When a theist asks,
“Why is there something rather than nothing?”
it is just a poor and unproductive way to ask “where did everything come from?”
The problem with the question, “Why is there something rather than nothing?” is that it is presented in a way as though “nothing” is another something that could “be,” which is not what “nothing” defines.
Only “something” can “be.” There cannot “be” nothing, because “nothing” doesn’t exist, it isn’t something, and therefore there isn’t anything to nothing to “be.”
We can’t say “well, there is both something and nothing” because nothing “isn’t.” There isn’t an “is” to nothing. There can only be an “is” to “something.”
But the question asks for an “is” to nothing – “Why ‘is’ there something rather than nothing?”
They might as well ask “why are circles round but squares aren’t?” It is just as silly.
What they really want to lead you to is that we don’t know exactly how something (matter, or what have you) came to existence. This often leads to the question, “how can something come from nothing” The theist will argue that because we don’t have that answer, then therefore “god did it.” Of course with this they are committing a logical fallacy, particularly an “argument from ignorance.” And if you use there claim against them, that if “something cannot come from nothing” than their god couldn’t have come from nothing, they will say, “but god has always existed and is outside of time and space.” So they believe a supernatural all-powerful, all-knowing being, has always been, but they can’t believe that perhaps something natural has always been? Seems rather curious and self-serving.