I wonder what it would mean for how we perceive ourselves if there were to be discovered evidence of a prehuman civilisation on the earth.
http://www.theatlantic.com/science/archive/2018/04/are-we-earths-only-civilization/557180/?fbclid=IwAR3dk6uhi7bjNFXJc9_4-bCSmfo3a7Qjxdnm9p504cFAf-NEcCH7wioeKNE (http://www.theatlantic.com/science/archive/2018/04/are-we-earths-only-civilization/557180/?fbclid=IwAR3dk6uhi7bjNFXJc9_4-bCSmfo3a7Qjxdnm9p504cFAf-NEcCH7wioeKNE)