I always like reading about time travely, fictiony stuff. I personally think that ruling out the many universes theory is a little silly when considering what “comes closest” to real time travel. As far as I’ve read, it’s a pretty well respected theory and has been tested at least as rigorously as going back in time (unless I’ve missed something).
Maybe it’s just me, but I think the idea that traveling back in time sets you on a new path (theoretically in a universe distinct from the one you came from) tracks a lot better than saying, “Well, if you go back in time to kill your grandpa, you just won’t be able to FOR SOME REASON.” If I have a loaded gun and I travel back directly in front of my grandfather a million times, will the gun misfire every time? Will I be fought off when I try to strangle him to death? What if I show up while he’s asleep? Will I just change my mind each time I materialize in front of him? Seems more likely that I’ll pull that trigger, he’ll hit the ground and a whole new set of events will branch from the previous universe.
PS. I love my grandfather and would never go back in time and murder him, but you know, fun thought experiments.
Below was the only video I could find with the chalkboard scene from Back to the Future in it after 2 1/2 minutes of searching.
I’m not sure if any of this is coherent. That’s ok.