I shouldn't be posting (too tired), but I'm excited that some discussion has started up on this film. You're right, Abulafia, about the film being about cinema itself; Nolan has even said that this is the closest he'll probably ever get to making a film about his job (I would say the surrogate Nolan of this film is Jackman's character).
Greathinker, I would go even further in the Yorke song to "you're just playing a part," or, at least, that's what really struck me through. This whole duality, the two birds, the two Bale characters, and the many Jackman characters, its all about our performance for other people. We must sacrifice our true self for the self others depend on, which is simply who they've decided we are. For this reason, I believe the Tesla machine worked. Well...actually, I haven't seen the film since the theater, so I'll just post something I saved just in case a conversation started in this thread. It sort of explains everything to an obnoxious extent, so forgive me in advance:
This conflict is perfectly represented in the fact that there are two "Professors", one that actually loves his wife, and the other that loves another, or something else, his art, because in his art he finds understanding, something he cannot find in people. His wife, however, expects him to be the same person every day, which is the person she pictures him to be. She constantly looks for the truth in him, but he must keep her at a distance, knowing that no one actually wants to know the secret, just what is presented (an actual line from the film, I believe, only about magic). The scene when he finally tells her he doesn't love her is so completely devastating because it is the truth, but it is something that can never be spoken. You can see her looking back at everything that has happened between them, her entire life, watching it crumble. She was his sacrifice, his prestige, since he did not offer himself to his own private death of "knowing". This is the whole point of the film, what is presented, what is believed to be the truth, and what is, which, in the analogy of the bird cage, is that the wonder that you just saw is actually heartbreak, but it is human nature to believe in the possibility of that wonder.
When Hugh Jackman's character sacrifices himself for his art, (which I believe to be the meaning at the end, that the machine does work, and that he kills himself off each night, since the second self left living would show others the trick, which is something they'd rather not know about - self sacrifice is the true path of an artist, after all) he is creating true magic, because he is damaging himself only; his magic is not at the expense of others. I saw this film as a constant defense for the continued existence of not just film, but cinema, and the experience of going to the theater. The narrative seems to draw attention to itself enough to say that film is also a magic act, and that everything being communicated to us could or could not be the truth, which actually tunes us into the multiple realities within a film (the art of filmmaking and our desire to escape), and within life. And actually, this film is so complete in this way of thinking, that we find that what we believed to be the absolute truth, both of the character's private journals being read without the other's knowledge, turns out to be nothing but lies made specifically to waste the reader's (and, in a sense, the viewer's) time. In the end, anything we think we've learned about the characters may or may not have actually happened.