We Do Not Know, but perhaps somewhere over 100 Billion people have existed on Earth.
Each one of them has lived in a time, and a place, in which people hunted, and gathered, and tilled, and bought, and sold, and traded, and built, and crafted shoes, and clothes, and goods, and weapons, and fought with one another, and helped one another, and laughed, and cried, and were afraid, and did all the things that human beings, inhabited by our various drives, find themselves impelled to do.
Fashioning our Backward Looking Story is difficult, because to understand what actually happened, we would have to do something like synthesize and accurately portray the experience that each of 100 Billion people had, and then try to piece together from that Evidence what actually happened.
We would have to accurately listen to and tell 100 Billion Stories... and then see if we could piece together the overarching and uniting Story.
But it is not that simple, because every day of our lives contains multiple stories. Even if we were to dramatically simplify and exclude information, it might be that each life would consist of at least 100 significant stories. So we would be dealing with at least 100 x 100 billion stories to start.
We know that even in one Time and Space, for instance at the scene of a crime, where you can record the experience of 10 or 20 different people, and perform forensic analysis, and locate video cameras, it can be extremely difficult to reconstruct what actually happened.
Now imagine that in every place where human beings live, minute by minute, hour by hour, such scenes are playing out simultaneously.
And the Reality that is unfolding in each Time and Space is being Perceived and Experienced by each and every Individual in a unique way.
This is why we can immediately be sure that history that attempts to depict What Actually Happened is not True. It is fractional, partial, redacted, and biased in dozens of ways at very best.