If Marty McFly showed up at your doorstep would you be surprised?
McFly has opened up a paradox in the time-space continuum. While the Back-to-the-Future movies deal with the hazards of messing up the continuum, future time travelers could use Marty’s existence to delve deeper into the future.
G.K. Chesterton’s Father Brown character once solved a murder by pointing to the one person who is there, but no one ever sees, the Mail carrier. Marty may play a similar role when it comes to the philosophy of time.
Those who engage in time travel are likely to get a skeptical eye when the tell people what they are engaging in. But without honesty and forthrightness they are likely to become entangled in the time-space continuum webs which Marty made famous in his blockbuster series.
By playing the character of Marty McFly time travelers can honestly admit that they are time traveling, and unsuspecting citizens will probably just ignore them. Thus they will be able to travel to practically any time which occurs, in our linear time frame, after the Back-to-the-Future movies came out, and so incognito simply by donning the costume of Marty.
One possible objection to this strategy comes from people who doubt the eternal nature of Marty’s films and wonder if he will still be a recognizable character 5 or ten thousand years in the future.
To which I say; come on. If people don’t recognize Marty McFly they don’t have a reason to exist, so the whole time-space continuum might as well blow itself up anyway.