He has a little chart. The spectrum from least abstraction to most:
1) practical: design
3) Pictoral: painting, drawing, graphics
4)Dramatic: stage drama
5) narrative: novel, story, non-fiction
6) Musical: poetry, dance, music
He argues film is unique in that it occupies all these levels of abstraction.
There are lots of in-betweens (poetry can have both narrative and musical elements for example).
This spectrum (connecting back to Aristotle's Poetics) may still be interesting, but isn't it seriously inaccurate after modernism?