Bishop (symbol)
Ariadne's totem is a small, uniquely weighted bishop, a chess piece that she fashions in order to know if she is in the real world or not. This specific totem symbolizes Ariadne's crafty, strategic nature in the context of the team's plan, as well as her ability to navigate mazes and labyrinths. Just as a chess player must anticipate his or her opponent's next moves and find resourceful ways forward, so too must Ariadne take into account the reactions of the projections within dreams when building worlds in her role as architect. The psychological nature of chess also represents the kind of psychological warfare that the team is engaged in while in Robert Fischer's dreaming mind.
Top (symbol)
Cobb's totem is a spinning top, which originally belonged to his dead wife Mal. Cobb's totem symbolizes his lingering feelings of guilt and regret over the circumstances of Mal's death. The final scene of the film, in which Cobb spins the top and walks away, first symbolizes the fact that he has finally overcome the feelings of grief he has harbored over Mal, which causes her to intervene in his dreams. Nolan has stated that the fact that Cobb goes outside to be with his children, leaving the top behind, also represents the fact that he has forsaken the world of dream-sharing and re-committed himself to the world of reality.
Pinwheel (symbol)
In the deepest layer of his dream, Robert Fischer opens his father Maurice's safe to find not only a will but also a small paper pinwheel, which makes Robert begin to cry. The pinwheel—a handmade toy belonging to Robert, kept as an heirloom—symbolizes Maurice's fatherly love for his son Robert. Previously in the film, Robert divulges to his uncle Peter that his father was cold and unfeeling, even after his mother's death. However, the pinwheel that Cobb and his team "incept" in Robert's mind convinces him that his father in fact had a sentimental affection for him that he kept carefully hidden away.
Ariadne, Theseus, and the Minotaur (allegory)
In Greek mythology, Ariadne was a Cretan princess who helped the prince Theseus navigate her father Minos's labyrinth and kill the Minotaur. In Inception, Ariadne helps Cobb navigate the labyrinthine environments of constructed dream-worlds in order to perform inception and evade projections like Mal. The film allegorically re-stages the Greek myth by showing how Ariadne helps Cobb (Theseus) navigate Robert Fischer's maze-like dream and defeat Mal (the Minotaur).
Train (symbol)
In Inception, trains are symbols for the enormous, self-generating power of thoughts and ideas. When Cobb and his team initially descend into Robert Fischer's dream, a freight train plows down the street, symbolizing the fact that Robert Fischer has militarized his subconscious and is alerted to their presence. When Ariadne descends in an elevator to Cobb's subconscious, she passes a roaring train, symbolizing the turbulence of Cobb's mind. After Cobb convinces Mal to wake up with him, they lie down together on train tracks, allowing themselves to be "struck" by the train—which represents the desire to return to reality. Trains also acquire symbolic meaning in the film as a motorized chain that resembles what we colloquially refer to as a "train" of thought.
