We tend to see the future as being an uncertain cloud of possibilities made concrete as they become the present, then etched in stone as the past that cannot be changed.
I’ve realized that there is a “champagne glass pyramid” metaphore that seems to work for the universe. There are many glasses at the bottom to start from, but they all wind up in the same place when working upwards. If you’re working back however, there’s a fork of two possible champagne glasses each step.
Because the universe is deterministic in nature, each state leads to the same result when the variables are constant. One moment gives one result. However, that result can be arrived at from more than one route. If you deal with deterministic universe of 2 dimensions, each moment can be arrived at from 2 previous instances. This is seen in a basic 2 dimensional iterative chaotic function which works as a quadratic, with 2 possible roots for each possible result.
that means that it is the future that is set in stone, but it’s the past that branches off into the uncertainty of possibilities. The route we followed is documented, but it’s one of many.
I just thought it was interesting that the idea of a forking tree of possibilities applies more to the past, than the future, and I’d welcome any additional input