There are many rumors going around about what is "The Island" and why Flight 815 crashed there. One theory suggests that they are all dead and are now in purgatory. They hinted on this in Season Two where Desmond told Jack that he'd "See him in another life." Also, Jin told Sun that they were being punished.

Another one is Locke's theory in Season One that they were all here for a reason. Most of the key characters did do something to help. Charlie died figuring out that the freighter outside the island was infact not Penelope's, Desmond's girlfriend, boat. It was actually her father's. Jack saved Ben's life by removing the tumor. Russo, the French women who recently died, pointed out that there were "Others" on the island. It was also Hurley's job to tell the rest of the forty survivors not to come into the other's territory.

Yet another one is that Jacob and "The Island" brought them here. Locke feels that he is The Islands messenger because as soon as he landed on The Island he regained feeling in his legs.