.: dum de dum .. :.

The exploration of the Joker's origin and the hopelessness that belies his "evil clown" persona is affected toward adding more depth to the character. With the events leading up to his scarring, the Joker had all of his sanity pushed and finally decided to bottle away his sanity and become insane in order to cope with the grief of his wife's and unborn child's deaths.

Another theme explores the possibility that Batman is just as insane as the criminals he faces ("You had a bad day once, am I right?" the Joker asks him, after which the Joker himself replies with "I know I am. I can tell. You had a bad day and everything changed."), but manifests insanity in a different way. In an interview, Alan Moore summarized the theme: "Psychologically Batman and the Joker are mirror images of each other."[2]

Says critic Geoff Kluck: "Both Batman and the Joker are creations of a random and tragic "one bad day." Batman spends his life forging meaning from the random tragedy, whereas the Joker reflects the absurdity of "life, and all its random injustice."[3]

The Joker's underlying motive is to illustrate the inherent insanity of Batman's mission: dressing up as a bat to fight criminals ("You had a bad day once, am I right? Why else would you dress up like a flying rat?"). It is only when Batman renders the Joker helpless and his extended assistance is rejected that the Dark Knight comes to appreciate the madman's aim, reacting just as the Joker would: laughing hysterically.

The Joker also serves as an unreliable narrator. He admits to his own uncertainty as he has disparate memories of the single event ("Sometimes I remember it one way, sometimes another... If I'm going to have a past, I prefer it to be multiple choice!"), accentuating the comic's depiction of "a world unraveling toward relentless urban violence and moral nihilism...."