jacks son was a hope and dream he had for the future as was the other baby from sun and claires baby too, just thoughts while dreaming...at least that was my daughters conclusion. a lost fanatic

okay but how then do you explain jack's father telling him that everything he remembered really had happened?

everything happened on the island the hurt, problems .but on a sideways or flashback it was their thoughts. , maybe in and out of reality . We'll never have all questions answered. My daughter thinks there will be a spinoff of lost featuring the unanswered.. she says it probably depends on how much the afterthoughts and controversy it generates. There is a lost website somewhere out there that fanatics view and contribute to while watching the show. I watched the show sporadically I am no expert