Reality and dreams
In Inception, Nolan wanted to explore "the idea of people sharing a dream space...That gives you the ability to access somebody's unconscious mind. What would that be used and abused for?" The majority of the film's plot takes place in these interconnected dream worlds. This structure creates a framework where actions in the real or dream worlds ripple across others. The dream is always in a state of production, and shifts across the levels as the characters navigate it. By contrast, the world of The Matrix (1999) is an authoritarian, computer-controlled one, alluding to theories of social control developed by thinkers Michel Foucault and Jean Baudrillard. However, according to one interpretation Nolan's world has more in common with the works of Gilles Deleuze and Félix Guattari.
David Denby in The New Yorker compared Nolan's cinematic treatment of dreams to Luis Buñuel's in Belle de Jour (1967) and The Discreet Charm of the Bourgeoisie (1972). He criticized Nolan's "literal-minded" action level sequencing compared to Buñuel, who "silently pushed us into reveries and left us alone to enjoy our wonderment, but Nolan is working on so many levels of representation at once that he has to lay in pages of dialogue just to explain what's going on." The latter captures "the peculiar malign intensity of actual dreams."
Deirdre Barrett, a dream researcher at Harvard University, said that Nolan did not get every detail accurate regarding dreams, but their illogical, rambling, disjointed plots would not make for a great thriller anyway. However, "he did get many aspects right," she said, citing the scene in which a sleeping Cobb is shoved into a full bath, and in the dream world water gushes into the windows of the building, waking him up. "That's very much how real stimuli get incorporated, and you very often wake up right after that intrusion".
Nolan himself said, "I tried to work that idea of manipulation and management of a conscious dream being a skill that these people have. Really the script is based on those common, very basic experiences and concepts, and where can those take you? And the only outlandish idea that the film presents, really, is the existence of a technology that allows you to enter and share the same dream as someone else."
Dreams and cinema
Others have argued that the film is itself a metaphor for filmmaking, and that the filmgoing experience itself, images flashing before one's eyes in a darkened room, is akin to a dream. Writing in Wired, Jonah Lehrer supported this interpretation and presented neurological evidence that brain activity is strikingly similar during film-watching and sleeping. In both, the visual cortex is highly active and the prefrontal cortex, which deals with logic, deliberate analysis, and self-awareness, is quiet. Paul argued that the experience of going to a picturehouse is itself an exercise in shared dreaming, particularly when viewing Inception: the film's sharp cutting between scenes forces the viewer to create larger narrative arcs to stitch the pieces together. This demand of production parallel to consumption of the images, on the part of the audience is analogous to dreaming itself. As in the film's story, in a cinema one enters into the space of another's dream, in this case Nolan's, as with any work of art, one's reading of it is ultimately influenced by one's own subjective desires and subconscious. At Bir-Hakeim bridge in Paris, Ariadne creates an illusion of infinity by adding facing mirrors underneath its struts, Stephanie Dreyfus in la Croix asked "Is this not a strong, beautiful metaphor for the cinema and its power of illusion?"