The past could be (only) that most probable entity inversely and retrospectively extrapolated from a current system state and material configuration or contents of present conscious experience. If all that is required in regards to logic and the relative relational consistency of all available empirical evidence is that the current (world) system state is consistent within itself, that it makes internal and plausible “sense” for it to have arrived at this configuration of observed or measurable artefacts and entities, then the past could be just as probabilistic and open as is the future – even at our macroscopic scale.
In this way, all possible paths that could have been followed by history actually occurred but it is as a peculiar artefact and persistent (yet enduring) illusion of sentience or consciousness that we project backwards in time that most probable path by which we rationalise the current state of matter, energy and the various artefacts and entities which populate the world of our experience. The past could be constantly rewritten and overwritten in just the same way that we assume the future will eventually be formally laid-down or encoded into a past from the possibility-space of all probable system-states. We would never know and could never prove it; which reduces the matter to pure metaphysical speculation.
If the past was as open to possibility as is the future, the present could still be exactly what it is.