We know that The Incident occurred in the late 70's because the Swan Orientation Film is dated 1980. We also know that Radzinsky removed that section of the Orientation Film containing the explicit warning not to attempt to use the Swan computer to try to contact the outside world ... that the sole purpose of the Swan computer was to enter the Numbers.
So ... I'm guessing that our 1997 Losties, on the run from Dharmaville, hook up with Sayid and go to the under-construction Swan. I think they use the Swan's computer to contact their 2005 friends (Sun, Locke, Frank and, well, Ben) and that this "contact" results in The Incident - which sends the 1977 Losties Back to the Future.
So ... I'm guessing that our 1997 Losties, on the run from Dharmaville, hook up with Sayid and go to the under-construction Swan. I think they use the Swan's computer to contact their 2005 friends (Sun, Locke, Frank and, well, Ben) and that this "contact" results in The Incident - which sends the 1977 Losties Back to the Future.
