INSURRECTION

He who controls the past controls the future. He who controls the present controls the past. — George Orwell

The loudest and most polarizing debate point between LOST fans to this day is whether the passengers on Flight 815 actually survived the crash.

It goes back to the very beginning when TPTB stated that the characters were survivors of a plane crash on mysterious tropical island. Viewers believed what the producers said. This was further confirmed in a way by Damon Lindelof in a 2006 interview where he said "When a character dies on the show, they’re dead. The only time you’ll see them again is in someone else’s flashback."  The writers initially claimed Lost would feature no actual resurrections. However, that was clearly not true as the series went forward in time. Sayid clearly died and was resurrected at the temple. Some viewers believe Alpert died in the hold of the Black Rock only to be revived by MIB as his pawn to kill Jacob. Jacob himself was resurrected in both adult and childhood form after he died in the statue. And Patchy died apparently several times in front of the castaways but returned to life.

Now some people believe that any magical island resurrections were just mere manifestations of a shape shifting smoke monster. 

On the other end of the opinion spectrum, many see The Island as afterlife, in the context of being a place of rebirth. It has been strongly suggested that the original crash killed the main characters, based upon human experience and what was first shown in the pilot episode. Additional evidence came in the form of the plane's discovery in Season 3 with 324 dead bodies aboard fueled this belief, as well as Naomi’s claim that everyone on that plane died. Later, the Widmore story line said he “faked” the wreckage in order to keep the island’s location secret, which in some respects makes no sense since he did not know where the island was located at the time.  An early episode script featured Kate jokingly referencing this theory to Sayid's annoyance, and the producers repeatedly dismissed it in interviews. The produers claimed that the characters eventually left and returned to the island, proving it existed on no separate plane of reality.
 
However, it was pervasive that characters kept saying the opposite. Early seasons portrayed life on the Island as the characters' experiences following a metaphorical death.  As Jack told Kate early in the first season, "Three days ago, we all died." Many characters reinvented themselves on the island, attempting to redeem themselves for old mistakes.Jacob in the final season eventually revealed that he brought people to the island to specifically give them a blank slate. 

Some characters believed the island was their literal afterlife. MIB convinced Richard that the island was hell, and Richard reverted to this belief years later, even though he'd left the island numerous times. Cooper also thought the island was hell. In “The Brig” Cooper found the island "a little hot for heaven." 



Off-island, Hurley believed Jack's perfect life - in love with Kate, raising a child - meant that they'd died and gone to heaven. He was wrong, but they later experienced an afterlife that was, for some, too good to be true. 
 
Characters also referenced heaven and hell separate from the Island.  Charlie once tried to baptize Aaron, and later Claire  asked Eko to baptize her and Aaron together, so they could reunite after death in heaven. According to Isabella, if MIB escaped from the Island, it would send them "all" to hell.  Lostpedia states that the script for the finale referred to the Heart of the Island, with the Light off, as the "cavern of hell," where things have "literally gone to hell."

And then there was the ghosts. Hurley and Miles could speak or hear the dead. Dead Charlie and Dead Ana Lucia had physical contact with Hurley. How could that be? Unless of course, Hurley was in the same plane of existence, i.e. he was also dead but failed to recognize or accept it. Acceptance of death was an underlying theme of the series. When Rose realized that the pain of her terminal cancer was gone, she knew she was dead. That is why she was at peace. That is why she knew she would be reunited with Bernard because they were both dead in the afterlife. And when the whispers were explained by dead Michael, that his spirit was trapped on the island and could not move on, it made sense why he was not shown in the sideways world.

There is also another way to look at the show: as a series of life times. Some Eastern religions believe that a person is reincarnated into several different lives in order to learn and attain enlightenment. One could perceive the characters as having several complete "lives" during the series: their pre-815 lives; their island lives; and their post-island lives (many contained in the afterlife of the sideways world). As easy as it was to suspend belief that the main characters survived a high-altitude fuselage separation, it is just as easy to believe that the characters were already dead and working their way through various second, third or fourth lives in the after life. 

So if one wants to start an immediate argument today, just bring up the fact that the 815ers died in the plane crash. Then also mention that the credibility of the story line told by the producers of the series is in doubt, especially after reading the original writer's guide. In any debate, there will be no final answer. Any plausible reasons and explanations were lost in the final season.