The Schopenhauerian themes in the film suggest broader issues of fear and desire, sentiment and sublimity, optimism and pessimism that are ubiquitous in Kubrick’s work.
https://www.academia.edu/34407233/The_Metaphysics_of_Sexual_Love_Stanley_Kubricks_Eyes_Wide_Shut
“Hey, Michael, didja ever read Herodotus? The Father of Lies?” or “Frankly, I’ve never understood why Schopenhauer is considered so pessimistic. I never thought he was pessimistic, did you, Michael?”—laughing at the four or five things he found so funny in this, with a winsome touch of self-deprecation, half-apologetic … It’s not my fault I’m so smart. And I’d think, Doesn’t he have anything else to do? But this is what he did. These calls were about information. They were about Stanley’s work