It is hard to say anything about creation ex-nihilo, except that we observe it. One instant nothing exists; the next, it does. There is little reason to either assert or deny such models as “the Big Bang”, though evangelical Christians get all worked up over them. The Big Bang is simply a backward extrapolation of observed physics, and why should that be objectionable? What are physicists supposed to do, stop the model at T minus 6,000 years and insert the Creator?
“Ex nihilo” doesn’t mean nothing existed before the creation existed; the Creator is eternal. Similarly, every human choice is ex nihilo. The personal organ of volition exists before the choice, but to analyze the choice itself — in the sense of the meaning of analyze as “break down into parts” — this is not possible. Such an analysis is one of the moments of logical tail-chasing in human thought. You think you find something interesting, but then you discover it is…your own tail.
There is an element of the pre-existent in every decision, but there is a new element in it as well, or it would not exist at all. The precursor elements can be analyzed but they are not interesting. That state of being which exists as the result of any human decision is precisely what is interesting, and happens to be precisely what is, formally and literally, out of nothing.
So all the parts of human choices that are interesting we call ” freedom of the will”, and the parts that are not we call “bondage of the will”. (Insert centuries and tomes of vitriolic debate here, none of which means a damn.)
So the question of “ex-nihilo” is really the question of free will. Human action looks exactly like divine creation ex-nihilo. We can observe it, but the response called for is an act of the synthetic organ, rather than the analytical organ. Our response is a wholistic response — one gestalt leaping into being in front of another. Not “let’s break this down into constituent parts so we can understand it better” but “how shall we act in response to this act? “