This film grows on me more every time I watch it. The only weak part is the episode with the two ships in the last half hour. Sure, I know why it was included, and it's significant for the plot, but at that late stage in the film we needed fast action, not slow lingering soul-searching.
Nevertheless, the statement in the film poster that I used for this post is very depressing. I wouldn't like to live in a world without rules. Whether it's the rules set by society or rules that I have created for myself, I need rules. Rules mean stability. Rules mean order. Without rules there is chaos. That's the goal of the Joker in this film. He doesn't want to get rich, he wants to see the city burn.
At the end of the film, and I apologise for the spoiler, Batman goes a way towards accepting this.
"Sometimes the truth isn't good enough. Sometimes, people deserve more".
That's an extremely negative attitude. If knowledge isn't based on the truth, what good is it? Indeed, if rules aren't based on the truth, what good are they?