I think QMers may know something about this.
you mean "block time" or multiverse?
i mean the one block universe, which means all "future things" are predetermined like a block. I think it derived from Albert Einstein's relativity.
The future is what you get when you apply the operator
Exp(-i H t/hbar) to the present state. So, given that the present state exists, the future also exists.
I believe SR (4D spacetime) is an argument for the blockworld
However only the existence of Closed Timelike Loops will be an ultimate proof
Finally exists <> predetermined (depending on single- or multi- history theories)
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