- last post: 01.01.0001 12:00 AM PDT
perhaps by saying i know your past, you future, cortana means that master chief's future IS his past.
and yes time travel or at least time anomolies seem to have something to do with the storyline, such as when 343 says "last time you asked me if i would activate the installation i said yes. after having sufficient time to ponder your query, my answer has not changed."
so either time is repeating itself (time loop, that crystal they found on reach probably caused the loop) or another spartan came to installation 04 before master chief.