Narrative History?

First, on what basis do people determine that Genesis 1 & 2 must be narrative history? I am regularly asked to prove that it is something else, as though by default it must be considered narrative history. But the way one usually identifies a literary genre, especially in the ancient world where things didn’t come labeled “mythology,” “history,” or “fiction,” is to build an acquaintance with related literature. Ever since I became acquainted with a much broader range of ancient near eastern literature, it has always seemed to me that this process should be reversed. Why should something that looks so very much like other ancient near eastern creation myths be regarded as narrative history?

Henry Neufeld talking about Genesis in light of theistic evolution