Originally Posted by Wesley Dodds
I guess part of why Batman doesn't kill is because he feels that deep down no-one is beyond saving. Even from themselves.
In this way, The Joker is the absolute living embodiment of one of his core beliefs.
It's not that he likes him at all -in fact, paradoxically, I think Bats despises the guy- but if he could redeem The Joker, make him see the error of his ways then that, in a way, would be his greatest triumph, no?
I mean The Killing Joke -THE Joker story- basically begins and ends with Bats trying to reason with the guy on a human level...
Just a theory.
I think it's more the contrary: when Batman tries to dialogue with the Joker he's talking with himself, with his crazy and sociopath side, he isn't trying to change the Joker, he's just trying to understand him. If you read Cacophony
of Kevin Smith there's a similar scene to the ending of The Killing Joke
where Bruce asks the Joker if he really wants to kill him and receives a hard but predictable reply. Bruce doesn't pretend change anything, he's in a delirant crusade with no end and the Joker is his partner in that spiral, the one who forces him to see the madness of Batman, so Bruce needs him, perhaps in the same way he needs Alfred or Gordon.