There is an ever-growing question regarding whether a time traveller can alter the past. The question leaves a vagueness in which have been debated by scientists and philosophers alike. Time travelling has been widely incorporated in literature and in the media as well; shows like Dr. Who and the novel The Time Machine includes traversing through time. But can a person really alter time? Can a person, supposedly by using a peculiar gadget, can travel back in time and change history?
Say, time travelling is plausible, and one person can really travel back in time, can one alter the past as depicted in movies and novels? Apparently not. For altering the past would provide inconsistency in terms of the timeline in the world the time traveller is in (call it, w_o) since travelling back in time would only mean the time traveller has gone back to a certain point in the timeline and altering the prior event would beget a different sequence of events. Therefore, it would only render time travelling as something of a useless discovery if one cannot do such a thing to alter the past.
But some scientists and/or philosophers do believe that such past alteration can occur within the premise of changing one point in the timeline provides a different sequence of events but still would hold true for a different world in a different universe; we call this divergent world, w_1. What makes them believe that such a thing can occur? The Multiverse. Since it has also been theorized that there is not just one universe, with one Earth and other planets across the galaxy, but a multiverse consisting of an infinite set of universes with infinite number of planets across an infinite set of galaxies, according to Brian Greene in his interview with Ted-Ed, where he states that:
"In the creation of multiple universes there are other Earths, other yous. But in each, you have made different decisions leading to another you but with another life (using this theory also means that there is likely an exact copy of you)."
So, if we assume that this theory is plausible and would still be consistent, then time travelling is not a waste of time; the past can be altered, every bad decision can be turned, and would provide the time traveller a happy ending.
But is that really the case? I implore you to comment your thoughts about the matter!
yes