Caution: Spoilers ahead for Joker

Joker is a highly ambiguous movie – so could Batman already exist within the film’s timeline? Audiences and critics have expressed a range of reactions towards the new Joker movie starring Joaquin Phoenix as the Clown Prince of Crime, but no one can argue that the release represents a massive step forward for comic book movies. A detailed and often disturbing character study, Joker has no clear hero, no clear antagonist and tells a distinctly non-traditional story full of twists, shocks and small references to wider DC canon.

Much of what takes place in Joker is left open to the audience’s interpretation, particularly with regards to the ending. Throughout Todd Phillips and Scott Silver’s script, viewers are reminded that they are dealing with a highly unreliable narrator and a key theme in Joker is how to separate reality from fantasy through a thick veil of madness. Consequently, it’s only natural to question details such as which scenes might be dreams, what era Joker is truly set in, and whether Arthur Fleck is indeed the true incarnation of the famous DC villain.

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One major point of discussion is how Joker relates to Batman’s origin story. A young Bruce Wayne appears in Joker, and the riots started by Fleck directly lead to the murders of Thomas and Martha Wayne, giving the impression that Joker has laid the foundations for the Caped Crusader to emerge onto the streets of Gotham City in later years. But is it possible that Batman already exists in Joker’s timeline?

Batman’s existence in Joker rests on the theory that most of the story takes place in Arthur Fleck’s mind. Fleck is revealed to have spent some time in a mental institution prior to the start of Joker, and is right back there in the final scene. Since the clocks in both asylum sequences tell the same time, and Fleck is revealed to be a notorious fantasist, there is widespread speculation that Fleck has been sitting inside Arkham Asylum (or whatever facility he’s been held in during the final scene) the entire time, dreaming up virtually all of the events seen in Joker.

If true, it would logically follow that while Fleck’s internal musings may be set in the 1980s, the final scene (and one of Joker’s few real moments) could be taking place years later, with Fleck mentally rewriting his past. It’s a common phenomenon that even when people dream about events in the past, they envision themselves as they look in the present, and this would explain why Fleck appears to be the same age in both his 1980s illusion and in the contemporary medical unit.

One of the key moments in Fleck’s fantasy sees Bruce Wayne’s parents murdered by a clown protester, but why would Fleck work this incident into his own imagined origin story? Perhaps because Bruce is the very reason Fleck is confined in Arkham Asylum during Joker’s final scene. Assuming Arthur Fleck is the real Joker, it’s entirely plausible that Batman has apprehended his arch-nemesis in the 2000s/2010s and locked him up in Arkham. Left with all the time in the world to reflect, Joker has been using his tenure in a padded cell to mentally rewrite how he first became a supervillain, intertwining his story into the Wayne murders in order to make himself responsible for Batman’s creation – a dark piece of comedy if ever there was one. This would explain why Fleck says his doctor wouldn’t get why he’s laughing, because she doesn’t know Batman’s true identity.

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While it’s possible that Batman exists in Joker and is directly responsible for Fleck being locked up in the final scene, it’s just as plausible that Batman is already a famous name in Gotham City, but has yet to cross paths with the villain. This theory depends entirely on how Joker’s ending is interpreted. Returning to the idea that Arthur Fleck has imagined much of the action that plays out on-screen, Joaquin Phoenix’s character might have been an Arkham resident for many years – from the time he was originally incarcerated to the very final scene. This would leave Fleck no time to start a career in criminality, but that could be because Joker is actually an origin story for its titular character.

If the man known as Arthur Fleck has been an asylum resident for years, the fantasy he indulges in could be an idealistic attempt to mentally rewrite history. A deeply damaged man going back into his childhood and acting out how he wanted things to happen – getting revenge on those who wronged him, becoming more confident, gaining widespread notoriety. This would explain why Zazie Beetz’s Sophie is scribbled out of Arthur’s memories halfway through the movie – Fleck originally imagined her as a love interest but decided it’d be more “fun” to make her a victim.

In this instance, Joker’s final scene could represent Fleck imagining and conceptualizing the villain know as the Joker, then emerging from his reverie and becoming the evil persona he just dreamed up, with his psychiatrist gaining the unfortunate title of victim number one.

Fleck obviously has a preoccupation with Thomas Wayne, so might’ve wrote the notorious Wayne murders into this tale in order to get some kind of mental closure and, since everyone knows about the Wayne murders, this would explain how Fleck got the details of the case (Zorro playing at the theater, the broken necklace) totally right. After killing his doctor, Fleck would’ve then broken out of the asylum, become the Joker for real, and finally encountered the Batman.

Related: Joker’s Ending Explained

There are several ways Batman could exist within the world of Joker, but another key question is which incarnation of the Dark Knight would Arthur Fleck be facing? Joker fundamentally doesn’t work within the DCEU and has already been confirmed as a standalone venture, so Batfleck can be officially taken off the table. The context of Matt Reeves’ forthcoming The Batman, starring Robert Pattinson, remains largely unknown at present but, given Joker’s box office success, Warner Bros. may want to incorporate the two films into one universe, making Pattinson the Batman to Phoenix’s Joker.

This will only happen if all parties involved agree to the move but even if they don’t, or if it’s too late in the day to rework The Batman into Joker’s universe, a future sequel to Todd Phillips’ movie could potentially include references and allusions to the Caped Crusader. While this would be a different version to Pattinson’s, Joker 2 wouldn’t have to show Batman directly, merely making it known that Phoenix’s villain has found his new best enemy. This setup would allow Batman to exist within Joker’s world, but without tying the film into any wider franchise implications, while also avoiding the pitfall of having two actors simultaneously playing Batman on the big screen.

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