I think my undergraduate theory class is going quite well, mostly because people are laughing and paying attention.
I had some insights while I was teaching (this always happens).
1) For Plato the problem with art is not the blatant lies, it's the lies in the form of the truth. So lightsabers and hyperspace are kind of fine, because we know they're lies, but what Star Wars says about how to parent could be suspect.
2) When Aristotle talks about the unities, unity of action has to do with (as you know) probability and necessity. A student asked about realist fiction—wouldn't gritty realism always fall within the category of unity of action?
I replied no, not always. Take Star Wars again. Imagine a scene that broke with the “necessity” part of the equation. Imagine Darth Vader having a moment of exhausted angst, opening a fridge one evening in his inner sanctum on board the star destroyer, popping off his helmet and pressing a nice cold Coke against his boiled-egg brow. And sighing.
It's always good to laugh in class...