Clues

Monumental works left behind by deceased civilizations offer clues indicating that prior inhabitants of Earth understood this world, and the universe in which it exists, better than we do.  And they seem to have accomplished this with just their brains and minds.  We don't know to what extent they used mathematics, if at all,  and the scientific method, beyond trial and error.  It seems they did not have computers or artificial intelligence, but they understood.  And we don't know how they reached that understanding.

For example, the meter was defined by the French Republic in 1793 as 1/10,000,000 the distance from the equator to the pole of the Earth.  Yet it appears in doorways of South American stonework that pre-dates  that definition by 400 years.  Was the unit of measure used long before it was defined by the French?

What we often have done, during our approximately 2500 years of civilization starting with the Greeks, is rediscover and redefine what was already known and understood by others.  We've added some to it, in mathematics, chemistry, medicine, et al, for examples.

There were civilizations in the Middle East that predate ours, some fragments of that knowledge may be extant in the people of that region.  Our religious and cultural differences seem to preclude our ever sharing that heritage and knowledge. 

All to often we lose the realization that we, those alive on Earth here in the 21st century, are not the first, not the smartest, not the best, and have much more to do to reach those same levels of understanding.