Every single moment of Inception is a dream. I think that in a couple of years this will become the accepted reading of the film, and differing interpretations will have to be skillfully argued to be even remotely considered. The film makes this clear, and it never holds back the truth from audiences. Some find this idea to be narratively repugnant, since they think that a movie where everything is a dream is a movie without stakes, a movie where the audience is wasting their time.

Except that this is exactly what Nolan is arguing against. The film is a metaphor for the way that Nolan as a director works, and what he's ultimately saying is that the catharsis found in a dream is as real as the catharsis found in a movie is as real as the catharsis found in life. Inception is about making movies, and cinema is the shared dream that truly interests the director.

I believe that Inception is a dream to the point where even the dream-sharing stuff is a dream. Dom Cobb isn't an extractor. He can't go into other people's dreams. He isn't on the run from the Cobol Corporation. At one point he tells himself this, through the voice of Mal, who is a projection of his own subconscious. She asks him how real he thinks his world is, where he's being chased across the globe by faceless corporate goons.