Template:Watsonian Versus Doylist
Watsonian or in-universe commentary takes the reality of a work as given, and thus restricts itself to making statements that are sensible within that reality. Watsonian explanations are things like "Character X was lying", "He had plastic surgery over the summer", and "The main character fell off a cliff". A more precise technical term for this is intradiegetic.
Doylist or out-of-universe commentary considers the work as a created object, and prefers explanations based on the real-world motivations or circumstances of the creators. Doylist explanations are things like "The author had a Better Idea", "The actor died, so they had to hire a new one", and "The author got sick of writing those books, so he killed off the main character". A technical term for this is extradiegetic.