The Psychology of The Double?

This film poses an interesting question as to why James Simon appears in the film (at all)? According to Simon (at least this is what I imagine), James is sent from another universe to basically torment Simon and make him look bad in front of everyone, most importantly in front of Hannah. However the film also poses the question as to whether Simon just made James up in his head and that he was actually never really there. The scenes where you can see that they share the same injuries are somewhat evidence of this, if he was a completely different person why would they feel the same injuries? I also have a theory that James is possibly be a part of Simon’s personality that is never let out (of his mind), the side he wishes he could be but never actually is due to his timid-ness and the fact that he feels so easily forgotten. There is a sense of ambiguity in the film to leave it up to the audience and to see how you portray Simon and the reason for James’s appearance. Personally I believe the idea that Simon made him up and that James is just a figment of his imagination, never actually being a real person. This is both because, I feel it would be more interesting that way and the idea that there is someone that looks exactly like you but completely opposite from your persoanlity and no one notices it, is ridiculous. However it is a film, so it’s possible. For me psychological ideas are more interesting and therefore I favor that one and I also feel that the injuries help support that idea.