Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
This entry is more specific than most, dealing primarily with Creationists. It's become a tired old cliche of theirs to ask, "How can you believe something came from nothing?"
There are many possible responses because we only have ideas for what the moment of the Big Bang might have been: We do not claim certainty or omniscience. Those of us without degrees in cosmology or astrophysics simply don't know with any great confidence. Those with them are working on the issue, and I don't know which ideas are favored.
First of all, the question is quite often used as a tu quoque fallacy: "God" isn't a useful answer to the question. Where did this "God" come from? How did he get the power to create a universe? Why did he bother? Combined with the lack of predictive ability of the god hypothesis, it's nothing but a supernatural placeholder.
Onto our guesses:
1. Something can come from nothing, so long as it's balanced out by an anti-something. That's one of the simple principles behind a lot of formula juggling done for practical science: You can get something if you also get its opposite.
2. There's no room for a nothing: Many people fail to understand that the Big Bang wasn't an explosion of stuff into empty space and time, it was an expansion of space and time itself. The very fabric of time and space were condensed with the matter. There was no "before the Big Bang" so there's no room for a "nothing," no prior time for "come from."
3. Something came from something else: It's possible that what we call our universe came from some event like "branes" colliding in a bigger universe, along a different sort of time axis. That universe might be eternal and infinite, or it might have come from a still larger universe ad infinitum. It may not be elegant, but I don't see any logical reason against such a progression.
I'm sure there are many other ideas I haven't covered, but just with these examples, it should be apparent that the use of this doggerel just isn't worthwhile.