I was going back and watching The Dark Knight again and wow, it’s still awesome. But I realized something.
In a meta-literary sense, Batman and the Joker are not simply nemeses, they are the same friggin’ dude.
Let me backtrack here.
Professor X and Magneto are not the same person. They have different pasts and personalities, and do things independantly of each other.
Lex Luthor are somewhat equal and opposite, but they are still not the same eprson. They want fundamentally different and unrelated things. Superman is going to basically laugh off Luthor’s Hannibal Lectures.
Green Lantern and Sinestro are perhaps a bit closer, but again, Sinestro has his own distinct past and he’s just a former good guy gone bad.
…
Not so with Joker and Batman. Think about it: according to the movies especially, bt to some degree in the comics, too, the Joker simply showed up sometime after Batman did. He’s damn near the one person in the universe with a deep enough understanding of the mind to challenge Batman. There are people with more smarts, and people with more tech, but nobody understands people like the Joker - except Batman. The battles between them are primarily battles of wits.
At the same time, the Joker (again, especially in the movies) is the fundamental opposite of Batman. He could have all the money in the world - he just doesn’t care about (cough remindanyoneofBruceWayne cough). Where Batman uses state of the art technology, The Joker pulls out bullets and gasoline bombs because precisely because it’s cheap.
And let’s look at their goals. The Joker is like what Batman could, and would have been, as a true follower of Ra’s al’Gul. Think: what is the Joker doing? He’s tearing the city apart just as Ra’s wanted. He’s taking the ordinary citizens and forcing them to fight and fight they will until the city goes up in chaos. The Joker is perhaps even worse than Ra’s, in that he doesn’t intend for the chaos to stop. But it’s the same program with just a different stopping place, and the fundamental view of mankind is the same.
In the meta-literary sense, The Joker is that part of Batman which fundamentally rejects society in all its forms. The Joker is what makes Bruce Wayne into Batman, and both have to exist for either to exist. If Batman vanished, or somehow got shot, the Joker would be bored out of his mind. If he didn’t just give up and go home, he’d go out in a mad frenzy of explosions which wreck the entire city. The Joker is Batman’s sense of humor almost. Even Bruce Wayne never laughs except for effect. The Joker is all the parts of who Bruce Wayne is as a human that can’t coexist with what he became as Batman. The Batman is utterly incorruptible, and so the Joker is completely corrupted beyond human understanding.
In the Joker’s own words, “You… complete me.”
And in his own twisted way, the movie Joker, from the very moment the two meet in the flesh, is trying to protect Batman. Both physically and emotionally, and even as he [The Joker] is out to mess with Batman’s head. Note how he warns Batman of a fundamental truth - that the city would turn on him (and it would) the minute he was no longer needed, or it became inconvenient.
Plus, on a more comic note, unless The Joker was truly a part of Batman, the interrogaton scene would have looked more like this: http://www.youtube.com/watch?v=w2yv8aT0UFc