But the thing one expects as given from a comic book movie is motivation. Your villain has his reasons for doing what he does, even if it is, as with Heath Ledger's Joker, just to watch the world burn. Harvey Dent delivers an about-face (ha ha I make funny) that is far too abrupt given what we've seen of the character to date.
People buy it not because it makes sense in the movie, but because it's Two-Face - they'll all expecting him to go nuts and start coin tossing the moment he gets the symbolic charring of half of his face. It fits the checklist but not the narrative.
I'm not sure I agree with this. I had a similar reaction the first time I saw TDK, but every time I've re-watched the movie, I've noticed little things that have made Dent's transformation more believable.
The important thing to realize about Dent is that he's really not the White Knight that he's built up to be. Dent is a flawed character from the start. Among other things, he's a control freak. He is more than willing to cheat and deceive other people to get what he wants and to get his way. And at the same time, he truly believes in his own ability to control and manipulate events and determine outcomes. He sees himself as a winner, when in reality, he's just a cheater.
All of these tendencies are symbolized and embodied by the two-headed coin, and his boast that he makes his own luck--both obvious examples of bad faith. He bullshits others into thinking that he is winning fairly. Then he bullshits himself
into thinking that he's winning fairly, by congratulating himself on his own skill at deception.
The Joker sees though Dent: this is why he places Dent in a situation that he truly can't
control, and forces him to play a game that can't be rigged. And Dent loses this game--badly. He not only doesn't get to be the hero--he loses the woman he loves, and winds up hideously burned.
Compared to the Joker, Dent is an amateur. The Joker outsmarts him completely, without even trying. In fact, the Joker isn't even all that concerned about Dent: his true target is Batman.
And it's the fact that the Joker has defeated
Dent, without even stretching himself, that provides the key to Dent's transformation. The Joker has taken the mask off of reality, and Dent cannot bear to look on the face underneath. He cannot face the fact that he is not
in control of events--that he is merely a pawn in the Joker's game with Batman--merely object, instead of subject. Similarly, he cannot face the fact that he is not a winner, and has never been a winner. He could only win by cheating--and the Joker has cheated him fair and square.
Once his self-image has been shattered, Dent can do one of two things: he can act in good faith, and acknowledge his own nature--or he can continue to act in bad faith. Unfortunately, it's his nature to deceive himself--and he does so by essentially reversing his previous worldview. Like so many losers, he refuses to acknowledge that he lost because his opponents were too strong and skillful for him. He refuses to acknowledge that there was any justice in his defeat. It was all just luck--chance. If he can't be in complete control of events, then he refuses to exercise any control at all: he'll just leave everything up to a coin flip.
In this case, of course, much like Anton Chigurh in No Country for Old Men
, Dent is continuing to act in bad faith. He's not really
leaving anything up to chance--just using the coin flip to deceive himself about his own agency. As Carla Jean says at the end of No Country for Old Men
: "The coin don't have no say. It's just you."
And in Dent's case, we see him getting around an inconvenient coin flip--giving himself a do-over--by flipping again, and then shooting Maroni's driver, when the coin won't allow him to shoot Maroni. He doesn't shoot the Joker, by contrast, because to do so despite an adverse coin flip would require more authenticity than he possesses. In the end, he really is Two-Face--to himself as much as he is to others.
You know--I never really thought about the parallels between Two-Face and Chigurh until I started writing this post. I'm sure someone else has discussed the possible connection between these two characters, and their movies.