Do all fictions occur in fictional worlds?

(with Battlestar spoilers)

So the big reveal in the series finale is that the characters we are watching our are ancestors, and that Hera, in particular, is the mitochondrial Eve. To normal people, this is just a nice plot twist. For people like me it is a little metaphysical puzzle.

Up to now, Battlestar has been painting a picture of a fictional world, a place that is like ours, but different in fairly rule governed ways. World-making like this has has been very popular in nerd fiction ever since Tolkien, and audiences have very high expectations of fictional worlds. Fictional languages now have to have invented grammar. We are expected to imagine all sorts of things are happening off screen. The Galactica presumably has a method for recycling waste. Somewhere there is a fictional person who wrote the fictional counterpart to "All along the Watchtower."

But fictional world-making is fairly new to art, and is still unusual as an explicit goal of an artwork. The recent miniseries about John Adams with Paul Giamatti and Laura Linney was historical fiction. We are not supposed to imagine that there is an alternative colonial America where it takes place. We are supposed to imagine it takes place in the real colonial America. But can we really do this, or in imagining, do we create a fictional universe? You might think we have to create a fictional universe, simply to deal with the fictional elements of the historical fiction. If the miniseries shows John and Abagail having a certain intimate conversation, where they treat each other as equals, we imagine that this is a part of long relationship full of such conversations, even though such a relationship may not have existed. Thus a parallel fictional world is created.

But this all seems to have too many moving parts. Suddenly, John Adams is not a fictional representation of American history, but a fictional representation of a fictional universe that resembles American history. But that can't be right. It is not like John Adams is some kind of steampunk alternative history where punchcard computing helps Washington defeat the British. It makes sense to say there is both a fictional representation and a fictional world for Battlestar because the writers go out of their way to make you feel like you are watching an incomplete representation of someplace very different, down to shaky cameras.

This is just a part of the problem of fictional reference, and I suppose the final twist in Battlestar doesn't really add anything to the debate. But it does blur the line between science fiction and historical fiction in a weird way. When the reveal happens, we are meant to feel as though the fictional world has been revealed to be our world. The emotional impact of the reveal wouldn't exist without this jab into the world of historical fiction. But the fictional world of Battlestar hasn't actually changed. It is still obviously fiction, because no one expects us to believe we have robot ancestors.

Hrm, if I had time in my life to do real philosophy I could figure this out.