no “when”?
My point was that if any universe were able to trough some singularity or black hole (my incompetence) to create a new universe, what if that has happened forever trough time backwards. And what if, if, if, if this universe will not. Stop?
I vaguely recall that observational evidence rules out straightforward eternal inflation and some other “multiverse” theories, so you would have to explain what the mechanism is.