The nature of hope and distrust in one amazing joke
as told to Batman by the Joker:
For a little context, in this story the Batman finally catches up with his arch enemy the Joker in an abandoned amusement park, where having gathered a band of misfits and mutants, the Joker is making his last stand. After shooting Barbara Gordon (the commissioner’s daughter) in a home invasion and kidnapping and torturing Commissioner Gordon, he sends an invite to the Batman to come to the park.
The batman, finally having had enough of the carnage that their vendetta has wrought, makes one last bid for a peaceful conclusion to the Joker. This is where the Joker tells him the joke above (see fig.1), where the Bat finally realises there is no saving the man (see fig.2). And this is when at last the Batman makes the decision to murder the Joker.