Superman III (1983)
You can read the above clip from Superman III as a dumb blonde joke writ large or as an insightful riff on philosophy. I am guessing it is the former rather than the latter.
Playing the supposed ditzy lover of the film's villain, Lorelei reveals she is a fan of Immanuel Kant's transcendental philosophy - the eighteenth-century European thinker's idea that he could bring together two schools of thought - empiricism and rationalism. At least that's the general idea of the book Lorelei's caught reading - The Critique of Pure Reason.
Lorelei: How can he say that pure categories have no objective meaning in transcendental logic? What about synthetic unity?
It looks like Lorelei has stumbled upon the truth of transcendental idealism - that things in themselves cannot really be known. Or did she?
I am pretty sure that even though the scene is pretty funny - it comes out of nowhere - and it is hilarious that the writers chose Kant to exemplify intelligence - it is probably more likely that the gag is inserted in this scene to subtly highlight the point that Superman has been split into two because Gus presented him with synthetic kryptonite. Ontologically - it's all f*&ked up. Who's going to make it right? Only Kant can do that, I suppose.
I feel like books make occasional appearances in films. And when books do appear, it is hard not to think they weren't put there for a thematic purpose. So why do you think the creators of Superman III decided to insert a copy of Kant's book into the movie? Let me know in the comments.