Submission # 3: Can time travel actually change history? If so, what are the issues with changing history through time travel?

Movies like Back to the Future, The Butterfly Effect and Project Almanac deal with the implications of changing something in the past and how it affects present day. For example, in Back to the Future Part II, Biff steals the time machine and uses it to travel back to 1955 and give an almanac to his younger self to get rich betting, then returns to 2015. When Marty, Doc, and Jennifer return to 1985, they see that the 1985 to which they return has changed dramatically. Because of Biff changing the past by giving himself an almanac that he would have otherwise never had, he changes the entire course of history for himself and those around him. This creates a parallel universe, and in the movie, the only way to fix it is to go back to the point when the history was altered (when young Biff got the almanac) and change it back so that it never happened. 

            There are also many other temporal paradoxes that come with time travel, for example, the Grandfather Paradox. The Grandfather Paradox is a hypothetical situation of what would happen if you traveled back in time, before your grandfather had any children, and killed your grandfather. This creates a paradox because if your grandfather was killed before he had kids, your parent would never be born and in turn you would never have been born. If you were never born, then you could never go back in time and kill your grandfather, which means that he never died. If he never died, then that means that you could have been born. This mind bending paradox is infamous for its complexity. Another variant of this paradox is the Hitler paradox which is a frequent trope in science fiction. In this paradox, the protagonist travels back in time to murder Adolf Hitler before he can instigate World War II. If Hitler was murdered, then there would be no reason for the travel, along with any knowledge that the reason ever existed, thus removing any point in travelling in time in the first place. The consequences of Hitler's existence are so monumental that for anyone born after the war is likely that their birth was influenced in some way by its effects, and thus the grandfather paradox would directly apply in some way. One ethical issue with the Hitler Paradox is that a variant of it deals with killing baby Hitler. This brings up problems because baby Hitler was innocent at that point, so by killing him, you are killing an innocent person. This also applies to any other serial killers, if the only possible way to stop a serial killer was to kill him while he was younger; would it be right (or even mandatory) to kill him while he is still innocent?

            Where do you draw the line? Who decides what should be changed? What if someone tried to change the timeline who was a religious or political extremist? Should we change the timeline to swing elections in a particular direction? If everyone was allowed to freely travel through time, they would change history constantly. What one changes in the past, affects the past lives of many others. There is really no way to know how time travel would affect history because we don’t know if anyone has ever changed history. This is a really difficult question to answer because we would only be speaking in hypothetical situations and that would not get us any closer in finding the answer. I guess the closest we would ever get to the answer is that by going back in time and changing history, we would create many paradoxes in present day and those paradoxes would in turn create more paradoxes.