There is a reason we don’t have a definitive backstory for the Joker, and never should.
I’m not familiar with comics much at all, and I can’t properly identify the particular issue or whatever that this takes place in, but I do know at some point, Batman sits on an omniscient chair that will answer any question he asks it. He asks the chair who the Joker is, and it tells him that there have been 3 Jokers. Batman cannot believe this.
So, even when we get so close to a definitive history, or just a simple name, we still can’t. Now, this is not to say that no writer as ever provided their own. There are several origin stories for the Joker, just none of them canon or the official explanation. This year, 2019, we got a Joker origin movie, simply titled Joker, and even that by itself is difficult to decipher; it gives us a backstory, while simultaneously not really. In Joker, we the audience aren’t entirely sure what really happened or what was simply in the guy’s head. The entire movie could have been in his head. There’s a YouTuber I’ve seen who thinks the entire Batman franchise is strictly in the Joker’s head.
So, why is Joker’s origin so enigmatic? He’s not exactly a character shrouded in darkness. He wears bright clothing, and before he commits a crime, he tells everybody what he’s going to do. Sure, he’s unpredictable, but once he’s out in the open, all eyes are upon him. In what way does that dictate that he must have his backstory as obscure as possible?
The answer lies in the fact that most people love the Joker, and what the Joker does. We all love Joker because we all see a piece of ourselves in him. Whatever his backstory, without a doubt, the man who became the Joker mentally snapped. That we can be certain of. And haven’t we all thought we’re on the brink of snapping? Just throwing our hands up saying, “Fuck it!” and just not caring anymore? We’ve all thought the world is hopeless, we’ve all thought there’s no point in caring anymore, and we’ve all at some point thought the world deserves to burn. The Joker didn’t just go crazy – I don’t think he is crazy – it’s more like the Joker gave up on it all. Bruce Wayne chose to fight crime, the man who became the Joker chose to embrace the ugly in the world. Both exist because of the filth in the world. Joker doesn’t even have regard for his own wellbeing anymore. Remember in The Dark Knight when he urges Harvey Dent to shoot him, all for the sake of making the chaos in Gotham last a little bit longer?
He’s a condition more than he is a character.
Providing him a solid backstory, like we have for Batman, would remove the philosophical essence of the character. We would start to think of him as that character only, nothing more. It’s the same reason the Joker himself doesn’t want to know what’s Batman’s secret identity is; he is far more concerned with what Batman represents, and challenging that, rather than the man behind the mask. As is the same way we ought to view the Joker. (In The Dark Knight, the Joker urges all of Gotham to kill the man about to expose Batman’s identity. That’s how much Joker doesn’t want to know.)Batman and the Joker are philosophical enemies more than they are physical enemies.