The world of Star Wars fan theories covers a lot of ground. Observations range from dark implications of the Star Wars movies to deep analysis of the Jedi Council. If they watch the films enough, fans can find evidence to support some pretty extreme ideas. Sometimes the theories offer a fun connection to another universe or a new way to look at the films, but one theory from Redditor /u/mcsupercool threatens to destroy everything we know about the Star Wars universe.
The theory filters the films through the idea that history is written by the victors, and asks what it means if the Star Wars films are based on the Rebel Alliance's version of the story. From that perspective, the theory says it's possible the Force never existed, and it was made up after the fact to lionize the heroes of the Rebellion. This line of thinking opens a Pandora's box of questions. Are the Jedi real? Was Luke crazy for thinking he spoke to ghosts? And what does the Rebel Alliance actually get out of telling this story?
The Rebel Alliance was outmatched in every way by the Empire. Emperor Palpatine's military force boasted bigger guns, more soldiers, and more money behind their efforts to control the galaxy. So, Princess Leia and her army of outsiders needed to give their followers something to believe in: the Force. It's possible the Rebel Alliance picked this supernatural power from an old religion to make their members think that if they have faith in themselves, they could overcome insurmountable odds.
If the Force exists as a tool to boost morale, then it's possible Yoda provides another construction to fill out the myth. Luke is the only person Yoda ever interacts with in the original trilogy, and it's unlikely anyone else would have a reason to visit a swampy, uninhabited planet like Dagobah. No one in the Star Wars universe outside of Luke - and the ghost of Obi-Wan - sees Yoda, yet they believe he exists.
The theory on Reddit argues Yoda could have been created to give the Rebellion's story a more mystical bent. It's also possible Luke needed to create a reason for why he went missing for a long time while the rest of the Rebels were engaged in battle.
In the case of Luke Skywalker, /u/mcsupercool's theory calls attention to the fact that Luke is alone almost every time he uses the Force. The few people who see him use the Force either die in battle or are a part of the Rebellion's top brass who benefit the most from convincing the galaxy the Force exists. Think about every time Luke used the Force - Luke was alone when he snagged his lightsaber from the ice on Hoth, and he may as well have been alone on Dagobah. The audience has to take Luke's most unbelievable feats at his word.
If the Rebel Alliance did fabricate the Force, they didn't spend very long thinking about it. One of the weirdest and least believable things about the Force is how uneven it is. It doesn't work in any specific way, and you don't have to be trained to be super powerful. You don't even have to be a Jedi to use the Force - you simply have to be born with a fantastical ability that manifests itself at an important time in your life.
In an article for Tor.com, Emily Asher-Perrin points out that in The Force Awakens, Rey can "call a lightsaber to her hand or resist the mental interrogation of a dark side user like Kylo Ren," all without guidance from a Jedi Master. Luke Skywalker was barely able to deflect a single shot with direct supervision from Obi-Wan Kenobi, so Rey's immediate control shows some inconsistencies in the nature of the Force.