All time travel stories have to contend with a science fiction trope we might call the “trickle forward” effect. Some writers simply ignore the effect, others use it to great (and often funny or tragic) advantage.
Personally, I love writing time travel stories. I’ve penned about half a dozen of them, all published in Analog. I’m working on a sort of twisted time travel novel at the moment and am grappling with a complex plot that relies on the trickle forward effect from multiple points in time. Obviously, this can be a blessing or a curse.
I was discussing time travel stories with Larry Niven one weekend at a con when he told me that he has some slightly twisted friends who like to dress in black suits and go about in the guise of Time Travelers. They spend their time abroad policing each other. If one of the number so much as picks up a gum wrapper and throws it away, the others will insist that he find the wrapper and return it to the spot.
The point is, that while many of us who even think about time travel, consider major events such as assassinations and wars as turning points in history, the truth is that the removal of a gum wrapper may be just as telling in the long run.
If the time traveler removes it, then it doesn’t stick to the shoe of a passing policeman, who doesn’t then bend over to remove it, thus being hit in the butt by a piece of refuse hurled from the hand of a 10 year old juvenile delinquent, who then is not collared and ultimately mentored by this same cop, and who therefore does not go on to become a great benefactor of homeless children, but instead becomes a subway artist who is tragically killed by the third rail in the tunnel near Grand Central while trying to paint Venus rising from a Dumpster on the flank of a subway car.
Food for thought provided by WP Kinsella who does the most beautiful and evocative writing about baseball I’ve ever read. (His prose makes we weep with joy at its sheer beauty and distress at my own inadequacy.) In one of his stories, he tangentially poses the question of how different history might have been if Fidel Castro had achieved his life’s dream to be an American Major League baseball player. Our hypothetical Time Traveler might find his mission is to make sure Castro is offered a minor league contract to play ball for the Yankees, or that Hitler receives words of encouragement in his art (possibly from a Jewish mentor) such that he becomes a successful painter and not a human epithet.
”Think big!” we are told. In the realm of time travel stories, it may be infinitely more interesting to think small.