Here, Nolan’s statement about ambiguity and point of view:
I’ve always believed that if you make a film with ambiguity, it needs to be based on a sincere interpretation. If it’s not, then it will contradict itself, or it will be somehow insubstantial and end up making the audience feel cheated. I think the only way to make ambiguity satisfying is to base it on a very solid point of view of what you think is going on, and then allow the ambiguity to come from the inability of the character to know, and the alignment of the audience with that character.
Interesting. For those writers who love open endings.