Change your thoughts and you change your world.
— Norman Vincent Peale
There was one point in the series were executives decided to pull back on a story line because they feared the audience would clearly believe that the whole series was all inside Hurley's head.
Hurley is involved in an accident in which a deck collapses as he steps onto it, killing two people. Even though there were too many people on the deck prior to his arrival, Hurley feels great guilt. He sinks into a depressive state, so his mother enters him into a psychiatric institution. There he creates an imaginary friend called "Dave" and meets Leonard Simms, a patient who keeps mumbling the numbers. Hurley's condition eventually improves; he leaves the institution and he resumes his job at a fast-food restaurant. He uses the numbers 4, 8, 15, 16, 23 and 42 in the lottery, and wins the jackpot of $114m. Hurley begins experiencing constant bad luck, and as his net worth increases, so does his bad luck. Hurley suspects the numbers he used to win the lottery are cursed, so visits the institution again to speak with Leonard He tells Hurley the man who could explain the mystery of the numbers, Sam Toomey, lives in Australia. Before Hurley can travel to Australia, his father returns to the family. He convinces Hurley to go to a psychic to cure his curse, but Hurley discovers his father has paid the psychic to lie.
Once in Australia, Hurley visits Sam Toomey's wife who
reveals that Sam was driven to suicide to escape his constant bad luck. Halfway through the return flight the plane hits turbulence splits in mid-air, crashing on an island in the South Pacific.
This is the basic foundation for Hurley. A young man who believes he is cursed by bad luck. He retreats from his curse by creating his own fantasy world as a protective barrier. Everything after the porch collapse could be his imagination. Everything. The mental hospital, Leonard, the doctors, staff, patients - - - everything, including his fast food work, his friendship with Johnny and the clerk, Starla, that he finally asks out but that relationship ends badly with his best friend stealing her away.
No matter how Hurley tries to create a fantasy world in his head, his mental processes always turn the tables on him like a conscious nightmare. So he adds more and more supernatural and magical elements to his thought processes in a complex labyrinth to hide from reality. All the characters we met on the series were created in Hurley's head.
In some way, all the action of the series centered around or through Hurley. But as some sort of self-preservation defense mechanism in his own brain, Hurley is never injured despite the island dangers. Even when he was kidnapped by the Others, they let him go back to the beach camp, where for no apparent reason, he did not tell the plane survivors of Jack, Sawyer or Kate's fate.
Another clue that everything was created in Hurley's head was the fact that the Numbers kept popping up in diverse circumstances. The Hatch door serial number. The Hatch countdown clock timer. The names of the Candidates. The lottery ticket. It is beyond coincidence. Those were Hurley's numbers. The numbers were the anchor for his mental issues.
We know that Hurley had a vivid imagination. He created "Dave," an imaginary friend who could physically push Hurley around. If Hurley created a Dave, who could have created the island and all the characters on it. He was a fan of complex and strange worlds like in Star Wars.
The further link to Hurley is that he was "special." He could see the mysterious Jacob. He could also talk to him. He would interact with ghosts. This could be a direct result of Hurley being "haunted" by the ghosts from the porch collapse. His guilt created a fantasy world to mentally punish him. He also saw visions of his "friends" throughout the series in odd situations, like Charlie, Claire, and Eko. He cannot tell whether Locke is real or a ghost when he is visited at the mental hospital.
Hurley was one not to freak out about his island situation. He was content to be in the background, friendly and laid back while the characters around him got the action. He was the man behind the curtain. He lived vicariously through his characters on the island stage.
Hurley could suffers from some form of delusional schizophrenia. He sees people, but he doesn't imagine events. Or Hurley suffers from Multiple Personality Disorder, also known as Dissociative Identity Disorder. He is thus the same person as imaginary friend, Dave. Or Hurley could have a combination of disorders including depression to create a catatonic fantasy world where he could have been Dave, who was Libby's ex-husband, which would explain their hidden connection. Hurley's fantasies created a Dave-Libby relationship to test his curse so that his primary consciousness would "have a chance" with her. It sounds crazy, but in the course of Hurley's memories, he lost his first crush Starla to Johnny. It would be difficult to reverse the course of lost love when your cursed depression controls all your thoughts.
Hurley is aware that he has mental problems. He believes he is crazy, which in turn
has resulted in several genuine mental instabilities, such as paranoia
and hallucinations. Those may have been enhanced by the people he may have met in school, the porch party, or the mental institution.
Hurley also manipulated some structure and items during the series. It is believed that he found Jacob's cabin and then made it disappear. He is the one who created the flashbacks in island time in order to run away from dealing with his own personal fears or grief. Hurley created the Hurley Bird as a warning device to his imaginary friends. Hurley started an 20 year old abandoned VW van on shear "hope." The jungle whispers were all the characters in his head trying to get through to his consciousness. Hurley created Jacob and MIB and the Candidates game in order to determine whether he was worthy of trust and respect in his own mind. If he could convince himself that he was worthy, like Luke Skywalker, he could free himself of his curses.
It did happen. Hurley wound up as the last Candidate to be the Guardian. He succeeded against his fears to become the leader. Even though he was always in charge of the events, he was never in mental control of the events, until he claimed the guardianship.
This was a crossroad. It could be considered a "breakthrough" moment. Instead, Hurley created another fantasy world, one on the light side as compared to the island's dark side. In the sideways world he was successful, confident, and in love. He gathered his imaginary friends together in the church so they all could go on his next adventure. None of the people in the church were dead because they were never alive. They were all living in Hurley's head.
The odd principle for resolution of the LOST series was a concept of "awakening." Wake up from what? Hurley was the last person to enter the church. His breakthrough would be to awaken from his fantasy-vegetative state in order to live a normal life. But in the sideways fantasy world, Hurley does not have a normal life but embraces the unknown in a new phase of his fantasy world.
The theory that it was all in Hurley's head makes sense to explain away the continuity errors, the unsolved mysteries, the unanswered questions or the skewed plot lines. An immature adult with mental disorders does not create a perfect hidden world of make-believe characters without making mistakes because he does not know any better. It may not be a satisfying premise for most viewers.