Drama (or we may say an invented story, i.e. fiction) is superior to history (a narrative of true events, i.e. nonfiction) because drama tells us what may happen, whereas history only tells us what has happened. Thus proposes the central thesis of A's Poetics. Back when I was primarily a fiction writer, I gloated when I was first treated to an exegesis of this foundation of literary criticism. "Aha!" I cried in triumph. "If Mr. Aristotle says so, it must be so!"
But then I found myself writing more and more nonfiction, and I was forced to pick a fight with the great Greek. Hmm. How very reckless of me, trying to go head to head with him! But I do have an argument, and it is this: perhaps this central claim of the Poetics is true if our field of enquiry is limited to human experience. (I say perhaps.) But if we are interested not only in what can happen among people but also in what can and does happen among stars and starfish, we can explore the physical world via nonfiction, and not be second-class literary citizens.
Aristotle was mainly discussing tragedy as the most noble literary expression because of its ability to produce katharsis, the cleansing esthetic experience of pity and fear. We can debate whether the ability to produce katharsis is the pinnacle of literary achievement. If we bend the definition a bit to suggest a profoundly moving emotional response, rather than just pity and fear, I think we can easily say that nonfiction can achieve this. I know I have often been moved to the point of tears when reading astronomy and physics and biology because -- because some of this stuff is just so amazing, so much more amazing than human imagination can invent. Oh, if only Aristotle could read contemporary science -- he might just change his mind.