It is a dsturbing fact that most people don't realise how little we know of our own history. Archaeological finds are few and far between - fewer and farther as we go back in time. 90% of human history is a complete blank and the assumption of millenia of negligible to slow progress followed by rapid advances in the last 2 000 years results only from the lack of known facts and Renaissance thinking.

We can't know, or even reasonably speculate, on the number and kind of civilisations that rose and feel before the few we have records of.