I think if we ever reach the point where we think we thoroughly understand who we are and where we came from, we will have failed.
Carl SaganWe've begun at last to wonder about our origins, star stuff contemplating the stars, organized collections of ten billion billion billion atoms contemplating the evolution of matter, tracing that long path by which it arrived at consciousness here on the planet Earth and perhaps throughout the cosmos. Our obligation to survive and flourish is owed not just to ourselves but also to that cosmos, ancient and vast, from which we spring.
Carl SaganIf you want to save your child from polio, you can pray or you can inoculate....Try science.
Carl SaganIt will not be we who reach Alpha Centauri, and the other nearby stars. It will be a species very like us - but with more of our strengths and fewer of our weaknesses.
Carl Sagan