We imagine the future containing an infinite amount of possibilities.
The present is more concrete, for obvious reasons. Sandwiched between the to-come and what-has-come.
But all of our conceptions of history suggest that the past can only have happened one way, and our best efforts unearth fossils. We view the now as both cause and effect, resultant of the past, but determinate of the future.
Why not view the past as the future, with an infinite amount of possibilities coinciding with right now?
Is the past a thing, or merely a concept? The same must be asked of the future.