Originally Posted by v2micca
There is one other detail that supports the ending is reality argument. Throughout the film, Cobb always is wearing his wedding band in flashbacks and dreams. He doesn't wear the ring in reality. In the last scene in the movie, he is not wearing his wedding ring.
That doesnt necessarily mean anything because the evolution of his character leads to the moment where he accepts his wife's death in the dream world (taking off the ring), and he returns to the same dream moment that he had not been able to get past before...seeing his kids' faces...only to move further on.
I think that there is no resolution, and that its intended to be ambiguous about waking life and dream states. Its saying that the line between them is blurry if there is one at all. Its the old mind-body problem.