Were Humans More Advanced Before Us?

Our technology may be thousands of years behind. Over humankind’s long tenure on Earth, were there civilizations greater than our own, now lost to time? How would we find them, and would we know if we did?

Scientific American recently published an article called “Could an Industrial Prehuman Civilization Have Existed on Earth before Ours?”. The author, Steven Ashley, wondered if we had the methods to tell if a civilization existed…