The idea of ?Inception? is to be a story crafted in the architecture of the mind ? Cobb?s mind. What people perceive to be real isn?t necessarily so, because the mind can make things appear to be as real as ever. An important thing to remember is the start of the film. Dom Cobb wakes up in a place that we later find out to be limbo ? more importantly, Saito?s limbo.
What happens next is something that is meaningless the first time a viewer watches the film. Saito is seen handling Cobb?s totem (which was a top that he took from Mal while in limbo). At first, this is meaningless. Upon a second viewing, the viewer should realize that everything that happens after this scene (the jump cut to Cobb?s attempt at extracting information from Saito, and so on) is something much deeper.
Saito promises to give Cobb the one thing that he wants, and that?s to find the way back home. How does he convince Cobb to do this? He tells him to ?take a leap of faith.? This is another line that goes unnoticed at first. On a second viewing, the viewer should remember that line as something that Mal told Cobb when she jumped off of the building. Is the picture becoming clearer yet?
Cobb seems to appear wherever he needs to go, whether it is Paris, or Mombasa, just like it were a dream. While in Mombasa, Cobb gets chased by anonymous agents (which he perceives to be Cobol agents) through a fantastic action sequence where Cobb escapes the dream-like narrow tunnel and is rescued by none other than Saito. A bit later, Cobb and Saito visit Yusef who brings them into a basement with various figures connected to the dream machine. The idea was for Cobb to experiment with the deep sedative. He does, and when he ?wakes up? he tries to use his totem only to be interrupted by Saito. Cobb never does find out if he is in the real world or not. In fact, he hasn?t been yet. He?s been in limbo ever since he got there with Mal. Ever since then, he?s been going deeper and deeper to the point where he created Saito as a projection to help him ?get back home? ? Did you really think Saito can just pick up the phone and make murder charges disappear? No. But, Cobb believes it and thus Saito is used to thrust Cobb further and further into a state of limbo ? where at the end of the journey, Cobb truly believes he is with his children after confronting and getting over his projection of Mal.
While in the limbo, Cobb, using Mal?s totem, put the idea in her head that she was in the dream world. She was, she just hadn?t realized it yet. What the viewer forgets is that all knowledge of limbo comes from Cobb?s character. To think that Cobb is 100% accurate about it is absolutely wrong. He wouldn?t know dream from reality ? not in the limbo that he describes to people ? and definitely not if inception were performed on him to believe that limbo truly was the real world.
Mal and Cobb never really left limbo ? at least, not that layer of it. When Mal jumped off the building, she gave herself the very same ?kick? that Ariadne improvised later on in the movie. Mal was right about still being in the dream world. Cobb was still engulfed in limbo and didn?t realize it. Cobb believed that if you die in limbo once the sedative wore off, you would simply wake up in the real world. That may be true, but it only happens if the sedative wore off. When Cobb and Mal had killed themselves with the train, the sedative was not worn off yet and they simply moved one layer deeper (this happens again at the end of the film when Saito picks up the gun in front of Cobb).
Cobb, deep in limbo, unknowingly uses the projections of his team to keep going deeper and deeper until the idea of inception is performed on his mind, and he truly believes he was able to find a way back home. Saito?s promise to Cobb was kept - in the form of Saito (a projection from Cobb) making sure that Cobb ended up in limbo, so that he could live his "life" with his kids (who are still wearing the same clothing as they did throughout the film).
The team were projections in Cobb?s mind the entire time. It?s how he was able to go to Miles in Paris and find an architect named Ariadne (a name which comes from a Greek mythology story about a labyrinth) who improvised the ?kick? at the end of the movie the same way that Cobb had seen (but not accepted as a dream) Mal do previously when she jumped off the building. It?s how Eames happened to know of Yusef, and so on and so forth. Everything Cobb needed to make this inception work happened to work out for him. It?s even how Cobb?s lawyer knew so quickly that Mal had gone to 3 different shrinks to be declared ?sane? and how he happened to have two tickets for Cobb to be able to get out of the country before the police would have arrested him.
The movie ends with Cobb appearing from place to place, going from limbo with Saito, to the plane where Saito magically makes one phone call to free Cobb from his problems, to walking through the airport, to meeting Miles who is with Cobb?s children. Cobb spins his totem and it spins just like it was a dream. He fixes his eyes on his children and the totem begins to lose speed ? this is because inception has worked ? Cobb truly believes he is in the real world. His totem will not spin like it did in the dream, not as long as he has his kids. The title of the film is now shown to us, making complete sense because the title was really Cobb?s journey through his own mind: INCEPTION
