[D-Roc]

I think that the notion of predestination is a very useful one in Lost. People often slate the episode "Stranger in a Strange Land", but actually it highlighted some important issues..especially regarding..as you say..characters being defined before they even realise it.

We can see this with Locke and Jack in particular. They seem to have a destiny which is already laid out for them - Jack aa great leader, but lonely and scared (according to Achera), and Locke a great man with always finds he way somehow.

And that's the thing..destiny in Lost isn't always guarenteed..there seem to exist elements of choice in between te steppeing stones of fate. Jack's choice to leave the island was him taking control of his own fate..which worked out quite well for some, since the spirits wanted Aaron far away from the island. But the island demands that he return..with the 6. Jack has seemingly taken a detour around the line that he was destined to take..

..and as you infer, perhaps there exists a residue of subconscius knowledge..a slight impression of what they are "supposed" to do and who they are "supposed" to be..