The director explained that he saw the film's final scenes as definitively the end of the Batman story as he conceived it, and reinforced his idea that Batman is essentially a symbol rather than a single man.
""For me, The Dark Knight Rises is specifically and definitely the end of the Batman story as I wanted to tell it," Nolan told Film Comment.
"The open-ended nature of the film is simply a very important thematic idea that we wanted to get into the movie, which is that Batman is a symbol. He can be anybody, and that was very important to us."
The final sequence in The Dark Knight Rises indicated that police officer John Blake (Joseph Gordon-Levitt) might take over the Batman cowl, as he was seen discovering Bruce Wayne's (Christian Bale) abandoned Batcave.
It was rumoured earlier this week that Gordon-Levitt would indeed play Batman in the upcoming Justice League, although this has since been denied by the actor's reps.
"Not every Batman fan will necessarily agree with that interpretation of the philosophy of the character," Nolan continued in reference to the symbol idea. "But for me it all comes back to the scene between Bruce Wayne and Alfred in the private jet in Batman Begins.
"The only way that I could find to make a credible characterisation of a guy transforming himself into Batman is if it was as a necessary symbol, and he saw himself as a catalyst for change and therefore it was a temporary process.
"To me, for that mission to succeed, it has to end, so this is the ending for me, and as I say, the open-ended elements are all to do with the thematic idea that Batman was not important as a man, he's more than that. He's a symbol, and the symbol lives on."
Watch Christopher Nolan discussing The Dark Knight Rises with Digital Spy below: