The parent comment brings up an intriguing point . Calling it crackpot makes you look cranky . Correct me if I ' m wrong , but afaik it ' s not like the humans of ten or even thirtythousand years ago were somehow born magically retarded or , on a core biological level , had enormously diminished mental capacity compared to the humans of today . Survivors of any lost civilizations would have retained knowledge of basic technologies and been able to reemploy them . If a hypothetical asteroid or another catastrophe in our near future destroyed America , China , Japan and all other technologically advanced countries , then any survivors remaining in , say , Africa or Papua New Guinea , will definitely NOT be able to reemploy any of our hitech microchip fabrication facilities or spacecraft launch sites or telescope arrays etc . left behind .