Things You Only Notice About Inception After Watching It More Than Once
When Cobb tells Ariadne that they need a totem – an object used to check whether you are in a dream or awake state in reality – he explains that no one else is supposed to touch your totem or know how does it work. Arthur elaborates, explaining how his totem is a charged die, and he’s the only one who knows how the die actually rolls. Cobb, using Mal’s spinning top as a totem, is unreliable for several reasons.
If the top was Mal’s totem before she died, she touched it and knew how it worked, disqualifying the item as a suitable totem for Cobb (unless, of course, you’re 100% sure that Mal is dead). At one point, Saito also touches the top, disqualifying it as a suitable totem. Additionally, Cobb tells Ariane how the spinning top is supposed to behave, rendering it useless as a totem, as there would be no way for him to use it to tell the difference between reality and a dream Ariane constructed.
David Kyle Johnson, who has a doctorate in philosophy, wrote a persuasive article on this subject for psychology today. Johnson argues (as do we) that the top is useless for Cobb because he knows how it works. “That is why a totem can only tell you that you are, as Arthur tells us, ‘not in someone else’s dream,'” he wrote. “Since you know how he behaves in the real world, he can behave that way in your dream.” Cobb’s top would only tell him if he’s in someone else’s dream, not his own. Ariadne and Mal, knowing how the apex works, compound these issues, suggesting he wouldn’t know if he was in Mal, Ariadne, or his own dream, rendering the totem useless.