Some ideas are:
- You branch off into another timeline and your actions make no difference to the previous timeline
- You’ve already taken said actions but just didn’t know about it so nothing changes
- Actions taken can have an effect (so you could suddenly erase yourself if you killed your parents)
- Only “nexus” or fixed events really matter, the timeline will sort itself out for minor changes
- something else entirely
Hmm don’t really agree, as you can observe different parts of space on different time periods due to light’s finite speed and time dilation and such. Not all parts of space are at the same time simultaneously. Also, relativity tells us that the state you observe is different from the state of another observer. So you can’t really write this number of the universe down (or at least, you can only write your own personal number down but it won’t be the same as anyone else’s number).