Tuesday, 12 August 2014
A Hypothetical Case
"...Hitler's father had been born as Alois Schicklgruber, illegitimate, result of a chance affair between an Austrian bourgeois and a housemaid of his...
"But if you headed off that liaison, which you could easily have done without harming anybody, then you aborted all history that followed. By 1935, say, the world would already be different. Maybe it would become better than the original (in some respects; for a while) or maybe it would become worse. I could imagine, for example, that humans never got into space. Surely they would not have done it anywhere near as soon; it might well have occurred too late to rescue a gutted Earth. I could not imagine that any peaceful utopia would have resulted." (Time Patrol, pp. 424-425)
Probably not. Events would have needed more direction than that. The only action discussed here is preventing the affair between Hitler's grandparents. Time travel theoreticians discuss the "Grandfather Paradox": what would happen to me if I killed one of my grandfathers before he met my grandmother?" We can talk about parents instead of grandparents and can prevent meetings without killing anyone.
The answer is that, if there is a single timeline, then no one did kill your grandfather before he met your grandmother and, if there are multiple timelines, then you can be born in one though not in another. There is no reason why you should cease to exist having killed your grandfather. Prevention of your conception prevents your birth. It does not allow you to exist into adulthood, then disappear.