On the implications of Time Travel
Almost every good work of Time Travel science fiction addresses the issue which is sometimes called the "Grandfather Paradox" and most of them conclude that going back in time and changing the past must be either impossible extremely difficult extremely dangerous or more than one of the above. This goes back a long way. In 1933, American author Nathaniel Schachner published a short story titled " Ancestral Voices " in Astounding Stories. In it, a time traveller goes back 5,000 years, accidentally kills one of his own direct ancestors in a brawl, and immediately fades out of existence. The modern form of the "Grandfather Paradox" was first formulated ten years later by René Barjavel (1943): Barjavel was the first to distil this concept into the exact family dynamic we reference today, presenting a character who travels back to deliberately eliminate his grandfather before his parents are conceived. There are three opposing theories about what happens if you...
